HIGH-TENSILE, THIN-WALL DIFFERENTIAL THREADED COUPLING
The disclosed embodiments include a differential coupling system, a method of coupling a first mandrel to a second mandrel and a coupler. In one embodiment, the system includes a first mandrel having a first external thread about an external surface of the first mandrel. The system also includes a second mandrel having a second external thread about an external surface of the second mandrel. The system further includes a coupler that includes a first internal thread that complements the first external thread of the first mandrel and a second internal thread that complements the second external thread of the second mandrel. The system further includes an aligning pin configured to engage a first aligning hole of the first mandrel and a second aligning hole of the second mandrel to restrict axial rotation between the first mandrel and the second mandrel when the first mandrel is engaged to the second mandrel.
The present disclosure relates to oil and gas exploration and production, and more particularly to a coupling subassembly for joining together tubing segments in a tool string.
Wells are drilled at various depths to access and produce oil, gas, minerals, and other naturally-occurring deposits from subterranean geological formations. Wells are also drilled in a variety of environments, including in deep water where ocean floor conditions may be softer or more unconsolidated. In such wells, drill strings and completion strings may extend to a variety of depths and may follow relatively circuitous paths to reach a location of a geological formation that is rich in extractable hydrocarbons.
To deploy tools at various locations and depths in the wellbore, a tool string, which may include a running tool, may be used to deploy tools or other devices. To form the tool string, tubing segments may be coupled together or with tooling subassemblies. These couplings may be achieved using coupling subassemblies that form robust, sealed joints between segments of tubing in a tool string. The coupling subassemblies also allow coupled tubing segments to disengage from each other.
The following figures are included to illustrate certain aspects of the present disclosure, and should not be viewed as exclusive embodiments. The subject matter disclosed is capable of considerable modifications, alterations, combinations, and equivalents in form and function, without departing from the scope of this disclosure.
The illustrated figures are only exemplary and are not intended to assert or imply any limitation with regard to the environment, architecture, design, or process in which different embodiments may be implemented.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTSIn the following detailed description of the illustrative embodiments, reference is made to the accompanying drawings that form a part hereof These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is understood that other embodiments may be utilized and that logical structural, mechanical, electrical, and chemical changes may be made without departing from the spirit or scope of the invention. To avoid detail not necessary to enable those skilled in the art to practice the embodiments described herein, the description may omit certain information known to those skilled in the art. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the illustrative embodiments is defined only by the appended claims.
Liner hanger systems and other types of tool strings may be used during well construction or well remediation and repair in locations ranging from just below the wellhead system to locations deep within a well. Tool strings used in such systems may therefore be extendable, and may include couplings that are tolerant of bending and vibration induced forces to resist decoupling within the wellbore. In particular, tool strings, such as Drill String Testing (DST) strings, that deploy running tools used to place or set downhole equipment, such as liner hangers, plugs or packers, may be resistant to such induced forces to maintain the integrity of the tool string and prevent the loss of the tool in the well. Tool strings that deploy other types of tools may be similarly resistant to such induced forces.
Some tool strings may include coupling assemblies where tubing segments are joined together by couplers to extend the tool string further into a formation. The present disclosure relates to a coupling assembly that tolerates the static and dynamic loads experienced by the tool string and prevents the tool string from decoupling due to hoop stress, vibration, torsion, and other forces that may be experienced when the tool string is rotated and/or manipulated in a well. The coupling assembly is also operable to withstand additional loads, which may result from non-conventional or unanticipated loading of threaded interfaces when the assembly is navigating a tight radius in the well. In some embodiments, the coupling assembly is used in a Landing String of a (DST string. In one of such embodiments, the coupling assembly is installed on an ocean floor subsea equipment such as a blowout preventer (BOP) to provide for disconnection and isolation of tubing pressure in case of a required ocean floor disconnect during the DST operations. In another one of such embodiments, the coupling assembly is installed on DST tools positioned further downhole from the ocean floor. In further embodiments, the coupling assembly is used to couple tubing segments in any suitable tool string, including, for example, a running tool for deploying a liner hanger.
Turning now to the figures,
Alternatively,
The tool string 128 may include sections of tubing, each of which are joined to adjacent tubing by threaded or other connection types, such as coupling assembly 100. The tool string 128 may refer to the collection of pipes, mandrels or tubes as a single component, or alternatively to the individual pipes, mandrels, or tubes that comprise the string. The term tool string is not meant to be limiting in nature and may include a running tool or any other type of tool string used to deploy the tool 144 or equipment in the wellbore. In some embodiments, the tool string 128 may include a passage disposed longitudinally in the tool string 128 that is capable of allowing fluid communication between the surface 124 of the well 102 and a downhole location 136. It is noted that the coupling assembly 100 described herein may be used to couple tubing segments in any suitable tool string, including, for example, a running tool for deploying a liner hanger.
