Information
-
Patent Grant
-
6712146
-
Patent Number
6,712,146
-
Date Filed
Friday, November 30, 200122 years ago
-
Date Issued
Tuesday, March 30, 200420 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Bagnell; David
- Collins; G M
Agents
-
CPC
-
US Classifications
Field of Search
US
- 175 320
- 166 651
- 166 377
- 166 2426
- 166 2427
- 166 664
-
International Classifications
-
Abstract
A disconnect assembly connecting two portions of a downhole assembly having a downhole apparatus attached to a coiled tubing string. The disconnect assembly includes a first housing connected to one portion of the downhole assembly and a second housing connected to another portion of the downhole assembly. The housings are releasably connected by a release assembly. The release assembly is coupled to a drive train on a motor by a connection transferring rotational motion into translational motion. The release assembly includes locking members having a connected position engaging both housings and a released position wherein the housings can be separated. The motor is connected to the surface by conductors extending through the coiled tubing whereby the motor may be actuated from the surface to move the release assembly between the connected and disconnected positions.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
Not Applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a releasable connection for a downhole assembly and more particularly to a releasable connection connecting a downhole tool to a coiled tubing string and still more particularly to a connection electrically actuated from the surface to disengage the coiled tubing string from a stuck downhole drilling tool or bottom hole assembly (BHA).
2. Description of the Related Art
Increasingly, the drilling of oil and gas wells is no longer a matter of drilling a vertically straight bore hole from the surface to the desired hydrocarbon zone. Rather, technology and techniques, such as directional drilling, have been developed to drill deviated, lateral or sometimes upwardly sloping boreholes. It is often not economically feasible or practical to use jointed drill pipe in extended reach wells. Therefore, tools and methods have been developed for drilling bore holes using coiled tubing, which may include one or more lengths of continuous, unjointed tubing spooled onto reels for storage in sufficient quantities to exceed the maximum length of the borehole. The coiled tubing may be metal coiled tubing or, using more current technology, composite coiled tubing.
In well drilling applications, a BHA, having various components, such as a downhole motor, steering assembly, and bit, is connected to the end of a coiled tubing string for drilling the borehole. Circumstances can arise in which it is desirable to disconnect the tubing string from the BHA, such as, for example, when the BHA gets stuck in the borehole during drilling and the tubing string must be disconnected from the BHA in order to facilitate fishing, jarring, or other operations for retrieving the BHA.
In using jointed pipe for drilling, torque can be applied to the threaded connections to actuate traditional disconnect means to disconnect the BHA. However, when using continuous tubing, such as metal or composite coiled tubing, torque can not be applied to disconnect the tubing string from the BHA, and an axial disconnection means must be utilized. Pre-installation of one or more axial release devices between the tubing string and the BHA assembly can provide a means to disconnect the coiled tubing string downhole if and when disconnection becomes necessary.
A variety of axial disconnect means have been used to disconnect a coiled tubing string, some of which use hydraulic or electrical lines that extend from the surface to the disconnect means to actuate a piston and cause release. One such device, described in U.S. Pat. No. 5,984,006, includes an emergency release tool that can electrically release coiled tubing from one or more downhole tools. The release tool includes a releasable slip forced against the coiled tubing by a loading nut. The coiled tubing is released by sending an electrical signal to a downhole release means. Once activated, the release means forces a piston upward until the piston engages a slip housing. The slip housing is coupled to the loading nut. The release means continues to force the piston and, consequently, the slip housing upward to separate the loading nut from the releasable slip, thereby disengaging the releasable slip from the coiled tubing.
Another such means, described in U.S. Pat. No. 5,323,853, includes redundant releasing mechanisms depending alternatively on either hydraulic or electrical actuation of a piston. The additional lines and cables, which run inside the well bore that are required to actuate the release, have the disadvantage of creating an obstruction to fluid flow during normal drilling operations.
