TRACTOR FOR INSTALLING TUBING ENCAPSULATED CABLE INTO COIL TUBING

Abstract

Tubing encapsulated cable is generally difficult to place in the interior of coil tubing. In various embodiments of the present invention tubing encapsulated cable is placed in the interior of coil tubing by attaching the tubing encapsulated cable to a tractor and allowing the tractor to pull the tubing encapsulated cable into the coil tubing. The tractor drive system may be a fluid drive system where an electric or other motor supplies power to a propeller or jet pump. The tractor drive system could also be a friction drive were electric or other motor supplies power to a drive wheel or treads. The tractor drive system could also be a push me pull me system where electric or other motor locks a portion of the tractor in place while moving the other portion forwards.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent Application No. 61/921,623 that was filed on Dec. 30, 2013.

BACKGROUND

Tubing encapsulated cable can be difficult to insert into coil tubing. Tubing encapsulated cable typically consists of one or more electrical conductors, a fiber optic cable, and possibly other cables or lines sheathed in a corrosion resistant alloy such as 316 stainless steel or a fiber reinforced composite sheath. The smooth outside surface and relatively small diameter of tubing encapsulated cable are desirable attributes for well intervention work because the relatively smooth surface may be more resistant to chemical attack than braided wire. Additionally, the relatively smooth surface and small diameter (0.125″-0.250″) minimizes viscous drag exerted upon the cable as fluids pumped through the coil tubing in the course of intervention operations pass by the cable. Because there is little drag on the tube wire, conventional pumping operations used to install braided wireline into coil tubing are not sufficient to install tubing encapsulated cable. Pumping fluid through the coil tubing during the installation of tubing encapsulated cable is required to assist in overcoming the capstan effect, caused by the friction between the coil tubing and the tubing encapsulated cable as the tubing encapsulated cable travels through the wound coil tubing.

There are numerous techniques that may be utilized to install tubing encapsulated cable into a long tubular member such as coil tubing. Such as hanging the coil into the well in order to allow the somewhat reliable force of gravity to pull the tubing encapsulated cable downward into the interior of the coil tubing. Another commonly known technique involves spooling out the coil tubing along a roadway, installing a rope, cable, or equivalent and using the rope or cable in a manner similar to that of an electrician's fish tape to pull the tubing encapsulated cable into the coil tubing. In these instances fluid may or may not be pumped into the coil tubing inserting the tubing encapsulated cable. Inserting the tubing encapsulated cable into coil tubing as described above can be an expensive operation. Wire and cable have been used with a tubular conduit since the late 1800s, conduit, like coil tubing, is a long tubular member that normally has wires and cables with a wide variety of outer armors run through it.

SUMMARY

One solution to the problem of running a long tubing encapsulated cable into coil tubing is to install into the coil tubing a self-propelled assembly that can attach to a tubing encapsulated cable. The self-propelled assembly could then pull the tubing encapsulated cable into the coil tubing. In one alternative the self-propelled assembly may pull a first line into the coil where the first line is attached to the tubing encapsulated cable so that the tubing encapsulated cable may then be pulled in to the coil tubing by the first line. In another alternative the self-propelled assembly may carry the first line or the tubing encapsulated cable on board. As the self-propelled assembly moves through the coil tubing the self-propelled assembly may then disburse either the first line or the tubing encapsulated cable as the self-propelled assembly moves through the coil tubing leaving the first line or tubing encapsulated cable in place in the coil tubing.

