Note: Descriptions are shown in the official language in which they were submitted.
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PULLER-THRUSTER OOWNHOLE TOOL
Field of the Invention
The present invention relates generally to methods and apparatus for movement
of equipment in passages,
and more particularly, the present invention relates to drilling inclined and
horizontally extending holes, such as an
oil well.
Background of the Invention
a
The act of drilling vertical, inclined, and horizontal holes plays an
important role in many industries such as
the petroleum, mining, and communications industries. in the petroleum
industry, far example, a typical ail well
comprises a vertical borehole which is drilled by a rotary drill bit attached
to the end of a drill string. The drill string
is typically constructed of a series of connected links of drill pipe which
extend between surface equipment and the
drill bit. A drilling fluid, such as drilling mud, is pumped from the surface
through the interior surface or flow channel
of the drill string to the drill bit. The drilling fluid is used to cool and
lubricate the drill bit, and remove debris and
rock chips from the borehole created by the drilling process. The drilling
fluid returns to the surface, carrying the
cuttings and debris, through the space between the outer surface of the drill
pipe and the inner surface of the
borehole.
Conventional drilling often requires drilling numerous boreholes to recover
oil, gas, and mineral deposits.
For example, drilling for oil usually includes drilling a vertical borehole
anti! the petroleum reservoir is reached. Oil
is then pumped from the reservoir to the surface. As known in the industry,
often a largo number of vertical
boreholes must be drilled within a small area to recover the oil within the
reservoir. This requires a large investment
of resources, equipment, and is very expensive. Additionally, the oil within
the reservoir may be difficult to recover
for several reasons. For instance, the size and shape of the oil formation,
the depth at which the oil is located, and
the location of the reservoir may make exploitation of the reservoir very
difficult. Further, drilling for oil located
under bodies of water, such as the North Sea, often presents greater
difficulties.
In order to recover oil from these difficult to exploit reservoirs, it may be
desirable to drill a borehole that
is not vertically orientated. For example, the borehole may be initially
drilled vertically downwardly to a
predetermined depth and then drilled at an inclination to vertical to the
desired target location. In other situations,
it may be desirable to drill an inclined or horizontal borehole beginning at a
selected depth. This allows the oil
located in difficult-to-reach locations to be recovered. These boreholes with
a horizontal component may also be used
in a variety of circumstances such as coal exploration, the construction of
pipelines, and the construction of
communications lines.
While several methods of drilling are known in the art, two frequently used
methods to drill vertical, inclined,
and horizontal boreholes are generally known as rotary drilling and coiled
tubing drifting. These types of drilling are
frequently used in conjunction with drilling for oil. In rotary drilling, a
drill string, consisting of a series of connected
segments of drill pipe, is lowered from the surface using surface equipment
such as a derrick and draw works.
Attached to the lower end of the drill string is a bottom hole assembly. The
bottom hole assembly typically includes
a drill bit and may include other equipment known in the art such as drill
collars, stabilizers, and heavy-weight pipe.
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The other end of the drill string is connected to a rotary table or top drive
system located at the surface. The top
drive system rotates the drill string, the bottom hole assembly, and the drill
bit, allowing the rotating drill bit to
penetrate into the formation. In a vertically drilled hole, the drill bit is
forced into the formation by the weight of
the drill string and the bottom hole assembly. The weight on the drill bit can
be varied by controlling the amount
of support provided by the derrick to the drill string. This allows, for
example, drilling into different types of
formations and controlling the rate at which the 6orehole is drilled.
w
The direction of the rotary drilled borehole can be gradually altered by using
known equipment such as a
downhole motor with an adjustable bent housing to create inclined and
horizontal boreholes. Downhole motors with
bent housings allow the surface operator to change drill bit orientation, for
exampte, with pressure pulses from the
surface pump. (t will be understood that orientation includes inclination,
asmuth, and depth components. Typical
rates of change of orientation of the drill string are t-3 degrees per 100
feet of vertical depth. Hence, over a
distance of about 3,000 feet, the drill string orientation can change from
vertical to horizontal relative to the surface.
A gradual change in the direction of the rotary drilled hole is necessary so
that the drill string can move within the
borehole and the flow of drilling fluid to and from the drill bit is not
disrupted.
Another type of known drilling is coiled tubing drilling. In coiled tubing
drilling, the drill string tubing is fed
into the borehole by an injector assembly. In this method the coiled tubing
drill string has specially designed drill
collars located proximate the drill bit that apply weight to the drill bit via
gravity pull. In contrast to rotary drilling,
the drill string is not rotated. Instead, a downhole motor provides rotation
to the drill bit. Because the coiled tubing
is not rotated or used to force the drill bit into the formation, the strength
and stiffness of the coiled tubing is
typically much less than that of the drill pipe used in comparable rotary
drilling. Thus, the thickness of the coiled
tubing is generally less than the drill pipe thickness used in rotary
drilling, and the coiled tubing generally cannot
withstand the same rotational and tension forces in comparison to the drill
pipe used in rotary drilling.
A known method and apparatus for drilling laterally from a vertical weft Gore
is disclosed in U.S. Patent
No. 4,365,fi76 issued to Boyadjieff, et al. The Boyadjieff patent discloses a
pneumatically powered drilling unit
which is housed in a specially designed carrier, and the carrier and drilling
unit are lowered to a desired position
within an existing vertical welt bore. The carrier and drilling units are then
pivoted into a horizontal position within
the vertical well bore. This pivotal movement is triggered by a person located
at the surface who pulls a string or
cable that is attached to one end of the carrier unit. From this horizontal
position, the drilling unit leaves the carrier
unit and begins drilling laterally to create an abrupt switch from a vertical
to a lateral hole. The carrier is removed
from the well bore once the drilling unit exists the carrier unit.
The drilling unit disclosed in the 8oyadjieff patent discharges air near the
drill bit to push the cuttings and
...
rock chips created by the drilling process around the drilling unit. These
cuttings are supposed to fall into a sump
located at the bottom of the vertical well bore. This causes the bottom end of
the vertical well bore to be filled
with debris and prevents the use of the vertical well bore. The debris may
also have a tendency to plug and fill
the lateral hole. The drilling unit moves within the lateral hole by a series
of teeth which are adapted to engage
the sidewall of the lateral hole while the hole is being bored. These teeth
transfer the drilling forces to the sidewalls
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of the hole to allow the drill bit to be pushed into the formation. The
drilling unit is also connected to a cable
guiding and withdrawal toot that is inserted iota the vertical well bore to
allow removal of the carrier and drilling
unit from the lateral hole.
Another method and apparatus for forming lateral boreholes within an existing
vertical shaft is disclosed
in U.S. Patent No. 5,425,429 issued to Thompson. The Thompson patent discloses
a device that is lowered into
a vertical shaft, braces itself against the sidewall of the vertical shaft,
and applies a drilling force to penetrate the
wall of the vertical shaft to form a laterally extending borehole. The device
is generally cylindrical and includes a
tap section that is sealed to allow complete immersion in drilling mud. The
top section also contains a turbine that
is powered by the drilling mud. The bottom section of the device is open to
the vertical shaft. The device is held
in place within the vertical shaft by a series of anchor shoes that are forced
by hydraulic pistons to engage the
sidewall of the vertical shaft. These hydraulic pistons are powered by the
turbine located in the tap section of the
device.
The device disclosed in the Thompson patent is anchored within the existing
vertical shaft to provide
support for the drilling unit as it drills laterally. The drilling unit uses
an extendable insert ram to drill laterally into
the surrounding formation. The insert ram consists of three concentric
cylinders that are telescopically slidable
relative to each other. The cylinders are hydraulically operated to extend and
retract the insert ram within the lateral
borehofe. A supply of modular drill elements are cyclically inserted between
the insect ram and the drill bit so that
the insert ram can extend the drill bit into the surrounding formation. In
operation, the drilling unit must be stopped
and retracted each time the length of the insert ram is to be increased 6y
inserting additional modular drill elements.
The insert ram must then re-extend to the end of the lateral borehole to begin
drilling again.
A further method for creating lateral bores is described in U.S. Patent No.
5,010,965 issued to Schmelzer.
The Schmelzer patent discloses a self-propelled ram boring machine for making
earth bores. The system is operated
using compressed air and is driven by a piston which triggers periodic blows
by a striking tip.
U.S. Patent No. 3,827,512 issued to Edmond discloses an apparatus for applying
a force to a drill bit. The
apparatus drives a striking bit, under hydraulic pressure, against a formation
which causes the striking bit to form
a borehole. In particular, the body of the apparatus is a cylinder containing
two hydraulically operated pistons.
Connected to the pistons are two anchoring assemblies which are located around
the exterior surface of the tool.
The anchoring assemblies contain a plurality of serrations and are
periodically actuated to engage the sidewall of
the borehole. These anchors provide support for the apparatus within the
borehole such that a drill bit can be forced
into the formation. The drill bit, however, can only be pushed in one
direction. Additionally, the drill hit can only
be periodically pushed into the formation because the apparatus must
repeatedly unanchor and repressurize the piston
chambers to move within the borehole.
Summary of the Invention
V
The present invention provides improved methods and apparatus for movement of
equipment in passages.
In a preferred embodiment, the present invention provides improved methods and
apparatus for moving drilling
equipment in passages. More preferably, the present invention allows drilling
equipment to be moved within inclined
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or completely horizontal boreholes that extend for distances beyond those
previously known in the art. the
equipment utilized for this purpose is structurally simple and provides for
easy in-the-field maintenance. The
structural simplicity of the present invention increases the reliability of
the tool. The equipment is also easy to
operate with lower initial and long-term costs than equipment known in the
art. Additionally, the present invention
is readily adapted to operate in environments where known methods and
appaeatuses are unable to function.
The apparatus is able to move a wide variety of types of equipment within a
borehole, and in a preferred
embodiment the present invention can solve many of the problems presented by
prior art methods of drilling inclined
and horizontal boreholes. For example, conventional rotary drilling methods
and coiled tubing drilling methods are
often ineffective or incapable of producing a horizontally drilled borehole or
a borehole with a horizontal component
because sufficient weight cannot be maintained on the drill bit. Weight on the
drill bit is required to force the drill
bit into the formation and keep the drill bit moving in the desired direction.
For example, in rotary drilling of long
inclined holes, the maximum force that can be generated by prior art systems
is often limited by the ability to deliver
weight to the drill bit. Rotary drilling of long inclined holes is limited by
the resisting friction farces of the drill string
against the borehole wall. For these reasons, among others, current horizontal
rotary drilling technology limits the
length of the horizontal components of boreholes to approximately 4,500 to
5,500 feet because weight cannot be
maintained on the drill bit at greater distances.
Coiled tubing drilling also presents difficulties when drilling or moving
equipment within extended horizontal
or inclined holes. For example, as described above, there is the problem of
maintaining sufficient weight on the drill
bit. Additionally, the coiled tubing often buckles or fails because frequently
too much force is applied to the tubing.
For instance, a rotational force on the coiled tubing may cause the tubing to
shear, while a compression force may
cause the tubing to collapse. These constraints limit the depth and length of
holes that can 6e drilled with existing
coiled tubing drilling technology. Current practices limit the drilling of
horizontally extending boreholes to
approximately 1,000 feet horizontally.
The methods and preferred apparatus of the present invention solve these prior
art problems by generally
maintaining the drill string in tension and providing a generally constant
force on the drill bit. The problem of tubing
buckling experienced in conventional drilling methods is no longer a problem
with the present invention because the
tubing is pulled down the borehole rather than being forced into the borehole.
Additionally, the current invention
allows horizontal and inclined holes to be drilled for greater distances than
by methods known in the art. The 500
to 1,500 foot limit for horizontal coiled tubing drilled boreholes is no
longer a problem because the preferred
apparatus of the present invention can force the drill bit into the formation
with the desired amount of force, even
in horizontal or inclined boreholes. In addition, the preferred apparatus
aliows faster, more consistent drilling of
diverse formations because farce can be constantly applied to the drill bit.
A preferred aspect of the present invention provides a method far propelling a
tool having a body within
a passage. The method includes causing a gripper including at least a gripper
portion to assume a first position that
engages an inner surface of the passage and limits relative movement of the
gripper portion relative to the inner
surface. The method also includes causing the gripper portion to assume a
second position that permits substantially
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free relative movement between the gripper portion and the inner surface of
the passage. The method further
includes a propulsion assembly for selectively continuously moving the body
with respect to the gripper portion while
the gripper portion is in the first position.
Another preferred aspect of the present invention provides a method for
propelling a tool having a generally
cylindrical body within a passage. The method includes causing a first gripper
portion to assume a first position that
engages an inner surface of the borehole passage and limits relative movement
of the first gripper portion relative
to the inner surface. Simultaneously, a second gripper portion assumes a
position that permits substantially free
relative movement between the second gripper portion and the inner surface of
the borehole. The body of the tool,
consisting of a central coaxial cylinder and a valve control pack, moves
within the borehole with respect to the first
gripper portion. The first gripper portion then assumes a second position that
permits substantially free relative
movement between the first gripper portion and the inner surface of the
passage, While the second gripper portion
engages the inner surface of the borehole and limits relative movement of the
second gripper portion relative to the
inner surface. At this time the body of the tool moves relative to the second
gripper portion. This process can be
repeated to allow the body of the tool to selectively continuously move with
respect to at least one gripper portion.
While prior art methods prevent continuous movement and drilling within a
borehole, the present invention allows
continuous operation, and a force can be constantly maintained on the drill
bit.
Another aspect of the present invention provides a method for propelling a
tool having a generally cylindrical
body within a passage. The method includes causing a first gripper portion to
assume a first position that engages
the inner surface of the borehole and limits relative movement of the first
gripper portion relative to the inner surface
of the borehole. The body of the tool is then moved with respect to the first
gripper portion. The first gripper
portion then assumes a second position that permits substantially free
relative movement between the first gripper
portion and the inner surface of the borehole. At this time a second gripper
portion assumes a first position that
engages an inner surface of the borehole and limits relative movement of the
second gripper portion relative to the
inner surface of the passage. The body of the tool is then moved with respect
to the second gripper portion. The
second gripper portion then assumes a second position that permits
substantially free relative movement between
the second gripper portion and the inner surface of the borehale. By
selectively continuously moving the body with
respect to at least one gripper portion when it is in the position that allows
substantially free relative movement
between the gripper portion and the inner surface of the borehole, the present
invention can continuously move within
the borehole.
Still another preferred aspect of the present invention provides a method of
propelling a tool having a
generally cylindrical body within a passage using first and second engagement
bladders. The first engagement
bladder is inflated to assume a position that engages an inner surface of the
passage and limits relative movement
of the first engagement bladder relative to the inner surface of the passage.