Another type of known release means depends for actuation on directing fluid flow so as to create backpressure and actuate a piston. U.S. Pat. No. 5,718,291 describes one such release mechanism that depends for actuation on either the use of backpressure created by flow through the mechanism, or if flow is prevented, the use of built-up pressure within a passage in the mechanism. In the first mode, backpressure created by flow through a restrictor above a shiftable sleeve overcomes a biasing spring to move the sleeve through a J-slot assembly until a passage is obstructed. Thereafter, pressure buildup in a second passage overcomes a shear pin, causing a piston to move and release dogs that lock two segments of the mechanism together. If flow is prevented, pressure buildup in the second passage causes the piston to move against the shifting sleeve to overcome the force of the spring and selectively move the sleeve through the J-slot assembly. A disadvantage of this release mechanism is that aligning the sleeve properly to engage the top of the J-slot assembly is cumbersome, requiring that pressure be created and removed by turning pumps on and off from the surface.
Still another conventional release device depends for actuation on dropping a ball into a well from the surface, sealing a flow passage, and building up pressure behind the ball to cause a disconnection. One such ball-drop release device is described in U.S. Pat. No. 5,419,399 and includes a housing with a slideable piston disposed within and releasably connected to the housing by shear screws. A ball is dropped into the well from the surface to seat with the upper end of the piston and block the flow passage, thereby creating pressure on a mandrel of the piston sufficient to overcome the shear screws. The mandrel moves downward such that keys align to fit into annular grooves on the mandrel to disengage notches, allowing the tubing to be disconnected from the drilling apparatus. A disadvantage of this device is that the operator must pull back or agitate the device to cause the keys to drop into the grooves should they fail to do so.
A further ball-drop release device is described in U.S. Pat. No. 5,526,888 and includes an upper and lower housing insertably connected and locked together by latch blocks, a slotted piston that operates the latch blocks, a pilot piston, and a lock-out mechanism operated by movement of the pilot piston. A sealing ball is dropped into the well and seats with the pilot piston to create a pressure differential sufficient to overcome shear pins, thereby allowing the pilot piston to axially shift downward. Movement of the pilot piston releases a lock-out mechanism such that the slotted piston extends axially to retract the latch blocks and thereby disconnect the upper and lower housings.
The present invention overcomes the deficiencies of the prior art.
SUMMARY OF THE INVENTION
The disconnect assembly of the present invention connects two portions of a downhole assembly having a downhole apparatus attached to a coiled tubing string. The disconnect assembly includes a first housing connected to one portion of the downhole assembly and a second housing connected to another portion of the downhole assembly. The housings are releasably connected by a release assembly. The release assembly is coupled to a drive train on a motor by a connection transferring rotational motion into translational motion. The release assembly includes locking members having a connected position engaging both housings and a disconnected position disengaging one of the housings. The motor is connected to the surface by conductors extending through the coiled tubing whereby the motor may be actuated from the surface to move the release assembly between the connected and released positions.
One embodiment features a selectively actuated disconnect assembly comprising: an outer housing; an inner housing having a cavity and disposed within the outer housing; a locking assembly disposed within the cavity for releasably locking the inner housing with the outer housing; an electrically actuatable power source housed in the cavity for actuating the locking assembly; a drive train coupled to the power source; and a connection coupling the locking assembly with the drive train for engaging and disengaging the locking assembly. In one embodiment of the invention, the disconnect assembly is disposed in a downhole assembly having a bottom hole assembly attached to a coiled tubing with conductors extending to the surface to an electric motor selectively actuatable from the surface; a lead screw having first and second ends and being coupled at the first end to the electric motor; a lead sleeve coupled to the first end of the lead screw and connected to a release shaft by a universal joint, the release shaft having an exterior surface with annular grooves and a plurality of locking pins disposed in transverse bores in the inner housing with one end disposed in the release shaft grooves in the unlock and released position and another end disposed in internal grooves about the outer housing in the locked and connected position.
The present invention also includes methods of disengaging a bottom hole assembly from coiled tubing, a method comprising: actuating an electric motor via a command signal; rotating a lead screw that is coupled to the electric motor and to a release shaft; axially moving the release shaft a distance sufficient to align grooves on the release shaft with the inner ends of radially extending pins, and moving the release shaft to cam the other ends of the pins out of the outer housing grooves.
