METHOD AND APPARATUS FOR DOWNHOLE INSTALLATION OF COILED TUBING STRINGS
A tool for releasably coupling a coiled tubing string to a primary tubing string includes: a tool body for coupling to a downstream end of the primary tubing string, the tool body comprising a locking mechanism for selectively coupling a coiled tubing end joint to the tool body, the locking mechanism being unlockable in response to fluid pressure inside the tool body exceeding a first threshold; a wellbore access mechanism openable in response to fluid pressure inside the tool exceeding a second threshold.
The present disclosure relates to methods and apparatus for downhole installation of coiled tubing strings.
BACKGROUNDCoiled tubing strings are installed adjacent to primary tubing strings in wellbores for many different applications. Sensor instrumentation, such as thermocouples or pressure sensors, for example, may be housed in coiled tubing strings. Coiled tubing strings may also be used in chemical injection or steam injection applications.
Coiled tubing strings have a relatively small diameter, which causes the coiled tubing strings to be flexible and, therefore, easily damaged during installation. Damage to the coiled tubing typically occurs when the tubing is pushed down from the surface into a vertical section of a horizontal well. Because coiled tubing installations may be up to 1500 m in length, sinusoidal or helical buckling often occurs. In addition, excessive force applied when pushing the coiled tubing downhole often results in damage to the coiled tubing string particularly at excessive dog leg severity, upset or coupling locations.
When coiled tubing is damaged during installation, the tubing may be unusable for the immediate installation and/or for subsequent installations, particularly when the tubing breaks or fails. In some cases, damage caused during installation is not discovered immediately and the coiled tubing is operational for a time. For example, thermocouples or other downhole sensors may operate for a time and then fail. When the tubing is pulled to the surface, it may be discovered that the thermocouple failure is a result of damage that occurred during installation.
Improvement in methods and apparatus for downhole installation of coiled tubing is therefore desirable.
SUMMARYIn an aspect of the present disclosure there is provided, a tool for releasably coupling a coiled tubing string to a primary tubing string, the tool including a locking mechanism for securing the coiled tubing string to the primary tubing string, the locking mechanism being releasable to de-couple the coiled tubing string from the primary tubing string in response to a first threshold pressure being reached; wherein a portion of the primary tubing string is openable to enable communication between a channel of the primary tubing string and the wellbore in response to a second, higher, threshold pressure being reached.
In another aspect of the present disclosure there is provided a tool for releasably coupling a coiled tubing string to a primary tubing string, the tool comprising: a tool body for coupling to a downstream end of the primary tubing string, the tool body comprising a locking mechanism for selectively coupling a coiled tubing end joint to the tool body, the locking mechanism being unlockable in response to fluid pressure inside the tool body exceeding a first threshold; a wellbore access mechanism openable in response to fluid pressure inside the tool exceeding a second threshold.
In still another aspect of the present disclosure there is provided a clamp assembly for coupling a coiled tubing string to a primary tubing string, the clamp assembly comprising; a coupler for coupling adjacent primary tubing members of the primary tubing string to one another; a clamp coupled to the coupler, the clamp comprising a hinge and a bracket located opposite the hinge, the bracket for receiving the coiled tubing string; wherein the bracket is sized for limiting non-axial movement of the coiled tubing string relative to the primary tubing string.
The following figures set forth embodiments of the invention in which like reference numerals denote like parts. Embodiments of the invention are illustrated by way of example and not by way of limitation in the accompanying figures.
Numerous details are set forth to provide an understanding of the embodiments described herein. The embodiments may be practiced without these details. In other instances, well-known methods, procedures, and components have not been described in detail to avoid obscuring the embodiments described.
Referring to
As shown in
Referring back to
The tool 10 includes a tool body 30, a cover 32 and upstream and downstream housings 34 and 36, respectively. The upstream and downstream housings 34, 36 are coupled to the tool body 30 using set screws 45. The upstream and downstream housings 34, 36 are shaped to provide upstream and downstream tapers so that the tool 10 does not get caught on objects encountered downhole during deployment or retrieval of the tool 10.
Referring also to
Referring to
The first and second bores 52, 54 are sized to slidably receive first and second pistons 64 and 66, respectively, of a locking mechanism. Downstream ends 70, 72 of the pistons 64, 66 extend through openings in a wall 68 of the tool body 30 and seals are provided between the wall 68 and the pistons 64, 66. A first opening 74 extends between the channel 44 and the first bore 52 and a second opening 76 extends between the channel 44 and the second bore 54. The openings 74, 76 allow for fluid communication between the channel 44 and the bores 52, 54.