The lowering of the tool string 128 may be accomplished by a lift assembly 106 associated with a derrick 114 positioned on or adjacent to the rig 104 or offshore platform 142. The lift assembly 106 may include a hook 110, a cable 108, a traveling block (not shown), and a hoist (not shown) that cooperatively work together to lift or lower a swivel 116 that is coupled an upper end of the tool string 128. The tool string 128 may be raised or lowered as needed to add additional sections of tubing to the tool string 128 to position the distal end of the tool string 128 at the downhole location 136 in the wellbore 130.
An illustrative embodiment of a coupling assembly 100 that may be used to couple together tubing segments in a tool string is described in more detail with regard to
The coupler 202 includes a threaded interface about an internal surface of the coupler 202 to engage the first mandrel 204 and second mandrel 206. In an embodiment, the coupler 202 includes a first internal thread 210 on a first end 236 of the coupler 202 and a second internal thread 212 on a second end 238 of the coupler 202. The first internal thread 210 engages a first external thread 218 of the first mandrel 204 and the second internal thread 212 engages a second external thread 226 of the second mandrel 206.
In some embodiments, the first internal thread 210 and the second internal thread 212 have different thread pitches. In such embodiments, the first external thread 218 is complementary to and engages the first internal thread 210 and the second external thread 226 is complementary to and engages the second internal thread 212.
One or more aligning pins 216 are inserted into first mandrel aligning holes 219 and second mandrel aligning holes 217. In the embodiment illustrated in
In some embodiments, the coupling assembly 100 further includes a locking mechanism 240, such as a locknut, positioned adjacent to the first end 236 or the second end 238 of the coupler 202. The locking mechanism 240 has a threaded interface 242 to engage the first mandrel 204 or second mandrel 206 and to prevent longitudinal motion of the coupler 202 with respect to the first mandrel 204 or the second mandrel 206. In one of such embodiments, multiple locking mechanisms (not shown) are positioned adjacent to both the first end 236 and the second end 238 of the coupler 202 to secure the coupler 202 and to prevent longitudinal motion of with respect to the first or the second mandrels 204 and 206.
The first visual indicator 266 may be a milled, etched, painted, or otherwise marked radial line, on the outer surface of the first mandrel 204 at a first, predetermined distance from the first end 230 of the first mandrel 204. In the embodiment of
The second visual indicator 267, similar to the first visual indicator 266, may be a milled, etched, painted, or otherwise marked radial line, on the outer surface of the second mandrel 206 at a first, predetermined distance from the second end 232 of the second mandrel 206. In some embodiments, the second visual indicator 267 provides a visual indication of a location of one of the second mandrel aligning holes 217 of the second mandrel 206. In other embodiments, the first and second visual indicators 266 and 267 provide a visual indication that the first mandrel 204 and second mandrel 206 are aligned. As such, the first and second visual indicators 266 and 267 provide readily identifiable alignment indications even when view of the aligning pins 216 and port interfaces 220 are hidden from view by the coupler 202.
In the embodiment illustrated in
An illustrative method of assembling the foregoing parts of the coupling assembly 100 is described with regard to
The second internal thread 212 of the coupler 202 is then threaded to the second external thread 226 of the second mandrel 206 to engage the second end 232 of the second mandrel 206 with the second end 238 of the coupler 202. Given that the first mandrel 204 is already engaged to the coupler 202, threading the coupler 202 to the second mandrel 206 causes the first mandrel 204 to disengage from the coupler 202 at the first engagement rate.
The differential pitch between the first internal thread 210 and second internal thread 212, however, induces the second mandrel 206 to axially engage the coupler 202 at a second engagement rate that is different than the first engagement rate (or disengagement rate of the first mandrel 204). For example, if the pitch of the first internal thread 210 and first external thread 218 is approximately three threads per inch while the thread pitch of the second internal thread 212 and second external thread 226 is approximately two threads per inch, then the coupler 202 will engage the second mandrel 206 approximately fifty percent faster than the coupler 202 will disengage from the first mandrel 204, thereby resulting in the first mandrel 204 moving toward the second mandrel 206 if the coupler 202 is turned while the first mandrel 204 and second mandrel 206 are constrained from rotating. In an embodiment, the first mandrel 204 and second mandrel 206 are constrained from rotating relative to one another by aligning pins 216.