The coil tubing may or may not be coiled around a reel while the self-propelled assembly pulls the tubing encapsulated cable or the first line into the coil tubing. It may be necessary to pump fluid through the coil tubing while inserting the tubing encapsulated cable. The fluid tends to provide some lubrication to the interface between the coil tubing and the tubing encapsulated cable. Additionally the turbulent flow of the fluid around the tubing encapsulated cable and also as the fluid flows through the coil tubing tends to cause the tubing encapsulated cable to vibrate reducing the overall friction between the coil and the tubing encapsulated cable. Also, as the fluid flows past the tubing encapsulated cable, the friction between the fluid and the tubing encapsulated cable tends to cause the tubing encapsulated cable to move in the same direction as the fluid thereby helping to push the length of tubing encapsulated cable. Additionally, it may be preferable to include a tensioning device between the flow tee where the fluid is injected into the coil tubing and the second reel of the tubing encapsulated cable to prevent the tubing encapsulated cable on the second reel from loose wrapping. The net tension in the tubing encapsulated cable between the self-propelled assembly and the tensioning device could be controlled by adjusting either the applied force from the self-propelled assembly or the tensioning device.

The tubing encapsulated cable could supply power and/or control signals to the self-propelled assembly. The self-propelled assembly could use electrical or hydraulic power supplied through the tubing encapsulated cable or the self-propelled assembly could utilize internal power such as batteries or other chemical means of power such as hydrogen peroxide decomposition or an internal combustion engine. In other embodiments the self-propelled assembly could utilize an electrical generator powered by the fluid flowing through the coil tubing.

In one embodiment, the self-propelled assembly may use motorized wheels that contact the inner surface of the coil tubing, tracks that contact the inner surface of the coil tubing, or a corkscrew motion where various portions of the self-propelled assembly contact the inner surface of the coil tubing to pull the tubing encapsulated cable into the coil tubing.

In another embodiment, the self-propelled assembly may consist of a shielded propeller that rotates and creates a pulling force to pull the tubing encapsulated cable into the coil tubing.

In certain instances it may be necessary to pump fluid through the coil tubing as the tubing encapsulated cable is installed into the coil tubing to reduce the capstan effect. Generally the capstan effect is where multiple wraps of cable or rope around a cylinder can result in a magnification of friction between the cable or rope and the cylinder. In this case the minor diameter of the coil as it is spooled on the drum would be analogous to the cylinder. The more wraps of rope around the drum or cylinder result in greater friction.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts an embodiment of a tractor powered by a fluid drive system puffing a length of tubing encapsulated cable through coiled tubing.

FIG. 2 depicts an embodiment of a tractor powered by a friction drive system pulling a length of tubing encapsulated cable through coiled tubing.

FIG. 3 depicts an embodiment of the present invention where the tractor powered by a push me pull me drive system is in an intermediate state.

FIG. 4 depicts an embodiment of the present invention where the tractor powered by a push me pull me drive system is in an extended state.

FIG. 5 depicts an embodiment of the present invention where the tractor powered by a push me pull me drive system is in a retracted state.

DETAILED DESCRIPTION

The description that follows includes exemplary apparatus, methods, techniques, or instruction sequences that embody techniques of the inventive subject matter. However, it is understood that the described embodiments may be practiced without these specific details.

FIG. 1 depicts an embodiment of the present invention where a tractor 10 powered by a fluid drive system 20 is pulling a length of tubing encapsulated cable 30 through fluid-filled coiled tubing 32. In this instance the fluid drive system 20 may be a propeller 22 on shaft 24. In this particular instance the propeller is configured such that as the shaft 24 is driven in the direction of arrow 26 the propeller 22 will provide thrust in the direction of arrow 28. While in this embodiment an external propeller is shown, the drive system 20 internalized within the housing 34 could be a jet pump, or any other known system utilizing the fluid as a driving media. Typically the shaft 24 is driven by motor (not shown) that resides about the interior of housing 34. The housing 34 may be sealed to prevent fluid from entering the housing 34. In certain instances it may be necessary for the housing 34 to have circumferential flutes such as flute 40 and 42. The flutes 40 and 42 may serve to provide additional area to dissipate heat and thus allow for cooling of the electric or other motor within the housing 34. Additionally the flutes 40 and 42 may serve as flow passages to allow the relative movement of fluid past the housing 34 as the housing 34 moves through fluid in the interior of coil tubing 32. Forward end 44 of housing 32 as well as rearward end 46 of housing 32 may be angled or have another shape to minimize drag on the housing 34 as the housing 34 moves through the fluid in the interior of coil tubing 32. The tractor 10 may be electrically, pneumatically, or hydraulically powered. The electrical power could be provided by internal batteries within the housing 32 or the power, whether pneumatic, hydraulic, or electric, could be provided through the tubing encapsulated cable 30. As shown the tubing encapsulated cable 30 is attached to the rearward end 46 of tractor 10 by a compression fitting 50.

