Note: Descriptions are shown in the official language in which they were submitted.
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Actuation System for an Oilfield Tubular Handling System
Field of the Invention
The present invention relates to an oilfield tool assembly and, in particular,
to an
actuation system for use during oilfield tubular string handling.
Background of the Invention
During oilfield drilling and borehole completion operations tubular strings
may be
handled in the form of a drill string, a casing string or a liner string for
drilling and/or
lining the borehole, etc. To grip a tubular and the tubular string, a tubular
gripping
tool may be used. In some operations, such as casing drilling and/or casing
running,
tubular gripping tool in the form of a casing clamp may be used to grip the
string at its
upper end.
A tubular gripping tool may be connected for manipulation by a top drive or
other
device, the entire assembly being suspended in a rig or derrick by a draw
works, if
desired.
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Tubular gripping tools may include gripping means that engage the tubular
being
handled. Gripping means may include, for example, devices that mechanically or
frictionally engage the tubular including, for example, slips, jaws, packers,
expandable members, etc., catch devices that hook under a shoulder on the
tubular
being handled, such as elevators, etc. and/or other members that exert a
mechanical or
physical force or field on the tubular to engage it. Tubular gripping tools
may also
include spears, which are intended to extend into the bore of a tubular being
handled.
An external gripping tool may include a spear positioned to extend into a
tubular
being handled and surrounded by gripping means that engage an outer surface of
the
tubular, while the spear is inserted into the inner diameter of the tubular.
An inside
gripping clamp may include a spear with gripping means thereon, such that when
the
spear extends into the bore of a tubular being handled the gripping means arc
positioned for engagement of the inner wall of the tubular.
An example of an inside gripping clamp is described in US Patent no. 6,742,584
of
Appleton, and assigned to the present assignee TESCO Corporation. An example
of
an external gripping clamp is described in US Patent no. 6,311,792 of Scott,
which is
also assigned to the present assignee.
A spear of a tubular gripping clamp may carry various tubular handling
mechanisms.
For example, a spear may include a seal thereabout which is selected to engage
and
create a seal against the inner diameter of the tubular being handled. During
operation, drilling fluid, commonly called mud and which can be liquid or gas-
based,
is pumped down through the spear and the seal creates a seal against the inner
diameter to maintain fluid pressure in the tubular string. The seal generally
is passive
and operates against a pressure differential.
In a well control incident, it may be desirable to shut in the well, including
sealing the
upper end of the tubular string. If such an incident occurs during the use of
a gripping
clamp, well control may be achieved by reliance on the seal about the clamp's
spear.
As a next step, or where a failure of the passive seal is encountered, it may
be
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desirable to support the tubular string in the floor of the derrick/rig and to
remove the
casing clamp from the tubular, such that the tubular string can be capped. In
a
situation where both the draw works and the spear seal fail, the well may be
very
difficult to control. In such a situation, a blow out preventer may be useful
for
carriage on the spear.
In addition or alternatively, a spear may carry other tubular handling
mechanisms
including for example, launching systems, such as for plug launching or tool
release
apparatus.
For spear-carried tubular handling mechanisms, such as a well control system
or a
launching system, an actuation system may be required to control the operation
of the
system. Because the tubular handling mechanism is carried on the spear, it may
be
necessary that at least a portion of the actuation mechanism be carried on the
spear.
Because the spear is often a rotating part, actuation mechanisms for spear-
carried
tubular handling mechanisms can add to the complexity of tubular handling
systems.
Summary of the Invention
In accordance with one aspect of the present invention, there is provided an
actuation
system for a tubular handling mechanism of a tubular handling assembly, the
actuation system comprising: a mud flow path passing through rotating parts
and non-
rotating parts of the tubular handling assembly; a valve assembly including a
valve
seat in the mud flow path and a ball, the valve seat positioned to be in
hydraulic
driving communication with the tubular handling mechanism; and a ball drop
assembly including an opening to the mud flow path through which the ball is
released and wherein the ball drop assembly opening is positioned in a non-
rotating
part.