The foregoing method induces the second mandrel 206 to move towards the first mandrel 204 until the first end 230 of the first mandrel 204 is engaged to the second end 232 of the second mandrel 206. The method may further include visually or optically inspecting the interface between the first mandrel 204 and second mandrel via the window 260 to determine if the first mandrel 204 is aligned with the second mandrel 206.
The above-disclosed embodiments have been presented for purposes of illustration and to enable one of ordinary skill in the art to practice the disclosure, but the disclosure is not intended to be exhaustive or limited to the forms disclosed. Many insubstantial modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the disclosure. For instance, although the flowcharts depict a serial process, some of the steps/processes may be performed in parallel or out of sequence, or combined into a single step/process. The scope of the claims is intended to broadly cover the disclosed embodiments and any such modification. Further, the following clauses represent additional embodiments of the disclosure and should be considered within the scope of the disclosure:
Clause 1, a differential threaded coupling system comprising: a first mandrel having a first external thread about an external surface of the first mandrel; a second mandrel having a second external thread about an external surface of the second mandrel; a coupler comprising a first internal thread that complements the first external thread of the first mandrel and a second internal thread that complements the second external thread of the second mandrel; and an aligning pin configured to engage a first aligning hole of the first mandrel and a second aligning hole of the second mandrel to restrict axial rotation between the first mandrel and the second mandrel when the first mandrel is engaged to the second mandrel.
Clause 2, the coupling system of clause 1, wherein each tooth of the first external thread and second external thread has a reverse lead flank angle of approximately −3 to −30 degrees and a trailing flank angle of approximately 30 to 60 degrees.
Clause 3, the coupling system of clause 2, wherein the reverse lead angle is approximately −7 degrees and the trailing flank angle is approximately 45 degrees.
Clause 4, the coupling system of any of clauses 1-3, wherein the first external thread and first internal thread have a first thread pitch and the second internal thread and second external thread have a second thread pitch, the second thread pitch being less than the first thread pitch, such that rotation of the coupler results in an engagement rate of the coupler to the second mandrel that is greater than a disengagement rate of the coupler to the first mandrel.
Clause 5, the coupling system of any of clauses 1-4, further comprising a plurality of port interfaces, each port interface forming a coupling between a first conduit of the first mandrel and a second conduit of the second mandrel.
Clause 6, the coupling system of any of clauses 1-5, wherein the plurality of port interfaces comprises an electrical connector, and wherein the electrical connector is coupled to a first conduit comprising an electrical conduit, and a second conduit comprising an electrical conduit.
Clause 7, the coupling system of any of clauses 1-6, wherein the plurality of port interfaces comprises a hydraulic connector, and wherein the hydraulic connector is coupled to a first conduit comprising a fluid conduit, and a second conduit comprising a fluid conduit.
Clause 8, the coupling system of any of clauses 1-7, wherein the coupler comprises a window for viewing the first mandrel and second mandrel when the first and second mandrels are coupled to the coupler.
Clause 9, a method of coupling a first mandrel to a second mandrel, the method comprising: aligning a first end of a first mandrel to a second end of a second mandrel, the first mandrel having a first external thread about an external surface of the first mandrel and the second mandrel having a second external thread about an external surface of the second mandrel; threading a coupler to the first mandrel to engage a first internal thread of the coupler to the first external thread of the first mandrel, wherein the first internal thread and first external thread have a first thread pitch; threading the coupler to the second mandrel to engage a second internal thread of the coupler to the second external thread of the second mandrel, wherein the second internal thread and second external thread have a second thread pitch, wherein the second thread pitch is less than the first thread pitch, such that rotating the coupler relative to the first mandrel and second mandrel simultaneously results in the coupler engaging the second mandrel at a faster rate than the coupler disengages the first mandrel, and the second mandrel being drawn towards the first mandrel until the first end of the first mandrel engages the second end of the second mandrel.
Clause 10, the method of clause 9, wherein aligning the first end of the first mandrel to the second end of the second mandrel comprises aligning an aligning pin with a first aligning hole of the first mandrel and a second aligning hole of the second mandrel, wherein the aligning pin is configured to restrict axial rotation between the first mandrel and the second mandrel when the first mandrel is engaged to the second mandrel.
