CA1298715C - Shear coupling assembly - Google Patents
Shear coupling assemblyInfo
- Publication number
- CA1298715C CA1298715C CA000575208A CA575208A CA1298715C CA 1298715 C CA1298715 C CA 1298715C CA 000575208 A CA000575208 A CA 000575208A CA 575208 A CA575208 A CA 575208A CA 1298715 C CA1298715 C CA 1298715C
- Authority
- CA
- Canada
- Prior art keywords
- head
- coupling member
- shear
- pump
- neck
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B17/00—Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Cables; Casings; Tubings
- E21B17/02—Couplings; joints
- E21B17/04—Couplings; joints between rod or the like and bit or between rod and rod or the like
- E21B17/06—Releasing-joints, e.g. safety joints
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B17/00—Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Cables; Casings; Tubings
- E21B17/02—Couplings; joints
- E21B17/04—Couplings; joints between rod or the like and bit or between rod and rod or the like
- E21B17/042—Threaded
- E21B17/0426—Threaded with a threaded cylindrical portion, e.g. for percussion rods
Abstract
"SHEAR COUPLING ASSEMBLY"
ABSTRACT OF THE DISCLOSURE
A shear coupling assembly is provided for connecting the rod of a downhole pump with the terminal member of a sucker rod string. The assembly involves two parts or coupling members which are threadably connected end to end during normal operations but which can relatively easily be parted if the pump becomes stuck, by pulling up on the still free sucker rod string. The first coupling member has a pin end incorporating an externally threaded head and a shear neck, of relatively reduced diameter, joining the head to the main body of the coupling member. The head has an axial, internally threaded counterbore, so that a tensioning tool may be screwed thereinto, the other end of the coupling member may be held, and the tool may be pulled to place the shear neck in tension. The second coupling member is a sleeve forming an axial bore therethrough. The second coupling member is adapted to thread onto the head of the first coupling member. To prepare the assembly for use, the tensioning tool is inserted, the sleeve is slipped over the tool, the tool is pulled to place the neck in tension, and the sleeve is threaded along the head until it abuts the main body of the first coupling member. The tensioning tool is then removed. The sleeve functions to hold the shear neck in a tensioned state. The tensioned neck is better able to sustain cyclic compressive loading in the course of reciprocation of the sucker rod string.
ABSTRACT OF THE DISCLOSURE
A shear coupling assembly is provided for connecting the rod of a downhole pump with the terminal member of a sucker rod string. The assembly involves two parts or coupling members which are threadably connected end to end during normal operations but which can relatively easily be parted if the pump becomes stuck, by pulling up on the still free sucker rod string. The first coupling member has a pin end incorporating an externally threaded head and a shear neck, of relatively reduced diameter, joining the head to the main body of the coupling member. The head has an axial, internally threaded counterbore, so that a tensioning tool may be screwed thereinto, the other end of the coupling member may be held, and the tool may be pulled to place the shear neck in tension. The second coupling member is a sleeve forming an axial bore therethrough. The second coupling member is adapted to thread onto the head of the first coupling member. To prepare the assembly for use, the tensioning tool is inserted, the sleeve is slipped over the tool, the tool is pulled to place the neck in tension, and the sleeve is threaded along the head until it abuts the main body of the first coupling member. The tensioning tool is then removed. The sleeve functions to hold the shear neck in a tensioned state. The tensioned neck is better able to sustain cyclic compressive loading in the course of reciprocation of the sucker rod string.
Description
~29871~
1 Field of the Invention
1 Field of the Invention
2 The present invention relates to a shear coupling
3 assembly for interconnecting the rod of a downhole pump with
4 the terminal member of the rod string which actuates the pump. The assembly is adapted to preferentially part when 6 the pump is stuck and the rod string is pulled.
8 In a pumped well, a reciprocating rod string is g used to actuate a downhole pump. The rod string is made up of a multiplicity of sucker rods connected end-to-end by 11 means of threaded couplings. Typically, a sucker rod might 12 have a length of 30 feet, a stem diameter of 5/8~l, an 13 externally threaded 7/8" pin coupling at one end and an 14 internally threaded 7/8" box coupling at the other end.
Alternatively, a single continuous rod may be used to extend 16 from the pump jack down to the pump. Hereafter the term ~rod 17 string" is used generically to denote the two types of pump-18 actuating rods.