In accordance with another broad aspect of the present invention, there is
provided an
oilfield tubular handling system for manipulating tubulars comprising: a
vertically
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movable power drive assembly for providing rotary movement; a longitudinally
extending output shaft rotatably turned about its longitudinal axis by the
power drive
assembly and movable vertically therewith; a pipe gripping mechanism coupled
to
and driven by the output shaft, the pipe gripping mechanism having a lower end
selected to grip and rotate an end of the tubular segment; a mud line
connected to the
vertically moveable power drive assembly; a mud flow path flowing through the
mud
line, the power drive assembly, the longitudinally extending output shaft and
then
through the pipe gripping mechanism; a valve seat positioned in the mud flow
path to
create a high pressure condition upstream of the valve seat; and a ball drop
assembly
selected to release a ball to seat on the valve seat and positioned to release
the ball to
the mud flow path upstream of the longitudinally extending output shaft.
It is to be understood that other aspects of the present invention will become
readily
apparent to those skilled in the art from the following detailed description,
wherein
various embodiments of the invention are shown and described by way of
illustration.
As will be realized, the invention is capable for other and different
embodiments and
its several details are capable of modification in various other respects, all
without
departing from the spirit and scope of the present invention. Accordingly the
drawings and detailed description are to be regarded as illustrative in nature
and not as
restrictive.
Brief Description of the Drawings
Referring to the drawings wherein like reference numerals indicate similar
parts
throughout the several views, several aspects of the present invention are
illustrated
by way of example, and not by way of limitation, in detail in the figures,
wherein:
Figure 1 is a schematic illustration of a hydraulic actuation system installed
in a
tubular handling assembly.
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Figure 2 is a schematic illustration of a blow out preventer assembly on an
installed
tubular gripping tool and including a hydraulic actuation system.
Figure 3 is an axial section along a tubular gripping tool including a primary
seal and
a backup expandable seal, with the left hand side showing the backup seal in a
non-
expanded condition and the right hand side showing the backup seal in an
expanded
condition.
Figure 4 is an axial section along a portion of a tubular gripping tool
including a
primary seal and a backup expandable seal, with the left hand side showing the
backup seal in a non-expanded condition and the right hand side showing the
backup
seal in an expanded condition.
Figures 5A and 5B are axial sections through a ball launch assembly useful in
the
present invention.
Description of Various Embodiments
The detailed description set forth below in connection with the appended
drawings is
intended as a description of various embodiments of the present invention and
is not
intended to represent the only embodiments contemplated by the inventor. The
detailed description includes specific details for the purpose of providing a
comprehensive understanding of the present invention. However, it will be
apparent
to those skilled in the art that the present invention may be practiced
without these
specific details.
Referring to Figure 1, an oilfield tubular handling system 1 is shown for
manipulating
tubulars and which includes an actuator system. The oilfield tubular handling
system
includes a vertically movable power drive assembly 3, a longitudinally
extending
output shaft 4, a pipe gripping mechanism 5, a mud line 6 and an actuation
system
including a valve seat 7 and a ball drop assembly 8.
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The power drive assembly 3 is operable to provide rotary drive to various
parts of the
tubular handling system including longitudinally extending output shaft 4 and
pipe
gripping mechanism 5. In particular, output shaft 4 is rotatably turned about
its
longitudinal axis x by, and is movable vertically with, the power drive
assembly. Pipe
gripping mechanism 5 is coupled to and driven by the output shaft. The pipe
gripping
mechanism has a lower end 5a selected to grip and rotate an end of a tubular
segment
14.
Mud line 6 is connected to power drive assembly 3 and acts as a conduit for a
mud
flow to the power drive assembly. In particular, mud line 6 forms part of a
mud flow
path flowing from a supply, first through the mud line, then through a passage
3a of
the power drive assembly, through a passage 4a of the longitudinally extending
output
shaft and then through the a passage 5b through pipe gripping mechanism 5.
An actuator system for actuating a tubular handling mechanism 9 is also
provided.
The actuator includes valve seat 7 positioned in the mud flow path useful to
catch a
ball 8a released from ball drop assembly 8 to create a high pressure condition
upstream of the valve seat. The ball drop assembly is selected to release a
ball to seat
on the valve seat. To facilitate and simplify the handling, operation and
construction
of the tubular handling system, the ball drop assembly is positioned in a non-
rotating
portion of the tubular handling system. During operation, the power drive
assembly
will drive output shaft 4 and pipe gripping mechanism 5, which is secured to
the
output shaft, to rotate. Thus, at least a portion of the power drive assembly
and the
mud line will be non-rotating portions of the tubular handling system. As
such, the
ball drop assembly may be positioned to release ball 8a to the mud flow path
upstream of passage 4a of output shaft 4. To avoid the complexity of the power
drive
assembly, it may be useful to install the ball drop assembly upstream of the
power
drive assembly wash pipe/swivel 3b. In the illustrated embodiment, ball drop
assembly 8 is positioned in a portion of the mud line, commonly known as the
Kelly
hose 6a. Seat 7 may be positioned anywhere along passages 3a, 4a, 5b or in a
tool
connected therebelow, but for actuation of many tubular handling mechanisms,
will
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generally be positioned in passages 4a or 5b. As such, ball 8a is sized to
pass through
the ID of all of the mud lines 6, and through any necessary passages 3a, 4a
and 5b to
reach and land in seat 7.
