GB2241009A - Sucker rod centralizer - Google Patents
Sucker rod centralizer Download PDFInfo
- Publication number
- GB2241009A GB2241009A GB9105864A GB9105864A GB2241009A GB 2241009 A GB2241009 A GB 2241009A GB 9105864 A GB9105864 A GB 9105864A GB 9105864 A GB9105864 A GB 9105864A GB 2241009 A GB2241009 A GB 2241009A
- Authority
- GB
- United Kingdom
- Prior art keywords
- sucker rod
- pipe
- rotatable
- slots
- hardness
- 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.)
- Granted
Links
- 239000000463 material Substances 0.000 abstract description 6
- 239000007769 metal material Substances 0.000 abstract description 3
- 229910000831 Steel Inorganic materials 0.000 description 4
- 239000003921 oil Substances 0.000 description 4
- 239000010959 steel Substances 0.000 description 4
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 229910001092 metal group alloy Inorganic materials 0.000 description 3
- 239000003129 oil well Substances 0.000 description 3
- 229910000881 Cu alloy Inorganic materials 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 229910001220 stainless steel Inorganic materials 0.000 description 2
- 241001415166 Alona Species 0.000 description 1
- 229910001018 Cast iron Inorganic materials 0.000 description 1
- 101150050927 Fcgrt gene Proteins 0.000 description 1
- 239000004677 Nylon Substances 0.000 description 1
- 238000010793 Steam injection (oil industry) Methods 0.000 description 1
- 241000566576 Tyto Species 0.000 description 1
- 239000003082 abrasive agent Substances 0.000 description 1
- 239000008186 active pharmaceutical agent Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 239000010779 crude oil Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 238000005755 formation reaction Methods 0.000 description 1
- 230000008774 maternal effect Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 229920001778 nylon Polymers 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK 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
- E21B17/10—Wear protectors; Centralising devices, e.g. stabilisers
- E21B17/1057—Centralising devices with rollers or with a relatively rotating sleeve
Landscapes
- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Mining & Mineral Resources (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Environmental & Geological Engineering (AREA)
- Fluid Mechanics (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Earth Drilling (AREA)
Abstract
The present invention relates to a device for centralizing at least one sucker rod within a production pipe and for reducing frictional forces between the pipe and the sucker rod(s). The device comprises an elongate, substantially cylindrical body member 12, a plurality of slots 14 within the member and a rotatable member 16 in each slot. Each rotatable member is formed from a metallic material having a hardness of at least about 50 Brinnel Hardness, less than the hardness of the material forming the production pipe tubing. The slots and the rotatable members are in a helical array to ensure that at least a plurality of said rotatable members are in contrast with the pipe. <IMAGE>
Description
BACKGROUND OF THE INVENTION
The present invention relates to oil production and in particular to a sucker rod guide centralizer for preventing production pipe and sucker rod wear by reducing friction forces between them.
Oil is withdrawn fron subterranean formations throuah a tubular production pipe formed from a string of tubing extending to the surface. The oil is lifted throuah the pipe by the action of a downhole pump actuated by a sucker rod string which is reciprocated at the surface by a pump ack. A sucker rod strina is made up of a multiplicity of individual sucker rods joined toaether end to end. Erch sucker rod comprises a main stem having a diameter typically in the ranae of from 3/4" to 1-1/2" and a length of about 30 feet.
In recent years, directional and deviate wells have become very popular in many oil fields. The use O; sucker rod strings in directional or deviated well bores has had problems. The rod string usually formed from steel tends to lie alona the low side of the production pipe and with time reciprocation of the rod string tends to wear away the wall of the pipe. Additional problems arise from the steam injection techniques used to improve the production of heavy and extra heavy crude oils.
Attempts have been made to deal with the frictional problems associated with tools or tubular structures used in production pipes by incorporating a centralizing device therein which serves to space the tool or tubular structure from the production pipe tubing and thereby reduce wear of the tubing wall. These centralizing devices have taken different forms such as a series of projections on the outer periphery of a coupling member and rollers or bearings incorporated within the structure of the sucker rod. U.S. Patent No. 2,722,462 to Tschirley illustrates one such device comprising an elastomeric collar having a row of bumps or projections attacned to a drill pipe. The bumps on the collar are designed to maintain a desired separation between the pipe and the surrounding casing. U.S. Patent No.
3,938,853 to Jurgens et al. illustrates a similar stabilizing device secured to a drill collar. The device has an inner sleeve and an outer sleeve with a series of lonaitudinally extending helical ribs. The primary deficiency of these devices is believed to be their tendency to wear out as a result of the frictional contact between the fixed centralizing elements and the production pipe.
U.S. Patent Nos. 2,466,239 to Holcombe, 2,601,748 to Weir and 4,577,327 to Kinley et al. illustrate guides usina rollers or bearing. In Holcombe, a series of wheels or rollers are mounted to a rod by a wing and keeper plate arrangement. In Weir, the bearing balls used to guide the sucker rod are locate in a series of longitudinally extendina grooves having intermediate races about the periphery of the rod. In Kinley et al., the centralizing device comprises a plurality of spring loaded centerina arms havina a series of rollers in a center segment.