An element of the toot then moves with
respect to the first engagement bladder. The second engagement bladder is in a
position allowing free relative
movement between the second engagement bladder and the inner surface of the
passage. The first engagement
bladder then deflates, allowing free relative movement between the first
engagement bladder and the inner surface
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of the passage. The second engagement bladder is then inflated to assume a
position that engages an inner surface
of the passage and limits relative movement of the second engagement bladder
relative to the inner surface. At this
time an element of the tool is moved with respect to the second engagement
bladder. This process can be cyclicly
repeated to allow the tool to generally continuously move forward within the
passage.
In a further preferred aspect of the present invention, an ambient fluid is
used to inflate the first and
second engagement bladders. Preferably, the ambient fluid is drilling fluid
or, more preferably, drilling mud. In this
aspect of the invention, the drilling mud used to inflate the bladder is from
the central flow channel of the drill
string. When the engagement bladders are deflated, the drilling mud is
preferably returned to the central flow
channel. This is referred to as an open system.
In another preferred embodiment of the present invention, a fluid such as
hydraulic fluid is used to inflate
the engagement bladders. The hydraulic fluid may be stored within a reservoir
within the tool or it may be pumped
from the surface to the engagement bladders through a flow line. This is
referred to as closed system.
Equipment known in the art for drilling horizontally extending boreholes is
relatively bulky and expensive both
in initial and long-term operating costs. These known devices also require
lengthy maintenance time as in-the-field
95 service is generally not a viable option. In contrast, the apparatus of the
present invention reduces the cost and
maintenance constraints of the known drilling methods. For example, the
present invention is easy to operate, with
lower initial and long-term costs than those known in the art. The present
invention also eases in-the-field
maintenance for several reasons. First. in this preferred embodiment, the
apparatus of the present invention is
designed to operate with ambient fluid. Preferably the ambient fluid is
drilling fluid or, more preferably, drilling mud.
Advantageously, when a fluid such as drilling mud is used to power the present
invention, problems of contamination
are eliminated. This design eases problems associated with deterioration of
the tool caused by the mixing of
different fluids. Alternatively, when a fluid such as hydraulic fluid is used
to power the invention, the hydraulic fluid
may be either stored within the body of the tool or pumped from the surface to
the tool. Second, many of the parts
of the present invention are easily removed and disconnected for in-the-field
changes of various elements. These
elements can simply be removed and replaced in-the-field, allowing quicker
changeovers and continued operation of
the tool. Significantly, this eliminates much of the dawn time of conventional
drilling equipment.
Another preferred aspect of the present invention provides a method for
propelling a tool having a generally
cylindrical body within a passage. The method includes causing a gripper
portion to assume a first position in which
the gripper portion engages an inner surface of the passage and limits
relative movement of the gripper portion
relative to the inner surface of the passage. The gripper portion is also
caused to assume a second position that
allows substantially free relative movement between the gripper portion and
the inner surface of the passage. A
propulsion assembly is provided for selectively moving the body with respect
to the gripper portion in the first
position. The power source includes a piston having a head reciprocally
mounted within a cylinder so as to define
a first chamber on one side of the head and a second chamber on the other side
of the head. The body of the tool
is selectively moved with respect to the gripper portion by forcing fluid into
the first or second chamber.
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Yet another preferred aspect of the present invention provides a method for
propelling a tool having a
generally cylindrical body within a passage in which the movement of the tool
is controlled from the surface. The
surface controls can preferably be manually or automatically operated. The
tool may be in communication with the
surface by a line which allows information to be communicated from the surface
to the tool. This line, far example,
may be an electrical fine (generally known as an "E-line"1, an umbilical line,
or the like. In addition, the tool may
have an electrical connection an the forward and aft ends of the tool to allow
electrical connection between devices
located on either end of the tool. This electrical connection, for example,
may allow connection of an E-line to a
Measurement While Drilling (MWD~ system located between the tool and the drill
bit. Alternatively, the toot and the
surface may be in communication by down linking in which a pressure pulse from
the surface is transmitted through
the drilling fluid within the fluid channel to a transceiver. The transceiver
converts the pressure pulse to electrical
signals which are used to control the tool. This aspect of the invention
allows the tool to be linked to the surface,
and allows Measurement While Drilling systems, for example, to be controlled
from the surface. Additional elements
known in the art may be linked to the various embodiments of the present
invention.
In another preferred aspect, the apparatus may be equipped with directional
control to allow the tool to
move in forward and backward directions within the passage. This allows
equipment to be placed in desired
locations within the borehole, and eliminates the removal problems associated
with known apparatuses. It will be
appreciated that the tool in each of the preferred aspects may also be placed
in an idle or stationary position with
the passage. Further, it will be appreciated that the speed of the tool within
the passage may be controlled.
Preferably, the speed is controlled by the power delivered to the tool.
These preferred aspects of the present invention can be used, for example, in
combination with drilling tools
to drill new boreholes which extend at vertical, horizontal, or inclined
angles. The present invention also may be used
with existing boreholes, and the present invention can be used to drilE
inclined or horizontal boreholes of greater
length than those known in the art. Advantageously, the toot can be used with
conventional rotary drilling
apparatuses or coifed tubing drilling apparatuses. The tool is also compatible
with various drill bits, motors, MWD
systems, downhole assemblies, pulling tools, lines and the like. The toot is
also preferably configured with connectors
which allow the tool to be easily attached or disconnected to the drill string
and other related equipment.
Significantly, the tool allows selectively continuous force to be applied to
the drill bit, which increases the life and
promotes better wear of the drill bit because there are no shocks or abrupt
forces on the drift bit. This continuous
force on the drill bit also allows for faster, more consistent drilling. It
will be understood that the present invention
can also be used with multiple types of drill bits and motors, allowing it to
drill through different kinds of materials.
It will also be appreciated that two or more tools, in each of the preferred
embodiments, may be connected
in series. This may be used, for example, to move a greater distance within a
passage, move heavier equipment
within a passage, or provide a greater force on a drill bit. Additionally,
this could allow a plurality of pieces of
equipment to be moved simultaneously within a passage.
Advantageously, the present invention can be used to pull the drill string
down the borehole. This
advantageously eliminates many of the compression and rotational forces on the
drill string, which cause known
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systems to fail. The invention is also relatively simple and eliminates many
of the
multiple parts required by the prior art apparatuses. Significantly, in one
preferred
aspect the tool is self-contained and can fit entirely within the borehole.
Further, the
gripping structures of the present invention do not damage the borehole walls
as do
the anchoring structures known in the art. For these and other reasons
described in
more detail below, the present invention is an improvement over known systems.
The present invention also makes drilling in various locations possible
because for example, oil reserves that are currently unreachable or
uneconomical to
develop using known methods and apparatuses can be reached by using an
apparatus of the present invention to drill horizontal or inclined boreholes
of extended
length. This allows economically marginal oil and gas fields to be
productively
exploited. In short, the preferred embodiments of the present invention
present
substantial advantages over the apparatus and methods disclosed in the prior
art.
Therefore, various aspects of the invention are provided as follows:
A self-propelled tool for moving within a passage, comprising:
a body;
a gripper movably engaged with said body, said gripper including at
least a gripper portion, said gripper portion having a first position in which
said
gripper portion limits movement of said gripper portion relative to an inner
surface of
said passage and a second position in which said gripper portion permits
substantially free relative movement between said gripper portion and said
inner
surface;
a propulsion assembly configured to selectively continuously pull and
thrust said body with respect to said gripper portion of said gripper in said
first
position, said propulsion assembly comprising a member fixed with respect to
said
body and movable with respect to said gripper, wherein said body is pulled and
thrust
with respect to said inner surface of said passage by moving said member with
3o respect to said gripper when said gripper portion is in said first
position; and
a control pack configured to control one of thrust, pull, and speed of
the tool by internally continuously regulating pressure within the tool or
internally
continuously controlling flow of fluid within the tool.
A self-propelled tool for moving within a passage, comprising:
a body;
a gripper including a first gripper portion and a second gripper portion,
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each of said gripper portions being movably engaged with said body, each of
said
gripper portions having an actuated position in which said gripper portion
engages an
inner surface of said passage to limit movement of said gripper portion
relative to
said inner surface of said passage and a retracted position in which said
gripper
portion permits substantially free relative movement between said gripper
portion and
said inner surface;
a propulsion assembly comprising:
a first propulsion assembly portion for selectively pulling and thrusting
said body with respect to at least said first gripper portion of said gripper,
said first
propulsion assembly portion comprising a first member fixed with respect to
said
body and movably engaged with said first gripper portion, wherein said body is
pulled
and thrust with respect to said inner surface of said passage by moving said
first
member with respect to said first gripper portion when said first gripper
portion is in
said actuated position; and
a second propulsion assembly portion for selectively pulling and
thrusting said body with respect to at least said second gripper portion of
said
gripper, said second propulsion assembly portion comprising a second member
fixed
with respect to said body and movably engaged with said second gripper
portion,
wherein said body is pulled and thrust with respect to said inner surtace of
said
passage by moving said second member with respect to said second gripper
portion
when said second gripper portion is in said actuated position; and
a switching mechanism configured to switch the gripper portions
between the actuated position and the retracted position, at any position of
the
gripper portions relative to said body, based upon the pressure differential
in at
least one of the first and second propulsion assembly portions.
A self-propelled tool for moving within a passage, comprising:
a body;
a gripper including a first gripper portion and a second gripper portion,
each of said gripper portions being movably engaged with said body, each of
said
gripper portions having an actuated position in which said gripper portion
engages an
inner surface of said passage to limit movement of said gripper portion
relative to
said inner surface of said passage and a retracted position in which said
gripper
portion permits substantially free relative movement between said gripper
portion and
said inner surface;
a propulsion assembly comprising:
a first propulsion assembly portion for selectively pulling and thrusting
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said body with respect to at least said first gripper portion of said gripper,
said first
propulsion assembly portion comprising a first member fixed with respect to
said
body and movably engaged with said first gripper portion, wherein said body is
pulled
and thrust with respect to said inner surface of said passage by moving said
first
member with respect to said first gripper portion when said first gripper
portion is in
said actuated position; and
a second propulsion assembly portion for selectively pulling and
thrusting said body with respect to at least said second gripper portion of
said
gripper, said second propulsion assembly portion comprising a second member
fixed
with respect to said body and movably engaged with said second gripper
portion,
wherein said body is pulled and thrust with respect to said inner surface of
said
passage by moving said second member with respect to said second gripper
portion
when said second gripper portion is in said actuated position; and
a switching mechanism configured to switch the gripper portions
between the actuated position and the retracted position, at any position of
the
gripper portions relative to said body, based upon the pressure differential
in at least
one of the first and second propulsion assembly portions, said switching
mechanism
comprising a valve configured to alternate between a first position and a
second
position, wherein in said first position said valve directs fluid within said
tool to and
from said gripper to bring said first gripper portion to said actuated
position and said
second gripper portion to said retracted position, and also wherein in said
second
position said valve directs fluid within said tool to and from said gripper to
bring said
first gripper portion to said retracted position and said second gripper
portion to said
actuated position.
A self-propelled tool for moving within a passage, comprising:
a longitudinal body;
a first engagement bladder movably engaged with said body, said first
engagement bladder having a first position in which said first engagement
bladder
engages an inner surface of said passage and limits movement of said first
engagement bladder relative to said inner surface of said passage and a second
position in which said first engagement bladder permits substantially free
relative
movement between said first engagement bladder and said inner surface;
a propulsion assembly configured to selectively pull and thrust said
body with respect to said first engagement bladder when said first engagement
bladder is in said first position; and
CA 02230185 2000-O1-12
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a direction control configured to reverse the direction of the tool at any
longitudinal position of the first bladder relative to said body.
An internally fluid pressure-regulated self propelled tool for moving within a
passage, comprising:
a body;
first and second gripper sections spaced apart axially on the body,
each gripper section having an actuated position for engaging an inner surface
of the
passage to limit movement of the actuated gripper section relative to the
inner
surface of the passage and a retracted position which permits substantially
free
relative movement between the retracted gripper section and the inner surface
of the
passage;
a propulsion system on the body, comprising (1 ) a first propulsion
assembly operative under fluid pressure for moving the first gripper section
to the
actuated position and the second gripper section to the retracted position for
selectively pulling and thrusting the body axially in the passage with respect
to the
first gripper section, and (2) a second propulsion assembly operative under
fluid
pressure for moving the second gripper section to the actuated position and
the first
gripper section to the retracted position for selectively pulling and
thrusting the body
axially in the passage with respect to the second gripper section;
a sensor for sensing fluid pressure differential in the first and in the
second propulsion assemblies; and
a fluid distributor on the body for cycling the flow of fluid under
pressure internally between the first propulsion assembly and the second
propulsion
assembly in response to sensed fluid pressure differentials in said propulsion
assemblies, to alternately actuate said first and second propulsion assemblies
to
apply controlled thrusting and pulling forces to the body for moving the tool
within the
passage.
A fluid pressure-actuated self-propelled tool for moving within a passage,
comprising:
a body having a flow channel for directing the flow of fluid' under
pressure;
first and second gripper sections spaced apart axially along the body;
a first propulsion assembly on the body operative under fluid pressure
to move the first gripper section to an actuated position for engaging an
inner surface
of the passage with the second gripper section retracted so the body is
movable in
CA 02230185 2000-O1-12
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the passage along a first stroke length relative to the first gripper section;
a second propulsion assembly on the body operative under fluid
pressure to move the second gripper section to an actuated position engaging
an
inner surface of the passage with the first gripper section retracted so the
body is
movable in the passage along a second stroke length relative to the second
gripper
section; and
a control valve assembly on the body in fluid communication with the
first and second propulsion assemblies for diverting a portion of the fluid
flow from
the flow channel for internally cycling the first and second gripper sections
between
the actuated and retracted positions thereof for controlling movement of the
body
along the first stroke length and along the second stroke length as pulling
and
thrusting forces are applied to the body.
A fluid pressure actuated self-propelled tool for moving within a passage
comprising:
a body;
first and second gripper sections spaced apart axially along the body;
a first propulsion assembly on the body operative under fluid pressure
to move the first gripper section to an actuated position for engaging an
inner surface
of the passage with the second gripper section retracted so the body is
movable in
the passage along a first stroke length relative to the first gripper section;
a second propulsion assembly on the body operative under fluid
pressure to move the second gripper section to an actuated position engaging
an
inner surface of the passage with the first gripper section retracted so the
body is
movable in the passage along a second stroke length relative to the second
gripper
section; and
a control valve assembly on the body in fluid communication with the
first and second propulsion assemblies for internally cycling the first and
second
gripper sections between the actuated and retracted positions thereof for
controlling
movement of the body along the first stroke length and the second stroke
length,
each propulsion assembly switching the gripper sections between the
actuated and retracted positions in response to sensing a preset differential
fluid
pressure at any location of the body along either the first or the second
stroke length.
