Note: Descriptions are shown in the official language in which they were submitted.
=
ELECTRONIC RELEASE TOOL
Background of the Invention
11] Generally, when completing a subterranean well for the production of
fluids, minerals, or gases
from underground reservoirs, several types of tubulars are placed downhole as
part of the drilling,
exploration, and completions process.
[2] These tubulars can include casing, tubing, pipes, liners, and
devices conveyed downhole by
tubulars of various types. Each well is unique, so combinations of different
tubulars may be lowered into
a well for a multitude of purposes.
[3] A subsurface or subterranean well transits one or more formations. The
formation is a body of
rock or strata that contains one or more compositions. The formation is
treated as a continuous body.
Within the formation hydrocarbon deposits may exist. Typically a wellbore will
be drilled from a surface
location, placing a hole into a formation of interest. Completion equipment
will be put into place,
including casing, tubing, and other downhole equipment as needed. Perforating
the casing and the
.. formation with a perforating gun is a well known method in the art for
accessing hydrocarbon deposits
within a formation from a wellbore.
[4] Explosively perforating the formation using a shaped charge is a
widely known method for
completing an oil well. A shaped charge is a term of art for a device that
when detonated generates a
focused explosive output. This is achieved in part by the geometry of the
explosive in conjunction with
an adjacent liner. Generally, a shaped charge includes a metal case that
contains an explosive material
with a concave shape, which has a thin metal liner on the inner surface. Many
materials are used for the
liner, some of the more common metals include brass, copper, tungsten, and
lead. When the explosive
detonates the liner metal is compressed into a super-heated, super pressurized
jet that can penetrate metal,
concrete, and rock. Perforating charges are typically used in groups. These
groups of perforating charges
are typically held together in an assembly called a perforating gun.
Perforating guns come in many styles,
such as strip guns, capsule guns, port plug guns, and expandable hollow
carrier guns.
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[5] Perforating charges are typically detonated by detonating cord in
proximity to a priming
hole at the apex of each charge case. Typically, the detonating cord
teiminates proximate to the
ends of the perforating gun. In this arrangement, a detonator at one end of
the perforating gun
can detonate all of the perforating charges in the gun and continue a
ballistic transfer to the
opposite end of the gun. In this fashion, numerous perforating guns can be
connected end to end
with a single detonator detonating all of them.
[6] The detonating cord is typically detonated by a detonator triggered
by a firing head. The
firing head can be actuated in many ways, including but not limited to
electronically,
hydraulically, and mechanically.
1171 Expendable hollow carrier perforating guns are typically manufactured
from standard
sizes of steel pipe with a box end having internal/female threads at each end.
Pin ended adapters,
or subs, having male/external threads are threaded one or both ends of the
gun. These subs can
connect perforating guns together, connect perforating guns to other tools
such as setting tools
and collar locators, and connect firing heads to perforating guns. Subs often
house electronic,
mechanical, or ballistic components used to activate or otherwise control
perforating guns and
other components.
[81 Perforating guns typically have a cylindrical gun body and a charge
tube, or loading tube
that holds the perforating charges The gun body typically is composed of metal
and is
cylindrical in shape. Within a typical gun tube is a charge holder designed to
hold the shaped
charges. Charge holders can be foimed as tubes, strips, or chains. The charge
holder will contain
cutouts called charge holes to house the shaped charges.
[91 Many perforating guns are electrically activated. This requires
electrical wiring to at
least the firing head for the perforating gun. In many cases, perforating guns
are run into the
well in strings where guns are activated either singly or in groups, often
separate from the
activation of other tools in the string, such as setting tools. In these
cases, electrical
communication must be able to pass through one perforating gun to other tools
in the string.
Typically, this involves threading at least one wire through the interior of
the perforating gun and
using the gun body as a ground wire.