Clause 11, the method of any of clauses 9 and 10, wherein aligning the first end of the first mandrel to the second end of the second mandrel comprises aligning a plurality of port interfaces, the method further comprising coupling a first conduit of the first mandrel to a second conduit of the second mandrel at each of the plurality of port interfaces.
Clause 12, the method of any of clauses 9-11, wherein the plurality of port interfaces comprises an electrical connector, and wherein each electrical connector is coupled to a first conduit comprising an electrical conduit, and a second conduit comprising an electrical conduit.
Clause 13, the method of any of clauses 9-12, wherein the plurality of port interfaces comprises a hydraulic connector, and wherein each hydraulic connector is coupled to a first conduit comprising a fluid conduit, and a second conduit comprising a fluid conduit.
Clause 14, the method of any of clauses 9-13, further comprising aligning a first visual indicator of the first mandrel to a second visual indicator of the second mandrel to align the first end of the first mandrel to the second end of the second mandrel.
Clause 15, the method of any of clauses 9-14, further comprising visually determining if the first end of the first mandrel is aligned with the second end of the second mandrel by observing the first mandrel and second mandrel through a window of the coupler.
Clause 16, the method of any of clauses 9-15, wherein each of the first external thread and second external thread has a reverse lead flank angle of approximately −3 to −30 degrees and a trailing flank angle of approximately 30 to 60 degrees.
Clause 17, the method of clause 16, wherein the reverse lead angle is approximately −7 degrees and the trailing flank angle is approximately 45 degrees.
Clause 18, a coupler comprising: a cavity having a first end for receiving a first mandrel and a second end for receiving a second mandrel; a first internal thread at the first end, the first internal thread having a thread profile that complements a first external thread of the first mandrel, wherein the first internal thread and first external thread have a first thread pitch; and a second internal thread having a thread profile that complements a second external thread of the second mandrel, wherein the second internal thread and second external thread have a second thread pitch, the second thread pitch being less than the first thread pitch such that rotating the coupler relative to the first mandrel and second mandrel simultaneously results in the coupler engaging the second mandrel at a faster rate than the coupler disengages the first mandrel.
Clause 19, the coupler of clause 18, further comprising a window to provide a view of the first mandrel and second mandrel when the first mandrel and second mandrel are engaged by the coupler.
Clause 20, the coupler of any of clauses 18 and 19, further comprising at least one visual indicator indicative of a rotational position of the coupler with respect to at least one of the first mandrel and the second mandrel.
Unless otherwise specified, any use of any form of the terms “connect,” “engage,” “couple,” “attach,” or any other term describing an interaction between elements in the foregoing disclosure is not meant to limit the interaction to direct interaction between the elements and may also include indirect interaction between the elements described. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. Unless otherwise indicated, as used throughout this document, “or” does not require mutual exclusivity. It will be further understood that the terms “comprise” and/or “comprising,” when used in this specification and/or the claims, specify the presence of stated features, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof. In addition, the steps and components described in the above embodiments and figures are merely illustrative and do not imply that any particular step or component is a requirement of a claimed embodiment.
It should be apparent from the foregoing that embodiments of an invention having significant advantages have been provided. While the embodiments are shown in only a few forms, the embodiments are not limited but are susceptible to various changes and modifications without departing from the spirit thereof.
Claims
1. A differential threaded coupling system comprising:
- a first mandrel having a first external thread about an external surface of the first mandrel;
- a second mandrel having a second external thread about an external surface of the second mandrel;
- a coupler comprising a first internal thread that complements the first external thread of the first mandrel and a second internal thread that complements the second external thread of the second mandrel; and
- an aligning pin configured to engage a first aligning hole of the first mandrel and a second aligning hole of the second mandrel to restrict axial rotation between the first mandrel and the second mandrel when the first mandrel is engaged to the second mandrel.
2. The system of claim 1, wherein each tooth of the first external thread and second external thread has a reverse lead flank angle of approximately −3 to −30 degrees and a trailing flank angle of approximately 30 to 60 degrees.
3. The system of claim 2, wherein the reverse lead angle is approximately −7 degrees and the trailing flank angle is approximately 45 degrees.
4. The system of claim 1, wherein the first external thread and first internal thread have a first thread pitch and the second internal thread and second external thread have a second thread pitch, the second thread pitch being less than the first thread pitch, such that rotation of the coupler results in an engagement rate of the coupler to the second mandrel that is greater than a disengagement rate of the coupler to the first mandrel.
5. The system of claim 1, wherein the coupler comprises a window for viewing the first mandrel and second mandrel when the first and second mandrels are coupled to the coupler.