19 There are occasions when the pump will become lodged or stuck in the well, either at its downhole operating 21 position or when being tripped out of the well. For example, 22 sand contained in the produced fluid may settle on top of the 23 pump and prevent its upward removal.
24 It is then desirable to be able to separate the rod string from the pump, in order to remove it so that 26 specialized equipment may be introduced into the tubing to 27 free the pump.
~ Zg~37~5 1 In most wells, the operators do not provide for a 2 parting means in the string at the juncture of the rods and 3 the pump. If the pump is stuck, the rod string is simply 4 pulled until parting occurs. This break can occur anywhere in the rod string, which can be a problem.
6 Heretofore, there have been shear assemblies used 7 at the junction of the pump and the rod string. The version 8 which we have seen in use involves joining male and female 9 coupling members with transversely extending shear pins. The shear pins are designed to part before the stem of a sucker 11 rod. However, there are two problems associated with this 12 assembly. Firstly, the shear pins are prone to premature 13 fatigue. This fatigue arises from the cyclic compressive 14 stress which is induced in the shear pins if the rod string ~'taps down~ at the base of each downstroke. Secondly, when 16 the shear pins are broken, their splinters drop onto the 17 pump; this can lead to problems in freeing the pump.
18 There exists, therefore, a need for a rod string 19 shear coupling assembly which is better adapted to undergo 20 cyclic compressive loading without failure and which may be 21 pulled apart without producing splinter pieces that are free 22 to drop down the tubing annulus.
24 In accordance with the invention, a shear coupling 25 assembly is provided having a pin coupling member and a box 26 coupling member. The pin coupling member has a pin end 27 comprising an externally threaded head and a shear neck, of 28 relatively reduced diameter, joining the head to the main lZ~871S
1 body of the coupling member. The head is counterbored 2 longitudinally from its forward end and internally threaded.
3 The main body of the pin coupling member is provided with 4 means for threadably connecting the member to the sucker rod string or, if inverted, to the pump. The main body further 6 provides a contact shoulder for a purpose explained shortly.
7 The box coupling member is an internally threaded sleeve into 8 which the head of the pin coupling member may be threaded.
9 The box coupling member also has means for threadably connecting it to the rod string or pump, as appropriate.
11 In assembling the device, the body of the pin 12 coupling member is held, a threaded tensioning tool, such as 13 a bolt or the like, is screwed into the head, the box 14 coupling member is slipped over the bolt, and a pull is applied to the bolt to tension the shear neck. The box 16 coupling member is then screwed along the head until it abuts 7 the pin coupling member by contacting the aforementioned 18 contact shoulder. The bolt is then released and removed.
19 The box coupling member functions to "lock in" the tension stress induced in the shear neck by pulling on the bolt.
21 Stated otherwise, the shear neck remains in a tensioned 22 state.
23 Broadly stated, the invention is a shear coupling 24 assembly for connecting the rod of a downhole pump with the terminal member of a rod string, comprising: a pin coupling 26 member having a pin end portion and a body end portion, said 27 pin end portion comprising an externally threaded head and a 28 shear neck joining the head to the body portion, said shear 29 neck being of sufficiently reduced diameter so that it will lZ91!3715 1 preferentially part when the pump is stuck and the rod string 2 is increasingly tensioned, said body portion having means, at 3 its end remote from the head, for threadably connecting with 4 one of the rod string or pump rod, said head having means for connecting with a tensioning tool; and a box coupling member 6 comprising an internally threaded sleeve threadably engaging 7 the head and having means for threadably connecting with the 8 other of the rod string or pump rod; said sleeve contacting 9 the body end portion of the pin coupling member; said shear neck being in a tensioned state.
12 Figure l is a sectional side view of one embodiment 13 of the shear coupling assembly; and 14 Figure 2 is a partly sectional side view of an alternative embodiment of the assembly.
17 With reference to Figure l, the shear coupling 18 assembly l comprises a pin coupling member 2 and a box 19 coupling member 3.
