Patent Application
20070277980
For a more complete understanding of the features and advantages of the present invention, reference is now made to the detailed description of the invention along with the accompanying figures in which corresponding numerals in the different figures refer to corresponding parts and in which:
While the making and using of various embodiments of the present invention are discussed in detail below, it should be appreciated that the present invention provides many applicable inventive concepts which can be embodied in a wide variety of specific contexts. The specific embodiments discussed herein are merely illustrative of specific ways to make and use the invention, and do not delimit the scope of the present invention.
Referring initially to
In the illustrated embodiment, tubular string 18 has been previously installed within well 22 such that an annulus 24 is formed between casing 26 and tubular string 18. Tubular string 18 has, for example, previously been used to produce fluids from a subterranean hydrocarbon bearing reservoir (not shown) that is intersected by well 22. Due to a flow rate decreased or other lack of productivity, however, it has been determined that a workover should be performed on well 22 including pulling tubular string 18. As described above, to control well 22 during the workover, a workover fluid must be circulated in to well 22. In order to allow such circulation, however, a communication path must be established between the interior of tubular string 18 and annulus 24.
As depicted in
As will be described in more detail below, a particular implementation of downhole power unit 12 includes an elongated housing, a motor disposed in the housing and a sleeve connected to a rotor of the motor. The sleeve is a rotational member that rotates with the rotor. A moveable member such as the above-mentioned moveable shaft is received within the threaded interior of the sleeve. Operation of the motor rotates the sleeve which causes the moveable shaft to move longitudinally. Accordingly, when downhole power unit 12 is operably coupled with downhole perforator 14 and the moveable member is activated, longitudinal movement is imparted to the mandrel of downhole perforator 14.
Preferably, a microcontroller made of suitable electrical components to provide miniaturization and durability within the high pressure, high temperature environments which can be encountered in an oil or gas well is used to control the operation of downhole power unit 12. The microcontroller is preferably housed within the structure of downhole power unit 12, it can, however, be connected outside of downhole power unit 12 but within an assoicated tool string moved into well 22. In whatever physical location the microcontroller is disposed, it is operationally connected to downhole power unit 12 to control movement of the moveable member when desired. In one embodiment, the microcontroller includes a microprocessor which operates under control of a timing device and a program stored in a memory. The program in the memory includes instructions which cause the microprocessor to control the downhole power unit 12.
The microcontroller operates under power from a power supply which can be at the surface of well 22 or, preferably, contained within the microcontroller, downhole power unit 12 or otherwise within a downhole portion of the tool string of which these components are a part. For a particular implementation, the power source provides the electrical power to both the motor of downhole power unit 12 and the microcontroller. When downhole power unit 12 is at the target location, the microcontroller commences operation of downhole power unit 12 as programmed. For example, with regard to controlling the motor that operates the sleeve receiving the moveable member, the microcontroller sends a command to energize the motor to rotate the sleeve in the desired direction to either extend or retract the moveable member at the desired speed. One or more sensors monitor the operation of downhole power unit 12 and provide responsive signals to the microcontroller. When the microcontroller determines that a desired result has been obtained, it stops operation of downhole power unit 12, such as by de-energizing the motor.
Even though
Referring next to
In the illustrated embodiment, tubular string 48 has been previously installed within well 52 such that an annulus 54 is formed between casing 56 and tubular string 48. As in the example above, tubular string 48 has previously been used to produce fluids from a subterranean hydrocarbon bearing reservoir (not shown) that is intersected by well 52 but it has been determined that a workover should be performed on well 52 including pulling tubular string 48. In order to allow circulation of the workover fluid, a communication path must be established between the interior of tubular string 48 and annulus 54.
As depicted in
Referring now to
In the illustrated embodiment, power assembly 104 includes a self-contained power source, eliminating the need for power to be supplied from an exterior source, such as a source at the surface. A preferred power source comprises a battery assembly 114 which may include a plurality of batteries such as alkaline batteries, lithium batteries or the like.
