CA1194858A - Recovery of ground drilling equipment - Google Patents
Recovery of ground drilling equipmentInfo
- Publication number
- CA1194858A CA1194858A CA000358939A CA358939A CA1194858A CA 1194858 A CA1194858 A CA 1194858A CA 000358939 A CA000358939 A CA 000358939A CA 358939 A CA358939 A CA 358939A CA 1194858 A CA1194858 A CA 1194858A
- Authority
- CA
- Canada
- Prior art keywords
- drilling
- extractor
- screw
- fitting
- tube
- 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
Links
- 238000005553 drilling Methods 0.000 title claims abstract description 44
- 238000011084 recovery Methods 0.000 title abstract description 12
- 238000010168 coupling process Methods 0.000 claims abstract description 10
- 238000005859 coupling reaction Methods 0.000 claims abstract description 10
- 230000000295 complement effect Effects 0.000 claims description 7
- 230000008878 coupling Effects 0.000 abstract description 2
- 239000006096 absorbing agent Substances 0.000 description 7
- 230000035939 shock Effects 0.000 description 7
- 241000282472 Canis lupus familiaris Species 0.000 description 3
- 239000011435 rock Substances 0.000 description 2
- 238000009825 accumulation Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 239000003129 oil well Substances 0.000 description 1
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
- E21B31/00—Fishing for or freeing objects in boreholes or wells
- E21B31/12—Grappling tools, e.g. tongs or grabs
- E21B31/20—Grappling tools, e.g. tongs or grabs gripping internally, e.g. fishing spears
Abstract
ABSTRACT
RECOVERY OF GROUND DRILLING EQUIPMENT
Drilling tubes 3 are provided with a threaded central bore 14 in coupling fittings 4, 15. An extractor 16 is provided with a complimentarily thread elongate member 17 which is engageable in the bores 14 for recovery of the tubes in the event of them becoming lost under ground during drilling.
RECOVERY OF GROUND DRILLING EQUIPMENT
Drilling tubes 3 are provided with a threaded central bore 14 in coupling fittings 4, 15. An extractor 16 is provided with a complimentarily thread elongate member 17 which is engageable in the bores 14 for recovery of the tubes in the event of them becoming lost under ground during drilling.
Description
RECOVERY OF GR~U~D DRILLI~G EQUIPMENT
The present invention relates to recovery of equipment lost underground during drilllng such as rock drilling, water-well drilling and oil well dri]ling. ~lerein this equipment is reEerred to as "ground drilling equipment"
Ground drilling equipment includes, Eor a typical 4" (102mm~
diameter bore hole, a "down the hole" drilling hammer with a ~" (102mm) diameter bit alld a string of 2 3/~" ~70mm) diameter drilling tubes extending down from a drilling platform to the hammer. Individual drilling tubes may be 9 ft. ~2750mm) long and consist of 1/8" (3mm) wall thickness tubing having male screw-coupling fittings at one end and female fittings at the other end.
From time to time the string breaks, generally at a weld between a fitting and the tubing, or less frequently in the middle of the tubing of a tube.
Extractors exist for recovering the equipment left down the bore hole in the event of a breakage. Conventional extractors consist of a stepped cone having a screw thread on both conical portions. When the break-age has occurred at the bottom of one drilling tube, where its tubing is welded to a fitting, the smaller conical portion engages in a central bore provided in the fitting, provided for the supply of compressed air to the hammer. ~lthough the extractor is hardenedJ its conical thread often fails to cut a thread in the fitting's central bore since the fitting is itself hardened to lengthen the life of its own thread. If the fitting is success-fully threaded~ the new thread is unlikely to extend for more than two threads on account of the taper. This length of thread may well prove insufficient to lift the weight oE the lost equipment.
If the breakage has occurred at the top of a tube or in the middle, the large diameter conical portion oE the extractor will engage the ~, tubing. There should be no problem with hardness here, but again only two threads may be cut, the tube being typically only approximately 1/8" (3mm) thick for 2 3/4" (70mm) tubing.
The ob~ect o:E the invention is to improve the chances of recovering lost equipment.
According to one aspect of the invention there is provided ground drilling equipment having at least one rotatably engageable adaption which is not untilized during normal use of the equipment and which is arranged to cooperated with a complementary rotatably-engageable extractor for recovery of the equipment in the event of loss of the 0quipment.