The pin coupling member 2 comprises a body portion 21 4, an externally threaded head 5 and a shear neck 6 joining 22 the head 5 with the body portion 4. The body portion 4 is of 23 greater width than the head 5 and forms a radial contact 24 shoulder 7. The shear neck 6 is of reduced diameter relative to the head 5. Specifically the shear neck 6 is designed to 26 preferentially part before the rod string (not shownl or pump 27 rod (also not shown)~ when the pump is stuck and the rod 1 string is subjected to increasing tension. The head 5 forms 2 an internally threaded axial counterbore 8 which extends 3 inwardly from its forward end. At its end remote from the 4 head 5, the body portion 4 forms an internally threaded axial bore 9, for connecting to one of the rod string or pump rod.
6 Turning now to the box coupling member 3, it 7 comprises a sleeve ll forming an internally threaded axial 8 bore 12. One end of the sleeve 11 is dimensioned to 9 th~eadably engage the head 5 and advance thereover. The other end of the sleeve ll is adapted to thread onto the pin 11 end of the other of the rod string or pump rod.
12 To assemble the device, the body portion 4 of the 13 pin coupling member 2 is suitably held and a bolt (not shown)is threaded into the head counterbore 8. The sleeve ll is slipped over the bolt. The bolt is then tensioned by 16 pulling on it, to thereby place the shear neck 6 in tension.
17 The sleeve 11 is then advanced along the head 5 until it 18 abuts the contact shoulder 7. The bolt is then removed. The 19 sleeve 11 functions to lock the shear neck 6 in a tensioned state.
21 The alternative embodiment shown in Figure 2 is 22 essentially the same as that shown in Figure 1. In this 23 case, the body portion 4 is provided with a threaded pin 10 24 for connection with the rod string or pump rod. Similarly, if desired the end of the sleeve 11 may be formed to provide a 26 pin at its end remote from the head 5.
~Z~8715 1 The invention is characterized by the following 2 advantages:
3 - there are no shear pin parts left free to drop 4 down the tubing annulus when parting occurs;
and 6 - the tensioned shear neck should remain in 7 tension even though the rod string may be 8 cyclically tapping down.
g The scope of the invention is set forth in the following claim.
8 In a pumped well, a reciprocating rod string is g used to actuate a downhole pump. The rod string is made up of a multiplicity of sucker rods connected end-to-end by 11 means of threaded couplings. Typically, a sucker rod might 12 have a length of 30 feet, a stem diameter of 5/8~l, an 13 externally threaded 7/8" pin coupling at one end and an 14 internally threaded 7/8" box coupling at the other end.
Alternatively, a single continuous rod may be used to extend 16 from the pump jack down to the pump. Hereafter the term ~rod 17 string" is used generically to denote the two types of pump-18 actuating rods.
19 There are occasions when the pump will become lodged or stuck in the well, either at its downhole operating 21 position or when being tripped out of the well. For example, 22 sand contained in the produced fluid may settle on top of the 23 pump and prevent its upward removal.
24 It is then desirable to be able to separate the rod string from the pump, in order to remove it so that 26 specialized equipment may be introduced into the tubing to 27 free the pump.
~ Zg~37~5 1 In most wells, the operators do not provide for a 2 parting means in the string at the juncture of the rods and 3 the pump. If the pump is stuck, the rod string is simply 4 pulled until parting occurs. This break can occur anywhere in the rod string, which can be a problem.
6 Heretofore, there have been shear assemblies used 7 at the junction of the pump and the rod string. The version 8 which we have seen in use involves joining male and female 9 coupling members with transversely extending shear pins. The shear pins are designed to part before the stem of a sucker 11 rod. However, there are two problems associated with this 12 assembly. Firstly, the shear pins are prone to premature 13 fatigue. This fatigue arises from the cyclic compressive 14 stress which is induced in the shear pins if the rod string ~'taps down~ at the base of each downstroke. Secondly, when 16 the shear pins are broken, their splinters drop onto the 17 pump; this can lead to problems in freeing the pump.
18 There exists, therefore, a need for a rod string 19 shear coupling assembly which is better adapted to undergo 20 cyclic compressive loading without failure and which may be 21 pulled apart without producing splinter pieces that are free 22 to drop down the tubing annulus.
24 In accordance with the invention, a shear coupling 25 assembly is provided having a pin coupling member and a box 26 coupling member. The pin coupling member has a pin end 27 comprising an externally threaded head and a shear neck, of 28 relatively reduced diameter, joining the head to the main lZ~871S
1 body of the coupling member. The head is counterbored 2 longitudinally from its forward end and internally threaded.