In one embodiment of the present invention, the disconnect assembly used to release a portion of the downhole assembly above a stuck point. The disconnect assembly of the present invention is most useful in coiled tubing drilling operations. A plurality of these disconnect assemblies can be deployed at different positions in the downhole assembly. This allows selective actuation of one or more of the disconnect assemblies in the downhole assembly to release that disconnect assembly which is the closest to the stuck point, thereby minimizing the length of the downhole assembly to be fished out, greatly increasing the chance of a successful fishing operation, and minimizing the damages to the BHA components during fishing.
A feature of the invention is that the disconnect assembly has a common electrical and mechanical connection. Further, the disconnect assembly is selectively reconnectable. This allows an operator to activate the disconnect assembly in an attempt to remove the downhole assembly. If the downhole assembly remains stuck despite the disconnect assembly having been activated, the stuck point for the downhole assembly is likely up-hole from the disconnect assembly. The operator can signal the disconnect to reconnect. The operator can then activate a disconnect assembly up-hole from the initially activated disconnect assembly. Another feature of the invention is that it does not use a taper wedge lock mechanism, which is a simple and common employment for this type of application. However, a taper wedge lock tends to seize up and become self-locking after a long period of down hole vibration in drilling, which makes release operation difficult, if not impossible. The disconnect assembly of the present invention utilizes locking pins and a release shaft. Being round in geometry, it minimizes the chance of being self-locking to prevent release.
Thus, the present invention comprises a combination of features and advantages which enable it to overcome various deficiencies of prior devices. The various characteristics described above, as well as other features, will be readily apparent to those skilled in the art upon reading the following detailed description of the preferred embodiments of the invention, and by referring to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
For a more detailed description of the preferred embodiment of the present invention, reference will now be made to the accompanying drawings, wherein:
FIG. 1A
is a schematic view of an example well with a downhole assembly;
FIG. 1B
is an enlarged view of the bottom hole assembly shown in
FIG. 1A
;
FIG. 2
is a cross-sectional view of the composite coiled tubing of
FIGS. 1A and 1B
showing conductors in the wall of the tubing;
FIG. 3
is a longitudinal cross section of an embodiment of the disconnect assembly of the present invention in the connected position;
FIG. 4
is a cross sectional view along plane
4
—
4
in
FIG. 3
;
FIG. 5
is an enlarged view of a portion of the disconnect assembly shown in
FIG. 3
;
FIG. 5A
is an enlarged exploded view of the universal joint shown in
FIG. 5
;
FIG. 5B
is an enlarge view of the universal joint shown in
FIGS. 5 and 5A
;
FIG. 6
is a longitudinal cross-sectional view of the disconnect assembly of
FIGS. 3-5
in the released position; and
FIG. 7
is a longitudinal cross-sectional view of the disconnect assembly of
FIGS. 3-5
in the disconnected position.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention is susceptible to embodiments of different forms. There are shown in the drawings, and herein will be described in detail, specific embodiments of the present invention with the understanding that the present disclosure is to be considered an exemplification of the principles of the invention, and is not intended to limit the invention to that illustrated and described herein.
The downhole assembly of the present invention preferably includes a composite coiled tubing string attached to a bottom hole assembly. Various embodiments of the present invention provide a number of different constructions of the bottom hole assembly, each of which is used for a downhole operation in one of many different types of wells including a new well, an extended reach well, extending an existing well, a sidetracked well, a deviated borehole, and other types of boreholes. It should be appreciated that the bottom hole assembly may be only a downhole tool for performing an operation downhole in the well. Often the downhole operation relates to the drilling and completing of a pay zone in the well but the present invention is not limited to such operations. The embodiments of the present invention provide a plurality of methods for using the system of the present invention. It is to be fully recognized that the different teachings of the embodiments discussed below may be employed separately or in any suitable combination to produce desired results in a downhole operation. In particular the present system may be used in practically any type of downhole operation. Reference to “up” or “down” are made for purposes of ease of description with “up” meaning towards the surface and “down” meaning towards the bottom of the borehole. Use of the term “coupled” herein means a direct or indirect connection that can be permanent or selectively connectable. Thus, if a first device “couples” to a second device, that connection may be through a direct connection, or through an indirect connection via other devices and/or connections.