FIG. 2 is an alternative embodiment for the tractor 100 utilizing a friction drive system to move the tractor 100 through the fluid-filled coil tubing 102 while pulling a length of tubing encapsulated cable 120. The housing 122 has a forward end 144 and a rearward end 146. The forward end 144 and the rearward end 146 of housing 122 may be angled or have another shape to minimize drag on the housing 122 as the housing 122 moves through the fluid in the interior of coil tubing 102. In certain instances it may be necessary for the housing 122 to have circumferential flutes such as flute 150. The flute 150 provides additional area to dissipate heat and thus allow for cooling of the electric or other motor within the housing 122. Additionally the flute 150 may serve as flow passages to allow the relative movement of fluid past the housing 122 as a housing 122 moves the fluid in the interior coil tubing 102. In this embodiment the friction drive system may be at least one drive wheel 104 and preferably other wheels such as wheels 106, 108, 110, 112, and 114 are used to reduce the friction between the housing 122 and the coil tubing 102. Any one of the wheels or all of the wheels 104, 106, 108, 110, 112, and 114 may be drive wheels. In certain instances one or all of the wheels may be replaced with tracks. In other instances it may be possible to put wheels on one side of the housing and a skid or skids on the opposing side of the housing. In certain instances the wheels, tracks, or skids may be circumferentially spaced about the housing. The wheels may be mounted on axles such as axle 124. In certain instances an axle such as axle 126 may be driven by an electrical or other type motor mounted within housing 122. Power to drive the electrical motor may be supplied by batteries within housing 122. In other instances the electrical or other power could be provided through the tubing encapsulated cable 130. As shown the tubing encapsulated cable 130 is attached to the rearward end 146 of tractor 100 by a compression fitting 150. In addition to supplying the electrical or other power required to drive the motor within housing 122 the tubing encapsulated cable 130 may also supply electrical, optical, or other control signals to the tractor 100. Additionally the tubing encapsulated cable 130 may transmit signals from the tractor 100 to the operator. Such signals could include a strain gauge to sense pressure on the tubing encapsulated cable 130 at the tractor 100 allowing the operator to apply more or less motive force as desired. Other signals may include pressure, temperature, tension on the tubing encapsulated cable 130, or motive power being produced by the tractor 100.

FIG. 3 depicts an embodiment of the present invention where the tractor 200 using a push me pull me drive system is in an intermediate state where neither the forward slips 210 and 212 nor the trailing slips 214 and 216 are in a fully extended position. In this intermediate state the tractor 200 may be inserted into the interior of coil tubing 202. Generally the push me pull me system has an electric or other motor powering a system to lock a portion of the tractor in place while moving the other portion forwards.

The tractor 200 has a main beam 220 with the leading end 230 and a trailing end 250. The main beam 220 is configured such that during operation of the tractor the distance between the leading end 230 and the trailing end 250 may be variable.