[10] Perforating guns and other tools are often connected lowered or conveyed
downhole
while connected to the surface using a wireline. When pulling the tool back to
the surface the
tool string may get stuck in the borehole. If too much tension is introduced
to the wireline it may
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fail with a part of the cable falling back into the borehole. Then a fishing
tool must be used to
grab the loose wireline and pull it back out. This may cause further failures
and requires more
use of a fishing tool. All of the wireline must be removed before a retrieval
tool, such as an
overshot style or wash-over style tool, can be used to pull the gun string out
itself. This
procedure of fishing out the tool may be costly and requires extensive time at
the wellsite along
with specialized tools.
[11] Releasable tools currently in use may include explosive tools, which use
a small booster
type explosive to shear a neck, and shear bolts that fail at a predesigned
point to allow the
wireline to be pulled out of the well intact when a tool string is stuck.
Issues with explosive tools
may include regulatory issues, transportation issues with the explosive, and
the safety concerns
of having to pull a live explosive from the wellbore every time the tool
string is brought to the
surface. Issues with shear bolts is that they may not always fail as designed
and an expensive tool
may be unnecessarily lost or stuck in the wellbore as a result, or the
wireline may still fail
because the shear bolts do not function properly.
3
.. =
Summary of Example Embodiments
[12] An example embodiment may include an apparatus for joining and
releasing downhole tools
having a first cylindrical portion housing a motor coupled to a super nut,
wherein the super nut converts
rotation motion into a set linear travel from a first stop to a second stop,
an indicator switch coupled to the
super nut, wherein the indicator switch can detect if the super nut has
reached the first stop or the second
stop, a second cylindrical portion located downhole of, and proximate to, the
first cylindrical portion
housing a push rod coupled to a collet, wherein the push rod is further
coupled to the super nut, the collet
further comprising a first conical portion and a second conical portion
connected by a cylindrical body,
wherein a tapered end of the first conical portion and a tapered end of the
second conical portion face
towards each other, at least one collet arm pivoting about a pin located
within the second cylindrical body
and having a rocker arm with a first contact area, a second contact area, and
a lever grip, in which the first
contact area is located proximate to the first conical portion, the second
contact area is located proximate
to the second conical portion, and the pivot point is located in between the
first conical portion and the
second conical portion of the collet.
[13] A variation of the example embodiment may include screw coupling the
motor to the super nut.
It may have a plurality of bearings on the screw. The at east one collet arm
may be a plurality of collet
arms located evenly about the center axis of the collet. It may include at
least one collet cutout in the
second cylindrical portion corresponding to the at least one collet arm. It
may include a feed thru
connector coupled to the second cylindrical portion and an umbilical
electrical cord connected to feed
thru connector. It may include a guide cutout within the first cylindrical
portion, having the first stop and
second stop, for the indicator switch to travel along. It may include a third
cylindrical portion that slides
over the second cylindrical portion, having an umbilical cord slot and a
plurality of pressure equalizing
vents. The super nut may be restricted from rotating and is free to slide
axially.
[14] An example embodiment may include a release tool for use in tool
strings in oil wells having a
drive unit including a motor and a super nut adapted to translate the super
nut axially in response to
rotation of the motor, a collet assembly including a plurality of collet arms
pivotably affixed to a collet
housing and a tapered inner collet shaft, a sensor adapted to detect the
position of the super nut at both
extremities of its axial movement, in which the axial translation of the super
nut translates the tapered
inner collet shaft axially and the axial translation of the inner
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collet shaft in one direction opens the collet arms and in the other direction
closes the collet
arms. It may further include any or all of a screw coupling the motor to the
super nut, a plurality
of bearings on the screw, a collet housing encompassing the collet assembly,
at least one collet
cutout in the second cylindrical portion corresponding to the at least one
collet arm, a detachable
umbilical electrical cord passing proximate to the collet assembly, and a feed
thru pin at each end
of the umbilical electrical cord. The super nut may be a linear actuating nut
that is restricted from
rotating axial and free to move linearly. It may include a cylindrical outer
housing that slides
over the collet housing, having an umbilical cord slot and a plurality of
pressure equalizing
vents. It may include an indicator switch coupled to the super nut, in which
the indicator switch
can detect when the super nut has reached either of the axial extremities of
its axial movement.