Referring initially to
FIG. 1A
, there is shown an exemplary operating environment for the disconnect assembly
10
of the present invention. At the surface, an operational system
12
includes a power supply
14
, a surface processor
16
, and a coiled tubing spool
18
. An injector head unit
20
feeds and directs coiled tubing
30
from the spool
18
into the well
22
. The downhole assembly
24
extending into the well
22
includes the coiled tubing string
26
and a bottom hole assembly
28
. The bottom hole assembly
28
is shown attached to the lower end of composite coiled tubing string
26
and extending into a deviated or horizontal borehole
32
. The lower end of the tubing string
26
may be connected to the bottom hole assembly
28
by a disconnect assembly
10
a.
Although the coiled tubing
30
is preferably composite coiled tubing, hereinafter described, it should be appreciated that the present invention is not limited to composite coiled tubing and may be steel coiled tubing with electrical conductors mounted on the steel coiled tubing. The composite tubing string
26
may include a plurality of lengths
30
a
and
30
b
of composite coiled tubing. The adjacent ends of the lengths
30
a
and
30
b
of coiled tubing
30
may be connected by the disconnect assembly
10
b
of the present invention. In the preferred embodiment described, disconnect assembly
10
c
connects one set of components making up the bottom hole assembly with another set of components of the bottom hole assembly
28
. It should be appreciated that this embodiment is described for explanatory purposes and that the present invention is not limited to a particular location in the downhole assembly. If a disconnect assembly
10
is not used to connect lengths
30
a
,
30
b
of composite coiled tubing
30
or to connect composite coiled tubing
30
to bottom hole assembly
28
, one type of alternative connector is disclosed in U.S. patent application Ser. No. 09/534,685 filed Mar. 24, 2000 and entitled “Coiled Tubing Connector.” It should be appreciated that the disconnect assembly
10
may be used in conjunction with the connector disclosed in the above identified application.
Referring now to
FIG. 1B
, there is shown one type of bottom hole assembly
28
made up of various components. Bottom hole assembly
28
has a first group of components including a bit
34
mounted on a drive shaft
36
, a bearing assembly
38
, a steering assembly
40
including an electronics section
42
and preferably a near bit orientation sensor
44
having an inclinometer and magnetometer, an upper constant velocity (CV) sub
46
, a power section
48
with wire subs, a check valve
50
, and a resistivity sub
52
. The bottom hole assembly
28
also has a second group of components including a sensor sub
54
with an orientation package, additional sensors and downhole control devices, a propulsion system
56
including a lower tractor back pressure control module
58
, a lower tension/compression sub
60
, pressure measurement sub
62
, an upper tractor back pressure control module
64
, an upper tension/compression sub
66
, and a supervisory sub
68
.
Disconnect
10
releasably connects the first and second groups of components of bottom hole assembly
28
and in particular releasably connects the bit
34
, steering assembly
40
and power section
48
with the propulsion system
56
. If a disconnect
10
is not used to connect composite coiled tubing
30
to bottom hole assembly
28
, one type of alternative connector is a flapper ball drop release
70
. See for example U.S. patent application Ser. No. 09/504,569 filed Feb. 15, 2000 and entitled “Recirculatable Ball-Drop Release Device for Lateral Oilwell Drilling Applications”, hereby incorporated herein by reference.
It should be appreciated that other tools may be included in the bottom hole assembly
10
. The tools making up the bottom hole assembly
10
will vary depending on the operation to be conducted downhole. It should be appreciated that the present invention is not limited to a particular bottom hole assembly and other alternative assemblies may also be used. Further it should be appreciated that the disconnect
10
may be used to connect any two groups of components making up the bottom hole assembly
28
.