Connected with power assembly 104 is the force generating and transmitting assembly. The force generating and transmitting assembly of this implementation includes a direct current (DC) electric motor 116, coupled through a gearbox 118, to a jackscrew assembly 120. A plurality of activation mechanisms 122, 124 and 126, as will be described, can be electrically coupled between battery assembly 114 and electric motor 116. Electric motor 116 may be of any suitable type. One example is a motor operating at 7500 revolutions per minute (rpm) in unloaded condition, and operating at approximately 5000 rpm in a loaded condition, and having a horsepower rating of approximately 1/30th of a horsepower. In this implementation, motor 116 is coupled through the gearbox 118 which provides approximately 5000:1 gear reduction. Gearbox 118 is coupled through a conventional drive assembly 128 to jackscrew assembly 120.
The jackscrew assembly 120 includes a threaded shaft 130 which moves longitudinally, rotates or both, in response to rotation of a sleeve assembly 132. Threaded shaft 130 includes a threaded portion 134, and a generally smooth, polished lower extension 136. Threaded shaft 130 further includes a pair of generally diametrically opposed keys 138 that cooperate with a clutch block 140 which is coupled to threaded shaft 130. Clutch housing 110 includes a pair of diametrically opposed keyways 142 which extend along at least a portion of the possible length of travel. Keys 138 extend radially outwardly from threaded shaft 130 through clutch block 140 to engage each of keyways 142 in clutch housing 110, thereby selectively preventing rotation of threaded shaft 130 relative to housing 110.
Rotation of sleeve assembly 132 in one direction causes threaded shaft 130 and clutch block 140 to move longitudinally upwardly relative to housing assembly 110 if shaft 130 is not at its uppermost limit. Rotation of the sleeve assembly 132 in the opposite direction moves shaft 130 downwardly relative to housing 110 if shaft 130 is not at its lowermost position. Above a certain level within clutch housing 110, as indicated generally at 144, clutch housing 110 includes a relatively enlarged internal diameter bore 146 such that moving clutch block 140 above level 144 removes the outwardly extending key 138 from being restricted from rotational movement. Accordingly, continuing rotation of sleeve assembly 132 causes longitudinal movement of threaded shaft 130 until clutch block 140 rises above level 144, at which point rotation of sleeve assembly 132 will result in free rotation of threaded shaft 130. By virtue of this, clutch assembly 112 serves as a safety device to prevent burn-out of the electric motor, and also serves as a stroke limiter. In a similar manner, clutch assembly 112 may allow threaded shaft 130 to rotation freely during certain points in the longitudinal travel of threaded shaft 130.
In the illustrated embodiment, downhole power unit 100 incorporates three discrete activation assemblies, separate from or part of the microcontroller discussed above. The activation assemblies enable jackscrew 120 to operate upon the occurrence of one or more predetermined conditions. One depicted activation assembly is timing circuitry 122 of a type known in the art. Timing circuitry 122 is adapted to provide a signal to the microcontroller after passage of a predetermined amount of time. Further, downhole power unit 100 can include an activation assembly including a pressure-sensitive switch 124 of a type generally known in the art which will provide a control signal, for example, once the switch 124 reaches a depth at which it encounters a predetermined amount of hydrostatic pressure within the tubing string or experiences a particular pressure variation or series of pressure variations. Still further, downhole power unit 100 can include a motion sensor 126, such as an accelerometer or a geophone, that is sensitive to vertical motion of downhole power unit 100. Accelerometer 126 can be combined with timing circuitry 122 such that when motion is detected by accelerometer 126, timing circuitry 122 is reset. If so configured, the activation assembly operates to provide a control signal after accelerometer 126 detects that downhole power unit 100 has remained substantially motionless within the well for a predetermined amount of time.
Working assembly 102 includes an actuation assembly 148 which is coupled through housing assembly 106 to be movable therewith. Actuation assembly 148 includes an outer sleeve member 150 which is threadably coupled at 152 to housing assembly 106. Threaded shaft 130 extends through actuation assembly 148 and has a threaded end 154 for coupling to other tools such as an actuator or a downhole perforator as will be described below.