More recently, a centralizing device comprisina a couplina device having a cylindrical body and a plurality of lenticular wheels positioned within slots in the body has been developed. To minimize scoring of the tubing wall, the wheel members are formed of a hard, non-abrasive material such as hard nylon. U.S. Patent tyTO. 4,621,690 to Klyne illustrates such a device.
Many of these devices when tested in wells having a temperature above 500OF have failed in aivina high performance work life. Often, the non-metallic components of the devices are the weak links because they cannot withstand the critical conditions in the oil wells. In the wheeled devices, failure is also often the result of too few wheels being in contact with the production pipe tubina.
Accordingly, it is an object of the present
invention to provide a device for centralizing a sucer rod string within a production pipe and for reducina
frictional forces therebetween.
It is a further object of the present invention to provide a device as above capable of withstanding typical oil well service conditions.
These and other objects and advantages will become more apparent from the following description and drawings.
SUMMARY OF THE IN & TION The device for centralizing a sucker rod strina within a production pipe and for reducing friction therebetween of the present invention comprises an elonaate, substantially cylindrical body member having a plurality of slots therein and a rotatable member mounted within each slot.This device represents an .mprovement over earlier devices in that each rotatable member is made from a metal or metal alloy having a hardness which is between about 50 to 150 Brinnel
Hardness, preferably about 50 Brinnel Hardness, less than the hardness of the harder production pipe tubing material wherein the relative hardness is maintained over time at well operating temperatures encountered downhole in the well, that is, at temperatures of 300OF and above. Suitable metal materials for the rotatable members include but are not limited to copper alloys and austenistic or ferritic stainless steel.
A further feature of the present invention IS the arrangement of the slots within the body members so as to form a helical array of rotatable members. In a preferred arrangement, the rotatable members are set at about thirty degrees clockwise with respect to adjacent ones of the rotatable members. It has been found that by providing such an array at least three of the rotatable members can be placed in contact with the production pipe tubing at one time.
The body member is preferably made of quenched and tempered steel and is provided with threaded boxes at each end for connection to a plurality of sucker rod.
The location and number of sucker rod centralizer devices used in a sucker rod string depend upon the deviation degree and depth of the well.
BRIEF DESCRIPTION OF THE DRBVINGS Figure 1 is a view in partial cross section of the centralizing device of the present invention:
Fiaure 2 is a sectional view of the device of Fiaure 1:
Figure 3 is a sectional view of a portion of device of Figure 1 illustrating the mounting of a rotatable member with a slot;
Figure 4 is a cross sectional view of a rotatable member used in the device of Figure 1.
DETAILED DESCRIPTION Referring now to the drawings, the sucker rod string centralizing device 10 is formed by an elongate, substantiallv cvlindrical body member 12. The meander 12 may have any desired length and diameter and may be formed from any suitable maternal such as quencned and tempered steel. For example, the member 12 may be manufactured in sizes of 3/4", 7/8", 1", 1-1/8", 1-1/4" and 1-1/2" to match commercial sucker rods.
The body member 12 may also have one or mcre flat surfaces or portions 28 to permit wrenching of the centralizer device. In addition, internally threaded, longitudinally extendina boxes 30 may be provided at each end for permitting the device 10 to be connected to one or more sucker rods 32 havina matina threaded pin ends.
A plurality of slots 14 are machined within the body member 12 for the purpose of accommodating a plurality of rotatable members 16, such as wheels or rollers, which serve to centralize the sucker rod string within the production tubing and reduce frictional forces therebetween. Each slot 14 preferably extends transversely through the member 12 and is oriented to have its longitudinal dimension substantially parallel to the lonaitudinal axis of the member 12. stile each slot may have any desired width, it is preferred that it be just slightly wider than the thickness t of a central portion 24 of the rotatable member 16 so as to substantially limit rotation of the member 16 to a plane substantially parallel to the longitudinal axis of the member 12.
The slots 14 are arranged about the body member 12 and are preferably set at an angle of about thirty dearees relative to each other. They are further arranaed so as to fcrn a helicoidal array. It has been found that by providing such an array, the total rotatable member surface area in contact with the production tubing is improved. Further, the forces acting per rotatable member are substantially decreased, thus improving the service life of both the device 10 and the production tubing. Still further, the probability of rotatable member failure is reduced as compared to other arrangements since the forces usually act substantially perpendicular to the rotatable member.
A rotatable member 16 such as a wheel is mounted for rotation in eac'n slot 14 about an axis defined by a pin 18 havina its ends positioned in bores 20. Any suitable means known in the art may be used to lock each pin within the bores 20. In a preferred arranaement, the pin 18 is oriented substantially transversely to both the longitudinal axis of the body member and the longitudinal dimension of the slot. Each pin is preferably formed from quenched and tempered steel. The member 16 is mounted for rotation about the pin 18 by an intermediate bearing 22. The use of an intermediate bearing 22 has been found to improve the service life of the rotatable member. Anv suitable bearing such as a cast iron plain bearing may be used for bearing 22.