As will be appreciated, ball 8a may be a ball, a dart, a plug or other device
that can
pass through the mud flow path to reach seat 7, but is selected, as by sizing
and
material selection, to be stopped by and sealed against the seat. It is to be
understood
that a ball drop assembly can operate in many different ways, for example, by
various
mechanisms that may not be adversely affected by normal drilling or tubular
running
operations and conditions, but may be actuated automatically or manually,
directly or
remotely when a ball is to be released. Assembly 9 may include a port to load
one or
more balls to a holding area and may include remotely or directly operated
handles,
gates or valves, remotely or directly actuated solenoids, etc.
While various ball launch assemblies may be of use in the present invention,
one
useful ball launch assembly is illustrated in Figures 5a and 5b to facilitate
understanding. In this illustrated embodiment, assembly includes a body 160
for
positioning inline in a stand pipe or kelly hose. Body 160 includes a bore 162
therethrough for placement in communication with the mud flow path arrow A. A
ball launching housing 164 is sized to accommodate a ball 166 in a ball
holding area
168, which can be loaded through a port 170. Ball holding area 168 is open to
bore
162, but is configured to retain ball 166 until it is desired that the ball be
launched into
bore 162 and, thereby, into mud flow path. In the illustrated embodiment, the
ball is
injected into bore 162 by a launch mechanism including a plunger 172.
The ball launch assembly of the presently illustrated embodiment also includes
a
purge and flush mechanism to facilitate injection and operation of the
assembly. In
particular, the ball launch assembly includes a valve 174 and a purge outlet
176.
While valve 174 is normally open to permit flow from inlet end 162a to outlet
end
I 62b of the bore, the valve may be selected to open inlet end 162a to purge
outlet 176
to permit a purge flow through bore 162, the valve and the purge outlet to
clear the
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bore of fluids, such as cement, that may adversely affect injection of ball
166 or to
initiate the flow of a second fluid behind the ball. The illustrated ball
launch
assembly also includes a flushing feature including a flushing channel 176
between
bore 162 and ball holding area 168, through which a flushing fluid flow, arrow
F, may
be passed to clean area 168.
The ball drop assembly and the ball seat may be part of an actuation system
for an
oilfield tubular handling mechanism 9. The oilfield tubular handling mechanism
may
take various forms and serve various purposes. In one embodiment, for example,
the
actuation system may serve to release a component, such as a plug, a cement
float, a
drop bar, a used portion which is no longer of use, from the gripping device
into a
tubular being handled. In another embodiment, the oilfield tubular handling
mechanism may be a hydraulically operated component such as a seal, a tool
release,
etc. The actuating system may operate as by use of any of a pressure
communicating
port, a piston, a sliding sleeve, a valve, shear pins, etc. In the illustrated
embodiment,
for example, tubular handling mechanism 9 includes a part 9a intended to be
released
from lower end 5a of the pipe gripping mechanism when it is desired to release
the
part. In the illustrated embodiment, tubular handling mechanism 9 includes a
sliding
sleeve 9b on which seat 7 is positioned. Sleeve 9b may be conveyed by a high
pressure condition, as is caused by ball 8 landing in seat 7, to break shear
pins 9c,
positioned to hold part 9a, such that the part is released from the pipe
gripping
mechanism and can pass down into the tubular.
Referring to Figure 2, a tubular handling system is shown including a tubular
handling
mechanism in the form of a blow out preventer assembly 10 for operating
between a
spear 22 of a tubular gripping tool, such as a casing clamp 12 of the external
gripping
type, as shown, or internal gripping type (Figure 3), and a tubular 14 gripped
capable
of being gripped by gripping means 15 on the clamp 12. Clamp 12 may be
connected
for manipulation by a power drive assembly, such as for example, a top drive
16 or
other device. The entire assembly of top drive 16 and clamp 12 may be
suspended in
a rig or derrick 18 by a draw works 20.