A method of propelling a tool having a body within a passage, comprising the
steps of:
causing a first gripper portion of a gripper to assume a first position in
CA 02230185 2000-O1-12
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which said first gripper portion engages an inner surface of said passage and
limits
movement of said first gripper portion relative to said inner surface;
causing said first gripper portion to assume a second position in which
said first gripper portion permits substantially free relative movement
between said
first gripper portion and said inner surface;
causing a second gripper portion of said gripper to assume a first
position in which said second gripper portion engages said inner surface of
said
passage and limits movement of said second gripper portion relative to said
inner
surface;
causing said second gripper portion to assume a second position in
which said second gripper portion permits substantially free relative movement
between said second gripper portion and said inner surface;
selectively continuously pulling and thrusting said body with respect to
at least one gripper portion of said gripper in said first position; and
controlling one of thrust, pull and speed of the tool by internally
continuously self-regulating at least one of pressure and flow of fluid within
the tool.
A method of propelling a tool having a generally cylindrical body and a
gripper
including a plurality of gripper portions within a passage, comprising:
causing a first gripper portion to assume a first position in which said
first gripper portion engages an inner surface of said passage and limits
movement of
said first gripper portion relative to said inner surface;
moving said body with respect to said first gripper portion when said
first gripper portion is in said first position;
causing said first gripper portion to assume a second position in which
said first gripper portion permits substantially free relative movement
between said
first gripper portion and said inner surface;
causing a second gripper portion to assume a first position in which
said second gripper portion engages an inner surface of said passage and
limits
movement of said second gripper portion relative to said inner surface;
moving said body with respect to said second gripper portion when
said second gripper portion is in said first position;
causing said second gripper portion to assume a second position in
which said second gripper portion permits substantially free relative movement
between said second gripper portion and said inner surface;
selectively continuously pulling and thrusting said body with respect to
at least one gripper portion of said gripper in said first position; and
CA 02230185 2000-O1-12
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switching the first gripper portion and the second gripper portion
between the first position and the second position at any time depending upon
conditions encountered by the tool within the passage.
A method of propelling a tool having a generally cylindrical body within a
passage, the tool having a gripper including a first engagement bladder and a
second
engagement bladder which are movably engaged with the body, comprising the
steps of:
inflating said first engagement bladder to cause said first engagement
1 o bladder to assume a first position in which said first engagement bladder
engages an
inner surface of said passage and limits movement of said first engagement
bladder
relative to said inner surface;
deflating said first engagement bladder so that said first engagement
bladder assumes a second position in which said first engagement bladder
permits
substantially free relative movement between said first engagement bladder and
said
inner surface; and
selectively continuously pulling and thrusting said body with respect to
at least one engagement bladder of said gripper in said first position.
An assembly for moving through a passage having a mouth, said assembly
forming at least a portion of a string having a first end adapted to be
positioned distal
said mouth from a second end of said string, comprising:
a self propelled tool, comprising:
a body having a length and defining an inner flow channel having a
first pressure;
a first barrel secured around and slidable along the length said body,
said first barrel at least partially defining a first fluid chamber;
a second barrel secured around and slidable along the length of said
body, said second barrel at least partially defining a second fluid chamber;
a first piston fixed with respect to said body positioned within said first
chamber, said first barrel being reciprocally movable with respect to said
first piston
from a first end position to a second end position;
a second piston fixed with respect to said body positioned within said
second chamber, said second barrel being reciprocally movable with-respect to
said
second piston from a first end position to a second end position;
a first bladder secured to said first barrel and having an interior, said
first bladder having a first position in which said first bladder limits
movement of said
CA 02230185 2000-O1-12
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first bladder relative to an inner surface of said passage and a second
position in
which said first bladder permits substantially free relative movement between
said
first bladder and said inner surface; and
a second bladder secured to said second barrel and having an
interior, said second bladder having a first position in which said second
bladder
limits movement of said second bladder relative to an inner surface of said
passage
and a second position in which said second bladder permits substantially free
relative
movement between said first bladder and said inner surface;
wherein a portion of said passage surrounding said tool defines a
second pressure, said tool further comprising a plurality of valves at least a
number
of which are configured to cooperatively selectably control fluid to said
first chamber
to move said first barrel relative said first piston, to said second chamber
to move
said second barrel relative said second piston, to said interior of said first
bladder to
move said first bladder between said first position of said first bladder and
said
second position of said first bladder and to said interior of said second
bladder to
move said second bladder between said first position of said second bladder
and
said second position of said second bladder, at least a number of said
plurality of
valves configured to control the speed of said tool through said passage for a
given
differential between said first pressure and said second pressure and for a
given load
on said tool, and at least a number of said plurality of valves configured to
limit the
load on said first end of said string while said first barrel is in a position
between said
first end position and said second end position of said first barrel and said
second
barrel is in a position between said first end position and said second end
position of
said second barrel.
An assembly for moving through a passage, comprising:
a length of tubing defining a first flow channel;
a working unit defining a second flow channel;
a self-propelled tool connected at a first end to said length of tubing
3o and at second end to said working unit, said tool comprising:
a body having a length and defining a third flow channel having a first
pressure and permitting fluid communication between said first flow channel
and said
second flow channel;
a first barrel secured around and slidable along the length said body,
said first barrel at least partially defining a first fluid chamber;
a second barrel secured around and slidable along the length of said
body, said second barrel at least partially defining a second fluid chamber;
CA 02230185 2000-O1-12
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a first piston fixed with respect to said body positioned within said first
chamber, said first barrel being reciprocally movable with respect to said
first piston;
a second piston fixed with respect to said body positioned within said
second chamber, said second barrel being reciprocally movable with respect to
said
second piston;
a first bladder secured to said first barrel exterior said body having an
interior, said first bladder having a first position in which said first
bladder limits
movement of said first bladder relative to an inner surface of said passage
while said
tool permits flow exterior said first barrel between said first barrel and
said inner
surface and a second position in which said first bladder permits
substantially free
relative movement between said first bladder and said inner surface; and
a second bladder secured to said second barrel exterior said body
having an interior, said second bladder having a first position in which said
second
bladder limits movement of said second bladder relative to an inner surface of
said
passage while said tool permits flow exterior said second barrel between said
second
barrel and said inner surface and a second position in which said second
bladder
permits substantially free relative movement between said second bladder and
said
inner surface;
wherein a portion of said passage surrounding said tool defines a
second pressure, said tool further comprising a plurality of valves at least a
number
of which are configured to cooperatively selectably control fluid to said
first chamber
to move said first barrel relative said first piston, to said second chamber
to move
said second barrel relative said second piston, to said interior of said first
bladder to
move said first bladder between said first position of said first bladder and
said
second position of said first bladder and to said interior of said second
bladder to
move said second bladder between said first position of said second bladder
and
said second position of said second bladder to pull said length of tubing
behind said
tool through said passage and thrust said working unit ahead of said tool
through
said passage and where in operation said length of tubing does not spin with
respect
to any of said first barrel, said second barrel and said inner surface of said
passage.
An assembly movable through a passage having a mouth and forming a
portion of a string having a first end adapted to be positioned distal said
mouth from a
second end of said string, said assembly comprising:
a self-propelled tool, comprising:
a body having a length and defining an inner flow channel having a
first pressure;
CA 02230185 2000-O1-12
8i
a first barrel secured around and slidable along the length said body,
said first barrel at least partially defining a first fluid chamber;
a second barrel secured around and slidable along the length of said
body, said second barrel at least partially defining a second fluid chamber;
a first piston fixed with respect to said body and positioned within said
first chamber, said first barrel being reciprocally movable with respect to
said first
piston from a first end position to a second end position;
a second piston fixed with respect to said body and positioned within
said second chamber, said second barrel being reciprocally movable with
respect to
said second piston from a first end position to a second end position;
a first bladder secured to said first barrel exterior said body and having
an interior, said first bladder having a first position in which said first
bladder limits
movement of said first bladder relative to an inner surface of said passage
while said
tool permits flow exterior said first barrel between said first barrel and
said inner
surface and a second position in which said first bladder permits
substantially free
relative movement between said first bladder and said inner surface; and
a second bladder secured to said second barrel exterior said body and
having an interior, said second bladder having a first position in which said
second
bladder limits movement of said second bladder relative to an inner surface of
said
passage while said tool permits flow exterior said second barrel between said
second
barrel and said inner surface and a second position in which said second
bladder
permits substantially free relative movement between said second bladder and
said
inner surface;
wherein a portion of said passage surrounding said tool defines a
second pressure, said tool further comprising a plurality of valves at least a
number
of which are configured to cooperatively selectably control fluid to said
first chamber,
said second chamber, said interior of said first bladder and said interior of
said
second bladder, at least a number of said plurality of valves permit being
configured
to said first barrel to change its direction of movement along said length of
said body
while in a position between said first end position and said second end
position of
said first barrel and at least a number of said plurality of valves permit
being
configured to said second barrel to change its direction of movement along
said
length of said body while in a position between said first end position and
said
second end position of said second barrel, and wherein further at least a
number of
said plurality of valves being configured to permit said tool to change its
direction of
movement within said passage.
CA 02230185 2000-O1-12
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An assembly movable through a passage having a mouth and forming a
portion of a string having a first end within said passage distal said mouth,
said
assembly comprising:
a self propelled tool, said tool comprising:
a body having a length and defining an inner flow channel having a
first pressure;
a first barrel secured around and slidable along the length said body,
said first barrel at least partially defining a first fluid chamber;
a second barrel secured around and slidable along the length of said
body, said second barrel at least partially defining a second fluid chamber;
a first piston fixed with respect to said body and positioned within said
first chamber, said first barrel being reciprocally movable with respect to
said first
piston from a first end position to a second end position;
a second piston fixed with respect to said body and positioned within
said second chamber, said second barrel being reciprocally movable with
respect to
said second piston from a first end position to a second end position;
a first bladder secured to said first barrel exterior said body and having
an interior, said first bladder having a first position in which said first
bladder limits
movement of said first bladder relative to an inner surface of said passage
while said
tool permits flow exterior said first barrel between said first barrel and
said inner
surface and a second position in which said first bladder permits
substantially free
relative movement between said first bladder and said inner surface; and
a second bladder secured to said second barrel exterior said body and
having an interior, said second bladder having a first position in which said
second
bladder limits movement of said second bladder relative to an inner surface of
said
passage while said tool permits flow exterior said second barrel between said
second
barrel and said inner surface and a second position in which said second
bladder
permits substantially free relative movement between said second bladder and
said
inner surface;
3o wherein a portion of said passage surrounding said tool defines a
second pressure, said tool further comprising a plurality of valves at least a
number
of which are configured to cooperatively selectably control fluid to said
first chamber,
said second chamber, said interior of said first bladder and said interior of
said
second bladder, at least a number of said plurality of valves permitting said
first
barrel to change its direction of movement along said length of said body
while in a
position between said first end position and said second end position of said
first
barrel and at least a number of said plurality of valves permitting said
second barrel
CA 02230185 2000-O1-12
8k
to change its direction of movement along said length of said body while in a
position
between said first end position and said second end position of said second
barrel,
and wherein further at least a number of said plurality of valves permit said
tool to
limit load on said first end of said string.
Brief Description of the Drawinas
These and other features of the invention will now be described with
reference to the drawings of preferred embodiments, which are intended to
illustrate
and not to limit the invention.
Figure 1A is schematic diagram of the major components of an embodiment
of the present invention in conjunction with a coiled tubing drilling system.
Figure 1 B is a schematic diagram of the major components of another
embodiment of the present invention in conjunction with a working unit.
Figure 2A is a cross-sectional view of another embodiment of the present
invention, showing the forward section in the thrust stage, the aft section in
the reset
stage, and the forward gripper mechanism inflated.
Figure 2B is a cross-sectional view of the embodiment in Figure 2A, showing
the forward section in the end-of-thrust stage, the aft section in the reset
stage, and
the forward gripper mechanism inflated.
Figure 2C is a cross-sectional view of the embodiment in Figure 28, showing
the forward section in the reset stage, the aft section in the thrust stage,
and the aft
gripper mechanism inflated.
3o Figure 2D is a cross-sectional view of the embodiment in Figure 2C, showing
the forward section in the reset stage, the aft section in the end-of thrust
stage, and
the aft gripper mechanism inflated.
Figure 2E is a cross-sectional view of the embodiment in Figure 2D, showing
the forward section in the thrust stage, the aft section in the reset stage,
and the
forward gripper mechanism inflated, similar to Figure 2A.
CA 02230185 2000-O1-12
81
Figure 3 is a process and instrumentation schematic diagram of the
embodiment in Figure 2A, with me forward gripper mechanism inflated.
Figure 4 is a process and instrumentation schematic diagram of the
embodiment in Figure 2A, with the aft grippes mechanism inflated.
Figure 5 is a cross-sectional view of another embodiment of the invention.
Figure 6 is an enlarged cross-sectional view of the front end of the
embodiment in Figure 5.
Figure 7 is an enlarged cross-sectional view of a piston-barrel assembly of
the embodiment in Figure 5.
Figure 8 is an enlarged cross-sectional view of the flow channels and
packerfoot assembly of the embodiment in Figure 5.
CA 02230185 1998-02-20
WO 97/08418 PCTlLTS96/13573
-9-
Figure 9 is a cross-sectional view of the packerfoot assembly in the
uninflated position taken along line 9-9
shown in Figure 8.
Figure 10 is a cross-sectional view of the packerfoot assembly in the inflated
position taken along line 9-9
shown in Figure 8.
Figure 11 is an enlarged cross-sectional view of the valve control pack of the
embodiment in Figure 5.
Figure 12 is an enlarged cross-sectional view of the connection between the
valve control pack and the
forward section of the embodiment in Figure 5.
Figure 13 is an enlarged cross-sectional view of the connection between the
valve control pack and the aft
section of the embodiment in Figure 5.
Figure 14 is an enlarged end view of the valve control pack taken along line
14-14 shown in Figure 1 t.
Figure 15 is an enlarged end view of the valve control pack taken along line
15-15 shown in Figure 11.
Figure 16 is a schematic diagram showing the flow path of the fluid through
the valve control pack of the
embodiment in Figure 5.
Figures 17A1-4 are four cross sections of the valve control pack taken along
the lines 17A1-4-17A1-4 of
Figure 15 with the valves removed.
Figure 17B is a cross section of the valve control pack taken along the line
17B-17B in Figure 14 with the
valves removed.
Figure 18 is a process and instrumentation schematic diagram of another
embodiment of the invention,
providing for a closed system showing the forward gripper mechanism inflated.
Figure 19 is a process and instrumentation schematic diagram of the embodiment
in Figure 18, showing
the aft gripper mechanism inflated.
Figure 20 is a process and instrumentation schematic diagram of yet another
embodiment of the invention,
providing for directional control, with the forward gripper mechanism inflated
and the directional control set in the
forward position.
Figure 21 is a process and instrumentation schematic diagram of the embodiment
in Figure 20, showing
the aft gripper mechanism inflated.
Figure 22 is a process and instrumentation schematic diagram of the embodiment
in Figure 20, showing
the forward gripper mechanism inflated and the directional control set in the
reverse position.
Figure 23 is a process and instrumentation schematic diagram of the embodiment
in Figure 22, showing
the aft gripper mechanism inflated.