Towards the forward end of mainbeam 220 is forward pivot point 228 attached to forward pushrods 270 and 272 and mainbeam 220. Mounted on forward pushrod 270 at the opposite end from forward pivot point 228 is slip 210. Mounted on forward pushrod 272 at the opposite end from forward pivot point 228 is slip 212. Forward pushrods 270 and 272 are connected at pivot point 228 and together form forward interior angle 232. A forward bias device 236, such as a torsion spring, is attached to both forward pushrods 270 and 272 centered about pivot point 228. The forward pivot point 228 is arranged to allow the distance 224 between the slips 210 and 212 to vary as disk 226 rotates about forward pivot point 228. Disk 226 is attached to the mainbeam 220 and forward pivot point 228 at forward pivot point 228. A motor 231 on mainbeam 220 drives the disk 226 and is connected to disk 226 by a driveshaft and gearbox (not shown). In certain instances the motor 231, driveshaft, and gearbox could be replaced with hydraulic or pneumatic cylinders. As the cylinder strokes out the forward slip pivot point 228 would move forward and when the cylinder strokes in the trailing pivot point 256 would move forward. The forward bias device 236 is arranged to maximize angle 232 in order to maintain forward slips 210 and 212 at their maximum distance 224 from each other. Any bias device utilized in this invention are typically springs but may include a gas cylinder, elastomeric disk, or any other biasing device known in the industry.

Towards the trailing end of mainbeam 220 is a trailing pivot point 256 attached to trailing pushrods 274 and 276 and to mainbeam 220. Mounted on trailing pushrod 274 at the opposite end from trailing pivot point 256 is slip 216. Mounted on trailing pushrod 276 at the opposite end from forward pivot point 256 is slip 214. Trailing pushrods 274 and 276 are connected at trailing pivot point 256 and together form forward interior angle 264. A trailing bias device 262 is attached to both trailing pushrods 274 and 276 centered about pivot point 256. The trailing pivot point 256 is arranged to allow the distance 278 between the slips 214 and 216 to vary. While the trailing bias device 262, also a torsion spring, is arranged to maximize angle 264 in order to maintain trailing slips 214 and slip 216 at their maximum distance 278 from each other. Disk 226 is connected to trailing pushrods 274 and 276 at trailing pivot point 256 through rod 258. Rod 258 is attached to disk 226 at pivot point 241.

The tractor 200 may be electrically powered. The electrical power could be provided by internal batteries mounted on mainbeam 220 or the electrical power could be provided through conductors within the tubing encapsulated cable 280. As shown the tubing encapsulated cable 280 is attached to the trailing end 250 of tractor 200 by a compression fitting 282.

FIG. 4 depicts the tractor 200 in its extended condition as it moves through coil tubing 202. In the extended condition motor 231 has caused disk 226 to rotate such that pivot point 241 is in its most rearward position. With the pivot point 241 in its most rearward position the distance 233 between forward slip 210 and trailing slip 216 is maximized. Additionally as disk 226 rotates to move pivot point 241 to its most rearward position rod 258 is pushed rearward by moving pivot point 256 rearward. Slips 214 and 216 are pushed outward against the interior of the coil tubing 202. Each of the slips 210, 212, 214, and 216 are configured to reduce the amount of force required for forward motion and increase the amount of force required for rearward motion. Such slips for example may include but are not limited to cast-iron slips, carbide slips, and wire or other types of stiff brushes. As pivot point 256 moves rearward each of the rearward slips 214 and 216 are in contact with the coil tubing walls and as the pivot point 256 moves rearward the rearward slips 214 and 216 tend to dig into the casing to further resist backward motion. Once pivot point 256 moves as far rearward as it is capable due to the rearward slips 214 and 216 digging into the casing, the disk 226 that is attached to pivot point 228 is forced to move forward thereby lengthening beam 220.

FIG. 5 depicts the tractor 200 in its retracted condition as it moves through coil tubing 202. In the retracted condition, motor 231 has caused disk 226 to rotate such that pivot point 241 is in its most forward position. With the pivot point 241 in its most forward position the distance 233 between forward slip 210 and trailing slip 216 is minimized. As disk 226 rotates to move pivot point 241 to its most forward position rod 258 is pulled forwards while moving pivot point 256 forwards. Slips 214 and 216 are pulled inwards from the interior of the coil tubing 202 thus unlocking the rear of the tractor from the coil tubing and allowing the rear of the tractor to move forward. As pivot point 241 moves forward each of the forward slips 210 and 212 are in contact with the coil tubing walls and as the pivot point 241 continues to move forward the forward slips 210 and 212 tend to dig into the casing to further resist backward motion. Once pivot point 241 moves as far forward as it is capable the rear pivot point 256 that is attached to the disk 226 via rod 258 is forced to move forward thereby shortening beam 220 due to the forward slips 210 and 212 digging into the casing preventing the disk 226 from moving backwards.