Referring now to
FIG. 2
, the coiled tubing
30
making up the string
26
preferably includes a tube made of a composite material and includes an impermeable fluid liner
72
, a layer of glass fiber
74
, a plurality of conductors around the liner
72
and glass layer
74
including power conductors
76
,
78
embedded in a protective resin
80
, a plurality of load carrying layers
82
forming a carbon fiber matrix, a wear layer
84
, a layer of polyvinylidene fluoride (PVDF)
86
, and an outer wear layer
88
formed of glass fibers. Impermeable fluid liner
72
is an inner tube preferably made of a polymer, such as polyvinyl chloride or polyethylene, or any other material which can withstand the chemicals in the drilling fluids to be used in drilling the well
22
and the temperatures to be encountered downhole. The inner liner
72
is impermeable to fluids and thereby isolates the load carrying layers
74
from the drilling fluids passing through the flow bore
89
of liner
72
. The load carrying layers
82
are preferably a resin fiber having a sufficient number of layers to sustain the required load of the string
26
suspended in fluid, including the weight of the string
26
and bottom hole assembly
28
. The fibers of load carrying layers
82
are preferably wound into a thermal setting or curable resin. Load carrying fibers
82
provide the mechanical properties of the string
26
. The wear layer
84
is preferably the outermost load carrying layer
82
and may be a sacrificial layer. Although only one wear layer
84
is shown, there may be additional wear layers as required. The PVDF layer
86
is impermeable to fluids and isolates the load carrying layers
82
. The outer wear layer
88
is preferably the outermost layer of fiber and is a sacrificial layer. Composite coiled tubing is also described in U.S. patent application Ser. No. 09/081,961 filed May 20, 1998 and entitled “Well System”, hereby incorporated herein by reference.
The power conductors
76
,
78
housed within the composite tubing wall extend along the entire length of composite coiled tubing string
26
and are connected to bottom hole assembly
28
. Conductors
76
,
78
are connected to power supply
14
and to surface processor
16
. Their downhole ends are connected to an electronics package in the bottom hole assembly
28
. The conductors
76
,
78
provide both power and command signals to the bottom hole assembly
28
. Further data may also be communicated through the conductors
76
,
78
.
Referring now to
FIGS. 3 and 4
, there is shown a disconnect assembly
10
having an inner housing
90
and an outer housing
92
. Inner housing
90
includes a threaded connection
94
for threaded engagement with the first grouping of BHA components and an electrical connection
96
for electrical connection to the first grouping of BHA components. A plurality of flow paths
95
, best shown in
FIG. 4
, extend through the longitudinal length of inner housing
90
for the flow of drilling fluids. Outer housing
92
includes a threaded connection
98
for threaded engagement with the second grouping of BHA components and an electrical connection
100
for electrical connection to the second grouping of BHA components. The electrical connections are electrically connected to conductors
76
,
78
in the wall of the composite tubing string
26
with conductors passing through passageways
101
extending longitudinally through the wall
128
of inner housing
90
. Outer housing
92
includes uphole and downhole sections
92
a
,
92
b
threadingly connected at
102
to facilitate the assembly of housing
92
with inner housing
90
. Outer housing
92
also has a pair of longitudinally spaced internal circumferential grooves
91
,
93
on its inside diameter. Internal locking grooves
91
,
93
have a rounded cross-section providing a camming surface. Inner housing
90
includes an upper fishing neck
106
having an electrical connector
108
making electrical connection with an electrical connector
112
mounted in the uphole section
92
b
of outer housing
92
. Inner housing
90
releasably couples with outer housing
92
, preferably via involute splines
104
. Splines
104
transmit any torque transferred between inner and outer housings
90
,
92
.
Referring now to
FIG. 5
, inner housing
90
further includes an axially extending longitudinal cavity
110
with a reduced diameter uphole portion forming a bore
114
. The uphole end of the bore
114
terminates at a transverse aperture
116
in alignment with plugged ports
118
a
,
118
b
in outer housing
92
. The uphole bore
114
forms a downwardly facing annular shoulder
122
. A medial reduced diameter portion of cavity
110
forms a reduced diameter cavity
120
disposed between bore
114
and the remainder
124
of cavity
110
. Reduced diameter cavity
120
forms an annular shoulder
121
. A plurality of transverse bores
126
extend from bore
114
through the outer wall
128
of inner housing
90
.
A release assembly
130
is disposed within inner housing
90
and includes a plurality of locking pins
132
engaging a release shaft
134
. Locking pins
132
are disposed in inner housing
90
by retainers
136
threaded into transverse bores
126
. Release shaft
134
has its uphole end slidably received in reduced diameter bore
114
and its downhole end connected by a connection
135
, hereinafter described, to a drive train
140
attached to an electric motor
138
housed in cavity
110
, hereinafter described. Release shaft
134
has a longitudinally extending, elongated slot
142
therein which receives a guide pin
144
mounted in the wall
128
of inner housing
90
to prevent relative rotation between release assembly
130
and inner housing
90
.