Referring also to
In order to assemble the tool 10, the tool body 30 is threaded onto the end 48 of the primary tubing string 14 and the primary tubing end joint 26 is threaded onto the opposite end of the tool body 30. The upstream housing portion 34, which is received on the primary tubing string 14, and the downstream housing portion 36, which is received on the primary tubing end joint 26, are then secured to the tool body 30 using set screws. The end portion 22 of the coiled tubing end joint 16 is then pushed into the coiled tubing-receiving channel until the end surface 40 of the coiled tubing end joint 16 abuts the plug 42. The end portion 22 forces the cams 84, 86 of the locking mechanism to pivot away from the coiled tubing string 12 as the coiled tubing end joint 16 advances and when the end portion 22 moves beyond the cams 84, 86, the cams 84, 86 are biased into abutment with the coiled tubing end joint 16. When the coiled tubing string 12 is secured to the primary tubing string 14 by the tool 10, the cams 84, 86 are in the locked position in which the downstream surfaces 94 of the cams 84, 86 abut the radially extending wall 24 of the coiled tubing end joint 16 and the axially extending surfaces 95 abut the cylindrical portion 20 of the coiled tubing end joint 16. In embodiments in which the radially extending wall is larger, the axially extending surfaces 95 may be spaced from the cylindrical portion when the cams 84, 86 are in the locked position.
In operation, after the coiled tubing string 12 has been secured to the primary tubing string 14 by the tool 10, the primary tubing string 14 is fed down a wellbore. When an installation location has been reached, fluid, such as water, for example, is pumped through the primary tubing 14. The fluid enters the channel 44 of the tool body 30 of the tool 10 and the tubing end joint 26. Because the tubing end joint 26 is sealed by the rupture disc 28, fluid is forced through the openings 74, 76 into the bores 52, 54 and pressure within the bores 52, 54 increases. When the pressure in the bores 52, 54 reaches a first threshold, the pistons 64, 66 are actuated to pivot the cams 84, 86 to an unlocked position in which the cams 84, 86 no longer engage the coiled tubing end joint 16. The coiled tubing string 12 may then be retracted from the tool 10. Fluid continues to be pumped into the primary tubing string 14 and when the pressure reaches a second threshold, the rupture disc 28 ruptures to open communication between the primary tubing string 14 and the wellbore. The primary tubing string 14 and the coiled tubing string 12 are then ready for use.
In the present example, the first threshold pressure is approximately 700 psi and the second threshold pressure is approximately 2000 psi. The thresholds are approximate and are determined based on the specifications of the rupture disc 28 and the specifications of the tool 10.
It will be appreciated by a person skilled in the art that the tool described herein is provided by way of example. Other tool configurations are possible. In general, any tool including a locking mechanism for securing the coiled tubing string to the primary tubing string that is actuable to release the coiled tubing string from the primary tubing string in response to a first threshold pressure within the tool and a channel that is openable to enable communication between a primary tubing string and the wellbore in response to a second, higher, threshold pressure may be used.
Referring to
Referring to
A plurality of slots 130 extend through the wall 132 of the fitting 112. The slots 130 are closed when the piston 120 is in an upstream position in which the piston 120 abuts the inwardly extending flange 124 to block communication between the channel 118 and the well. The slots 130 are open when the piston 120 is in a downstream position in which the piston 120 abuts the end surface 128 of the transition member 114. In the present example, six slots are provided in the wall 132 of the fitting 112. It will be appreciated by a person skilled in the art that any number of slots 130 may be used as long as the flow area of the slots generally equals the total open area of the primary tubing. Further, it will be appreciated by a person skilled in the art that the slot arrangement may be replaced with another wellbore access mechanism.
A pressure line 134 extends through a first line fitting 136, which is received in the piston 120 and coupled thereto, through the channel 118, through a second line fitting 138, which is received in the transition member 114 and coupled thereto, and through a bore 140 of the transition member 114 in order to communicate with the tool body 116. The first line fitting 136 includes a pair of seals 142 and is slidable relative to the pressure line 134.
Internal threads 144 are provided at the upstream end 122 of the fitting 112 for mating with a threaded end of the primary tubing string. Internal threads 146 are provided at the downstream end 126 of the fitting 112 for mating with a threaded upstream end 148 of the transition member 114.