3 The main body of the pin coupling member is provided with 4 means for threadably connecting the member to the sucker rod string or, if inverted, to the pump. The main body further 6 provides a contact shoulder for a purpose explained shortly.
7 The box coupling member is an internally threaded sleeve into 8 which the head of the pin coupling member may be threaded.
9 The box coupling member also has means for threadably connecting it to the rod string or pump, as appropriate.
11 In assembling the device, the body of the pin 12 coupling member is held, a threaded tensioning tool, such as 13 a bolt or the like, is screwed into the head, the box 14 coupling member is slipped over the bolt, and a pull is applied to the bolt to tension the shear neck. The box 16 coupling member is then screwed along the head until it abuts 7 the pin coupling member by contacting the aforementioned 18 contact shoulder. The bolt is then released and removed.
19 The box coupling member functions to "lock in" the tension stress induced in the shear neck by pulling on the bolt.
21 Stated otherwise, the shear neck remains in a tensioned 22 state.
23 Broadly stated, the invention is a shear coupling 24 assembly for connecting the rod of a downhole pump with the terminal member of a rod string, comprising: a pin coupling 26 member having a pin end portion and a body end portion, said 27 pin end portion comprising an externally threaded head and a 28 shear neck joining the head to the body portion, said shear 29 neck being of sufficiently reduced diameter so that it will lZ91!3715 1 preferentially part when the pump is stuck and the rod string 2 is increasingly tensioned, said body portion having means, at 3 its end remote from the head, for threadably connecting with 4 one of the rod string or pump rod, said head having means for connecting with a tensioning tool; and a box coupling member 6 comprising an internally threaded sleeve threadably engaging 7 the head and having means for threadably connecting with the 8 other of the rod string or pump rod; said sleeve contacting 9 the body end portion of the pin coupling member; said shear neck being in a tensioned state.
12 Figure l is a sectional side view of one embodiment 13 of the shear coupling assembly; and 14 Figure 2 is a partly sectional side view of an alternative embodiment of the assembly.
17 With reference to Figure l, the shear coupling 18 assembly l comprises a pin coupling member 2 and a box 19 coupling member 3.
The pin coupling member 2 comprises a body portion 21 4, an externally threaded head 5 and a shear neck 6 joining 22 the head 5 with the body portion 4. The body portion 4 is of 23 greater width than the head 5 and forms a radial contact 24 shoulder 7. The shear neck 6 is of reduced diameter relative to the head 5. Specifically the shear neck 6 is designed to 26 preferentially part before the rod string (not shownl or pump 27 rod (also not shown)~ when the pump is stuck and the rod 1 string is subjected to increasing tension. The head 5 forms 2 an internally threaded axial counterbore 8 which extends 3 inwardly from its forward end. At its end remote from the 4 head 5, the body portion 4 forms an internally threaded axial bore 9, for connecting to one of the rod string or pump rod.
6 Turning now to the box coupling member 3, it 7 comprises a sleeve ll forming an internally threaded axial 8 bore 12. One end of the sleeve 11 is dimensioned to 9 th~eadably engage the head 5 and advance thereover. The other end of the sleeve ll is adapted to thread onto the pin 11 end of the other of the rod string or pump rod.
12 To assemble the device, the body portion 4 of the 13 pin coupling member 2 is suitably held and a bolt (not shown)is threaded into the head counterbore 8. The sleeve ll is slipped over the bolt. The bolt is then tensioned by 16 pulling on it, to thereby place the shear neck 6 in tension.
17 The sleeve 11 is then advanced along the head 5 until it 18 abuts the contact shoulder 7. The bolt is then removed. The 19 sleeve 11 functions to lock the shear neck 6 in a tensioned state.
21 The alternative embodiment shown in Figure 2 is 22 essentially the same as that shown in Figure 1. In this 23 case, the body portion 4 is provided with a threaded pin 10 24 for connection with the rod string or pump rod. Similarly, if desired the end of the sleeve 11 may be formed to provide a 26 pin at its end remote from the head 5.
~Z~8715 1 The invention is characterized by the following 2 advantages:
3 - there are no shear pin parts left free to drop 4 down the tubing annulus when parting occurs;
and 6 - the tensioned shear neck should remain in 7 tension even though the rod string may be 8 cyclically tapping down.
g The scope of the invention is set forth in the following claim.