The plurality of collet arms may further include at least one collet arm
pivoting about a pin
located within the second cylindrical body and having a rocker arm with a
first contact area, a
second contact area, and a lever grip at the end of the collet arm. The first
contact area and the
second contact area of the rocker arm shaped collet arm may be located
proximate to, and
mechanically engaged with the collet shaft.
.. [15] An example embodiment may include an apparatus for joining and
releasing downhole
tools having a first cylindrical portion housing a linear actuator that
provides linear actuation
from a first stop to a second stop, an indicator switch coupled to the linear
actuator, wherein the
indicator switch can detect when the linear actuator has reached the first
stop or the second stop,
a second cylindrical portion located downhole of, and proximate to, the first
cylindrical portion
housing a push rod coupled to a collet, in which the push rod is further
coupled to the super nut,
the collet further including a first conical portion and a second conical
portion connected by a
cylindrical body, wherein the slant of the first conical portion and the
second conical portion face
towards each other, at least one collet arm pivoting about a pin located
within the second
cylindrical body and having a rocker arm with a first contact area, a second
contact area, and a
lever grip, in which the first contact area is located proximate to the first
conical portion, the
second contact area is located proximate to the second conical portion, and
the pivot point is
located in between the first conical portion and a the second conical portion
of the collet.
[16] A variation of the example embodiment may include a screw coupling the
motor to the
super nut and a plurality of bearings on the screw. The at least one collet
arm may be a plurality
of collet arms located evenly about the center axis of the collet. It may
include at least one collet
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cutout in the second cylindrical portion corresponding to the at least one
collet arm. It may
include an umbilical electrical cord connected to the second cylindrical
portion using a feed thru
connector. It may include a guide slot in the first cylindrical portion for
the indicator switch to
travel along. It may include a third cylindrical portion that slides over the
second cylindrical
portion, having an umbilical cord slot and a plurality of pressure equalizing
vents. The linear
actuator may include a motor coupled to a super nut, in which the super nut
converts rotation
motion into a linear travel.
[17] An example embodiment may include a method for joining and releasing
downhole tools
including aligning a releasable tool with a quick change sub, activating a
motor in a first
direction to capture the quick change sub with a plurality of arms, detecting
the travel of the
plurality of arms, and confirming that the plurality of arms have traveled
sufficiently to lock the
releasable tool to the quick change sub. It may further include lowering the
releasable tool into a
wellbore. It may include pulling up on the releasable tool while it is in the
wellbore. It may
include activating the motor in a second direction to release the plurality of
arms from the quick
change sub. It may include detecting the travel of the plurality of arms when
releasing the quick
change sub. It may include confirming that sufficient travel of the plurality
of arms has occurred,
wherein the releasable tool is fully released from the quick change sub. It
may include removing
the releasable tool from the wellbore. It may include lowering a retrieving
tool into the borehole
to retrieve the quick change sub and any tool string located downhole of and
couple to the quick
change sub.
[18] An example embodiment may include a releasable tool system including a
first
cylindrical housing comprising a motor coupled to a super nut, in which the
super nut converts
rotation motion into a set linear travel from a first stop to a second stop,
an indicator switch
coupled to the super nut, in which the indicator switch can detect when the
super nut has reached
the first stop or the second stop, a second cylindrical housing located
downhole of, and
proximate to, the first cylindrical portion housing a push rod coupled to a
collet, wherein the
push rod is further coupled to the super nut, the collet further having a
first conical portion and a
second conical portion connected by a cylindrical body, in which the slant of
the first conical
portion and the second conical portion face towards each other, at least one
collet arm pivoting
about a pin located within the second cylindrical body and having a rocker arm
with a first
contact area, a second contact area, and a lever grip, in which the first
contact area is located
6
proximate to the first conical portion, the second contact area is located
proximate to the second conical
portion, and the pivot point is located in between the first conical portion
and the second conical portion
of the collet, a cylindrical quick change sub with a narrow neck portion
located within the second
housing, in which the lever grip of the at least one collet arm engages with
the narrow neck portion.