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A mud flow path may be defined by lines and pipes 21a, commonly termed a
standpipe 28 and a kelly hose, on the rig extending between a mud supply and
the top
drive, a passage through the top drive 21b and an axial bore 21c through the
clamp
that opens at an end of a clamp spear 22 disposed in the tubular, when a
tubular is
gripped. The mudflow path provides that drilling fluid can be pumped from a
mud
supply to the tubular. A passive seal 19 may be mounted about the spear to act
against fluids migrating up between the spear and the tubular during normal
operations.
In a well control incident such as a well kick or other pressure surge from
the
formation, it may be desirable to shut in the well, including sealing the
upper end of
the tubular string. If such an incident occurs during the use of an inside
gripping
clamp and the passive seal about the clamp and the draw works fails, the blow
out
preventer assembly 10 can be operated to create a seal between the clamp and
the
tubular inner wall, to in effect seal the upper end of the tubular string.
The blow out preventer assembly may include an expandable seal 23 carried on
the
tubular gripping tool, the seal being expandable to seal between the tool and
the
tubular's inner wall. Seal 23 is not normally driven out into engagement with
the
inner wall of the tubular, but only when it is necessary to contain a surge
from the
formation. The seal may be selectively expandable, for example, by a hydraulic
drive. A hydraulic drive may be provided, for example, by means of a system
according to the present invention.
In the embodiment of Figure 2, for example, expandable seal 23 may be mounted
between a retainer and a piston 26 and can be driven by applying hydraulic
pressure
against piston 26 such that it is driven against the seal to cause it to
extrude
outwardly. The actuator system for driving the piston may include a ball drop
mechanism 24a including a ball 24b that is sized to pass from mechanism 24a
through
the mud flow path to a ball valve seat 24c to cause a seal in bore 21c through
the
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clamp. Seat 24c is positioned in bore 21c downstream of a port 25
communicating
hydraulic pressure to the piston. In this position, a ball launched to seal
against the
seat can be used to increase the fluid pressure against the piston to drive it
against seal
23.
Ball drop mechanism 24a is positioned upstream of any rotating parts including
the
clamp and the top drive. In this embodiment, the ball drop mechanism is
positioned
in a standpipe 28 adjacent the rig floor, which facilitates access thereto.
The ball 24b
is sized to pass through the ID of all of the mud flow lines 21a, through the
top drive
passage 21b and through axial bore 21c of the clamp spear to reach seat 24c.
As will be appreciated, ball 24b may be a ball, a dart, a plug or other device
that can
pass through the mud flow path, but is selected, as by sizing and material
selection, to
be stopped by and sealed against the seat. A ball drop mechanism can operate
in
many different ways, for example, by various mechanisms that may not be
adversely
affected by normal drilling or tubular running operations and conditions, but
may be
actuated automatically or manually, directly or remotely when a ball is to be
released.
Mechanisms may include, remotely or directly operated handles, gates or
valves,
remotely or directly actuated solenoids, etc.
Thus, the embodiment of Figure 2 provides a method for shutting in a well
during use
of a tubular gripping tool and when it remains with its spear positioned in
the upper
end of a tubular string extending into the well, which may occur during a well
incident and when the passive seal of the clamp fails and the draw works
cannot be
operated to remove the clamp from the end of the tubing string. The method can
include expanding an clamp spear expandable seal, such as seal 23, which is
positioned about a spear for example spear 22 of the tubular gripping tool to
create a
seal between the spear and the inner diameter of the tubular string, thereby
to seal the
upper end of the tubular string.
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The expandable seal may be expanded by a drive system that can be actuated
selectively when it is desired to expand the seal. Various drive mechanisms
may be
useful, such as an arrangement that uses drilling mud to drive expansion, as
in Figures
2, or a system using another form of hydraulic pressure.
It may be useful to test the operation of the seal, since it may only be used
occasionally, but when used may be of great importance. In a test, for
example, it
may be useful to conduct a flow test wherein a ball 24b is pumped from its
release
point to ensure that it can pass to seat without being obstructed.
