Threaded connector for well servicing applications
A threaded connection assembly comprises a nut, a multiplier connected to the nut via a first threaded interface having a first number of threads per inch and a well servicing pipe coupling connected to the multiplier via a second threaded interface having a second number of threads per inch. A method of forming a threaded connection for a well servicing application comprises forming a pipe coupling between two well servicing pipe sections and threading a connector to the pipe coupling to form a threaded connection without impact loading the connector. Another method for forming a threaded connection comprises disposing a first pipe section partially within a nut, threading a multiplier into the nut, threading the multiplier onto a second pipe section, and leveraging the multiplier against the nut, or vice versa.
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STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENTNot applicable.
REFERENCE TO A MICROFICHE APPENDIXNot applicable
FIELD OF THE INVENTIONThe present invention relates generally to threaded connectors comprising differential thread pitches, and methods of making up a pipe connection via such threaded connectors. More particularly, the present invention relates to threaded connectors for well servicing applications and methods of connecting two pipe sections together by leveraging one component of a threaded connector against another.
BACKGROUNDThreaded connectors, such as a union comprising an internally threaded nut, for example, may be used to provide a preloaded threaded connection between two sections of pipe in a well servicing application. Such threaded connectors are commonly used for high pressure manifolding connections in well servicing applications, such as fracturing, stimulating, and cementing operations. Typically, the equipment, such as pumps, blenders, and threaded connectors, for example, that is required to rig up a manifolding network to a wellhead is transported to the wellsite. As the manifolding network is connected to the wellhead, two pipe sections may be coupled and a union with internal threads and external wings or lugs may be used to form a threaded connection with the two pipe sections by impact loading. First, a pin-end pipe section extends into a box-end pipe section with a face seal provided between them. Then the union is installed over the coupled pipe sections by internal threads on the union engaging external threads on one or both of the pipe sections to form the threaded connection. Finally, the threaded connection is preloaded to prevent the face seal from extruding under pressure. To preload the threaded connection, a sledge hammer is typically used to apply force to the radially extending lugs on the union, thereby rotating the union and tightening the threaded connection until a desired amount of preload force is achieved.
A significant amount of preload force may be required to maintain the face seal when under pressure. Hence, the impact load necessary to make up the threaded connection can be significant, requiring repeated blows of a sledge hammer that may weigh approximately 6 to 8 pounds, for example. Such impact loading may lead to various types of physical injuries, including stress-related injuries, to the personnel who make up these connections, especially in extremely cold or extremely hot environments.
Thus, a need exists for alternative apparatus and methods to make up threaded connections in well servicing applications without impact loading. The ability to make up threaded connections without impact loading may remove hazards associated with swinging hammers, trip hazards due to hydraulic and pneumatic lines and power tools, and flying debris from impact on traditional connections. Due to the significant preload force required in such threaded connections, the alternative apparatus and methods must be capable of applying the requisite preload force to maintain a positive face seal between two pipe sections when that threaded connection is under pressure.
SUMMARY OF THE INVENTIONIn one aspect, the present disclosure relates to a threaded connection assembly comprising a nut, a multiplier connected to the nut via a first threaded interface having a first number of threads per inch (first TPI), and a well servicing pipe coupling connected to the multiplier via a second threaded interface having a second number of threads per inch (second TPI). The first threaded interface and the second threaded interface may be at least partially formed simultaneously. In an embodiment, the first TPI is less than the second TPI. The threaded connection assembly may further comprise a negative equivalent TPI between the nut and the well servicing pipe coupling. In an embodiment, the nut connects to the well servicing pipe coupling via a non-threaded connection. The well servicing pipe coupling may comprise a pin-end pipe section disposed partially within a box-end pipe section with a face seal provided therebetween. The nut and the multiplier may rotate in opposite directions to form the second threaded interface. The threaded connection assembly may further comprise a torque tool that simultaneously imparts a rotational force to the nut and an opposite rotational force to the multiplier. In various embodiments, the torque tool simultaneously engages a hole in the nut and a hole in the multiplier, or a spline on the nut and a hole in the multiplier, or vice versa, or a spline on the nut and a spline on the multiplier. The torque tool may comprise a mechanical tool, a hydraulic tool, a pneumatic tool, an electrical tool, or a combination thereof.