[19] The example embodiment may include one or more of the following, a
screw coupling the motor
to the super nut, a plurality of bearings on the screw, at least one collet
cutout in the second cylindrical
portion corresponding to the at least one collet aim, an umbilical electrical
cord connected to the second
cylindrical portion using a feed thru connector, a guide cutout in the first
cylindrical portion for the
indicator switch to travel along, a third cylindrical portion that slides over
the second cylindrical portion,
having an umbilical cord slot and a plurality of pressure equalizing vents, an
electronic housing with an
electronics board located proximate to and uphole from the first cylindrical
housing, or at least one or
more perforating guns coupled downhole from and proximate to the quick change
sub. The at least one
collet arm may be a plurality of collet arms located evenly about the center
axis of the collet. The
releasable tool may be conveyed downhole on a wireline.
119A1 In a broad aspect, the present invention pertains to a release tool for
use in tool strings in oil wells
comprising a drive unit including a motor and a super nut adapted to translate
the super nut axially in
response to rotation of the motor. A collet assembly includes a plurality of
collet arms pivotably affixed
to a collet housing and a tapered inner collet shaft, and a sensor is adapted
to detect the position of the
super nut at both extremities of its axial movement. The axial translation of
the super nut in a first
direction results in axially translating the tapered inner collet shaft
axially in the first direction resulting in
opening the collet arms, and axial translation of the super nut in a second
direction results in axially
translating the tapered inner collar shaft axially in the second direction
resulting in closing the collet arms.
[19B] In a further aspect, the present invention embodies a method for joining
and releasing downhole
tools. The method comprises equalizing the pressure within a releasable tool,
aligning the releasable tool
with a quick change sub, and activating a motor in a first direction to engage
the releasable tool with the
quick change sub with a plurality of arms. The method detects engagement of
the plurality of arms to
lock the releasable tool to the quick change sub, releases the quick change
sub, detects the plurality of
arms is not fully engaged, and detects the plurality of arms is fully
disengaged.
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Brief Description of the Drawings
[20] For a thorough understanding of the present invention, reference is made
to the following
detailed description of the preferred embodiments, taken in conjunction with
the accompanying
drawings in which reference numbers designate like or similar elements
throughout the several
figures of the drawing. Briefly:
FIG. 1 depicts an exploded view of an assembly of an example embodiment.
FIG. 2 depicts a side view of an assembly of an example embodiment.
FIG. 3A depicts an underside view of a collet arm.
FIG. 3B depicts an over the top view of a collet arm.
FIG. 4 depicts an exploded view of an indicator switch assembly.
20
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Detailed Description of Examples of the Invention
[21] In the following description, certain terms have been used for
brevity, clarity, and
examples. No unnecessary limitations are to be implied therefrom and such
terms are used for
descriptive purposes only and are intended to be broadly construed. The
different apparatus,
systems and method steps described herein may be used alone or in combination
with other
apparatus, systems and method steps. It is to be expected that various
equivalents, alternatives,
and modifications are possible within the scope of the appended claims.
[22] An example embodiment is shown in FIG. 1 of a release tool 100. The
collet drive
assembly 100 includes a motor 127 housed in a motor housing 104 and coupled to
a drive
housing 105. A super nut 117 is slideably engaged with the inner bore of the
drive housing 105.
The drive housing 105 has a guide slot 128, a guide block 116 is secured to
the super nut 117 via
screws 115. The uphole end of the guide slot 128 acts as a first stop,
indicating the super nut 117
has bottomed out in the uphole direction. The downhole end of the guide slot
128 acts as a
second stop, indicating that the super nut 117 has bottomed out in the
downhole direction. The
super nut 117 is prevented from rotating due to the guide block 116 acting in
the guide slot 128
and it can move laterally, bound by the first stop and the second stop of
guide slot 128. The drive
housing 105 has a second slot, not shown, that allows indicator switch 106 to
be coupled to the
super nut 117. The super nut 117 has internal fine threads 129 on one side and
internal course
threads 130 on the opposite side. The drive housing 105 couples to the collet
sub 119. The collet
sub has two cutouts 157 adapted to allow the installation of collets 113.