With reference to Figure 3, another tubular handling system is shown including
tubular handling mechanism in the form of a blow out preventer assembly. In
Figure
3, the blow out preventer is installed on an inside gripping clamp 112. Clamp
112
may be used for gripping an oilfield tubular 114 and may include an end 139
formed
for connection to a top drive or other means for manipulating and/or
suspending the
clamp in a rig. Clamp 112 may include a spear 122 sized to extend into the
bore of
the tubular to be gripped, gripping slips 140, or other gripping means,
positioned on
the spear and drivable to engage the tubular to be gripped, a bore 121 through
the
clamp and its spear through which drilling fluid can pass into the tubular and
a
primary seal 142 about the spear to create a seal between the spear the inner
wall of
the tubular. Primary seal 142 may be expandable in response to an at least
operationally generated fluid pressure differential in the tubular. Clamp 112
may
further include a secondary seal 123 about the spear which is selectively
operable to
create a seal between the spear the inner wall of the tubular and, therefore,
may be
operated as a blow out preventer as a back up to primary seal 142. An enlarged
view
of the portion of the clamp about the primary and secondary seals is shown in
Figure
4.
As will be appreciated, clamp 112 may include any or all of the various
additional
parts shown in the illustrated embodiment such as a stabbing guide, a mud
saver
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valve, a tubular stop flange, etc. Slips 140 and the drive system for the
slips may take
various forms, including those forms illustrated,
In normal operation of clamp 112, spear 122 is inserted into a tubular bore to
grip the
tubular during connection to or break out from a tubular string. When spear
122 is
inserted into a tubular, primary seal 142 may seal against the inner wall of
the tubular
to contain drilling fluids in the tubular. In this normal operation, secondary
seal 123
is maintained in a non-expanded condition such that it remains spaced from or
not
actively sealed against the tubular inner wall. This is shown in the left hand
quarter
sections of Figures 3 and 4.
Should a back up for primary seal 142 be necessary, seal 123 can be expanded
to seal
against the tubular inner wall.
Although many drive systems are possible, the drive system illustrated in
Figures 3
and 4, acts by release of a ball 124c from a ball drop mechanism positioned in
a non-
rotating part of the top drive or mud lines somewhere upstream of a seat 124d
in bore
121. Ball 124c may be pumped with the drilling mudflow into the clamp to seal
against seat 124b so that mud pressure can be used to inflate the seal.
Seal 123, as in the illustrated embodiment, may be an extrudable ring packer
mounted
between a fixed retainer ring 150 and a piston ring 124a, shown as a two-part
arrangement including a piston face 152. Piston face 152 may be open in a
hydraulic
chamber 154 in fluid communication with bore 121. Piston ring 124a may be
secured
in position by one or more shear pins 156. Shear pins 156 may be selected to
prevent
movement of piston 124a under normal pressures but to permit movement when
fluid
pressures in excess of a selected rating are applied against face 152. An
example of
normal operational pressure where the packer would not be activated is 3,000
psi. In
this case the shear pins may be set to actuate at 3,500 to 3,750 psi. A
ratchet
arrangement 158 may be disposed between spear 122 and piston ring 124a to lock
the
piston into its pressure driven, energized position.
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As noted, pressures sufficient to shear pins 156 may be applied by landing a
ball 124c
against seat 124d such that pressure can be increased above the ball. This
increased
pressure may be communicated, arrows P. to chamber 154 and against face 152.
Induced movement of piston 124a causes seal 123 to extrude out, arrow E,
between
the piston and retainer 150.
The various parts of the tubular handling system and actuator system may be
made of
materials, and with methods, conducive to use in the oilfield industry, as
will be
appreciated.
The previous description of the disclosed embodiments is provided to enable
any
person skilled in the art to make or use the present invention. Various
modifications
to those embodiments will be readily apparent to those skilled in the art, and
the
generic principles defined herein may be applied to other embodiments without
departing from the spirit or scope of the invention. Thus, the present
invention is not
intended to be limited to the embodiments shown herein, but is to be accorded
the full
scope consistent with the claims, wherein reference to an element in the
singular, such
as by use of the article "a" or "an" is not intended to mean "one and only
one" unless
specifically so stated, but rather "one or more". All structural and
functional
equivalents to the elements of the various embodiments described throughout
the
disclosure that are know or later come to be known to those of ordinary skill
in the art
are intended to be encompassed by the elements of the claims. Moreover,
nothing
disclosed herein is intended to be dedicated to the public regardless of
whether such
disclosure is explicitly recited in the claims. No claim element is to be
construed
under the provisions of 35 USC 112, sixth paragraph, unless the element is
expressly
recited using the phrase "means for" or "step for".
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