Figure 24 is a process and instrumentation schematic diagram of a further
embodiment of the invention,
with electrical controls and a directional control valve.
Detailed Description of the Preferred Embodiments
As shown in Figure 1A, an apparatus and method for moving equipment within a
passage is configured in
accordance with a preferred embodiment of the present invention. in the
embodiments shown in the accompanying
figures, the apparatus and methods of the present invention are used in
conjunction with a coiled tubing drilling
CA 02230185 1998-02-20
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WO 97/08418 PCT/US96/13573
.10.
system 100. It will be appreciated that the present invention may be used to
move a wide variety of tools and
equipment within a borehole, and the present invention can be used in
conjunction with numerous types of drilling,
including rotary drilling and the like. Additionally, it will be understood
that the present invention may be used in
many areas including petroleum drilling, mineral deposit drilling, pipeline
installation and maintenance, communications,
and the like.
It will be understood that the apparatus and method for moving equipment
within a passage may be used
in many applications in addition to drilling. For example, these other
applications include well completion and
production work for producing oil from an oil well, pipeline work, and
communication activities. It will be appreciated
that these applications require the use of other equipment in conjunction with
a preferred embodiment of the present
device so that the device can move the equipment within the passage. It will
be appreciated that this equipment,
generally referred to as a working unit, is dependent upon the specific
application undertaken.
For example, one of ordinary skill in the art will understand that weU
completion typically requires that the
reservoir be logged using a variety of sensors. These sensors may operate
using resistivity, radioactivity, acoustic,
and the like. Other logging activities include measurement of formation dip
and borehole geometry, formation
sampling. and production logging. These completion activities can be
accomplished in inclined and horizontal boreholes
using a preferred embodiment of the device. For instance, the device can
deliver these various types of logging
sensors to regions of interest. The device can either place the sensors in the
desired location, or the device may
idle in a stationary position to allow the measurements to be taken at the
desired locations. The device can also
be used to retrieve the sensors from the well.
Examples of production work that can be performed with a preferred embodiment
of the device include
sands and solids washing and acidizing. It is known that wells sometimes
become clogged with sand and other
solids that prevent the free flow of oil into the borehole. To remove this
debris, specially designed washing tools
known in the industry are delivered to the region, and fluid is injected to
wash the region. The fluid and debris then
return to the surface. These washing tools can be delivered to the region of
interest by a preferred embodiment
of the device, the washing activity performed, and the tool returned to the
surface. Similarly, wells can become
clogged with hydrocarbon debris that is removed by acid washing. Again, the
device can deliver the acid washing
tools to the region of interest, the washing activity performed, and the acid
washing tools returned to the surface.
In another example, a preferred embodiment of the device can be used to
retrieve objects, such as damaged
equipment and debris, from the borehole. For example, equipment may become
separated from the drill string, or
objects may fall into the borehole. These objects must be retrieved or the
borehole must be abandoned and plugged.
Because abandonment and plugging of a borehole is very expensive, retrieval of
the object is usually attempted. A
variety of retrieval tools known to the industry are available to capture
these lost objects. This device can be used
to transport retrieving tools to the appropriate location, retrieve the
object, and return the retrieved tool to the
surface.
In yet another example, a preferred embodiment of the device can also be used
for coiled tubing
completions. As known in the art, continuous-completion drill string
deployment is becoming increasingly important
CA 02230185 1998-02-20
WO 97!08418 PCTlUS96/~3573
_71.
in areas where it is undesirable to damage sensitive formations in order to
run production tubing. These operations
require the installation and retrieval of fully assembled completion drill
string in boreholes with surface pressure.
This device can be used in conjunction with the deployment of conventional
velocity string and simple primary
production tubing installations. The device can also be used with the
deployment of artificial lift installations.
Additionally, the device can also be used with the deployment of artificial
lift devices such as gas lift and downhole
flow contra! devices.
In a further example, a preferred embodiment of the device can be used to
service plugged pipelines or other
similar passages. Frequently, pipelines are difficult to service due to
physical constraints such as location in deep
water or proximity to metropolitan areas. Various types of cleaning devices
are currently available for cleaning
pipelines. These various types of cleaning tools can be attached to the device
so that the cleaning tools can be
moved within the pipeline.
In still another example, a preferred embodiment of the device can be used to
move communication lines
or equipment within a passage. Frequently, it is desirable to run or move
various types of cables or communication
lines through various types of conduits. This device can move these cables to
the desired location within a passage.
It will be understood that two or more of the preferred embodiments of the
device may be connected in
series. This may be used, for example, to allow the device to move a greater
distance within a passage, move
heavier equipment within a passage, or provide a greater force on a drill bit.
Additionally, this could allow a plurality
of pieces of equipment to be moved simultaneously within a passage.
As can be seen from the above examples, preferred embodiments of the device
can provide transportation
or movement to various types of equipment within a passage.
Basic Svstem Components
As shown in Figure 1 A, the coiled tubing drilling system 100 typically
includes a power supply 102, a tubing
reel 104, a tubing guide 106, and a tubing injector 110, which are well known
in the art. As known, coiled tubing
114 is inserted into a borehole 132, and drilling fluid is typically pumped
through the inner flow channel of the coiled
tubing i 14 towards a drill bit 130 located at the end of the drill string.
Positioned between the drill bit 130 and
the coiled tubing 114 is a pulley-thruster downhole tool i 12. The drill bit
130 is generally contained in a bottom
hole assembly 120, which can include a number of elements known to those
skilled in the art such as a downhole
motor 122, a Measurement While Drilling (MWD) system 124, and an orientation
device which is not shown in the
accompanying figures. The pulley-thruster downhole tool 112 is preferably
connected to the coiled tubing 114 and
the bottom hole assembly 120 by connectors 116 and 126, respectively,
described below. It will be understood that
a variety of known methods may be used to connect the pulley-thruster downhole
tool 112 to the coiled tubing 114
and bottom hole assembly 120. In this system, the drilling fluid is pumped
through the inner flow channel of the
coiled tubing 114, through the pulley-thruster downhole tool 112 to the drill
bit 130. The drilling fluid and drilling
debris return to the surface in passages between the exterior surface of the
tool 112 and the inner surface of the
borehole 132, and the spacing between the exterior surface of coiled tubing
114 and the inner surface of the
borehole 132.
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-12-
When operated, the tool 112 is configured to move within the borehole 132.
This movement allows, for
example, the tool 112 to maintain a preselected force on the drill bit 130
such that the rate of drilling can he
controlled. The tool 112 can also be used to maintain a preselected force on
the drill bit 130 such that the drill
bit 130 is constantly being forced into the formation. Alternatively, the tool
112 may be used to move various types
of equipment within the borehole 132. Advantageously, in coiled tubing
drilling, for example, the tool 112 allows
sufficient force to be maintained on the drill bit 130 to permit drilling of
extended inclined or horizontal boreholes.
4
Significantly, because the tool 112 pulls the coiled tubing 114 through the
borehole 132, this eliminates many of
the compression forces that cause coiled tubing in conventional systems to
fail.
It wilt be understood that the apparatus of the preferred embodiment is used
to produce extended horizontal
or inclined boreholes in conjunction with this or similar coiled tubing
drilling surface equipment, or with a rotary
drilling system, as known in the art. The tool 112, however, may also be
utilized with other types of drilling
equipment, logging systems, or systems for moving equipment within a passage.
As seen in Figure 1B, in another preferred embodiment, the tool 112 can be
used in conjunction with a
working unit 119. This allows the tool 112 to move the working unit 119 within
the borehole 132. For example,
the tool 112 can place the working unit 119 in a desired location, or the toot
112 may idle the working unit 119
in a stationary position for a desired time. The tool 112 can also be used to
retrieve the working unit 119 from
the borehole 132. The working unit 119 may include various sensors,
instruments and the like to perform desired
functions within the borehole 132. For example, the working unit 119 may be
used with well completion equipment,
sensor equipment, logging sensor equipment, retrieval assembly, pipeline
servicing equipment, and communications
line equipment. The tool 112 andlor working unit 119 may be connected to the
surface by a connection line 134.
Tho connection fine 134 may, for instance, provide power or communication
between the tool 112 and the surface.
Referring to Figures 2A and 2B, the major components of the pulley-thruster
downhole tool 112 are
illustrated. As seen in Figures 2A and 2B, the tool 112 generally comprises a
series of three concentric cylindrical
pipes 201: an innermost cylindrical pipe 204, a second or middle cylindrical
pipe 210, and a third or outer cylindrical
pipe 214. The tool 112 is also divided into a forward section 200, an aft
section 202, and a center section 203.
The innermost cylindrical pipe 204 defines a central flow channel 206 which
extends through the forward, aft, and
center sections 200, 202, and 203, respectively, of the tool 112. The second
cylindrical pipe 210 surrounds the
innermost cylindrical pipe 204 at a distance from the innermost cylindrical
pipe 204, to create a first inner channel
or annulus 21 Z in which fluid may flow. As shown in the accompanying figures,
the first annulus 212 is divided
into a first aft annulus 212A in the aft section 202 of the tool 112 and a
first forward annulus 212F in the forward
section 200 of the tool 112. The first aft annulus 212A and first forward
annulus 212F are generally referred to
as return flow annuli because these annuli allow fluid to return from the
forward section 200 and aft section 202
to the center section 203 of the tool 112 during the reset stage. The outer
cylindrical pipe 214 surrounds the
second cylindrical pipe 210 at a distance from the second cylindrical pipe
210, defining a second inner flow channel
or annulus 216. The second annulus 216 is divided into a second aft annulus
216A in the aft section 202 of the
tool 112 and a second forward annulus 216F in the forward section 200 of the
tool 112. The second annuli 216A
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and 216F are generally referred to as a power flow annuli because these annuli
allow fluid to flow from the center
section 203 to the forward and aft sections 200 and 202, respectively, during
the thrust stage. The central flow
channel 206, the return flow annuli 212A and 212F, and the power flow annuli
216A and 216F are in fluid
communication with a valve control pack 220 located in the center section 203
of the tool 112. The tool also
includes a forward gripper mechanism 222 located in the forward section 200
and an aft gripper mechanism 207
located in the aft section 202.
Fixed to the exterior surface of the outer cylindrical pipe 214 of the forward
section 200 are two forward
pistons 224. The forward pistons 224 are positioned within corresponding
forward barrel assemblies 226. The
forward barrel assemblies 226 reciprocate about the fixed forward pistons 224,
and the forward gripper mechanism
222 is attached to the forward barrel assemblies 226 such that the forward
gripper mechanism 222 moves with
the forward barrel assemblies 226. The forward pistons 224, the forward barrel
assemblies 226, and the outer
surface of the outer cylindrical pipe 214 generally define forward reset
chambers 230 and forward power chambers
232 in the forward section 200 of the tool 112.
Fixed to the exterior of the outer cylindrical pipe 214 of the aft section 202
of the tool 112 are two aft
pistons 234. The aft pistons 234 are positioned within the corresponding aft
barrel assemblies 236. The aft barrel
assemblies 236 reciprocate about the fixed aft pistons 234, and the aft
gripper mechanism 207 is attached to the
aft barrel assemblies 236 such that the aft gripper mechanism 207 moves with
the aft barrel assemblies 236. The
aft pistons 234, the aft barrel assemblies 236, and the outer surface of the
outer cylindrical pipe 214 generally
define aft reset chambers 240 (Figure 2B) and aft power chambers 242 in the
aft section 202 of the tool 112.
As shown in Figures 2A and 2B, the power flow annuli 216A and 216F are in
fluid communication with
the forward gripper mechanism 222 because fluid can flow through the forward
power chambers 232 (Figure 2B)
of the forward piston and barrel assembly. The power flow annulus 216A is also
in fluid communication with the
aft gripper mechanism 207 through the aft power chambers 242 of the aft piston
and barrel assembly. The return
flow annuli 212F and 212A are in fluid communication with the forward and aft
reset chambers 230, 240 (Figures
2A and 2B) of the forward and aft sections 200 and 202, respectively. It will
be understood that arty number of
forward or aft piston and barrel assemblies may be used depending upon the
intended use of the tool 112.
Advantageously, because the piston and barrel assemblies are located in
series, the toot 112 may be arranged to
develop a large amount of thrust or force.
Overview of Svstem Flow Pattern and Operation
Figures 2A-ZE illustrate the general flaw of fluid within the toot 112. In
this embodiment, the tool 112
is located within a borehole 132. The borehole 132 shown in the accompanying
figures is horizontal, but it will be
understood that the borehole 132 may be of any orientation depending upon the
intended use of the tool 112.
Although not shown in the accompanying Figures 2A-2E, the coiled tubing 114 is
preferably connected to the tool
112 by box connector 116 and the bottom hole assembly 120 is preferably
connected to the tool 112 by pin
connector 126. The box and pin connectors 116, 126 are described in more
detail below. Thus, as shown, the
forward section 200 of the toot 112 is located proximate the bottom hole
assembly 120. It will be appreciated that
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these forward and aft designations are only used for clarity in describing the
tool 112 shown in the attached tigures,
and the actual designations are dependent upon the particular orientation of
the toot 112. Further, one of ordinary
skill in the art will recognize that the tool 112 may be used for a wide
variety of purposes, such as logging or
moving equipment within a borehole, and that a variety of known equipment may
be attached to the tool 112.
When the tool 112 is used in conjunction with rotary or coiled tubing
drilling, the drill string provides drilling
fluid to the central flow channel 206. Typically, the drilling fluid is
drilling mud which is pumped from the surface,
through the drill string and central flow channel 206, to the bottom hole
assembly 120. The drilling fluid is returned
to the surface in the area between the inner surface 246 of the borehole 132
and the outer surface of the tool 112.
As shown in Figures 2A-2E, the tool 112 is configured to allow a portion of
the drilling fluid contained within the
central flow channel 206 to enter the toot 112 through an opening 205. The
opening 205 is preferably located in
the center section 203 of the tool 112, such that the fluid can enter the
valve control pack 220. As described
below, the valve control pack 220 directs the flow of fluid within the tool
112.
In particular, as shown in Figure 2A, the drilling fluid is directed to the
valve control pack 220 through the
power flow annulus 216F to the forward power chambers 232. Drilling fluid also
flows through the forward power
chambers 232 to the forward gripper mechanism 222. As the drilling fluid flows
into the forward gripper mechanism
222, a forward expandable bladder 250 inflates, contacting and applying a
force against the inner surface 246 of
the borehole 132. This force fixes the forward gripper mechanism 222 of the
toot 112 relative to the inner surface
246 of the borehole 132. This also fixes the forward barrel assemblies 226
relative to the borehole 132 because
the forward barrel assemblies 226 are rigidly attached to the forward gripper
mechanism 222. As seen in Figures
2A and 2B, in this position the forward pistons 224 are almost contacting the
aft ends of the forward barrel
assemblies 226, and forward expandable bladder 250 is inflated. Once the
forward expandable bladder 250 is
inflated, the drilling fluid continues to fill the space between the aft ends
of the forward barrel assemblies 226 and
forward pistons 224, so as to fill the forward power chambers 232. Because the
forward pistons 224 can
reciprocate within the forward barrel assemblies 226, the pressure of the
fluid in the forward power chambers 232
begins to push the forward pistons 224 towards the forward end of the forward
barrel assemblies 226. The
forwardly moving forward pistons 224, which ace securely attached to the outer
cylindrical pipe 214 of the three
concentric cylindrical pipes 201, also cause the three concentric cylindrical
pipes 201 to move forward a
corresponding distance d. For example, if the forward pistons 224 are pushed
forward a distance d relative to the
fixed forward barrel assemblies 226, the three concentric cylindrical pipes
201 are also pushed forward a distance
d because the three concentric cylindrical pipes 201 and forward pistons 224
are securely interconnected. Thus,
as seen in Figures 2A and 2B, this causes the tool 112 to be generally pushed
forward a distance d.