Each locking pin
132
has an inner and an outer end
146
and
148
, respectively, and extends radially from release shaft
134
towards outer housing
92
, best shown in FIG.
4
. Release shaft
134
further comprises external circumferential release grooves
150
alignable with the inner pin ends
146
in the release position shown in
FIG. 6
whereby locking pins
132
are received in release grooves
150
. External release grooves
150
have a cross-section with a generally flat bottom and tapered sides. As shown in
FIGS. 3-5
, inner pin ends
146
are not aligned with external circumferential release grooves
150
in the connected position.
Still referring to
FIGS. 3-5
,
5
A, and
5
B release assembly
130
further includes a lead screw sleeve
152
connected to release shaft
134
by a universal joint
154
. Universal joint
154
allows rotational movement between release shaft
134
and lead screw sleeve
152
to accommodate bending of the downhole assembly
24
. Universal joint
154
is a coupling of preferably three pieces, namely release shaft
134
, segment
220
, and lead screw sleeve
152
. Release shaft
134
has aperture
156
, lead screw sleeve
152
has aperture
160
and segment
220
has apertures
225
and
230
. When universal joint
154
is assembled (see FIG.
5
B), aperture
156
and aperture
230
are aligned, and aperture
160
aperture
225
are aligned. Pins
164
are inserted into the apertures to prevent separation of release shaft
134
and lead screw sleeve
152
.
The drive train
140
is supported within cavity
110
by a support sleeve
166
having a central aperture
168
therethrough with an annular restrictive flange
172
in the central portion thereof forming a bushing
174
therethrough for receiving the drive train
140
. Seals
167
,
169
are disposed between inner housing
90
and support sleeve
166
. The drive train
140
includes a lead screw
170
threadingly received at one end by lead screw sleeve
152
. Lead screw
170
includes a central blind bore
176
and an external annular bearing flange
178
engaging a bearing washer
180
disposed between annular restrictive flange
172
and annular bearing flange
178
.
A converter
182
is coupled to drive shaft
184
of motor
138
at its downhole end and to lead screw
170
at its uphole end via a pin
186
. Converter
182
rotates within the bushing
174
of the support sleeve
166
. Seals
194
are disposed between bushing
174
and lead screw
170
.
Support sleeve
166
has a flanged end
190
. Flanged end
190
engages the annular shoulder
121
. A pressure compensator piston
192
is disposed about lead screw sleeve
152
and within support sleeve
166
. A seal
196
is disposed between lead screw sleeve
152
and pressure compensator piston
192
, and seal
198
is disposed between piston
192
and support sleeve
166
.
A lubricating fluid fills the space around release assembly
130
and drive train
140
including bore
114
, lead screw sleeve
152
, and central aperture
168
. As the release assembly
130
and drive train
140
move, the lubricating fluid must be allowed to flow and not inhibit the movement of the release assembly
130
or drive train
140
. Therefore an uphole pressure release port
200
is disposed adjacent the uphole end of release shaft
134
in transverse aperture
116
and a downhole pressure release ports
202
are disposed in central blind bore
176
.
Electrical motor
138
is coupled via cap screws
204
to a retainer sleeve
206
mounted on an electronics package
208
disposed downhole of motor
138
in cavity
110
. Electric motor
138
is connected through conductors
76
,
78
to the surface
212
and can be commanded from the surface
212
to rotate in either clockwise or counterclockwise direction, i.e., either the release direction or the connect direction. A retainer
210
is threaded into the downhole end of cavity
110
to mount motor
138
and the electronics package
208
in cavity
110
of inner housing
90
. Male electrical connector
96
extends through the retainer
210
connecting the electronics package
208
with the bottom hole assembly
28
threadingly connected to the downhole end
94
of inner housing
90
. As best shown in
FIG. 4
, wire ways
101
extend longitudinally through the wall
128
of inner housing
90
to maintain an electrical connection from the surface
212
through the disconnect assembly
10
to the bottom hole assembly
28
.
