CA2239715A1 - Anchoring device - Google Patents
Anchoring device Download PDFInfo
- Publication number
- CA2239715A1 CA2239715A1 CA002239715A CA2239715A CA2239715A1 CA 2239715 A1 CA2239715 A1 CA 2239715A1 CA 002239715 A CA002239715 A CA 002239715A CA 2239715 A CA2239715 A CA 2239715A CA 2239715 A1 CA2239715 A1 CA 2239715A1
- Authority
- CA
- Canada
- Prior art keywords
- anchoring device
- well conduit
- mandrel
- well
- anchoring
- 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.)
- Abandoned
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
- E21B23/00—Apparatus for displacing, setting, locking, releasing, or removing tools, packers or the like in the boreholes or wells
- E21B23/004—Indexing systems for guiding relative movement between telescoping parts of downhole tools
- E21B23/006—"J-slot" systems, i.e. lug and slot indexing mechanisms
-
- 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
- E21B23/00—Apparatus for displacing, setting, locking, releasing, or removing tools, packers or the like in the boreholes or wells
- E21B23/01—Apparatus for displacing, setting, locking, releasing, or removing tools, packers or the like in the boreholes or wells for anchoring the tools or the like
Description
TEM File No. 207.1 TITLE: ANCHORING DEVICE
FIELD OF THE INVENTION
The present invention relates to devices for anchoring and catching well equipment within a well conduit, and in particular devices for anchoring well equipment within the well in both directions longitudinally and in one rotational direction.
BACKGROUND OF THE INVENTION
Various types of devices for anchoring and catching well equipment are known which use either a right hand thread, a left hand thread, or both. These threaded types of anchoring devices suffer from several drawbacks, one being that such threaded components tend to seize or jam during operations, particularly during emergency release operations, and stop pins are susceptible to breakage during use. Jammed anchoring devices are difficult to dislodge, resulting in time delays, lost productivity and increased operating costs. Jammed anchoring devices can also cause significant damage to well equipment, including conduits and casings. Threaded anchoring devices are also expensive to manufacture.
Solutions to at least some of the above-noted problems have been proposed by the present applicant in co-pending Canadian Patent Application no. 2,160,647, which describes a helical bearing and associated helical groove. The present invention, however, provides an improved groove of shorter distance and altered configuration which further overcomes the limitations and disadvantage of prior art devices, as will become apparent in the description. In particular, only about a quarter turn is required to set and unset the teeth of the present anchoring device whereas three or more turns are needed for prior anchors. Multiple turns are not merely inconvenient but are undesireable in soft, sandy-type formations (e.g. oil sands) where it could be difficult to determine whether the multiple turns are unsetting the anchoring device or undoing the tubing threads.
DESCRIPTION OF THE DRAWINGS
Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, wherein:
Figure 1 is an elevated side view of an anchoring device according to a preferred embodiment of the present invention within a well conduit shown in cross-section;
Figure 2 is a sectional view along line 2-2 of fig. l, showing the anchoring device in an unset position within the well conduit;
Figure 3 is a view similar to fig.2 but with the anchoring device in a set position;
Figure 4 is a perspective view of a mandrel of the anchoring device of fig.l showing an improved bearing and groove arrangement according to the present invention;
Figure 4a is a detailed view of the bearing of fig.4;
Figure Sa is a sectional view along line Sa~Sa of fig.2;
Figure Sb is a sectional view along line Sb-Sb of fig.3; and Figure 6 is a close-up view in fig:3 of a slip's downwardly facing teeth engaging the well conduit.
FIELD OF THE INVENTION
The present invention relates to devices for anchoring and catching well equipment within a well conduit, and in particular devices for anchoring well equipment within the well in both directions longitudinally and in one rotational direction.
BACKGROUND OF THE INVENTION
Various types of devices for anchoring and catching well equipment are known which use either a right hand thread, a left hand thread, or both. These threaded types of anchoring devices suffer from several drawbacks, one being that such threaded components tend to seize or jam during operations, particularly during emergency release operations, and stop pins are susceptible to breakage during use. Jammed anchoring devices are difficult to dislodge, resulting in time delays, lost productivity and increased operating costs. Jammed anchoring devices can also cause significant damage to well equipment, including conduits and casings. Threaded anchoring devices are also expensive to manufacture.
Solutions to at least some of the above-noted problems have been proposed by the present applicant in co-pending Canadian Patent Application no. 2,160,647, which describes a helical bearing and associated helical groove. The present invention, however, provides an improved groove of shorter distance and altered configuration which further overcomes the limitations and disadvantage of prior art devices, as will become apparent in the description. In particular, only about a quarter turn is required to set and unset the teeth of the present anchoring device whereas three or more turns are needed for prior anchors. Multiple turns are not merely inconvenient but are undesireable in soft, sandy-type formations (e.g. oil sands) where it could be difficult to determine whether the multiple turns are unsetting the anchoring device or undoing the tubing threads.