In an alternate configuration, the outer cylindrical pipe 234 and the inner
mandrel 556 can have matching
splines or grooves. This allows the transmission of rotational displacement
from the coiled tubing 114 through the
connector 116 to the aft barrel assemblies 236 through the aft expandable
bladder 252 to the inner surface 246
of the borehole 132. This configuration advantageously prevents rotational
displacement from the downhofe motor
122 being delivered to the coiled tubing 114, thus assisting in the prevention
of helical buckling.
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As seen in Figure 2B, the forward pistons 224 have been pushed forward
proximate the forward ends of
the forward barrel assemblies 226. While the forward pistons 224 are moving
forwardly in the forward section 200
of the tool 112, the pressure in the return flow annulus 212A is causing the
aft pistons 234 to be reset. In
particular as shown in Figure 2A, the aft pistons 234 are initially located
proximate the forward ends of the aft
barrel assemblies 236. During the reset stage the aft barrel assemblies 236
are reset by the fluid in the return flow
annulus 212A which fills the aft reset chambers 240 tthe space between the
forward end of the aft barrel
assemblies 236 and the aft pistons 234) of the aft section 202. The fluid in
the aft reset chambers 240 forces
the aft barrel assemblies 236 to move relative to the aft pistons 234. This is
because the aft pistons 234 are fixed
with respect to the outer cylindrical pipe 214 and the three concentric
cylindrical pipes 201, while the aft barrel
assemblies 236 are slidably mounted about the aft pistons 234 (note that the
aft expandable bladder 252 of the
aft gripper mechanism 207 is not inflated during the reset stage!. The fluid
filling the forward reset chambers 230
causes the aft pistons 234 to be located proximate the aft ends of the aft
barrel assemblies 236, as shown in Figure
2B. The too! 112 is preferably configured such that the aft pistons 234 are
reset prior to the completion of the
forward section 200 thrust stage.
in Figure 2B, the forward pistons 224 and the three concentric cylindrical
pipes 201 have been pushed
forward a distance d, while the aft pistons 234 are reset. At this point, as
shown in Figure 2C, the forward
expandable bladder 250 of the forward gripper mechanism 222 begins to deflate,
and fluid flows from the valve
control pack 220 into the power flow annulus 216A into aft power chambers 242
and the aft gripper mechanism
207 of the aft section 202 of the tool 112. As fluid flows into the aft
gripper mechanism 207, the aft expandable
bladder 252 inflates, contacting and applying a force against the inner
surface 246 of the borehole 132. This force
fixes the aft gripper mechanism 207 and aft bane! assemblies 236 with respect
to the borehole 132, as shown in
Figure 2C.
As fluid enters the aft power chambers 242, the aft pistons 234 begin to move
forward relative to the aft
barrel assemblies 236 and toward the forward ends of the aft barrel assemblies
236. This movement propels the
aft pistons 234 and three concentric cylindrical pipes 201 of the tool 112
forward. This causes the tool 112 to
move forwardiy within the borehole 132 while simultaneously pulling the coiled
tubing 114 behind it. The fluid in
the forward reset chambers 240 of the aft section 202 is forced out into the
return flow annulus 212A by the
forward movement of the aft pistons 234, providing pressure in the return flow
annulus 212A. Simultaneously, fluid
is driven through the return flow annulus 212F into the forward reset chambers
230 of the forward section 200
of the tool 112 to reset the forward pistons 224 and forward barrel assemblies
226. fn a similar manner to that
described above, fluid forces the forward barrel assemblies 226 to move
forward relative to the forward pistons 224
(note that the forward expandable bladder 250 is not inflated during the reset
stage). The reset stage causes the
forward pistons 224 to be located proximate the aft ends of the forward barrel
assemblies 226, as shown in Figure
2D.
At this point, the forward expandable bladder 250 begins to inflate,
contacting and applying a force against
the inner surface 246 of the borehole 132. The aft expandable bladder 252 then
begins to deflate. As shown in
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Figure 2E, the flow cycle can then begin again because the piston and barrel
positions are the same as shown in
Figure 2A. Advantageously, the operation of the tool t 12 in the manner
described above allows the tool 112 to
selectively continuously move within the borehole 132. This permits the tool
112 to quickly move within the
borehole 132 and, in a preferred embodiment, to continuously force a drill bit
130 into the formation. A continuous
force on the drill bit 130 can significantly increase the rate of drilling and
life of the drill bit because, for example,
the drill bit 130 can drill at a generally continuous rate. In contrast, known
systems repeatedly surge or force the
drill bit into the formation which slows the drilling process and greatly
increases the stresses on the drill bit, causing
premature bit wear and failure.
Flow Through the 1lalve Control Pack
Figures 3 and 4 illustrate the valve control pack 220 in schematic form. In
this preferred embodiment, the
valve control pack 220 includes four valves: the idler startlstop valve 304,
the six-way valve 306, the aft reverser
valve 310, and the forward reverser valve 312. Before the drilling fluid
reaches these valves, the fluid preferably
flows through a filter system. Specifically, fluid flows from the central flow
channel 206, through the opening 205
and into five filters 302. The five filters 302 are in parallel arrangement to
increase the reliability of the tool 112
because the tool 112 can operate with three of the five filters 302 not
functioning. This allows the tool 112 to
be operated for a much longer period of time before the filters 302 must be
cleaned or replaced. In addition, the
parallel filter configuration minimizes pressure losses of the fluid entering
the tool 112. The filters 302 are
preferably positioned within the tool 112 to allow easy access and removal so
that each filter or all the filters 302
may be quickly and easily replaced.
The filters 302 are designed to remove particles and debris from the drifting
fluid which increases the
reliability and durability of the tool 112 because impurities that may wear
and damage tool elements are removed.
Filtering also allows greater tolerances of the various elements contained
within tool 112. Preferably, the filters 302
are designed to remove particles greater than 73 microns in diameter. It will
be appreciated that the size and
number of filters 302 may be varied according to numerous factors, such as the
type of drilling fluid utilized or the
tolerances of the tool 112. Preferably, filters 302 are a wire mesh filter
manufactured by Ejay Filtration, Inc. of
Riverside, California.
The filtered drilling fluid then flows to the idler startfstop valve 304 which
controls whether fluid flows
through the valve control pack 220. Thus, the idler startlstop valve 304
preferably acts like an onloff switch to
control whether the tool 112 is moving within the borehole 132. Preferably,
the idler startlstop valve 304 is set
at some predetermined pressure set-point, 500 psid, for example. This pressure
set-point is based on differential
pressure between the central flow channel 2D6 and the pressure in the idler
starttstop valve 304 pilot line, which
connects the central flaw channel 206 and the exterior surface of the tool
112. When the pressure of the drilling
fluid in the central flow channel 206 exceeds the predetermined pressure set-
point, the idler startlstop valve 304
actuates allowing fluid to enter the idler startlstop valve 304. When the
idler start/stop valve 304 opens, the filtered
drilling mud flows from the idler start/stop valve 304 into the six-way valve
306. The six-way valve 306 can be
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actuated into one of three positions, two of which are shown in Figures 3 and
4. The center position, not
illustrated, is an idle position that prevents fluid flow into the six-way
valve 306.
As seen in Figure 3, the six-way valve 306 is shown in position to supply
fluid to the aft power chambers
232 of the forward section 200 of the tool 112. In this position, flow exits
the six-way valve 306 through opening
C2 where it is directed through the power flow annulus 216F into the forward
section 200 forward power chambers
232 and into the forward gripper mechanism 222. The drilling fluid inflates
the forward expandable bladder 25D
of the forward gripper mechanism 222. The forward expandable bladder 250
assumes a position contacting the inner
surface 246 of the borehole 132 preventing free relative movement between the
borehole 132 and the forward
expandable bladder 250. The forward pistons 224, connected to the outer
cylindrical pipe 214, move forward
relative to the forward barrel assemblies 226 as fluid fills the forward
section 20D forward power chambers 232.
This causes the three concentric cylindrical pipes 201, which are connected to
the forward pistons 224, to move
forward.
Simultaneously, flow exits the six-way valve 306 through opening C3, enters
the return flow annulus 212A,
proceeds into the aft section 202 of the tool, and flows into the aft section
202 aft reset chambers 240. The
pressure of the fluid in the aft reset chambers 240 causes the aft barrel
assemblies 236 to move forward relative
to the aft pistons 234. The forward movement of the aft barrel assemblies 236
causes fluid in the aft power
chambers 242 and the aft gripper mechanism 207 to flow into the power flow
annulus 216A. This fluid then flows
into the six-way valve 306 through passage C1. Simultaneously, flow is driven
out of the forward section 200
forward reset chambers 230, into the return flow annulus 212F, and into the
six-way valve 306 through part C4.
These movements generally show the forward section 200 thrust stage or power
stroke. During this power
stroke the forward section 200 causes the three concentric cylindrical pipes
201 to move forward within the
borehole 132. Advantageously, in a preferred embodiment, this movement can be
used to force the drill bit 130 into
a formation. At the end of the forward section 200 power stroke, the six-way
valve 306 is actuated due to
pressure differences between the aft reverser valve 310 and the forward
reverser valve 312. This. pressure
differential is caused by the pressure difference between the flow leaving the
aft section 202 aft power chambers
242 and the flow entering the forward section 200 forward power chambers 232.
These flows enter the power
flow annulus 216 and flow to the forward reverser valve 312 and the aft
reverser valve 310, respectively. This
pressure differential causes the six-way valve 306 to move into position to
supply fluid to the aft section 20Z aft
power chambers 242, as shown in Figure 4.
In the position shown in Figure 4, drilling fluid flows from the central flow
channel 206 through the opening
205 through the five parallel filters 302 and into the idler startlstop valve
304. From the idler startlstop valve 304,
the drilling fluid flows into the six-way valve 306. Fluid exits the six-way
valve 306 through passage C1 where it
flaws through the power flow annulus 216A to the aft gripper mechanism 207.
The aft expandable bladder 252
of the aft gripper mechanism 207 inflates as drilling fluid flows into it from
the power flow annulus 216A. The aft
expandable bladder 252 assumes a position contacting the inner surface 246 of
the borehole 132 preventing free
relative movement between the borehole 132 and the aft expandable bladder 252.
Fluid also flows through passage
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C1, through the power flow annulus 216A and into the aft section 202 aft power
chambers 242. The pressure of
the fluid in the aft power chambers 242 pushes the aft pistons 234 forward.
The three concentric cylindrical pipes
201 are also pushed forward because the pipes 201 are connected to the aft
pistons 234.
Simultaneously, fluid is directed from the six-way valve 306, through passage
C4, and the return flow
annulus 212F, and into the forward section 200 forward reset chambers 230. The
fluid pressure in the forward
reset chambers 230 causes the forward barrel assemblies 226 to move forward
relative to the forward pistons 224.
This also causes the fluid in the forward gripper mechanism 222 and the
forward section 200 forward power
chambers 232 to flow into the power flaw annulus 216F. This fluid in the power
flow annulus 216F then flows
into the six-way valve 306 through passage C2. These movements comprise the
aft section 202 power stroke.
During this power stroke, the three concentric cylindrical pipes 201 move
forward within the borehole 132. At the
end of the aft section 202 power stroke, the forward reverser valve 312
actuates the six-way valve 306 due to
pressure differences between the forward reverser valve 312 and the aft
reverser valve 310. This activation forces
the six-way valve 306 into the position illustrated in Figure 3. This cyclic
movement between the positions of Figure
3 and Figure 4 continues until the tool 112 is stopped. Preferably, the tool
112 is stopped by decreasing the
pressure of the drilling fluid in the central flow channel 206 to create a
differential pressure below the predetermined
set-point such that the idler startlstop valve 304 is not activated.
Detailed Structure of the Forward and Aft Sections
Figures 5-17 provide a more detailed view of the structure of a preferred
embodiment of the present
invention. As best seen in Figures 5 and 6, the forward section 200 of the
pulley-thruster downhole tool 112 is
linked to the bottom hole assembly 120 or other similar equipment by a
connector 502. The connector 502 is
preferably a pin connector which readily allows connection of the tool 112 to
a variety of different types of
equipment. Most preferably, the pin connector 502 includes a plurality of
threads 501 which allows threaded
connection of the tool 112 to the bottom hate assembly 120 and other known
equipment. The pin connector 502
can withstand a large amount of torque to ensure a secure connection of the
tool 112 to the bottom hofe.assembly
120. The other end of connector 502 is coupled to the three concentric
cylindrical pipes 201. As described above,
the three concentric cylindrical pipes 201 include the innermost cylindrical
pipe 204 which defines the central flow
channel 206. The second or middle cylindrical pipe 210 surrounds the innermost
cylindrical pipe 204 at a distance
from the innermost cylindrical pipe 204, defining the first flow channel or
return flow annulus 212F. The outer
cylinder pipe 214 surrounds the second cylindrical pipe 210 at a distance from
the second cylindrical pipe 210,
defining a power flow annulus 216F. The innermost cylindrical pipe 204 has a
thickness ranging from 0.0625 to
0.500 inches, most preferably 0.085 inches. The innermost cylindrical pipe 204
can be constructed of various
materials, most preferably stainless steel. Stainless steel is used to prevent
corrosion, increasing the life of the tool
112. The innermost cylindrical pipe 204 defines a central flow channel 206
ranging in diameter from 0.6 to 2.0
inches, most preferably 1.0 inch. The second cylindrical pipe 210 has a
thickness ranging from 0.0625 to 0.500
inches, most preferably 0.085 inches. The second cylindrical pipe 210 can be
constructed of various materials, most
preferably stainless steel. The outer cylindrical pipe 214 surrounding the
second cylindrical pipe 210 can be
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.19.
constructed of various materials, most preferably high strength steel, type
4130. The outer cylindrical pipe 214 has
a thickness ranging from 0.12 to 1.0 inches, most preferably 0.235 inches.
Preferably, the connector 502 is
threadably connected to the outer cylindrical pipe 214 to allow for easy
assembly and maintenance of the tool 112.