Retaining cover 114
slides over collet sub 119. The retaining cover 114 has an umbilical slot 132
and pressure
equalizing vents 133. A push rod 124 has a first end having exterior fine
threads 134 adapted to
thread into the internal fine threads 129 of super nut 117. The push rod 124
has a second end
having threads 135 for engaging to the inner threads of the collet 125. 0-
rings 118 are used to
seal the electronics in the outer housing of the electronics module. Feed thru
pin 120 connects to
an electrical connection within the collet sub 119 and allows an umbilical
wire to run from the
feed thru pin 120, along the umbilical slot 132, and into another feed thru
pin not shown in this
FIG. 1. The feed thru pins linked via an umbilical wire allows an electrical
connection to pass
through the collet sub 119 to additional tools further downhole in a tool
string. If the release tool
releases an attached downhole tool string then the umbilical will separate at
the feed thru pin. In
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this example embodiment there are two collet arms 113, however there may a
plurality of collet
arms of two or more.
[23] 0-rings 110 and 111 combine with screw 109 to hold the retaining cover
114 in place.
Screws 112 and 109 are used to couple the retaining cover 114 over the collet
sub 119. 0-ring
123 and backup ring 122 are coupled to the fine threaded end of the push rod
124. Retaining
screw 126 fixes collet 125 to the threads 135 of the push rod 124 to prevent
rotation The
cylindrical outer edge 160 provides a surface for the collets to positively
hold against using a
hanging end.
[24] During operation power is provided via the HP/HT connector 102, which is
sealed with
o-rings 101 and 103 into the motor housing 104. As the motor 127 spins it uses
a gear reduction
to provide low speed and high torque. The gear box has a splined output that
engages a screw
with exterior course threads. The course threads of the screw (not shown)
engage with the
internal course threads 130 of the super nut 117. As the screw turns it causes
the super nut 117 to
translate forward or backward within the drive assembly housing 105. This
lateral movement can
be detected by the indicator switch 106 that is fastened to the super nut 117
using screws 107. As
the indicator switch 106 travels in its slot in the drive assembly housing
105, it can detect
whether it has fully stopped forward, backwards, or if it is in between. This
fully stopped signal
will be used by the tool electronics to deactivate the motor 127. Fully
stopped forward, or
downhole, or the second stop, corresponds to the collet arms 113 being fully
engaged. Fully
stopped backwards, or uphole, or the first stop, corresponds to the collet
aims 113 being fully
released.
[25] The combination of super nut 117 and motor 127 acts as a linear actuator
or linear step
motor. A linear actuator operates by rotating an electric motor, which may
include a stepper
motor, and converts the rotation into linear actuation. Typically a screw from
the motor engages
a nut, the nut is then physically restrained from rotating, but allowed to
move linearly. This nut,
which is referred to as a super nut in this application, will then move
linearly in some proportion
to the number of turns of the motor as determined by the threads used to
couple the nut with the
screw and the gear reduction. The nut may be constrained with a captive shaft
screw, an external
screw, or in this case a guide block 116 screwed externally onto the nut and
sliding in a guide
slot 128. The super nut 117 is responsible for converting the rotational
torque output from the
motor 127 into a linear force to move push rod 124 uphole or downhole. The
super nut 117 has a
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flat surface 136 for mounting the guide 116 via fasteners 115. There is a
second flat surface,
located 180 degrees about the axis from the first flat surface 136, which is
mounted to the
indicator switch assembly 106, held in place via fasteners 107. Fasteners 108
secure the super
nut 117 fine threads 129 to the fine threads 134 of the push rod 124. The
movement of the super
nut 117 causes lateral movement in the push rod 124, which causes movement in
the collet 125.
.. As the collet 125 moves downhole laterally, the first inner conical surface
137 pushes against the
outer angled end 138 of the collet arms 113. This downhole movement forces the
collet arms
113, which are pinned via pin 121 between the outer angled end 138 and the
inner angled end
139, to rotate inwards about the pins 121, which engages the grip ends 161
with the quick change
sub or upper body of a tool string being coupled to the release tool 100.