In operation, downhole power unit 100 is adapted to cooperate directly with a downhole perforator or indirectly with a downhole perforator via an actuator depending upon the particular implementation the downhole perforator assembly of the present invention. Specifically, prior to run in, outer sleeve member 150 of downhole power unit 100 is operably associated with a mating tubular of a downhole perforator or an actuator as described below. Likewise, shaft 130 of downhole power unit 100 is operably associated with a mating mandrel of a downhole perforator or an actuator as described below. As used herein, the term operably associated with shall encompass direct coupling such as via a threaded connection, a pinned connection, a frictional connection, a closely received relationship and may also including the use of set screws or other securing means. In addition, the term operably associated with shall encompass indirect coupling such as via a connection sub, an adaptor or other coupling means. As such, an upward longitudinal movement of threaded shaft 130 of downhole power unit 100 exerts an upward longitudinal force upon the mandrel to which it is operably associated that initiates the operation of either the downhole perforator or the actuator that is associated therewith as described below.
As will be appreciated from the above discussion, actuation of motor 116 by activation assemblies 122, 124, 126, and control of motor 116 by the microcontroller results in the required longitudinal movement of threaded shaft 130. In the implementation wherein the downhole perforator assembly includes an actuator, threaded shaft 130 is only required to move a short distance to exert sufficient force to break certain shear pins then the pressure differential created within the actuator is used to operate the downhole perforator. In the implementation wherein the downhole perforator assembly does not includes an actuator, threaded shaft 130 is required to move a short distance to exert sufficient force to break certain shear pins then continues its upward movement for a longer stroke to directly operate the downhole perforator to both radially extend and radially retract the penetrator of the downhole perforator. In either case, downhole power unit 100 may be preprogrammed to perform the proper operations prior to deployment into the well. Alternatively, downhole power unit 100 may receive power, command signals or both from the surface via an umbilical cord. Once the perforating operation is complete, the downhole perforator assembly of the present invention may be retrieved to the surface.
Even though a particular embodiment of a downhole power unit has been depicted and described, it should be clearly understood by those skilled in the art that other types of downhole power devices could alternatively be used with the downhole perforator assembly of the present invention such that the downhole perforator assembly of the present invention may establish communication between the interior of a downhole tubular and the surrounding annulus.
Referring now to
Slidably and sealing disposed within outer housing 162 is a mandrel 176. Mandrel 176 includes an upper connector 178 that is designed to threadably couple to shaft 130 of downhole power unit 100. Mandrel 176 has a radially expanded section 180 including a seal groove having a seal 182 located therein, which provides the sealing relationship with the interior of outer housing 162. Mandrel 176 also has a radially expanded lower section 184.
Actuator 160 further includes a piston 186 that is slidably and sealing disposed within outer housing 162. Piston 186 has a radially reduced upper portion 188 that is positioned above radially expanded lower section 184 of mandrel 176. Radially reduced upper portion 188 includes an exterior seal groove having a seal 190 located therein, which provides a sealing relationship with the interior of outer housing 162. Radially reduced upper portion 188 also includes an interior seal groove having a seal 192 located therein, which provides a sealing relationship with the exterior of mandrel 176. When assembled in this manner, an atmospheric chamber 194 is created within actuator 160 between seals 182, 190, 192. Piston 186 is initially fixed relative to outer housing 162 by a plurality of shear pins 196 at least one of which may include a fluid passageway 198 to allow communication of annular fluid pressure into the interior of actuator 160 below seals 190, 192, thus establishing a pressure differential thereacross. The fluid passageway may include a choke or other flow control device to meter the rate at which annular fluid may enter the interior of actuator 160. Piston 186 includes a lower connector 200 that is designed to threadably couple to shaft 202. Shaft 202 has a lower threaded end 204.