As best seen in Figure 6, the ends of the innermost cylindrical pipe 204, the
second cylindrical pipe 210,
and the outer cylindrical pipe 214 are connected to a coaxial cylinder end
plug 504. The coaxial cylinder end plug
. 504 engages the ends of the three concentric cylindrical pipes 201 and helps
maintain the proper spacing between
the three concentric cylindrical pipes 201. As shown in Figure 6, the pin
connector 502 surrounds the and of the
outer cylindrical pipe 214 and mates with a stress relief groove 601 in the
outer cylindrical pipe 214. ft will be
appreciated that the various embodiments of the present invention are intended
for use in a wide range of
applications. Accordingly, the dimensions will vary upon the intended use of
the invention and a wide variety of
known materials may be used to construct the invention. Seal 603 is Located
between the inner surface of the outer
cylindrical pipe 214 and the coaxial cylinder end plug 504 to help prevent
fluid from escaping at the connection.
A seal loot shown) located between the inner surface of the outer cylindrical
pipe 214 and the coaxial cylinder end
plug 504 also helps prevent fluid from escaping at the connection.
The aft section 202 of the pulley-thruster downhole toot 112 is linked to
known equipment, such as the
drill string, by a connector 510. As best seen in Figure 5, the connector 510
is preferably a box connector which
allows quick connection and disconnection of the tool 112 to the drill string.
The aft section 202 of the pulier-
thruster downhole tool 112 also includes an innermost cylindrical pipe 204, a
central flow channel 206, a second
cylindrical pipe 210, a first flow channel or return flow annulus 212A, an
outer cylindrical pipe 214, and a second
flow channel or a power flow annulus 216A. The preferred dimensions and
materials are generally the same as
described above, but one skilled in the art will recognize that a wide variety
of dimensions and materials may be
utilized, depending upon the specific use of the tool 112.
As seen in Figure 5, the aft ends of the innermost cylindrical pipe 204, the
second cylindrical pipe 210,
and the outer cylindrical pipe 2i4 are attached to the connector 510. The
connector 510 preferably includes threads
503 to allow easy connection and aid in mating the connection elements. This
box connector 510 can endure a large
amount of torque, which helps ensure a secure connection and increases the
reliability of the toot 112. A coaxial
cylinder end plug 512 engages the aft ends of the innermost cylindrical pipe
204, the second cylindrical pipe 210,
and the outer cylindrical pipe 214. Seals 514 are located between the inner
surface of the outer cylindrical pipe
214 and the coaxial cylinder end plug 512 prevent fluid from escaping.
As best seen in Figures 5 and 7, a fourth cylindrical pipe or forward piston
skin 516 surrounds a portion
of the forward section of the outer cylindrical pipe 214 at a distance from
the outer cylindrical pipe 214. Positioned
between the skin 516 and the outer cylindrical pipe 214 are forward barrel
ends 522. The forward barrel ends 522
are rigidly connected to the forward piston skin 516 by means of connectors
524, such as screws. Seals 526 are
placed between the inner surface of the forward piston skin 516 and the top
surfaces of the forward barrel ends
522, and between the bottom surfaces of the forward barrel ends 522 and the
outer surface of the outer cylindrical
pipe 214 to prevent the escape of fluid from the forward fluid chamber 520.
Seals 526 are preferably graphite
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reinforced Teflon or elastomer with urethane reinforcement. The forward barrel
ends are preferably configured to
slide along the outer surface of the outer cylindrical pipe 214.
As shown in Figuro 7, a forward piston assembly 530 is also located between
the forward piston skin 516
and the outer cylindrical pipe 214. Connectors 532 attach the forward piston
assembly 530 to the outer cylindrical
pipe 214 and the second cylindrical pipe 210. Thus, the forward piston
assembly 530, which is rigidly fixed to the
outer cylindrical pipe 214, is slidably movable relative to the forward piston
skin 516. Seals 534 are located
between the inner surface of the forward piston skin 516 and the top of the
forward piston assembly 530, and
between the bottom of the forward piston assembly 530 and the outer surface of
the outer cylindrical pipe 214 to
prevent fluid from passing around the outer surfaces of the forward piston
assembly 530. The area between the
forward piston skin 516, forward piston assemblies 530, outer cylindrical pipe
214, and forward barrel ends 522
defines a forward fluid chamber 520. The forward piston assembly 530 is
located within the forward fluid chamber
520 so as to divide the forward fluid chamber 520 into a forward section 536
and an aft section 540. The forward
section 536 is in fluid communication with the return flow annulus 212F. A
port liner 505, preferably constructed
of steel, finks the return flow annulus 212F and the forward section 536 of
the forward fluid chamber 520 to
prevent the flow of fluid iota the power flow annulus 216F. The aft section
540 is in fluid communication with the
power flow annulus 216F. A spacer plate 507 may be used to prevent the
pinching off of flow in the power flaw
annulus 216F and the return flow annulus 212F.
A fourth cylindrical pipe or aft piston skin 570 surrounds a portion of the
aft section of the outer cylindrical
pipe 214 at a distance from the outer cylindrical pipe 214. Positioned between
the aft piston skin 570 and the
outer cylindrical pipe 214 are aft barrel ends 574. The aft barrel ends 574
are rigidly connected to the aft piston
skin 570 by connectors 524. Seals 526 are placed between the inner surface of
the aft piston skin 570 and the
top surfaces of the aft barrel ends 574, and between the bottom surfaces of
the aft barrel ends 574 and the outer
surface of the outer cylindrical pipe 214 to prevent the escape of fluid from
the aft fluid chamber 572. The aft
barrel ends ate preferably configured to slide along the outer surface of the
outer cylindrical pipe 214.
An aft piston assembly 576 is also located between the skin 570 and the outer
cylindrical pipe 214.
Connectors 532 attach the aft piston assembly 576 to the outer cylindrical
pipe 214 and the second cylindrical pipe
210. Thus, the aft piston assembly 576, which is rigidly fixed to the outer
cylindrical pipe 214, is slidably movable
relative to the aft piston skin 570. Seals 534 are located between the inner
surface of the aft piston skin 570 and
the top of the aft piston assembly 576 and between the bottom of the aft
piston assembly 576 and the outer
surface of the outer cylindrical pipe 214 to prevent fluid from passing around
the outer surfaces of the aft piston
assembly 576. The area between the aft piston skin 570, aft piston assemblies
576, outer cylindrical pipe 214,
and aft barrel ends 574 defines an aft fluid chamber 572. The aft piston
assembly 576 is located within the aft
fluid chamber 572 so as to divide the aft fluid chamber 572 into a forward
section 580 and an aft section 582.
The forward section 580 is in fluid communication with the return flow annulus
212A. A port liner 505 links the
return flow annulus 212A and the forward section 580 of the aft fluid chamber
572 to prevent the flow of fluid
into the power flow annulus 216A. The aft section 582 is in fluid
communication with the power flow annulus
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216A. A spacer plate (not shown) may be used to prevent the pinching off of
flow in the power flow annulus 216A
and the return flow annulus 212A.
The aft end of the forward piston skin 516 attaches to a gripper mechanism.
More specifically, the gripper
mechanism includes an expandable bladder to grip the inner surface 246 of the
borehole 132. In this preferred
embodiment the gripper mechanism is a packerfoot assembly 550 that includes an
eiastomeric body 552. As shown
in Figure 8, the aft end of the forward piston skin 516, in this preferred
embodiment, attaches to a ~packerfoot
attachment barrel end 542. The packerfoot attachment barrel end 542 surrounds
the outer surface of the outer
cylindrical pipe 214 and is slidable relative to the outer surface of the
outer cylindrical pipe 214. Tho forward piston
skin 516 is connected to the packerfoot attachment barrel end 542 by means of
a connector 544, shown in
phantom. Seals 54fi are located between the inner surface of the piston skin
516 and the top surface of the
packerfoot attachment barrel end 542, and between the bottom surface of the
packerfoot attachment barrel end 542
and the outer surface of the outer cylindrical pipe 214. These seals 546
prevent fluid from escaping from the
forward fluid chamber 520. The aft section of the packerfoot attachment barrel
end 542 contains threads 801 to
allow connection of a forward gripper mechanism 222. The forward gripper
mechanism 222 preferably consists of
an expandable bladder. More preferably, the forward gripper mechanism 222
consists of a packerfaot assembly 550.
The packerfoot assembly 550 is a gripping structure designed to engage the
inner surface 246 of the borehole t32
and prevent movement of the packerfoot assembly 550 relative to the borehole
132. The packerfoot assembly, in
the preferred embodiment, may be supplied by Oil State industries in Dallas,
Texas.
The packerfoot assembly 550 contains an efastomeric body 552 that inflates
when filled with fluid. The
elastomeric body 552 can be made of a variety of known efastomeric materials,
the preferred material being
reinforced graphite or iCevlar 49. The elastomeric body 552 attaches to the
packerfoot assembly 550 by means of
blind caps 554. The blind caps 554 are cylinders which fasten the ends of the
elastomeric body 552 to an inner
mandrel 556. The blind caps 554 are preferably made of 4130 Steel. The blind
caps 554 are attached to the inner
mandrel 556 by connectors such as set screws 560 and shear pins 562. While the
preferred embodiment of the
packerfoot assembly 550 uses set screws 560, shear pins 562, and chemical
bonding, it is possible to fasten the
blind caps 554 to the inner mandrel 556 using many fastener means known in the
art. The aft end of the inner
mandrel 556 preferably contains pads 564 located between the inner mandrel 556
and the outer cylindrical pipe 214.
The pads 564 are constructed of graphite reinforced Teflon in the preferred
embodiment, but any stable material with
a low coefficient of friction could be utilized. A connector such as a
retaining screw 566 bonds the inner mandrel
556 to the pad 564. The pad 564 enables the packerfoot assembly 550 to be
sfidably movable relative to the outer
cylindrical pipe 214. This movability allows the packerfoot assembly 550 to
slide relative to the outer cylindrical
pipe 214 as the forward piston skin 516 slides relative to the forward piston
assembly 530.
Shown in Figure 9, the inner mandrel 556 also contains fluid channels 584. The
fluid channels 584 connect
the elastomeric body 552 with the aft section 540 of the forward fluid chamber
520. The fluid channels 584 allow
fluid to flow from the power flow annulus 216F through the fluid channels 584
and into the volume between the
elastomeric body 552 and the inner mandrel 556 of the packerfoot assembly 550.
The efastomeric body 552 inflates
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to a position such that it engages the inner surface 246 of the borehole 132,
preventing free relative movement
between the elastomeric body 552 and the inner surface 246 of the borehole
132.
Figures 9 and 10 show cross sections of the packerfoot assembly 550 in the
uninflated and inflated
positions, respectively. In the uninflated position the elastomeric body 552
is located proximate the inner mandrel
556. As the aft section 540 of the forward fluid chamber 520 fills with fluid
from the power flow annulus 216F,
this fluid enters the fluid channels 584. In the preferred embodiment, ten
fluid channels 584 are located in the inner
mandrel 556. The fluid flowing in the channels 584 begins to expand the
eiastomeric body 552 to create a channel
1001 between the elastomeric body 552 and the inner mandrel 556, although a
single complete annulus or any
number of channels could be used. The preferred embodiment allows inflation
and deflation at the most effective
rate. The fluid fills the channel 1001 expanding the elastomeric body 552 to
contact the inner surface 246 of the ,
borehole 132, preventing relative movement between the inner surface 246 and
the packerfoot assembly 550, as
shown in Figure 10.
As shown in Figure 5, the aft end of the aft piston skin 570 attaches to a
packerfoot attachment barrel
end 542. The packerfoot attachment barrel end 542 is located proximate the
outer surface of the outer cylindrical
pipe 214 and is slidable relative to the outer surface of the outer
cylindrical pipe 214. The aft piston skin 570 is
connected to the packerfoot attachment barrel end 542 by means of a connector
544, shown in phantom. Seals
546 are located between the inner surface of the aft piston skin 570 and the
top surface of the packerfoot
attachment barrel end 542 and between the bottom surface of the packerfoot
attachment barrel end 542 and the
outer surface of the outer cylindrical pipe Z74. The seals 546 are preferably
Teflon-graphite composite or elastomer
with urethane reinforcement. These seals 546 prevent fluid from escaping from
the aft fluid chamber 572. The
aft section of the top portion of the packerfoot attachment barrel end 542
contains threads 801 to allow connection
of the packerfoot assembly 550.
Detailed Structure of the Valve Control Pack
As best seen in Figure 5, the valve control pack 220 is located in the center
section 203 of the. tool 112
between the forward section 200 and the aft section 202. Figures 11-13 show
enlarged views of the valve control
pack 220 and its connections to the forward and aft sections 200 and 202,
respectively. The valve control pack
220 includes an innermost flow channel or center bore 702. The forward and aft
ends of the valve control pack
220 connect to the innermost cylindrical pipe 204 by means of stab pipes 602.
The stab pipes 602 are designed
to fit within the center bore 702 and the central flow channels 206 of the
forward and aft sections 200 and 202,
to allow fluid to flow to and from the return flow annuli 212A and 212f
through valve control pack 220. The stab
pipes 602 are generally constructed of high strength stainless steel and range
in inside diameter from 0.4 to 2.0
inches, most preferably 0.6 inches. The stab pipes 602 have threads 605 on the
ends that connect to the valve
control pack 220 to ease connection and ensure a proper fit. Seals 604 and 607
are located between the outer
surface of the stab pipes 602 and the inner surface of the innermost
cylindrical pipe 204. These seals 604 and 607
are preferably constructed of metal and the seals 604 and 607 prevent fluid
from leaving the central flow channel
206 and entering the return flow annulus 27 2 or other fluid chambers within
the valve control pack 220. The valve
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control pack 220 connects to the innermost cylindrical pipe 204, the second
cylindrical pipe 210, and the outer
cylindrical pipe 214 by means of coaxial cylinder assembly flanges 6D6. A
coaxial cylinder assembly flange 606 is
bolted to the forward and aft ends of the valve control pack 220 by a
plurality of connectors 610. Seals 612
located between the coaxial cylinder assembly flanges 606 and the second
cylindrical pipe 210 prevent fluid from
entering the various passages of the valve control pack 220.
Four radially outward extending stabilizer blades 614 are preferably connected
to the front section 200 and
the aft section 202 of the pullet-thruster downhole tool 112. These stabilizer
blades 614 are used to properly
position the valve control pack 220 within the borehole 132. Preferably, the
valve control pack 220 is centered
within the borehole 132 to facilitate the return of the drilling fluid to the
surface. The stabilizer blades 614 are
preferably constructed from high strength material such as steel. More
preferably, the stabilizer blades are
constructed of type 4130 steel with an amorphous titanium coating to tower the
coefficient of friction between the
blades 614 and the inner surface 246 of the borehole 132 and increase fluid
flow around the stabilizer blades 614.