DESCRIPTION OF THE DRAWINGS
Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, wherein:
Figure 1 is an elevated side view of an anchoring device according to a preferred embodiment of the present invention within a well conduit shown in cross-section;
Figure 2 is a sectional view along line 2-2 of fig. l, showing the anchoring device in an unset position within the well conduit;
Figure 3 is a view similar to fig.2 but with the anchoring device in a set position;
Figure 4 is a perspective view of a mandrel of the anchoring device of fig.l showing an improved bearing and groove arrangement according to the present invention;
Figure 4a is a detailed view of the bearing of fig.4;
Figure Sa is a sectional view along line Sa~Sa of fig.2;
Figure Sb is a sectional view along line Sb-Sb of fig.3; and Figure 6 is a close-up view in fig:3 of a slip's downwardly facing teeth engaging the well conduit.
-2-DESCRIPTION OF PREFERRED EMBODIMENTS
The anchoring device of the present invention, generally designated by reference numeral 10 in the figures, is located inside a well conduit 12 and has well equipment 14 attached above and below. Referring to figs. l & 2, a slip 16 is shown positioned within a generally rectangular opening 21 in slip retainer 20. Typically at least three slips are suitably positioned about the anchoring device. Each slip 16 has gripping teeth 18 for engaging the inner well conduit wall 32. A feature of the present invention is shown in fig.6 in that the teeth 18 are pointed in one direction, namely downwardly (i.e. away from the surface of the well) so as to grip the wall 32 during compression of the anchoring device, and to reduce or avoid interference and resistance by the slips 16 when removing the anchoring device, as opposed to teeth on prior slips which point in both directions. An upper cap screw 22 is shown contacting a shoulder 24 on the slip retainer 20.
A drag body 26 can be seen to accommodate a drag means 28 and a friction surface 30 which contacts the inner well conduit wall 32. The well equipment 14 is shown attached to a mandrel 34.
Referring to fig.2, the anchoring device 10 in the well conduit 12 has a cone element 36 shouldered against the mandrel 34. The cone element 36 has a conical surface 38, and cone set screws 40 retain the cone element 38 on the mandrel 34. The drag body 26 accommodates the drag means 28 and has drag springs 42 to urge the drag means 28 outwardly against the inner well conduit wall 32. The drag means 28 frictionally contacts the inner well conduit wall 32 to urge the drag body 26 to remain stationary within the well conduit while the mandrel 34 rotates within. The upper cap screws 22 are shown to contact the slip retainer's shoulder 24 to prevent the slip retainer 20 from moving upward and from allowing the slip 16 to contact the 'cone element 36. The upper cap screw 22
The anchoring device of the present invention, generally designated by reference numeral 10 in the figures, is located inside a well conduit 12 and has well equipment 14 attached above and below. Referring to figs. l & 2, a slip 16 is shown positioned within a generally rectangular opening 21 in slip retainer 20. Typically at least three slips are suitably positioned about the anchoring device. Each slip 16 has gripping teeth 18 for engaging the inner well conduit wall 32. A feature of the present invention is shown in fig.6 in that the teeth 18 are pointed in one direction, namely downwardly (i.e. away from the surface of the well) so as to grip the wall 32 during compression of the anchoring device, and to reduce or avoid interference and resistance by the slips 16 when removing the anchoring device, as opposed to teeth on prior slips which point in both directions. An upper cap screw 22 is shown contacting a shoulder 24 on the slip retainer 20.
A drag body 26 can be seen to accommodate a drag means 28 and a friction surface 30 which contacts the inner well conduit wall 32. The well equipment 14 is shown attached to a mandrel 34.
Referring to fig.2, the anchoring device 10 in the well conduit 12 has a cone element 36 shouldered against the mandrel 34. The cone element 36 has a conical surface 38, and cone set screws 40 retain the cone element 38 on the mandrel 34. The drag body 26 accommodates the drag means 28 and has drag springs 42 to urge the drag means 28 outwardly against the inner well conduit wall 32. The drag means 28 frictionally contacts the inner well conduit wall 32 to urge the drag body 26 to remain stationary within the well conduit while the mandrel 34 rotates within. The upper cap screws 22 are shown to contact the slip retainer's shoulder 24 to prevent the slip retainer 20 from moving upward and from allowing the slip 16 to contact the 'cone element 36. The upper cap screw 22
-3-also prevents the drag body 26 from moving off of the mandrel 34 should pins 44 shear, as described later. The drag body 26 also has a conical surface 138 which is out of contact with the slip 16 in the unset position, as is the cone's conical surface 38.
Upper and lower retaining rings or sleeves 46 and 48, respectively, keep the drag means 28 from escaping the anchoring device 10. Lower cap screws 50 attach the lower retaining ring 48 to the drag body 26, which ring also keeps the pins 44 within the drag body 26.