While the embodiments are described with reference to various implementations and exploitations, it will be understood that these embodiments are illustrative and that the scope of the inventive subject matter is not limited to them. Many variations, modifications, additions and improvements are possible.

Plural instances may be provided for components, operations or structures described herein as a single instance. In general, structures and functionality presented as separate components in the exemplary configurations may be implemented as a combined structure or component. Similarly, structures and functionality presented as a single component may be implemented as separate components. These and other variations, modifications, additions, and improvements may fall within the scope of the inventive subject matter.

Claims

1. A tractor to install a tubing encapsulated cable in coil tubing comprising:

a housing,

a power source,

a connection to the tubing encapsulated cable, and

a friction driver.

2. The tractor of claim 1 wherein, the housing is sealed to prevent a fluid from entering the housing.

3. The tractor of claim 1 wherein, the housing has lengthwise grooves.

4. The tractor of claim 3 wherein, the lengthwise grooves allow fluid to pass the housing.

5. The tractor of claim 3 wherein, the lengthwise grooves assist in dissipating heat.

6. The tractor of claim 1 wherein, the power source is in the interior housing.

7. The tractor of claim 1 wherein, the power source is outside of the coil tubing and is accessed through the tubing encapsulated cable.

8. The tractor of claim 1 wherein, the friction driver is a wheel.

9. The tractor of claim 1 wherein, the friction driver is a track.

10. The tractor of claim 1 further comprising a sensor.

11. The tractor of claim 10 wherein, the sensor is a strain gauge.

12. A tractor to install a tubing encapsulated cable in coil tubing comprising:

a housing,

a power source,

a connection to the tubing encapsulated cable, and

a fluid driver.

13. The tractor of claim 12 wherein, the housing is sealed to prevent a fluid from entering the housing.

14. The tractor of claim 12 wherein, the housing has lengthwise grooves.

15. The tractor of claim 14 wherein, the lengthwise grooves allow fluid to pass the housing.

16. The tractor of claim 14 wherein, the lengthwise grooves assist in dissipating heat.

17. The tractor of claim 12 wherein, the power source is in the interior housing.

18. The tractor of claim 12 wherein, the power source is outside of the coil tubing and is accessed through the tubing encapsulated cable.

19. The tractor of claim 12 wherein, the fluid driver is a propeller.

20. The tractor of claim 12 wherein, the fluid driver is a pump.

21. The tractor of claim 12 further comprising a sensor.

22. The tractor of claim 21 wherein, the sensor is a strain gauge.

23. A tractor to install a tubing encapsulated cable in coil tubing comprising:

a frame,

a power source,

a connection to the tubing encapsulated cable, and

a driver moving the first portion forwards and then a second portion forwards.

24. The tractor of claim 23 wherein, the power source is on the frame.

25. The tractor of claim 23 wherein, the power source is outside of the coil tubing and is accessed through the tubing encapsulated cable.

26. The tractor of claim 23 wherein, the first portion engages the coil tubing while the second portion moves forward.

27. The tractor of claim 23 wherein, the second portion engages the coil tubing while the first portion moves forward.

28. The tractor of claim 23 wherein, the first portion engages the coil tubing with slips.

29. The tractor of claim 23 wherein, the first portion engages the coil tubing with brushes.

30. The tractor of claim 23 further comprising a sensor.

31. The tractor of claim 30 wherein, the sensor is a strain gauge.