The stabilizer blades 614 are connected to the coaxial cylinder assembly
flanges 606 a plurality of fasteners, such
as bolts Inot shown in the accompanying figuresl. The stabilizer blades 614
are preferably spaced equidistantly
around the valve control pack body 616. The stabilizer blades 614 are spaced
from the valve control pack 220,
allowing fluid to exit the valve control pack 220 and flow out around the
stabilizer blades 614. This fluid then flows
back to the surface with the return fluid flow through the passage between the
inner surface 246 of the borehole
132 and the outer surface of the tool 112.
The valve control pack 220 also includes a valve control pack body 616. The
valve control pack body 616
is preferably constructed of a high strength material. More preferably, the
valve control pack body 616 is machined
from a single cylinder of stainless steel, although other shapes and materials
of construction are possible. Stainless
steel prevents corrosion of the valve control pack body 616 while increasing
the life and reliability of the tool 112.
As shown in Figure 11, the valve control pack body 616 ranges in diameter from
1 to 10 inches, preferably 3.125
inches. The valve control pack body 616 contains a number of machined bores
620. These bores 620 tNithin the
Z5 valve control pack body 616 allow fluid communication within the valve
control pack 220 and between the valve
control pack 220 and the forward and aft sections 200 and 202.
Figures 14 and 15 provide cross-sectional views of the valve control pack 220.
The center bore 702 is
located generally in the middle of the valve control pack body 616. The center
bare 702 ranges in diameter from
0.4 to 2.0 inches, most preferably 0.60 inches. The center bore 702 connects
to the central flow channel 206 by
the stab pipes 602, described above, which allow fluid communication between
the aft section 202 central flow
channel ZO6 and the forward section 200 central flow channel 206. Four
additional boreholes 704, 706, 710, and
712 are located generally equidistantly from each other along a cross section
of the valve control pack body 616.
These four bores 704, 706, 710, and 712 are generally equally spaced from the
center bore 702. These four bores
704, 706, 710, and 712 are each the same size and range in diameter from 0.25
to 2.0 inches, preferably 1.0
inches. As discussed in connection with Figure 16, valves are inserted into
each of these four bores 704, 706, 710,
and 712. While the orientation of the bores of the preferred embodiment are
described, one skilled in the art would
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know that various bore and valve configurations would produce similar fluid
flow patterns within the puffer-thruster
downhole tool 11Z.
Several other bores 620, for example, are also located within the valve
control pack body 616, allowing
fluid communication between the four bores 704, 706, 710, and 712; between the
four bores 704, 706, 710, and
712 and the center bore 702; and between the four bores 7D4, 7D6, 710, and 712
and the exterior of the valve
control pack body 616. These bores 620 are best seen in Figures 11, 14, and
15. As seen in Figure 11, far
example, these bores 620 may run generally parallel to the innermost
cylindrical pipe 204. Within the valve control
pack 220, other bores (not shown in the accompanying figures) run at various
angles relative to the innermost
cylindrical pipe 204. These bores are specifically discussed in connection
with Figure 17A.
As best seen in Figures 14 and 15, four flapper valves 714 ace located on the
exterior of the valve control
pack body 6i6 adjacent to the stabilizer blades 614. These flapper valves 714
allow fluid to be expelled from the
four bores 704, 706, 710, and 712 to the exterior of the valve control pack
220 through the ports which intersect
and run at angles relative to the four bores 704, 706, 710, and 712. These
ports are discussed in connection with
Figures 16 and 17A below. The flapper valves 714 are preferably made of
elastomeric material and are fastened
to the exterior of the valve control pack body 616 by means of fasteners 716.
This design allows fluid to escape
the valve control pack 220 while preventing fluid pressure from building up
and preventing clogging of the valve
control pack 220. Specifically, the flapper valves 714 flex away from the
outer surface of the valve control pack
body 616 to allow fluid to exhaust from the tool 112, but the flapper valves
714 wilt not allow material to enter
the tool 112. This design also minimizes the cross-sectional area of the valve
control pack 220. The crass-sectional
area of the valve control pack 220 desirably fills between 50 to 80 percent of
the cross-sectional area of the
borehole 132. More specifically, the cross-sectional area of the valve control
pack 220 most desirably fills
approximately 70 percent of the cross-sectional area of the borehole 132. This
allows fluid carrying debris to return
to the surface in the passage between the inner surface 246 of the borehoie
132 and the exterior of the tool 112
while minimizing pressure loss up the passage to the surface.
Figure 16 shows a physical representation of the valves 304, 306, 310 and 312
contained within the valve
control pack 220 and schematically shows the flows within the valve control
pack 220. The valves 304, 306, 310
and 312 fit within bores 712, 706, 710 and 704, respectively. Figure 17A shows
cross sections of the valve
control pack body 616 into which the valves 302, 306, 310, and 312 are placed.
The valves 304, 3D6 310 and
312 do not require alignment within the bores 712, 706, 710, and 704 of the
valve control pack body 616 because
of the use of recessed lands foot shown) on sleeves 901. Other known methods
for aligning the valves within the
corresponding bores may also be utilized with the present invention. Each of
the valves 304, 306, 310 and 312
can be actuated to control the fluid flow within the valve control pack 220.
As known in the art, valve actuation
alters the flow pattern through a valve by one of several known methods. The
valves of the present invention are
actuated by moving a valve body 903 relative to a fixed, nonmoving sleeve 901.
As the valve body 903 moves,
different ports, individually labeled below, in the sleeve 901 and valve body
903 align to create a flow pattern.
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Referring to Figures 12 and 13, a majority of fluid in the central flow
channel 206 enters the forward end
of the center bore 702 of the valve control pack 220 and flows through the
valve control pack 220. The fluid exits
the valve control pack 220 through the forward end of the center bore 702.
flowing toward the drill bit 130.
Part of the flow enters the tool 112 through the valve control pack 220.
Figures 16 illustrates the fluid
flow paths through the valve control pack 220. Fluid in the center bore 702 of
the valve control pack 220 can enter
the idler startlstop valve 304 through a series of filters 302, in a manner
similar to that described above and shown
in Figure 17B. The fluid leaves the five parallel filters 302 and enters a
flow channel 912 leading to the idler
startlstop valve 304. Flow channel 912 is one of the bores 620 described in
connection with Figures 11, 14, and
i5. As fluid exits the five filters 302 and enters the flow channel 912,
pressure builds up in the flow channel 912
that connects the five parallel filters 302 and the idler start(stop valve
304, as shown in Figure 16. The idler
startlstop valve 304 actuates when the differential pressure between the fluid
in the flow channel 912 and the fluid
in the idler start)stop valve 304 exceeds the pressure set-point, for example,
500 psid. The forward end of the idler
start)stop valve 3D4 contains a fluid piston assembly 914, while the aft end
of the idler start)stop valve 304
contains a Bellevue spring 916, preferably constructed of steel. The fluid
piston assembly 914 in the forward end
and the Bellevue spring 916 in the aft end of the idler startlstop valve 304
work in conjunction with each other to
activate the idler startlstop valve 304. The Bellevue spring 916 has a spring
constant such that a specific force
is required from the fluid piston assembly 914 to compress the Bellevue spring
916. This spring force is what
provides the pressure set-point of the idler start)stop valve 304. Thus, when
pressure builds up in the fluid channel
912 connecting the fluid piston assembly 914 of the idler start)stop valve 304
and the five filters 302, fluid will
ZO begin to flow into a fluid piston chamber 920 through port P101. It will be
appreciated that the spring constant
of the Bellevue spring 916 can be selected according to the intended use of
the toot 112. Further, alternate types
of springs may be used as known in the art.
Figure 17A shows the ports, individually labeled, within the valve control
pack body 616 that allow fluid
communication between the horizontal bores 620 and the valves 304, 306, 310
and 312. As the fluid piston
chamber 920 fills with fluid, a piston 922 is pushed toward the aft end of the
valve control pack 220 which pushes
the valve body 903 toward the aft end of the valve control pack 220 and
compresses the Bellevue spring 916. As
the fluid piston chamber 920 continues to fill with fluid, the Bellevue spring
916 continues to compress. The valve
body 903 moves allowing flow from flow channels, such as 912, to pass through
the sleeve 901 into a valve
chamber 905 between the valve body 903 and the sleeve 901. Fluid enters the
valve chamber 905 of the idler
startlstop valve 304 through a port P103. Thus, the idler start)stop valve 304
has both an active position in which
the Bellevue spring 916 is sufficiently compressed and an inactive position in
which the Bellevue spring 916 is not
sufficiently compressed. In the active position, fluid flows into the idler
start)stop valve 304 through port P103,
while no fluid enters when the idler startlstop valve 304 is in the inactive
position. When the idler start)stop valve
304 shifts from an active to inactive position, the Bellevue spring 916 moves
from a compressed position to an
uncompressed position forcing the piston 922 toward the forward end of the
valve control pack 220.
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Figure 16 shows that in the active position fluid flows through the five
filters 302 into the idler start/stop
valve 304. The idler start)stop valve 304 has a main fluid exit channel 924.
Fluid enters the exit channel 924
through part P105 and flows from the idler start)stop valve 304 to the aft
reverser valve 310, the six-way valve
306, and the forward reverser valve 312. Tha idler start)stop valve 304 also
contains four exit ports P107 which
allow fluid to escape from the idler startlstop valve 304 to the exterior of
the valve control pack 220 through the
flapper valves 714. These exit ports P107 allow exhaust from within the valve
304 and prevent clogging within
the valve 304. The fastener holes 980 used to attached the flapper valves 714
to the valve control pack body 616
are shown in Figure 17A.
As shown in Figure 16, fluid flows through the idler start( stop valve 304,
out port P105, and into the aft
reverser valve 310 through port P109. The aft reverser valve 310 has a fluid
piston assembly 914 at the aft end
of the valve control pack 220 and a Bellevue spring 916 at the forward end of
the valve control pack. The piston
922 of the aft reverser valve 310 is actuated by flow to the power flow
annulus 216F of the forward section 200
of the pulley-thruster downhole tool 112. This fluid flows through a flow
channel 926 and enters the fluid piston
chamber 920 through port P111. Flow channel 926 is one of the bores 620 shown
in Figures 11, 14, and 15.
Thus, fluid flows from the forward section 200 power flow annulus 216F into a
flow channel 926 which connects
to the piston chamber 920 through a port P111. Pressure in flow channel 926
causes fluid to fill the fluid piston
chamber 920 of the aft reverser valve 310. As the fluid piston chamber 920
fills, a piston 922 is pushed forward
pushing the valve body 903 forward compressing the Bellevue spring 916. The
valve body 903 moves forward
relative to the fixed sleeve 901 allowing flow from flow channels, such as
924, to pass through the sleeve 901 into
a valve chamber 905 between the valve body 903 and the sleeve 901. Thus, the
aft reverser valve 310 has both
an active position in which the Bellevue spring 916 is sufficiently compressed
and an inactive position in which the
Bellevue spring 916 is not sufficiently compressed. In the active position,
fluid flows into the aft reverser valve 310
from the idler start)stop valve 304 through port P109, while no fluid enters
when the aft reverser valve 310 is in
the inactive position.
In the active position, fluid exits the aft reverser valve 310 through port
P113 into exit channel 930 leading
to the six-way valve 306. The aft reverser valve 310 also contains four exit
ports P107 which allow fluid to escape
from the valve control pack 220 to the exterior of the valve control pack 220
through the flapper valves 714. The
exit ports P107 allow removal of fluids and reduces the tendency for plugging
by contamination. When the aft
reverser valve 310 shifts from an active to inactive position, the Bellevue
spring 916 moves from a compressed
position to an uncompressed position, forcing the piston 922 toward the aft
end of the valve control pack 220. As
the piston 922 moves toward the aft end of the valve control pack 220, the
fluid in the fluid piston chamber 920
drains out of the chamber 920 through port P141, into a drain channel 932, and
into the passage between the valve
control pack 220 and the inner surface 246 of the barehole 132 through an
orifice 934. The orifice 934 controls
the rate of fluid exiting the fluid piston chamber 920 through the drain
channel 932. Advantageously, the system
is designed to continue to operate even if the drain channels should be
partially or completely plugged. This
increases the reliability and durability of the tool 112.
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The six-way valve 306 contains fluid piston assemblies 914 at both the forward
and aft ends which work
in conjunction with each other to control the flow of fluid. As fluid from the
aft reverser valve 310 enters the fluid
chamber 920 at the aft end of the six-way valve 306 from channel 930 through
port P115, the piston 922 pushes
the valve body 903 forward relative to the fixed sleeve 901. As the valve body
903 moves forward the fluid
chamber 920 at the aft end fills and fluid drains from the fluid chamber 920
at the forward end out port P117
through drain channel 936. This fluid flows through the drain channel 936,
past the orifice 940, and into the
passage between the valve control pack 220 and the inner surface 246 of the
borehole 132. Conversely, as fluid
from the forward reverser valve 312 enters the fluid chamber 920 at the
forward end of the six-way valve 306 from
a channel 942 through port P119, the piston 922 pushes the valve body 903
towards the aft end of valve control
pack 220 relative to the fixed sleeve 901. As the valve body 903 moves toward
the aft end, the fluid chamber 920
at the forward end fills, and fluid drains from the fluid chamber 920 at the
aft end out port P121 through drain
channel 944. This fluid flows through drain channel 944, past orifice 946, and
iota the passage between the valve
control pack 220 and the inner surface 246 of the borehole 132.
In the various actuated positions, fluid from the idler startlstop valve 304
flows through exit channel 924
and enters the six-way valve 306 through ports P123 and P125. Fluid also
enters and exits the six-way valve 306,
depending on the position of the valve, from the forward section Z00 power
flow annulus 216F through flow channel
926, the forward section 200 return flow annulus 212F through flow channel
952, the aft section 202 power flaw
annulus 216A through flow channel 954, and the aft section 202 return flow
annulus 212A through flow channel
956 through ports P127, P129, P131, and P133, respectively.
The six-way valve 306 contains five exit ports P707 which allow fluid to
escape from the six-way valve
306 to the exterior of the valve control pack 220 through the flapper valves
714. These exit ports P107 prevent
pressure build-up within the valve 306 and prevent clogging within the valve
306.
As shown in Figure 16, fluid flows through the idler start! stop valve 304,
out port P105, and into the
forward reverser valve 312 through port P135. The forward reverser valve 312
has a fluid piston assembly 914
at the forward end of the valve control pack 220 and a Bellevue spring 916 at
the aft end of the valve control pack.
The piston 922 of the forward reverser valve 312 is actuated by flow from the
power flow annulus 216A of the
aft section Z02 of the pulley-thruster downhole tool 112. This fluid flows
through a flow channel 954 and enters
the fiuid piston chamber 920 through port P137. Pressure in flow channel 954
causes fluid to fill the fluid piston
chamber 920 of the forward reverser valve 312. As the fluid piston chamber 920
fills, a piston 922 is pushed
toward the aft end of the valve body 903 and the Beilevue spring 916 is
compressed. The valve body 903 moves
towards the aft end relative to the fixed sleeve 901 allowing fluid flow from
flow channels, such as 954, to pass
through the sleeve 901 and into a valve chamber 905 between the valve body 903
and the sleeve 901. Thus, the
forward reverser valve 312 has both an active position in which the Bellevue
spring 916 is sufficiently compressed
and an inactive position in which the Bellevue spring 916 is not sufficiently
compressed. In the active position, fluid
flows into the forward reverser valve 3I2 from the idler startlstop valve 304
through port P135, while no fluid
enters when the forward reverser valve 312 is in the inactive position.