Referrina now to Figure 4, the rotatable member 16 has a central portion 24 with a thickness t which is sufficiently larae enough to enable the member 16 to act as a thrust bearing for minimizina frictional forces between the cylindrical body member 12 and itself. The member 16 further comprises a portion 25 on each side of the central portion havina a thickness T and an end portion 26 which is preferably semicircular in cross section and has a radius substantially equal to half of the thickness T. It has been found that by providing such semi-circular end portions the contact area per rotatable member is maximized. Of course, the member 16 may have any desired diameter.
In accordance with the present invention, the service life of both the device 10 and the production pipe tubing 34 are improved by forming each rotatable member 16 from a metal or metal alloy having a hardness which at temperatures above 300OF is from at least about 50 to about 150 Brinnel Hardness (HB), preferably about 50 HB, less than the hardness of the harder material forming the production tubing. It has been found that by using such a hardness differential, damaae to the production tubing can be prevented.
The metal or metal alloy from which each member 16 is formed should be capable of maintaining the aforementioned relative hardness character is tics with respect to the production tubing substantially ccnstant over time at the service temperatures encountereo downhole of the well, generally at 300 cm or above. It is also desirable that the material forming each member 16 aae substantially at the same rate as the material forming the production tubing 34. Of course, the particular material selected for the members 16 is also in part determined by the corrosiveness and temperature of the fluid produced from the oil well.Suitable metallic materials for the rotatable members include, but are not limited to, copper alloys having a hardness
in the range of from about 50 HB to about 200 HB and austenistic or ferritic stainless steel such as AISI 316. The production tubing 34 may be formed from API JSS. In addition to the improving service life, it has been found that the above mentioned hardness differential reduces frictional wear of the tubing by the rotatable member.
While the member 12 may have any desired number of slots and the device 10 may have any number of rotatable members, it is preferred that there be six slots and six rotatable members. It has been found that when six slots and rotatable members are used, at least three of the rotatable members are always in contact with the production tubina.
It is apparent that there has been provided in accordance with this invention a sucker rod centralizer which fully satisfies the objects, means and advantages set forth hereinbefore. While the invention has been described in combination with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications and variations as fall within the spirit and broad scope of the appended claims.
Claims (2)
1. A device for centralizing at least one sucker rod within a production pipe and for reducing frictional forces between said pipe and said at least one sucker rod which comprises an elongate, substantially cylindrical body member having a longitudinal axis, a plurality of slots within said member arranged in helical array with adjacent ones of said slots being oriented at an angle of about 300 with respect to each other, and a rotatable member mounted within each slot for contacting said pipe whereby said helical array of said slots ensures that at least a plurality of said rotatable members are in contact with said pipe.
2. A device as set forth in claim 1 wherein at least three rotatable members are in contact with a wall of said production pipe.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US07/098,929 US4871020A (en) | 1987-09-21 | 1987-09-21 | Sucker rod centralizer |
GB8820864A GB2210085B (en) | 1987-09-21 | 1988-09-05 | Sucker rod centralizer |
Publications (3)
Publication Number | Publication Date |
---|---|
GB9105864D0 GB9105864D0 (en) | 1991-05-08 |
GB2241009A true GB2241009A (en) | 1991-08-21 |
GB2241009B GB2241009B (en) | 1992-03-04 |
Family
ID=32472207
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB9105864A Expired - Fee Related GB2241009B (en) | 1987-09-21 | 1991-03-20 | Sucker rod guide centraliser. |
Country Status (1)
Country | Link |
---|---|
GB (1) | GB2241009B (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2000043629A1 (en) * | 1999-01-22 | 2000-07-27 | Weatherford/Lamb, Inc. | Friction reducing tool and method for its use in a wellbore |
WO2004015238A1 (en) | 2002-08-12 | 2004-02-19 | Eni S.P.A. | Integral centraliser |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB894117A (en) * | 1959-10-26 | 1962-04-18 | Halliburton Tucker Ltd | Improvements relating to means for lowering equipment into oil wells |
GB2210084A (en) * | 1987-09-21 | 1989-06-01 | Intevep Sa | Well centralizer |
-
1991
- 1991-03-20 GB GB9105864A patent/GB2241009B/en not_active Expired - Fee Related
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB894117A (en) * | 1959-10-26 | 1962-04-18 | Halliburton Tucker Ltd | Improvements relating to means for lowering equipment into oil wells |
GB2210084A (en) * | 1987-09-21 | 1989-06-01 | Intevep Sa | Well centralizer |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2000043629A1 (en) * | 1999-01-22 | 2000-07-27 | Weatherford/Lamb, Inc. | Friction reducing tool and method for its use in a wellbore |
US6688409B1 (en) | 1999-01-22 | 2004-02-10 | Weatherford/Lamb, Inc. | Friction reducing tool and method for its use in a wellbore |
WO2004015238A1 (en) | 2002-08-12 | 2004-02-19 | Eni S.P.A. | Integral centraliser |
Also Published As
Publication number | Publication date |
---|---|
GB9105864D0 (en) | 1991-05-08 |
GB2241009B (en) | 1992-03-04 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20030905 |