In operation, an upward force is placed on mandrel 176 by downhole power unit 100 via shaft 130 moving radially expanded section 180 into contact with shoulder 170 which breaks shear pins 196 and releases piston 186 from its initial fixed relationship with outer housing 162. Once piston 186 is free to move relative to outer housing 162, the differential pressure acting on seals 190 causes piston 186 to move upwardly relative to outer housing 162 and mandrel 176. This upward movement of piston 186 upwardly shifts shaft 202. As such, use of the downhole power unit 100 in combination with actuator 160 provides for higher velocity in the longitudinal movement transferred to the downhole perforator than through use of the downhole power unit 100 alone. Accordingly, when it is desirable to create high velocity longitudinal movement to accomplish a tubular penetration, actuator 160 may be included with the downhole perforator assembly of the present invention.
Even though a particular embodiment of an actuator has been depicted and described, it should be clearly understood by those skilled in the art that other types of actuators could alternatively be used in the downhole perforator assembly of the present invention.
Referring now to
Slidably and sealing disposed within outer housing 222 is a mandrel 234. Mandrel 234 includes an upper connector 236 that is designed to threadably couple to shaft 130 of downhole power unit 100 or shaft 202 of actuator 160. Mandrel 234 has a radially expanded section 236 including a seal groove having a seal 238 located therein, which provides the sealing relationship with the interior outer housing 222. Mandrel 234 has a slotted ramp member 240 having an increasing slope section 242, a flat section 244 and a decreasing slope section 246. Mandrel 234 is initially fixed relative to outer housing 222 via shear pins 248.
Downhole perforator 220 also includes a penetrator 250 that is disposed between mandrel 234 and outer housing 222. Penetrator 250 has a base section 252 that is received within slotted ramp member 240 of mandrel 234 and slides along slotted ramp member 240 when mandrel 234 is shifted longitudinally upwardly relative to outer housing 222. Penetrator 250 also has a punch member 254 that is received within penetrator opening 228 of outer housing 222.
In operation, an upward force is placed on mandrel 234 directly by downhole power unit 100 via shaft 130 or by actuator 160 via piston 186 which breaks shear pins 248 releasing mandrel 234 from its initial fixed relationship with outer housing 222. As mandrel 234 is shifted longitudinally upwardly relative to outer housing 222, punch member 254 is radially outwardly extended from outer housing 222 as base section 252 slides along increasing slope section 242 of mandrel 234. Once flat section 244 is behind base section 252, punch member 254 is in its fully radially extended position. Continued upward shifting of mandrel 234 relative to outer housing 222 will then retract punch member 254 back into outer housing 222 as base section 252 slides down decreasing slope section 246. In this manner, downhole perforator 220 is able to create an opening through the sidewall of the tubular in which downhole perforator 220 is located.
Referring now to
Slidably and sealing disposed within outer housing 262 is a mandrel 278. Mandrel 278 includes an upper connector 280 that is designed to threadably couple to shaft 130 of downhole power unit 100 or shaft 202 of actuator 160. Mandrel 278 has a radially expanded section 282 including a seal groove having a seal 283 located therein, which provides the sealing relationship with the interior outer housing 262. Mandrel 278 has a longitudinal slot 284. Mandrel 278 is initially fixed relative to outer housing 262 via shear pins 286.
Downhole perforator 260 also includes a penetrator 288 that is disposed within longitudinal slot 284 of mandrel 278 and longitudinal slot 272 of other housing 262. Penetrator 288 is rotatably mounted to mandrel 278 via a pin 290. Penetrator 288 also has an alignment pin 292 that is positioned within radial slot 274 of outer housing 262.
In operation, an upward force is placed on mandrel 278 directly by downhole power unit 100 via shaft 130 or by actuator 160 via piston 186 which breaks shear pins 286 releasing mandrel 276 from its initial fixed relationship with outer housing 262. As mandrel 278 is shifted longitudinally upwardly relative to outer housing 262, penetrator 288 rotates within longitudinal slot 284 of mandrel 278 and longitudinal slot 272 of other housing 262 about pin 290 and alignment pin 292 moves radially outwardly in radial slot 274 of outer housing 262. As penetrator 288 rotates, a cutting surface 294 of penetrator 288 extends radially outwardly from outer housing 262. Continued upward shifting of mandrel 278 relative to outer housing 262 continues to rotate penetrator 288 until it is retracted into outer housing 262. In this manner, downhole perforator 260 is able to create a longitudinal cut through the sidewall of the tubular in which downhole perforator 260 is located.