Referring now to figs. 4 and 4a as well; a bearing 52 accommodates the pins 44 within a hole 54. According to an important aspect of the present invention the helical bearing 52 is generally cylindrical in shape for ease of maneuverability within an elongate groove 56 which accommodates the bearing 52. The bearing 52 slides along the groove 56, and may be made to roll within the groove if desired. The groove 56, which may be termed a helical groove since it extends about a portion of the cylindrical surface of the mandrel 34, appears in fig. 4 as an inverted "7". The helical groove 56 has a transverse or "horizontal" portion 56a terminating with an enlarged slot 57a, a diagonal portion 56b terminating at 57b, and an elbow or setting point 56c intermediate the transverse and diagonal portions 56a, 56b.
Figure 3 shows the anchoring device in the set position. In operation, the anchoring device is brought to the set position by first running the anchoring device to the setting depth in the well conduit 12. In the preferred embodiment the well equipment 14, including the anchoring device 10, is then lifted a short distance (typically about 4 inches, due mostly to tubing stretch from weight of tubing string) and the mandrel 34 is rotated in a first direction (i.e. to the "left" or counterclockwise in the embodiment shown) a quarter turn to move the bearing 52 and pin 44 from the slot 57a to the setting point 56c along the horizontal portion 56a of the helical groove 56, as indicated by arrow 70 in fig.4. The
Upper and lower retaining rings or sleeves 46 and 48, respectively, keep the drag means 28 from escaping the anchoring device 10. Lower cap screws 50 attach the lower retaining ring 48 to the drag body 26, which ring also keeps the pins 44 within the drag body 26.
Referring now to figs. 4 and 4a as well; a bearing 52 accommodates the pins 44 within a hole 54. According to an important aspect of the present invention the helical bearing 52 is generally cylindrical in shape for ease of maneuverability within an elongate groove 56 which accommodates the bearing 52. The bearing 52 slides along the groove 56, and may be made to roll within the groove if desired. The groove 56, which may be termed a helical groove since it extends about a portion of the cylindrical surface of the mandrel 34, appears in fig. 4 as an inverted "7". The helical groove 56 has a transverse or "horizontal" portion 56a terminating with an enlarged slot 57a, a diagonal portion 56b terminating at 57b, and an elbow or setting point 56c intermediate the transverse and diagonal portions 56a, 56b.
Figure 3 shows the anchoring device in the set position. In operation, the anchoring device is brought to the set position by first running the anchoring device to the setting depth in the well conduit 12. In the preferred embodiment the well equipment 14, including the anchoring device 10, is then lifted a short distance (typically about 4 inches, due mostly to tubing stretch from weight of tubing string) and the mandrel 34 is rotated in a first direction (i.e. to the "left" or counterclockwise in the embodiment shown) a quarter turn to move the bearing 52 and pin 44 from the slot 57a to the setting point 56c along the horizontal portion 56a of the helical groove 56, as indicated by arrow 70 in fig.4. The
-4-mandrel 34 is next rotated in a second direction opposite to the first direction (i.e. to the "right" or clockwise in the embodiment shown) and dropped down to move the bearing 52 and pin 44 from the elbow 56c to the end 57b along the groove's helical transverse portion 56b. During this latter rotation to the right (also about a quarter turn) the conical surfaces 38 and 138 on the cone element 36 and the drag body 26, respectively, move toward each other. The conical surfaces 38, 138 contact the respective concave inner surfaces 58 and 60 of the slips 16 to drive the slips outwardly. The gripping teeth 18 contact and bite into the inner well conduit wall 32 and cease moving. The mandrel 34 and the attached well equipment 14 is therefore set, namely they can not move with respect to the well conduit 12 in a downwardly longitudinal direction, nor any further in the rotational setting direction. Figure Sb shows the anchoring device 10 set with the slips 16 in contact with the inner well conduit wall 32.
The anchor is unset by reversing the above setting procedure. The mandrel 34 is rotated about a quarter turn in the first direction (i. e. to the left, or counterclockwise, in the instant case) and lifted to move the bearing 52, pin 44 and the drag body downwardly. Hence, the conical surfaces 36 and 136 separate and move away from the inner concave surfaces 58 and 60 of the slips 16 to allow the slips to retract. A spring 62 connected to the backside of each slip 16 urges the slip 16 away from the inner well conduit wall 32. The mandrel 34 is then rotated a quarter turn in the second direction (i.e.
to the right, clockwise) to bring the bearing 52 to the slot 57a which keeps the bearing in that location while the anchoring device 10 is moved to a different position in the well conduit for resetting or is removed entirely from the well conduit. Figure Sa shows the anchoring device 10 unset with the slips 16 retracted from the inner well conduit wall 32.