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As shown in
The tool 110 includes a locking mechanism that is similar to the locking mechanism of the embodiment of
Referring to
The rotating shear joint 182 allows for rotation of the coiled tubing string 12 relative to the end joint 176. Because the rotating shear joint 182 is assembled using shear pins 188, if for any reason, the coiled tubing cannot be retracted from the tool 110, the connection between the upstream body 184 and the downsteam body 186 of the rotating shear joint 182 may be sheared and the coiled tubing 12 retracted. In one example, six shear pins 188, which have a maximum combined rating of 10000 lbs, couple the upstream body 184 and the downsteam body 186 to one another. In this example, pulling the coiled tubing 12 with a force that exceeds 10000 lbs will cause the shear pins 188 to shear so that the coiled tubing 12 may be retracted. The rotating shear joint 182 may also be used in place of the welded joint of the embodiment of
In operation, after the coiled tubing string 12 has been secured to the primary tubing string 14 by the tool 110, the primary tubing string is fed down a wellbore. When an installation location has been reached, fluid, such as water, for example, is pumped through the primary tubing string. The fluid enters an upstream end of the channel 118 of the fitting 112 and the pressure line 134. Fluid from the pressure line 134 is forced through openings into the bores 166, 168 and pressure within the bores 166, 168 increases. When the pressure in the bores 166, 168 reaches a first threshold, the pistons 170, 172 are actuated to pivot the cams 84, 86 to an unlocked position in which the cams 84, 86 no longer engage the coiled tubing end joint. The coiled tubing string 12 and end joint 176 may then be retracted from the tool 110. Fluid continues to be pumped into the primary tubing string and when the pressure within the fitting 112 reaches a second threshold, the shear pins 115 fail and the piston 120 slides into a downstream position to open the slots 130, which opens communication between the primary tubing string and the wellbore. The primary tubing string and the coiled tubing string 12 are then ready for use.
The tool 110 is a low-profile tool that includes an overall outer diameter that is less than an outer diameter of couplings of the primary tubing string. In one example, the primary tubing string has a diameter of 2⅞ inches with couplings having an outer diameter of 3½ inches. In this example, the overall outer diameter of the tool 110 is less than 3½ inches. As will be understood by a person skilled in the art, depending on the diameter of the primary tubing string, the fitting 112 of the tool 110 is interchanged with other fittings 112 in order to match the flow area of the slots with the total open area of the primary tubing.
The tool 10, 110 facilitates downhole installation of coiled tubing strings by coupling a coiled tubing string to a primary tubing string. The tool 10, 110 has a low profile so that modifications to the wellbore are not required to accommodate the tool 10, 110.
In an embodiment, the pistons are fitted with snap rings in order to restrict reverse movement of the pistons after they have been actuated. The snap rings provide a fail safe arrangement so that in the event that the fluid pressure is not able to maintain the pistons in the actuated position, the snap rings are able to perform this function.
In another embodiment, clamps are included to couple the coiled tubing 12 to the primary tubing string 10 along the length of the primary tubing string 10. Referring to
Referring also to
The bracket 224 includes a first side member 236 and a second side member 238. The side members 236, 238 include outwardly extending arms 240 for retaining the coiled tubing 12 and projections 242 that abut one another generally at a centreline of the first clamp 204. Openings 246 extend through the projection 242 of the first side member 236 and are aligned with openings 248 that extend partially through the projection 242 of the second side member 238. The openings 246, 248 receive fasteners 250, which secure the first clamp member 218 and the second clamp member 220 to one another. Openings 252 extend through the first side member 236 and the second side member 238 and are aligned with one another to receive a fastener 254 that passes through the opening 216 of the axial projection 214 of the coupler 206 that is sandwiched between the first side member 236 and the second side member 238.
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Although the example of
The clamps 204, 208 described herein couple the coiled tubing string 12 to the primary tubing string 10 along a length thereof rather than at a single location (ie. at the tool 10, 110). This arrangement avoids installations in which the coiled tubing string 12 becomes wrapped around the primary tubing string 10 in a helical manner, which leads to difficulties extracting the coiled tubing string 12 without damage occurring thereto.
Specific embodiments have been shown and described herein. Modifications and variations may occur to those skilled in the art. All such modifications and variations are believed to be within the scope and sphere of the present invention.
Claims
1. A tool for releasably coupling a coiled tubing string to a primary tubing string, the tool comprising:
- a tool body for coupling to a downstream end of the primary tubing string, the tool body comprising a locking mechanism for selectively coupling a coiled tubing end joint to the tool body, the locking mechanism being unlockable in response to fluid pressure inside the tool body exceeding a first threshold;
- a wellbore access mechanism openable in response to fluid pressure inside the tool exceeding a second threshold.
2. The tool of claim 1, wherein the wellbore access mechanism is located upstream of the tool body.
3. The tool of claim 1, comprising a rotating shear joint coupled to the coiled tubing end joint for receiving an end of the coiled tubing string.