Uphole movement of the
collet 125 will cause the second inner conical surface 131 to engage the inner
angled ends 139 of
the collets 113, thereby causing the collets 113 to rotate outwards about the
pins 121,
corresponding to the collet arms being released. This release action
disengages the grip ends 161
from the quick change sub or upper portion of a tool string coupled downhole
from the release
tool 100.
[26] An example embodiment is depicted in FIG. 2 showing a side cross section
view of an
assembled release tool 100. Top sub 146 is coupled to electronic housing 144.
Electronics board
145 is located within the electronic housing 144. An electrical contact pin
147 provides an
electrical signal through the top sub 146 and into the electronic housing 144.
The metal exterior
of the electronic housing 144 and all of the other exterior metallic portions
provide the ground
.. for any electrical signals. Connecting sub 151 couples the electronic
housing 144 with the motor
housing 142. The motor 127 is located within the motor housing 144. The motor
127 is coupled
to the screw 143 via a spline interface. The bearings 141 hold the screw 143
in place. Screw 143
is coupled to the super nut 117 via coarse threads 130. As the motor 127 turns
it causes the super
nut to move laterally within the bore 152. Push rod 124 is threaded into the
super nut 117 via fine
.. threads 129. Push rod 124 is coupled to collet 125. Collet 125 causes the
collet arms 113 to pivot
or rotate inward or outward about pin 121.
[27] Still referring to FIG. 2, when the motor 127 spins, it causes the
collet 125 to move
laterally downhole or uphole. When the collet 125 moves upwards, or uphole, or
left in FIG. 2,
the second inner conical surface 131 engages with the inner angled end 139 of
the collet arms
113, causing the collet arm 113 to rotate outwards about the pin 121. When the
collet 125 moves
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downwards, or downhole, or right in FIG. 2, the first inner conical surface
137 pushes against the
outer angled end 138, causing the collet arms 113 to rotate inwards about pin
121. Movement
downhole by the collet 125 will cause the end of the collet arms 113 to lock
against the
cylindrical surface 160, thus creating positive locking that prevents the
collet arms 113 from
releasing while the collet 125 is in its furthest downhole position. As the
collet arms 113 rotate
inward, the grip ends 161 engage with the neck 153 of the quick change sub
148. The guide
block 116 can be seen mounted to a flat surface 136 of the super nut 117 and
slideably engaged
with the guide slot 128. The indicator switch 106 can be seen engaged to a
flat surface 155 and
slideably engaged with the guide slot 156. The uphole end, or left side, of
guide slots 136 and
155 correspond to a first stop, or fully released collet arms 113. The
downhole end, or right side,
of the guide slots 136 and 155 correspond to a second stop, or fully engaged
collet arms 113.
[28] An umbilical 140 provides an electrical connection around the collet
mechanism and is
engaged on either end by feed thru connections 120. An electrical contact 150
in sub 149
provides the continuity of the electrical signal to subsequent downhole tools,
such as perforating
guns. The umbilical connection is breakable if the release tool must release
the collet arms 113.
[29] Referring to FIG. 3A, the collet arm 200 has a thru hole 201 for a pin to
rotate about. The
grip end 205 is a raised portion, cylindrical portion that is stepped from the
partial cylindrical
main body 206 The grip end 205 is adapted to engage the neck portion of a
quick change sub
The outer angled end 207 is adapted to engage a conical portion of a collet
and rotate the collet
arm 200 inwards about the thru hole 201. The inner angled end 208 is adapted
to engage a
conical portion of a collet and rotate the collet arm 200 outwards about the
thru hole 201. The
hanging end 202 slips over a collet and provides positive locking force with
the collet arms fully
rotated inwards and engaged against a quick change sub neck. The hanging end
202 hangs over
the edge of a conical portion of a collet where the collet has a cylindrical
surface. The fillet
portion 203 allows the edge of the collet arm 200 to slide into the cutouts of
the collet sub.