In another aspect, the present disclosure relates to a method of forming a threaded connection for a well servicing application comprising forming a pipe coupling between two well servicing pipe sections, and threading a connector to the pipe coupling to form a threaded connection without impact loading the connector. The well servicing application may comprise fracturing, stimulating or cementing. The method may further comprise preloading the threaded connection without impact loading the connector, and performing the well servicing application, wherein the preloading prevents a seal in the pipe coupling from extruding during the well servicing application. In an embodiment, threading the connector to the pipe coupling comprises leveraging a portion of the connector against another portion of the connector. In an embodiment, preloading the threaded connection comprises imparting a rotational force to a first portion of the connector and simultaneously imparting an opposite rotational force to a second portion of the connector.
In yet another aspect, the present disclosure relates to a method of forming a threaded connection for a well servicing application comprising disposing a first pipe section partially within a nut, threading a multiplier into the nut, threading the multiplier onto a second pipe section, and leveraging the multiplier against the nut, or vice versa. The method may further comprise attaching the nut to the first pipe section via a non-threaded connection. In an embodiment, the method further comprises simultaneously imparting opposite rotational forces to the multiplier and the nut to tighten the threaded connection. The rotational forces may be imparted mechanically, hydraulically, pneumatically, electrically, or a combination thereof. The method may further comprise providing a face seal between the first pipe section and the second pipe section, tightening the threaded connection to provide a sufficient preload to prevent the face seal from extruding during the well servicing application, and performing the well servicing application.
In still another aspect, the present disclosure relates to a torque tool comprising a first engaging portion that engages a first component of a connector, a second engaging portion that engages a second component of the connector, and a threaded shaft extending between the first engaging portion and the second engaging portion, wherein rotation of the threaded shaft simultaneously imparts opposite rotational forces to the first component and the second component of the connector. In an embodiment, the first engaging portion and the second engaging portion are disposed at a 90 degree angle. The torque tool may further comprise a load-bearing shaft extending between the first engaging portion and the second engaging portion. In various embodiments, the first engaging portion engages a hole or a spline in the first component of the connector, and the second engaging portion engages a hole or a spline in the second component of the connector.
BRIEF DESCRIPTION OF THE DRAWINGSFor a more detailed description of the present invention, reference will now be made to the accompanying drawings, wherein:
Certain terms are used throughout the following description and claims to refer to particular components. This document does not intend to distinguish between components that differ in name but not function. In the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to . . . ”.
DETAILED DESCRIPTIONVarious embodiments of threaded connectors for use in well servicing applications will now be described with reference to the accompanying drawings, wherein like reference numerals are used for like features throughout the several views. There are shown in the drawings, and herein will be described in detail, specific embodiments of threaded connectors operable to connect two pipe sections together without the application of an impact load, with the understanding that this disclosure is representative only and is not intended to limit the invention to those embodiments illustrated and described herein. The embodiments of the threaded connectors and the methods disclosed herein may be used in any type of well servicing application where it is desired to connect two pipe sections together. It is to be fully recognized that the different teachings of the embodiments disclosed herein may be employed separately or in any suitable combination to produce desired results.
Referring again to
TPIEQ=(TPInut-multiplier×TPImultiplier-box) /(TPInut-multiplier−TPImultiplier-box)
where:
-
- TPIEQ is the equivalent number of threads per inch between the nut 130 and the box-end pipe section 230,
- TPInut-multiplier is the number of threads per inch at the nut-multiplier threads 145, and
- TPImultiplier-box is the number of threads per inch at the multiplier-box threads 155.
One advantage of this fine equivalent TPI is that less torque must be applied to the threaded connection 110 to reach a desired preload during make up.