The anchor is unset by reversing the above setting procedure. The mandrel 34 is rotated about a quarter turn in the first direction (i. e. to the left, or counterclockwise, in the instant case) and lifted to move the bearing 52, pin 44 and the drag body downwardly. Hence, the conical surfaces 36 and 136 separate and move away from the inner concave surfaces 58 and 60 of the slips 16 to allow the slips to retract. A spring 62 connected to the backside of each slip 16 urges the slip 16 away from the inner well conduit wall 32. The mandrel 34 is then rotated a quarter turn in the second direction (i.e.
to the right, clockwise) to bring the bearing 52 to the slot 57a which keeps the bearing in that location while the anchoring device 10 is moved to a different position in the well conduit for resetting or is removed entirely from the well conduit. Figure Sa shows the anchoring device 10 unset with the slips 16 retracted from the inner well conduit wall 32.
-5-An alternate method of unsetting the anchoring device 10 is to pull upwardly on the mandrel 34 until the maximum shear strength of the pins 44 is exceeded.
The pins 44 will therefore shear off of the bearings 52 to allow the mandrel 34 and cone element 36 to be lifted. Once the conical surface 38 of the cone element 36 moves away from the slips 16, the spring 62 urges each slip 16 to retract from the inner well conduit wall 32.to free the anchoring device 10 for removal from the well conduit 12. Good results have been obtained using three pins 44, each with a maximum shear strength of about 6000 lbs.
Some of the advantages of the present invention may now be better appreciated.
An important advantage over prior threaded designs is that the anchoring device 10 requires a mere quarter turn in both directions and a pull or push straight up or down to either set or unset the catcher within the well conduit 12. Three or more turns are needed to set or unset prior threaded anchoring devices which is inconvenient and particularly undesireable in soft, sandy-type formations where it may be diWcult to determine whether the multiple turns are unsetting the anchoring device or undoing the tubing threads. The unidirectional teeth 18 on the slips 16 also help reduce unwanted resistance when removing the anchoring device from the well conduit after unsetting.
The above description is intended in an illustrative rather than a restrictive sense and variations to the specific configurations described may be apparent to skilled persons in adapting the present invention to specific applications. Such variations are intended to form part of the present invention insofar as they are within the spirit and scope of the claims below. For instance, the incline of the diagonal portion 56b of the groove 56 may be altered to address particular design specifications, or the amount of twist may be changed from a quarter to, say, a half turn, although this is not preferred.
The pins 44 will therefore shear off of the bearings 52 to allow the mandrel 34 and cone element 36 to be lifted. Once the conical surface 38 of the cone element 36 moves away from the slips 16, the spring 62 urges each slip 16 to retract from the inner well conduit wall 32.to free the anchoring device 10 for removal from the well conduit 12. Good results have been obtained using three pins 44, each with a maximum shear strength of about 6000 lbs.
Some of the advantages of the present invention may now be better appreciated.
An important advantage over prior threaded designs is that the anchoring device 10 requires a mere quarter turn in both directions and a pull or push straight up or down to either set or unset the catcher within the well conduit 12. Three or more turns are needed to set or unset prior threaded anchoring devices which is inconvenient and particularly undesireable in soft, sandy-type formations where it may be diWcult to determine whether the multiple turns are unsetting the anchoring device or undoing the tubing threads. The unidirectional teeth 18 on the slips 16 also help reduce unwanted resistance when removing the anchoring device from the well conduit after unsetting.
The above description is intended in an illustrative rather than a restrictive sense and variations to the specific configurations described may be apparent to skilled persons in adapting the present invention to specific applications. Such variations are intended to form part of the present invention insofar as they are within the spirit and scope of the claims below. For instance, the incline of the diagonal portion 56b of the groove 56 may be altered to address particular design specifications, or the amount of twist may be changed from a quarter to, say, a half turn, although this is not preferred.
-6-
Claims
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002239715A CA2239715A1 (en) | 1998-06-05 | 1998-06-05 | Anchoring device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002239715A CA2239715A1 (en) | 1998-06-05 | 1998-06-05 | Anchoring device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2239715A1 true CA2239715A1 (en) | 1999-12-05 |
Family
ID=29275838
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002239715A Abandoned CA2239715A1 (en) | 1998-06-05 | 1998-06-05 | Anchoring device |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2239715A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101761318A (en) * | 2010-02-25 | 2010-06-30 | 中国石油化工股份有限公司 | Underground hydraulic pressure back-off device |
-
1998
- 1998-06-05 CA CA002239715A patent/CA2239715A1/en not_active Abandoned
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101761318A (en) * | 2010-02-25 | 2010-06-30 | 中国石油化工股份有限公司 | Underground hydraulic pressure back-off device |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued | ||
| FZDE | Discontinued |
Effective date: 20000908 |