6. The system of claim 1, further comprising a plurality of port interfaces, each port interface forming a coupling between a first conduit of the first mandrel and a second conduit of the second mandrel.
7. The system of claim of claim 6, wherein the plurality of port interfaces comprises an electrical connector, and wherein the electrical connector is coupled to a first conduit comprising an electrical conduit, and a second conduit comprising an electrical conduit.
8. The system of claim of claim 6, wherein the plurality of port interfaces comprises a hydraulic connector, and wherein the hydraulic connector is coupled to a first conduit comprising a fluid conduit, and a second conduit comprising a fluid conduit.
9. A method of coupling a first mandrel to a second mandrel, the method comprising:
- aligning a first end of a first mandrel to a second end of a second mandrel, the first mandrel having a first external thread about an external surface of the first mandrel and the second mandrel having a second external thread about an external surface of the second mandrel;
- threading a coupler to the first mandrel to engage a first internal thread of the coupler to the first external thread of the first mandrel, wherein the first internal thread and first external thread have a first thread pitch; and
- threading the coupler to the second mandrel to engage a second internal thread of the coupler to the second external thread of the second mandrel, wherein the second internal thread and second external thread have a second thread pitch,
- wherein the second thread pitch is less than the first thread pitch, such that rotating the coupler relative to the first mandrel and second mandrel simultaneously results in the coupler engaging the second mandrel at a faster rate than the coupler disengages the first mandrel, and the second mandrel being drawn towards the first mandrel until the first end of the first mandrel engages the second end of the second mandrel.
10. The method of claim 9, wherein aligning the first end of the first mandrel to the second end of the second mandrel comprises aligning an aligning pin with a first aligning hole of the first mandrel and a second aligning hole of the second mandrel, wherein the aligning pin is configured to restrict axial rotation between the first mandrel and the second mandrel when the first mandrel is engaged to the second mandrel.
11. The method of claim 9, wherein aligning the first end of the first mandrel to the second end of the second mandrel comprises aligning a plurality of port interfaces, the method further comprising coupling a first conduit of the first mandrel to a second conduit of the second mandrel at each of the plurality of port interfaces.
12. The method of claim 11, wherein the plurality of port interfaces comprises an electrical connector, and wherein each electrical connector is coupled to a first conduit comprising an electrical conduit, and a second conduit comprising an electrical conduit.
13. The method of claim 11, wherein the plurality of port interfaces comprises a hydraulic connector, and wherein each hydraulic connector is coupled to a first conduit comprising a fluid conduit, and a second conduit comprising a fluid conduit.
14. The method of claim 9, further comprising aligning a first visual indicator of the first mandrel to a second visual indicator of the second mandrel to align the first end of the first mandrel to the second end of the second mandrel.
15. The method of claim 14, further comprising visually determining if the first end of the first mandrel is aligned with the second end of the second mandrel by observing the first mandrel and second mandrel through a window of the coupler.
16. The method of claim 9, wherein each of the first external thread and second external thread has a reverse lead flank angle of approximately −3 to −30 degrees and a trailing flank angle of approximately 30 to 60 degrees.
17. The method of claim 16, wherein the reverse lead angle is approximately −7 degrees and the trailing flank angle is approximately 45 degrees.
18. A coupler comprising:
- a cavity having a first end for receiving a first mandrel and a second end for receiving a second mandrel;
- a first internal thread at the first end, the first internal thread having a thread profile that complements a first external thread of the first mandrel, wherein the first internal thread and first external thread have a first thread pitch; and
- a second internal thread having a thread profile that complements a second external thread of the second mandrel, wherein the second internal thread and second external thread have a second thread pitch, the second thread pitch being less than the first thread pitch such that rotating the coupler relative to the first mandrel and second mandrel simultaneously results in the coupler engaging the second mandrel at a faster rate than the coupler disengages the first mandrel.
19. The coupler of claim 18, further comprising a window to provide a view of the first mandrel and second mandrel when the first mandrel and second mandrel are engaged by the coupler.
20. The coupler of claim 18, further comprising at least one visual indicator indicative of a rotational position of the coupler with respect to at least one of the first mandrel and the second mandrel.
Type: Application
Filed: Dec 15, 2015
Publication Date: Aug 23, 2018
Inventors: Robert Brice PATTERSON (Fort Worth, TX), Benjamin Thomas DERRYBERRY (Plano, TX), Paul David RINGGENBERG (Frisco, TX)
Application Number: 15/754,266