In one embodiment, the threaded connector 100 is designed such that the number of threads per inch at the nut-multiplier threads 145 (TPInut-multiplier) is less than the number of threads per inch at the multiplier-box threads 155 (TPImultiplier-box), which results in a negative equivalent number of threads per inch (−TPIEQ) between the nut 130 and the box-end pipe section 230 per the above equation. For example, where TPInut-multiplier =3 and TPImultiplier-box =4, the TPIEQ =− 12. This negative −TPIEQ enables the multiplier 140 to thread into the nut 130 in a rotational direction opposite the direction the multiplier 140 rotates when threading onto the box-end pipe section 230. Specifically, after the multiplier 140 has been partially threaded onto the box-end pipe section 230 via the multiplier-box threads 155, the multiplier 140 may then be threaded into the nut 130 by rotating the multiplier 140 in the opposite direction. Thus, the multiplier 140 actually begins threading off of the box-end pipe section 230 as it threads onto the nut 130 at a faster rate to tighten the connection. This design is functionally advantageous for several reasons. First, the multiplier 140 threads into, not out of, the nut 130 as the threaded connection 110 is tightened. Second, the threaded connection 110 is made up by leveraging the nut 130 against the multiplier 140. Such leveraging eliminates the need for impact loading or for leverage from another source besides the threaded connector 100 components 130, 140 during make up of the threaded connection 110.
In another embodiment, the TPIEQ between the nut 130 and the box-end pipe section 230 may be positive. Per the above equation, a positive equivalent number of threads per inch (+TPIEQ) between the nut 130 and the box-end pipe section 230 would result if the number of threads per inch at the nut-multiplier threads 145 (TPInut-multiplier) were greater than the number of threads per inch at the multiplier-box threads 155 (TPImultiplier-box). Then, the multiplier 140 would have to rotate in the same direction to thread into the nut 130 and to thread onto the box-end pipe section 230. This would prevent the nut 130 from providing leverage for the multiplier 140 when tightening the threaded connection 110. Thus, leverage for this tightening process would have to be provided by another source besides the threaded connector 100 components 130, 140, or the threaded connection 110 would have to be made up by another method.
Referring now to
In the final step of make up, as depicted in
Thus, the threaded connection 110 shown in
During the final stage of make up of the threaded connection 110, the torque tool 300 is inserted into the threaded connector 100 by inserting the multiplier-engaging pin 390 into one of the holes 180 in the multiplier 140 and the nut-engaging pins 370, 380 into two adjacent bores 190 in the nut 130, as shown in perspective front and back views in
A socket wrench, torque wrench, drill or similar tool may then be inserted into the hex 310 of the torque tool 300 to apply a rotational force to the threaded shaft 320, thereby causing it to rotate or thread out of the first support 340. As the threaded shaft 320 threads out of the first support 340, it acts to push the first support 340 away from the second support 350. Further, because the threaded shaft 320 is not slideable relative to the second support 350, and the second support 350 is fixed relative to the third support 360, rotation of the threaded shaft 320 also pushes the first support 340 and the third support 360 apart. This action causes the nut 130 and the multiplier 140 to rotate in opposite directions, thus tightening the threaded connection 110. Also, because the number of threads per inch at the nut-multiplier threads 145 (TPInut multiplier) is less than the number of threads per inch at the multiplier-box threads 155 (TPImultiplier-box), the nut 130 actually tightens onto the multiplier 140 faster than the multiplier 140 threads off of the box-end pipe section 230.
One of ordinary skill in the art will readily appreciate that the torque tool 300 depicted and described above represents only one possible tool design that could be utilized to tighten the threaded connection 110. In fact, any tool capable of simultaneously engaging both the nut 130 and multiplier 140 and applying a force that causes the nut 130 and the multiplier 140 to rotate opposite each other may be used instead of torque tool 300 to tighten the threaded connection 110. The bores 190 of the nut 130 and the holes 180 of the multiplier 140 are provided purely for a mechanical means of leverage. As one of ordinary skill in the art will understand, this leverage may be applied mechanically, electrically, pneumatically, hydraulically or by another means.
In another embodiment of the threaded connector 100, the nut 130 may be replaced with a spline nut 600 as depicted in
The foregoing descriptions of specific embodiments of threaded connectors 100 comprising a nut 130, 600 and a multiplier 140, and methods for making up threaded connections 110 between two pipe sections 220, 230 using such threaded connectors 100, have been presented for purposes of illustration and description and are not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously many other modifications and variations of these embodiments are possible. In particular, the specific number of threads per inch at the nut-multiplier threads 145 (TPInut-multiplier) and/or the number of threads per inch at the multiplier-box threads 155 (TPImultiplier-box) could be modified to permit quicker assemblage of the threaded connection 110. Also, the nut 130 and the multiplier 140 could be modified to utilize design features other than bores 180, holes 190 or splines 610, as depicted in
While several embodiments of threaded connectors 100 and methods for making up threaded connections 110 have been shown and described herein, modifications may be made by one skilled in the art without departing from the spirit and the teachings of the invention. The embodiments described are representative only, and are not intended to be limiting. Many variations, combinations, and modifications of the applications disclosed herein are possible and are within the scope of the invention. Accordingly, the scope of protection is not limited by the description set out above, but is defined by the claims which follow, that scope including all equivalents of the subject matter of the claims.