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In the active position, fluid exits the forward reverser valve 312 through
port P139 into exit channel 942
leading to the six-way valve 306. The forward reverser valve 31 Z also
contains four exit ports P107 which allow
fluid to escape from the valve control pack 220 to the exterior of the valve
control pack 220 through the flapper
valves 714. When the forward reverser valve 312 shifts from an active to
inactive position, the Bellevue spring 916
moves from a compressed position to an uncompressed position forcing the
piston 922 toward the forward end of
the valve control pack 220. As the piston 922 moves toward the forward end of
the valve control pack 220, the
fluid in the fluid piston chamber 920 drains out of the chamber 920 through
port P143, into a drain channel 960,
and into the passage between the valve control pack 220 and the inner surface
246 of the borehole 132 through
an orifice 962. The orifice 962 helps maintain pressure within the fluid
piston chamber 920.
The valve control pack 220 thus controls fluid distribution to the forward and
aft sections 200 and 202
of the puller-thruster downhole tool 112. Figures 16 and 17A show a preferred
embodiment illustrating the actuation
positions of the idler startlstop valve 304, the six-way valve 306, the aft
reverser valve 310, and the forward
reverser valve 312. One skilled in the art will recognize that various valve
actuations and types of fluid
communication may be utilized to achieve the flow patterns depicted in Figures
3 and 4. One skilled in the art will
also appreciate that, while the preferred embodiment of the valve control pack
is illustrated, other flow distribution
systems can be used in place of the valve control pack 220. The preferred
embodiment of the valve control pack
220 eases in-the-field maintenance. Reliability and durability increase due to
the construction and design of the valve
control pack 220.
Figure 17B provides a cross-sectional view of the valve control pack 220 with
the valves 304, 306, 310,
and 312 removed. As shown, the horizontal bores 620 in the valve control pack
body 616, which run generally
parallel to the innermost cylindrical pipe 204, are in fluid communication
with ports, for example P139. These
horizontal bores 620 and angled ports, like P139, allow fluid transfer between
the valves 304, 306, 310, and 312
and fluid transfer to the rest of the pulley-thruster downhole tool 112 as
described.
Closed System Embodiment
Using drilling mud as the operating fluid for the system has several
advantages. First, using drilling fluid
prevents contamination of hydraulic fluid and the associated failures. While
using hydraulic operating fluid may
require supply lines and additional equipment to supply fluid to the tool 112,
drilling mud requires no supply lines.
Drilling mud use increases the reliability of the tool 112 as fewer elements
are necessary and fluid contamination
is not an issue. Figures 18 and 19 show another preferred embodiment of the
present invention in which the puller-
thruster downhole tool 112 operates as a closed system. Figure 18 shows the
pulley-thruster downhole tool 112
located within a borehole 132. The system is similar to that shown in Figure
3, except that the fluid is not ambient
fluid. Preferably, the fluid in the closed system is hydraulic fluid. As in
Figure 3, Figure 18 shows the forward
section 200 in the thrust stroke and the aft section 200 in the reset stage. A
fluid system 1800 provides the fluid
in this configuration. A fluid storage tank 1801 serves as the source of fluid
to the five parallel filters 302. Fluid
is pumped from the storage tank 1801 by a pump 1802 to the five parallel
filters 302, from which it is distributed
throughout the tool 112 as in Figure 3. The pump 1802 is powered by a motor
1804. The fluid system can be
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located within the power-thruster downhole tool 112 or at the surface. Figure
19, similar to Figure 4, shows the
closed system with the forward section 200 resetting and the aft section 202
in the thrust stroke. A valve 1806,
preferably a check valve, is used to control the pressure of the fluid within
the system.
The closed system shown in Figures 18 and 19 allows the tool 112 to be
operated with a cleaner process
fluid. This reduces wear and deterioration of the tool 112. This configuration
also allows operation of the tool 112
in environments where drilling mud cannot be used as a process fluid foe
various reasons. It will be appreciated that
the fluid system 1800 can be located within the toot 112 such that the entire
device fits within the borehole 132.
Alternatively, the fluid system 1800 can be located at the surface and a line
may be used to allow fluid
communication between the tool 112 and the fluid system 1800.
Directionally Controlled System Embodiment
In another embodiment, the pulley-thruster downhole tool 112 can be equipped
with a directional control
valve 2002 to allow the tool 112 to move in the forward and reverse directions
within the borehole 132 as shown
in Figures 20-23. While the standard tool 112 can simply be pulled out of the
borehole 132 from the surface,
directional control allows the toot 112 to be operated out of the borehole 132
using the same method of operation
described above. The directional control valve 2D02 is preferably located
within the valve control pack 220. One
skilled in the art will recognize that the position of the valve 2002 within
the valve control pack 220 can vary so
long as the fluid flow paths shown in Figures 20-23 are maintained. Other than
the insertion of the directional
control valve 2002, the operation and structure of the toot 112 is generally
the same as that described in Figure
3. In operation, the directional control valve 2002 has an actuated position
and an unactuated position. The
directional control valve 2002 has a pressure set-paint, for example, 750
psid. When the differential pressure
between the fluid passing thraugh the five parallel filters 302 and the fluid
in the directional control valve 2002
exceeds the pressure set-point, the directional control valve 2002 is
actuated. Also shown are the bladder sensing
valves 2004.
Figure 20 shows the directional control valve 2002 in an unactuated position.
Fluid flows from the forward
section 20D power flow annulus 216F to the aft reverser valve 310 through the
directional control valve 2002. Fluid
also flaws from the aft section 202 power flow annulus 216A to the forward
reverser valve 312 through the
directional control valve 2002. When the directional control valve is actuated
in this position, the operation and
motion of the tool 112 within the borehole 132, as shown in Figures 20 and 21,
is the same generally as that
described in Figures 3 and 4. This causes the tool 112 to be propelled in ane
direction within the borehole 132.
It will be recognized that the directional control valve 2002 allows movement
of the tool 112 in two opposite
directions, allowing the tool to move in forward and reverse directions within
the borehole 132.
When the differential pressure exceeds the pressure set-point, the directional
control valve 2002 actuates
to the position shown in Figures 22 and 23. In this position fluid flows from
the forward section 200 power flow
annulus 216F to the forward reverser valve 312 through the directional control
valve 2002. Fluid also flows from
the aft section 202 power flow annulus 216A to the aft reverser valve 310
through the directional control valve
2002. The directional control valve 2002 reverses the destination of these
flows from the destinations shown in
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Figures 3 and 4. This causes the forward reverser valve 312 to be actuated
before the aft reverser valve 3tQ,
causing the tool 112 to move toward the other end of the borehole 132 and
opposite the direction of movement
shown in Figures 20 and 21 when the directional control valve 2002 was in the
unactuated position. This directional
control valve 2002 allows the tool 112 to he removed from the borehole 132
without any additional equipment.
The toot 112 is self-retrieving when equipped with the directional control
valve 2002. This also allows the tool 112
to move equipment and other tools away from the distal end of the barehole
132.
For reversing services, where motion of the tool is desired to be toward the
surface and away from the
bottom of the borehole 132, the directional control valve 2002 and the bladder
sensing valves 2004 are activated.
This reverses the action of the pistons 224 and 234 and causes the gripper
mechanisms 222, 207 to be activated
in the proper sequence to permit the three cylindrical pipes 201 to move
toward the surface; the reverse of the
normal direction towards the bottom of the borehole 132.
Electrically Controlled Embodiment
While the standard tool 112 is pressure controlled and activated, it may be
desirable to equip the tool 112
with electrical control lines. The standard tool 112 is pressure activated and
has a lower cost than a tool 112 with
electrical control. The standard tool has greater reliability and durability
because it has fewer elements and no wires
which can be cut as does the electrically controlled tool 112. To be
compatible with existing systems or future
system, electrical control may be required. As such, Figure 24 shows the
pulley-thruster downhole tool 112 equipped
with electrical control lines 2402. The electrical control lines 2402 are
connected to the idler startlstop valve 304
and the directional control valve 2002. In this embodiment, the idler
startlstop valve 304 and the directional control
valve 2002 are solenoid operated rather than pressure operated as in the
previously discussed embodiments. It is
known in the art that electrical controls can be used to actuate valves and
these types of equipment can also be
used with the tool 112 of the present invention. The electrical lines
typically connect to a control box, not shown,
located at the surface. Alternatively, a remote system could be used to
trigger a control box located within the
pulley-thruster downhole tool 112. Energization of the idler startlstop valve
304 would open the valve 304 and the
tool 112 would move as discussed in relation to Figures 2A-2E. Similarly, the
tool 112 could be instructed to move
in the reverse direction toward the surface by energization of the directional
control valve 2002. The directional
control valve 2002 would produce the same motion discussed in relation to
Figures 20-23.
The electrical fines 2402 would preferably be shielded within a protective
coating or conduit to protect the
electrical fines 2402 from the drilling fluid. The electrical lines 2402 may
also be constructed of or sealed with a
waterproof material, and other known materials. The electrical lines 2402
would preferably run from the control
box at the surface to the idler startlstop valve 304 and the directional
control valve 2002 through the central flow
channel 206 and the center bore 702 of the valve control pack 220. One skilled
in the art will recognize that these
electrical fines 2402 may be located at various other places within the tool
112 as desired. These electrical lines
2402 then carry electrical signals from the control box at the surface to the
idler startlstop valve 304 and the
directional control valve 2002 where they trigger the solenoid to open or
close the valve.
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Alternatively, the electrical lines 2402 could lead to a mud pulse telepathy
system rigged for down linking.
Mud pulse telepathy systems are known in the art and are commercially
available. In down linking. a pressure pulse
is sent from the surface through the drilling mud to a downhole transceiver
that converts the mud pressure pulse
into electrical instructions. Electrical power for the transceiver can be
supplied by batteries or an E-line. These
electrical instructions actuate the idler startlstop valve 304 or the
directional control valve 2002 depending on the
desired operation. This system allows direct control of the toot 112 from the
surface. This system could be utilized
with a bottom hole assembly 120 that includes a Measurement While Drilling
device 124 with down finking capability,
as known in the art.
Electrical controls can also be used with bottom hole assemblies 120 that
contain E-line (electrical line)
controlled Measurement While Drilling devices 124. These electrical controls
allow the tool 112 to be conveniently
operated from the surface. Additional E-fines could be added to the E-line
bundle to permit additional electrical
connections without affecting the operation of the tool 112.
the tool 132 can also be equipped with electrical connections on the forward
and aft ends of the tool 112
that communicate with each other. These electrical connections would allow
equipment to operate off power
supplied to the toot 112 from the surface or by internal battery. These
connections could be used to power many
elements known in the art, and to allow electrical communication between the
forward and aft ends, 200 and 202,
of the tool 112.
While the preferred embodiments of the pullet-thruster downhole toot t 12 are
described, the tool 112 can
be constructed on various size scales as necessary. The embodiment described
is effective for drilling inclined and
horizontal holes, especially oil wells.
Although this invention has been described in terms of certain preferred
embodiments, other embodiments
apparent to those of ordinary skill in the art are also within the scope of
this invention. Accordingly, the descriptions
above are intended merely to illustrate, rather than limit the scope of the
invention.
i
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APPEND1X A
Part Description
No.
100 coiled tubing drilling system
102 power supply
104 tubing reel
t06 tubing guide
11 D tubing injector
112 pulley-thruster downhole tool
114 coiled tubing
116 connector
119 working unit
120 bottom hole assembly
122 downhole motor
124 Measurement While Drilling /MWD) system
126 connector
130 drill bit
132 borehole
134 connection line
200 forward section
201 concentric cylindrical pipes
202 aft section
203 center section
204 innermost cylindrical pipe
205 opening
206 central flow channel
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Part Description
No.
207 aft gripper mechanism
210 second cylindrical pipe
212 first annulus (return flow annulus)
212A first aft annulus
212F first forward annulus
214 outer cylindrical pipe
216 second annulus (power flow annulus)
216A second aft annulus
216F second forward annulus
220 valve control pack
222 forward gripper mechanism
224 forward pistons
226 forward barrel assemblies
230 forward reset chambers
232 forward power chambers
234 aft pistons
236 aft barrel assemblies
240 aft reset chamber
242 aft power chambers
246 inner surface
250 forward expandable bladder
252 aft expandable bladder
302 five filters
304 idler startlstop valve
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Part No. Description
306 six-way valve
310 aft reverser valve ,
312 forward reverser valve
501 threads
502 connector
503 threads
504 coaxial cylinder end plug
505 port liner
507 spacer plate
510 connector
512 coaxial cylinder end plug
514 seals
516 forward piston skin
520 forward fluid chamber
522 forward barrel ends
524 connectors
526 seals
530 forward piston assembly
532 connectors
534 seals
536 forward section (of the forward fluid
chamber 520)
540 aft section (of the forward fluid chamber
520)
542 packerfoot attachment barrel end
544 connector
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Part No. Description
546 seals
i
550 packerfoot assembly
552 elastomeric body
554 blind caps
556 inner mandrel
560 set screws
562 shear pins
564 pads
566 connector
570 aft piston skin
572 aft fluid chamber
574 aft barrel ends
576 aft piston assembly
580 forward section (of the aft fluid chamber
572)
582 aft section (of the aft fluid chamber
572)
584 fluid channels
60i stress relief groove
602 stab pipes
603 seal
604 seals
605 threads
606 coaxial cylinder assembly flanges
607 seals
610 connectors
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Part No. Description
612 seals
614 stabilizer blades
616 valve control pack body
620 bores
702 center bore
704 borehole
706 borehofe
710 borehole
712 borehole
714 flapper valves
716 fasteners
80i threads
901 sleeves
903 valve body
905 valve chamber
912 flow channel
914 fluid piston assembly
916 Bellevue spring
920 fluid piston chamber
922 piston
924 channel
926 flow channel
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Part Description
No.
930 channel
932 drain channel
934 orifice
936 drain channel
940 orifice
942 channel
944 drain channel
946 orifice
952 flow channel
954 flow channel
956 flow channel
960 drain channel
962 orifice
980 fastener holes
1001 channel
1800 fluid system
1801 fluid storage tank
1802 pump
1804 motor
1806 valve
2002 directional control valve
2004 bladder sensing valves
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Part No. Description
2402 electrical control lines
P101 port
P103 port
Pf 05 port
P107 exit ports
P109 port
P11 f port
P113 port
P115 port
P117 port
Pll9 port
P121 port
P123 port
P125 port
Pf 27 port
P129 port
P131 port
P133 port
P135 port
P137 part ,
P139 port
P141 port
P143 port