Referring now to
Slidably and sealing disposed within outer housing 302 is a mandrel 314. Mandrel 314 includes an upper connector 316 that is designed to threadably couple to shaft 130 of downhole power unit 100 or shaft 202 of actuator 160. Mandrel 314 has a radially expanded section 318 including a seal groove having a seal 320 located therein, which provides the sealing relationship with the interior of outer housing 302. Mandrel 314 has a rack section 322 that has a plurality of teeth 324. Mandrel 314 is initially fixed relative to outer housing 302 via shear pins 326.
Downhole perforator 260 also includes a pair of oppositely disposed penetrators 328, 330 that are respectively positioned within longitudinal slots 308, 310 of other housing 302. Penetrators 328, 330 are rotatably mounted to outer housing 302 via respective pins 332, 334. Each penetrator 328, 330 includes a plurality of teeth that mesh with teeth 324 of mandrel 314.
In operation, an upward force is placed on mandrel 314 directly by downhole power unit 100 via shaft 130 or by actuator 160 via piston 186 which breaks shear pins 326 releasing mandrel 314 from its initial fixed relationship with outer housing 302. As mandrel 314 is shifted longitudinally upwardly relative to outer housing 302, the teeth of penetrators 328, 330 mesh with teeth 324 of mandrel 314 such that penetrators 328, 330 rotate within longitudinal slots 308, 310 of other housing 302 about pins 332, 334. As penetrators 328, 330 rotate, cutting surfaces 336, 338 of penetrators 328, 330 extend radially outwardly from outer housing 302. Continued upward shifting of mandrel 314 relative to outer housing 302 continues to rotate penetrators 328, 330 until they are retracted into outer housing 302. In this manner, downhole perforator 300 is able to create a pair of longitudinal cuts through the sidewall of the tubular in which downhole perforator 300 is located.
Referring now to
Slidably disposed within outer housing 362 is a mandrel 380. Mandrel 380 includes an upper connector 382 that is designed to receive shaft 130 of downhole power unit 100 or shaft 202 of actuator 160 therein. In the illustrated embodiment, set screws 384 are used to secure the received shaft within upper connector 382. Mandrel 380 has a longitudinal slot 386.
Downhole perforator 360 also includes a penetrator 388 that is disposed within longitudinal slot 386 of mandrel 380 and longitudinal slot 370 of other housing 362. Penetrator 388 is rotatably mounted to mandrel 380 via a pin 390. Longitudinal movement of mandrel 380 relative to housing 362 is initially prevent by lock pin 378 which initially prevents Rotation of penetrator 388.
In operation, an upward force is placed on mandrel 380 directly by downhole power unit 100 via shaft 130 or by actuator 160 via piston 186 which breaks lock pin 378 releasing mandrel 380 from its initial fixed relationship with outer housing 362. As mandrel 380 is shifted longitudinally upwardly relative to outer housing 362, penetrator 388 rotates within longitudinal slot 386 of mandrel 380 and longitudinal slot 370 of other housing 362 about pin 390 and with the aid of pin 376. As penetrator 388 rotates, a cutting surface 392 of penetrator 388 extends radially outwardly from outer housing 362. Continued upward shifting of mandrel 380 relative to outer housing 362 continues to rotate penetrator 388 until it is retracted into outer housing 362. In this manner, downhole perforator 360 is able to create a longitudinal cut through the sidewall of the tubular in which downhole perforator 360 is located.
While this invention has been described with reference to illustrative embodiments, this description is not intended to be construed in a limiting sense. Various modifications and combinations of the illustrative embodiments as well as other embodiments of the invention, will be apparent to persons skilled in the art upon reference to the description. It is, therefore, intended that the appended claims encompass any such modifications or embodiments.