Claims
1. A threaded connection assembly comprising:
- a nut;
- a multiplier connected to the nut via a first threaded interface having a first number of threads per inch (first TPI); and
- a well servicing pipe coupling connected to the multiplier via a second threaded interface having a second number of threads per inch (second TPI).
2. The threaded connection assembly of claim 1 wherein the first TPI is less than the second TPI.
3. The threaded connection assembly of claim 1 wherein an equivalent TPI between the nut and the well servicing pipe coupling is negative.
4. The threaded connection assembly of claim 1 wherein the first threaded interface and the second threaded interface are at least partially formed simultaneously.
5. The threaded connection assembly of claim 1 wherein the nut connects to the well servicing pipe coupling via a non-threaded connection.
6. The threaded connection assembly of claim 1 wherein the nut and the multiplier rotate in opposite directions to form the second threaded interface.
7. The threaded connection assembly of claim 6 further comprising a torque tool that simultaneously imparts a rotational force to the nut and an opposite rotational force to the multiplier.
8. The threaded connection assembly of claim 7 wherein the torque tool simultaneously engages a hole in the nut and a hole in the multiplier.
9. The threaded connection assembly of claim 7 wherein the torque tool simultaneously engages a spline on the nut and a hole in the multiplier, or vice versa.
10. The threaded connection assembly of claim 7 wherein the torque tool simultaneously engages a spline on the nut and a spline on the multiplier.
11. The threaded connection assembly of claim 7 wherein the torque tool comprises a mechanical tool, a hydraulic tool, a pneumatic tool, an electrical tool, or a combination thereof.
12. The threaded connection assembly of claim 1 wherein the well servicing pipe coupling comprises: a pin-end pipe section disposed partially within a box-end pipe section with a face seal provided therebetween.
13. A method of forming a threaded connection for a well servicing application comprising:
- forming a pipe coupling between two well servicing pipe sections; and
- threading a connector to the pipe coupling to form a threaded connection without impact loading the connector.
14. The method of claim 13 further comprising:
- preloading the threaded connection without impact loading the connector; and
- performing the well servicing application;
- wherein the preloading prevents a seal in the pipe coupling from extruding during the well servicing application.
15. The method of claim 13 wherein threading the connector to the pipe coupling comprises leveraging a portion of the connector against another portion of the connector.
16. The method of claim 14 wherein preloading the threaded connection comprises imparting a rotational force to a first portion of the connector and simultaneously imparting an opposite rotational force to a second portion of the connector.
17. The method of claim 14 wherein the well servicing application comprises fracturing, stimulating or cementing.
18. A method of forming a threaded connection for a well servicing application comprising:
- disposing a first pipe section partially within a nut;
- threading a multiplier into the nut;
- threading the multiplier onto a second pipe section; and
- leveraging the multiplier against the nut, or vice versa.
19. The method of claim 18 further comprising attaching the nut to the first pipe section via a non-threaded connection.
20. The method of claim 18 further comprising simultaneously imparting opposite rotational forces to the multiplier and the nut to tighten the threaded connection.
21. The method of claim 20 wherein the rotational forces are imparted mechanically, hydraulically, pneumatically, electrically, or a combination thereof.
22. The method of claim 18 further comprising:
- providing a face seal between the first pipe section and the second pipe section;
- tightening the threaded connection to provide a sufficient preload to prevent the face seal from extruding during the well servicing application.
23. The method of claim 22 further comprising performing the well servicing application.
Type: Application
Filed: Dec 2, 2005
Publication Date: Jun 7, 2007
Applicant: Halliburton Energy Services, Inc. (Houston, TX)
Inventors: Brad Bull (Duncan, OK), Kenneth Neal (Duncan, OK)
Application Number: 11/292,981
International Classification: E21B 43/25 (20060101); E21B 17/02 (20060101);