[30] Referring to FIG. 3B, the collet arm 200 has a thru hole 201 for a pin to
rotate about. The
grip end 205 is a raised portion, cylindrical portion that is stepped from the
partial cylindrical
main body 206 The grip end 205 is adapted to engage the neck portion of a
quick change sub
The outer angled end 207 is adapted to engage a conical portion of a collet
and rotate the collet
arm 200 inwards about the thru hole 201. The upper cylindrical portion 204 is
substantially the
same radius as the collet sub, allowing the collet aim 200 to fit inside the
cutouts and maintain
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the outer cylindrical dimensions of the collet sub. The hanging end 202 slips
over a collet and
provides positive locking force with the collet arms fully rotated inwards and
engaged against a
quick change sub neck. The hanging end 202 hangs over the edge of a conical
portion of a collet
where the collet has a cylindrical surface. The fillet portion 203 allows the
edge of the collet arm
200 to slide into the cutouts of the collet sub.
[31] An example embodiment of an indicator switch assembly 300 is shown in FIG
4. The
main body 301 houses the spring loaded indicator switch. The switch assembly
can detect
contact on two ends. The first end has a spring plunger 304, located with an L-
bracket 303, with
a solder lug 305 being held against the L-bracket 305 by nut 306. The second
end has a spring
plunger 308, located with an L-bracket 307, with a solder lug 309 being held
against the L-
bracket 307 by nut 310. Screws 302 couple the L-brackets 303 and 307 to the
main body 301. As
the switch assembly 300 slides down a switch slot in the drive assembly
housing, the switch
assembly 300 will detect when it has bottomed out on the downhole side of the
slot,
corresponding to the collet arms being fully engaged with the quick change
sub. If it detects
bottoming out on the uphole side of the slot, this corresponds to the collet
arms being fully
released from the neck of the quick change sub. If neither plunger 304 or 308
is in contact then
the operator of the tool will know that the collet is somewhere in the middle
between fully
released and fully engaged Whether the collet arms are fully engaged or
partially engaged will
inform the operator on how to attempt to retrieve the tool string. Spring
plunger 304 screws into
hole 313. Holes 312 are used to couple the indicator switch assembly 300 to a
super nut on a
linear actuator. Screws 302 screws into holes 311.
[32] One of the potential benefits in using an electronically releasable
tool is that an operator
does not have to break a wireline connection when pulling up on a stuck tool
and then fish out
the broken wireline. Instead, the operator could simple decide to release the
tool based on the
amount of tension already in the wireline, without shearing any component. The
releasable tool
can then release from the stuck tool string, thus preserving the wireline.
Afterwards a retrieve
tool, such as an overshot style fishing tool (a tool that grabs the stuck
tool) or wash-over tool (a
pipe that covers a portion or all of the stuck tool string) as examples, may
be used to retrieve the
stuck tool string. Since the operator will have a positive signal from the
indicator switch that the
collet arms are fully engaged, fully disengaged, or neither, the operator will
be able to make a
more informed decision on how to remove a stuck tool string.
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[33] Although the invention has been described in terms of embodiments which
are set forth
in detail, it should be understood that this is by illustration only and that
the invention is not
necessarily limited thereto. For example, terms such as upper and lower or top
and bottom can be
substituted with uphole and downhole, respectfully. Top and bottom could be
left and right,
respectively. Uphole and downhole could be shown in figures as left and right,
respectively, or
.. top and bottom, respectively. Generally downhole tools initially enter the
borehole in a vertical
orientation, but since some boreholes end up horizontal, the orientation of
the tool may change.
In that case downhole, lower, or bottom is generally a component in the tool
string that enters the
borehole before a component referred to as uphole, upper, or top, relatively
speaking. The first
housing and second housing may be top housing and bottom housing,
respectfully. Terms like
wellbore, borehole, well, bore, oil well, and other alternatives may be used
synonymously.
Terms like tool string, tool, perforating gun string, gun string, or downhole
tools, and other
alternatives may be used synonymously. The alternative embodiments and
operating techniques
will become apparent to those of ordinary skill in the art in view of the
present disclosure.
Accordingly, modifications of the invention are contemplated which may be made
without
departing from the spirit of the claimed invention.
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