Claims (2)
EXCLUSIVE PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS
FOLLOWS:
1. A shear coupling assembly for connecting the rod of a downhole pump with the terminal member of a rod string, comprising:
a pin coupling member having a pin end portion and a body end portion, said pin end portion comprising an externally threaded head and a shear neck joining the head to the body portion, said shear neck being of sufficiently reduced diameter so that it will preferentially part when the pump is stuck and the rod string is increasingly tensioned, said body portion having means, at its end remote from the head, for threadably connecting with one of the rod string or pump rod, said head having means for connecting with a tensioning tool; and a box coupling member comprising an internally threaded sleeve threadably engaging the head and having means for threadably connecting with the other of the rod string or pump;
said sleeve contacting the body end portion of the pin coupling member;
said shear neck being in a tensioned state.
a pin coupling member having a pin end portion and a body end portion, said pin end portion comprising an externally threaded head and a shear neck joining the head to the body portion, said shear neck being of sufficiently reduced diameter so that it will preferentially part when the pump is stuck and the rod string is increasingly tensioned, said body portion having means, at its end remote from the head, for threadably connecting with one of the rod string or pump rod, said head having means for connecting with a tensioning tool; and a box coupling member comprising an internally threaded sleeve threadably engaging the head and having means for threadably connecting with the other of the rod string or pump;
said sleeve contacting the body end portion of the pin coupling member;
said shear neck being in a tensioned state.
2. The assembly as set forth in claim 1 wherein:
the head forms an internally threaded counter bore extending axially inwardly from its end to provide the means for connecting with a tensioning tool.
the head forms an internally threaded counter bore extending axially inwardly from its end to provide the means for connecting with a tensioning tool.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000575208A CA1298715C (en) | 1988-08-19 | 1988-08-19 | Shear coupling assembly |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000575208A CA1298715C (en) | 1988-08-19 | 1988-08-19 | Shear coupling assembly |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1298715C true CA1298715C (en) | 1992-04-14 |
Family
ID=4138582
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000575208A Expired - Lifetime CA1298715C (en) | 1988-08-19 | 1988-08-19 | Shear coupling assembly |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1298715C (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2011075326A1 (en) * | 2009-12-17 | 2011-06-23 | Weatherford/Lamb. Inc. | Shear coupling assembly for use with rotary and reciprocating pumps |
| CN103089166A (en) * | 2013-02-22 | 2013-05-08 | 李汉余 | Sucker rod connector |
| US9605493B2 (en) | 2014-06-23 | 2017-03-28 | Arthur W. Lauder | Downhole coupling |
| US11428259B2 (en) | 2020-03-30 | 2022-08-30 | Plainsman Mfg. Inc. | Shear coupling and method of assembling same |
| US11965537B2 (en) | 2020-03-30 | 2024-04-23 | Plainsman Mfg. Inc. | Shear coupling and method of assembling same |
-
1988
- 1988-08-19 CA CA000575208A patent/CA1298715C/en not_active Expired - Lifetime
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2011075326A1 (en) * | 2009-12-17 | 2011-06-23 | Weatherford/Lamb. Inc. | Shear coupling assembly for use with rotary and reciprocating pumps |
| AU2010332110B2 (en) * | 2009-12-17 | 2013-10-17 | Weatherford Technology Holdings, Llc | Shear coupling assembly for use with rotary and reciprocating pumps |
| US8636057B2 (en) | 2009-12-17 | 2014-01-28 | Weatherford/Lamb, Inc. | Shear coupling assembly for use with rotary and reciprocating pumps |
| CN103089166A (en) * | 2013-02-22 | 2013-05-08 | 李汉余 | Sucker rod connector |
| US9605493B2 (en) | 2014-06-23 | 2017-03-28 | Arthur W. Lauder | Downhole coupling |
| US11428259B2 (en) | 2020-03-30 | 2022-08-30 | Plainsman Mfg. Inc. | Shear coupling and method of assembling same |
| US11965537B2 (en) | 2020-03-30 | 2024-04-23 | Plainsman Mfg. Inc. | Shear coupling and method of assembling same |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed | ||
| MKEC | Expiry (correction) |
Effective date: 20121205 |