In operation, the electric motor
138
is actuated from the surface
212
causing drive shaft
184
to rotate drive train
140
. As drive train
140
rotates, lead screw
170
rotates within lead screw sleeve
152
. Depending upon the direction of rotation of the electric motor
138
, the connection
135
causes release shaft
134
to either reciprocate towards or away from motor
138
. Thus, upon command from the surface, electric motor
138
moves release shaft
134
either to the connecting position shown in
FIGS. 3-5
or the releasing and released positions shown in
FIGS. 6-7
.
One or more of release shaft
134
, locking pins
132
, internal circumferential grooves
91
,
93
, and/or external circumferential grooves
150
comprise a lock
214
that is capable of releasably locking outer housing
92
, connected to the second grouping of BHA components, to inner housing
90
, connected to a first grouping of BHA components, while connection
146
serves a means for engaging and disengaging lock
214
.
In the connected position as shown in
FIGS. 3-5
, locking pins
132
are aligned and disposed within internal circumferential grooves
91
,
93
of outer housing
92
and carry the axial load between outer housing
92
and inner housing
90
. Locking pins
132
are maintained in the locked position by release shaft
134
.
FIG. 6
shows disconnect assembly
10
in the released position. Upon command from the surface, electric motor
138
actuates, thereby actuating and rotating lead screw
170
. As lead screw
170
rotates within screw sleeve
152
, release shaft
134
moves axially downhole by virtue of the threaded engagement between lead screw
170
and lead screw sleeve
152
forming connection
135
. Thrust of lead screw
170
is taken by bearing flange
178
and bearing washer
180
. As previously stated, guide pin
144
and longitudinally elongated slot
142
prevent relative rotation between shaft
134
and inner housing
90
causing release shaft
134
to move axially, but prevent release shaft
134
from rotating. As shown in
FIG. 6
, lead screw
170
has moved release shaft
134
axially such that external circumferential grooves
150
are now aligned with locking pins
132
.
Still referring to
FIG. 6
, disconnect assembly
10
is shown in the released position after a command signal has been sent to electric motor
138
to disengage disconnect assembly
10
. Actuation of motor
138
preferably occurs directly from the surface
212
, preferably via conductors
76
,
78
extending through the wall of composite coiled tubing string
26
. For example, the operator can send a command signal to electric motor
138
directing motor
138
to disengage disconnect assembly
10
. If there are multiple disconnect assemblies
10
used in downhole assembly
24
, each disconnect assembly
10
is assigned a unique command address. The command from the surface
212
includes the command address of the disconnect assembly
10
to be disconnected. If the address of a particular disconnect assembly
10
matches the command signals, electric motor
138
of that disconnect assembly
10
is activated and rotates lead screw
170
. When lead screw
170
is actuated by electric motor
138
in response to a disengage command, lead screw
170
axially pulls release shaft
134
toward electric motor
138
. Once external circumferential grooves
150
align with locking pins
132
, the released position of
FIG. 6
occurs and pins
132
can move radially into external circumferential grooves
150
. After pins
132
have moved out of internal circumferential grooves
91
,
93
and into external circumferential grooves
150
, disconnect assembly
10
is in the released a position and outer housing
92
is ready to be separated from inner housing
90
and pulled out of the hole while the inner housing
90
with the first grouping of BHA components remains in the borehole.
FIG. 7
shows outer housing
92
and inner housing
90
in the disconnected position. As shown, pins
132
have moved into external circumferential grooves
150
and outer housing
92
has been disconnected from inner housing
90
. Outer housing
92
can then be pulled out of the borehole, leaving fishing neck
106
exposed uphole for a fishing operation to retrieve that portion of the BHA stuck in the borehole.
On occasions, outer housing
92
cannot be separated from inner housing
90
after disconnect assembly
10
being activated and placed in the released positions. This indicates that the stuck point for the downhole assembly
26
is up-hole from disconnect assembly
10
. The present invention allows a command signal to be sent to electric motor
138
to turn lead screw
170
in the opposite direction, i.e., in the direction to push release shaft
134
axially away from electric motor
138
. Release shaft
134
will then be moved axially until locking pins
132
are cammed radially outwards and outer ends
148
engage internal circumferential grooves
91
,
93
. This locks the tool for normal operation, as shown in
FIGS. 3-5
. The operator can now choose to activate another disconnect assembly
10
above the one just being activated to attempt a release further uphole.