4. The tool of claim 1, comprising a clamp coupled to a coupler of the primary tubing string, the clamp for receiving the coiled tubing string at a location along a length of the primary tubing string.
5. The tool of claim 1, wherein the tool body comprises:
- a first end for coupling to a primary tubing string;
- a second end for coupling to a primary tubing end joint;
- an inner surface defining a channel and first and second bores, the channel for receiving fluid from an outlet of the primary tubing string, the first and second bores being in fluid communication with the channel through openings located adjacent an upstream end of the first and second bores; and
- a coiled tubing string support for receiving an end joint of the coiled tubing string;
- first and second pistons slidably received in the first and second bores;
- first and second cams coupled to the outer surface of a tool body housing at locations circumferentially spaced on either side of the coiled tubing string support, the first and second cams being movable between a locked position in which the cams abut an upstream side of a radially extending structure of the coiled tubing string end joint and an unlocked position in which the first and second cams are radially spaced from the radially extending structure, the first and second cams being biased toward the locked position and being movable in response to movement of the first and second pistons;
- wherein when fluid pressure within the tool body exceeds the first threshold, the first piston and the second piston are actuated to move the first cam and the second cams to the unlocked position for releasing the coiled tubing string and when the fluid pressure within the tool body exceeds the second threshold, the channel of the tool body being opened.
6. The tool of claim 1, wherein the tool body comprises:
- a coiled tubing receiving channel for receiving a downstream portion of the coiled tubing end joint;
- a first end for coupling to a transition member, the transition member for receiving an upstream portion of the coiled tubing end joint to direct the coiled tubing end joint into the coiled tubing receiving channel;
- first and second bores for receiving fluid from an outlet of the primary tubing string,
- first and second pistons slidably received in the first and second bores;
- first and second cams coupled to the outer surface of the housing at locations circumferentially spaced on either side of the coiled tubing string support, the first and second cams being movable between a locked position in which the cams abut an upstream side of a radially extending structure of the coiled tubing string end joint and an unlocked position in which the first and second cams are radially spaced from the radially extending structure, the first and second cams being biased toward the locked position and being movable in response to movement of the first and second pistons;
- wherein when fluid pressure within the tool body exceeds the first threshold, the first piston and the second piston are actuated to move the first cam and the second cams to the unlocked position for releasing the coiled tubing string.
7. The tool of claim 6, wherein the first and second bores receive fluid through a pressure line for communicating with the outlet, the pressure line extending through the transition member.
8. The tool of claim 1, wherein the wellbore access mechanism comprises:
- a fitting for coupling to a downstream end of the primary tubing string, the fitting comprising slots extending through a wall of the fitting;
- a piston slidable though a channel of the fitting between a first position in which communication between the channel and the wellbore is blocked and a second position in which communication between the channel and the wellbore is open; and
- shear pins coupling the piston to the fitting;
- wherein the shear pins fail in response to the fluid pressure exceeding the second threshold to release the piston to the second position.
9. The tool of claim 1, comprising a transition member between the tool body and the wellbore access mechanism, the transition member for transitioning the coiled tubing end joint into a position within the tool body.
10. The tool of claim 1, wherein the tool body is bullnose-shaped.
11. The tool of claim 5, wherein the first and second pistons are fitted with snap rings.
12. The tool of claim 6, wherein the first and second pistons are fitted with snap rings.
13. A clamp assembly for coupling a coiled tubing string to a primary tubing string, the clamp assembly comprising;
- a coupler for coupling adjacent primary tubing members of the primary tubing string to one another;
- a clamp coupled to the coupler, the clamp comprising a hinge and a bracket located opposite the hinge, the bracket for receiving the coiled tubing string;
- wherein the bracket is sized for limiting non-axial movement of the coiled tubing string relative to the primary tubing string.
14. The clamp assembly of claim 13, wherein the clamp comprises cutouts for receiving axially extending projections of the coupler to couple the clamp to the primary tubing string.
15. The clamp assembly of claim 13, wherein the clamp assembly is openable for receiving the primary tubing string by pivoting first and second clamp members about a hinge pin of the hinge.
16. The clamp assembly of claim 14, comprising a second clamp coupled to axially extending projections extending from an opposite end of the coupler.
17. The clamp assembly of claim 14, wherein the axially extending projections comprise circumferentially extending openings for receiving fasteners to couple the clamp to the coupler.
Type: Application
Filed: Dec 19, 2013
Publication Date: Jun 26, 2014
Inventors: Chad Barber (Calgary), Denis Gilbert (Calgary), Arnoud Struyk (Calgary)
Application Number: 14/135,314
International Classification: E21B 23/00 (20060101); E21B 17/02 (20060101);