While preferred embodiments of this invention have been shown and described, modifications thereof can be made by one skilled in the art without departing from the spirit or teaching of this invention. The embodiments described herein are exemplary only and are not limiting. Many variations and modifications of the system and apparatus are possible and are within the scope of the invention. Accordingly, the scope of protection is not limited to the embodiments described herein, but is only limited by the claims that follow, the scope of which shall include all equivalents of the subject matter of the claims.
Claims
- 1. A disconnect for well drilling operations from the surface, comprising:a body; a motor disposed on said body and being selectively actuatable from the surface; a lead screw having one end coupled to said motor; a release plunger coupled to another end of said lead screw; and a plurality of pins disposed about said release plunger on said body.
- 2. The disconnect of claim 1, further comprising:said body having a cavity; and said motor, lead screw, and release plunger being disposed in said cavity.
- 3. The disconnect of claim 2, further including a housing having internal recesses adapted to receive one end of said pins and wherein said release plunger has external grooves adapted to receive another end of said pins.
- 4. The disconnect of claim 3, wherein said release plunger has an longitudinally elongated slot in which is slidingly disposed a guide pin on said body.
- 5. The disconnect of claim 4, wherein said release plunger includes a universal coupling joining first and second portions of said plunger, said second portion being coupled to said lead screw.
- 6. The disconnect of claim 5, further comprising a piston disposed about said release plunger.
- 7. The disconnect of claim 5, further comprising:a first seal sealingly engaging said piston and said release plunger; and a second seal sealingly engaging said piston and said body.
- 8. The disconnect of claim 7, further comprising a pressure release disposed adjacent said first portion of said release plunger.
- 9. The disconnect of claim 7, wherein said body further comprises a fishing neck.
- 10. The disconnect of claim 9, further including a housing around said body, said body and housing having inter-engaging splines.
- 11. An electro-mechanical disconnect for a coiled tubing assembly, comprising:a body having a cavity, said body capable of coupling to the coiled tubing; an electric motor housed within said cavity; a lead screw housed within said cavity, said lead screw having one end coupled to said electric motor; a plunger housed within said cavity and coupled to another end of said lead screw, said plunger having at least one circumferential groove therearound; and at least one pin extending radially from said plunger and capable of moving into said external circumferential groove.
- 12. The disconnect of claim 11, further comprising coiled tubing telescopingly engaged with and coupling to said body, said coiled tubing having at least one internal circumferential groove.
- 13. The disconnect of claim 11, wherein said release plunger comprises a longitudinally elongated slot receiving a plunger guide pin on said body to prevent rotation of said plunger upon movement of said lead screw.
- 14. A disconnect for well drilling operations, comprising:a housing having internal grooves; and a body disposed within said housing; a plunger disposed in said body and having two external grooves and being capable of being moved among a drilling position, a release position, and a disengaged position; a lead screw threadingly engaged with said plunger; an electric motor coupled to said lead screw; and a plurality of pins mounted on said body and engaging said plunger.
- 15. A method of disengaging a bottom hole assembly from coiled tubing, comprising:actuating an electric motor via an electrical command signal; rotating a screw that is coupled to the electric motor and is threadingly coupled to a release plunger; axially moving the release plunger a distance sufficient to align grooves on the plunger with radially extending pins.
- 16. The method of claim 15, further comprising continuing to axially move the release plunger until the outer ends of the radially extending pins disengage from respective grooves on the interior of the coiled tubing.
- 17. A method of disengaging a tool from coiled tubing, comprising:sending an electric command signal to an electric motor in a body coupled to a section of the coiled tubing, the coiled tubing having channels on its interior; actuating an electric motor in response to the electrical command signal; rotating a mechanism coupled to the electric motor and to a release plunger; preventing rotational movement of the release plunger; and axially moving the release plunger a distance sufficient to align grooves on the plunger with the inner ends of radially extending pins.
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