According to a second aspect of the invention there is provided an extractor :Eor recovering ground drilling equipment in accordance with the first aspect of the invention, the extractor having a rotatably engageable adaption complementary to the adaption of the drilling equipment and means including a boss for coupling the extractor to a string of drilling tubes.
According to a third aspect of the invention there is provided a method of recovering ground drilling equipment consisting in feeding an extractor of the second aspect of the inVentiOJI to lost drilling equipment of the first aspect, the extractor being coupled to a recovery string of drilling tubes, engaging the rotatably engageable adaption of the lost drilling equipment with the complementary rotatably-engageable adaptiosl of the extractor and withdrawing the recovery string of drilling tubes, the extractor and the lost drilling equipment.
For recovering a string of drilling tubes, the extractor comprises an elongate screw threaded member and a boss from which the threaded member extends. Preferably, the boss is adapted to be connected to a recovery string by means of a female thread.
, 5~3 For recovery with this extractor, the dri]ling tubes are provided with a female thread ln the central bores of the fittings, the thread being complementary to that of the elongate threaded member. Although it is possible for the thread to be included in only one of the male and female fittings, the o~her being bored out to pass the elongate member of the extractor, it is preferred that both fittings of a drilling tube are provided with the female thread. Further, it is preferred that the male fittings are counter-bored along the axial extent of their male threads, to allow engagement of the extractor in an adjacent female fitting where a male thread has broken off.
Preferably the elongate member is of sufficient length to pass through the full length of one tube. This enables the fitting at the far end of a broken tube to be engaged when the fitting at the near end has broken off.
The end of the elongate member remote from the boss is preferably pointed to provide self-centering when a fitting is engaged. Preferably the elongate member has an axial compressed air bore. An indication of whether the extractor has engaged the lost equipment can be gained by passing air through the extractor. If it has engaged, the hammer will start operating.
To further improve the drilling tube fittings and the extractor, it is proposed that the spanner flats thereon should be shallower than the ; 20 presently used flats which are machined to the extent of defining a square which is continuous in cross-section across the fittings. Further it is proposed that the flats at right angles to each other sllould be longitud-ina~ly spaced. }lowever, conventional square section flats may be used.
It is envisaged that normally the invention will be employed in respect of drilling tubes in the range of diameters 2 1/2" (64mm) to 5 l/2"
(1285mm) but it may also be employed for larger range of drilling tubes for example l l/2" ~38mm) to 8" ~20~0mm).
Ano~her equlpment breakage which can occur is fai.lure of the shock absorber in the hammer. The shock absorber connects th~ hammer to the drilling string with the result that the hammer is lost down the hole i.f the shock absorber breaks.
For recovery of the hammer, it is pre-ferably providecl with a pair of bayonet fitti.ng slots and an extractor is provided with a complementary pair of ba~onet fitting dogs.
Preferably the bayonet slots are directed in ~he normal direction of rotation i.e. clockwise, and the trailing edges of the slots are chamfered to keep the slots clear of drilling debris.
To help understanding of the invention, various embodiments thereo:E will now be described with reference to the accompanying drawings in which:
Figure 1 is a side view of a conventional extractor;
Figure 2 is a side view - partly sectioned - of a drilling tube in accordance wi.th the invention;
Figure 3 is a side view of a drilling tube e~tractor i.n accordance with the invention;
Figure 4 is a side view of a hammer having a broken shock absorber and of a hammer extrac~or in accordance with the invention; and Figure 5 is a plan view on line V-V in Figure 4.
The drilling tube 3 shown in Figure 2 has an upper female screw-coupling fitting 4 and a lower male screw-coupling fitting 5 j~. both fittings being welded to tubing at weld 6 and having spigots 7 that extend into the tubing. It is at either of of the we~ds 6 that the tube is most likely to fail. The male fitting ~ has a male screw threaded end 8 adapted to screw in~o ,.
~ ' ..
the fcmale screw threaded socket 9 of another tube. The fittings are hardened to prolong the life of the threads at 8,9. The threads may be of standard Whitworth profile or rope threads for example and may be tapered.
To facilitate unscrewing oE joined male and female fittings they are provided with spanner f]ats 10 which do not extend across as much of the width of the fittings as they might to obviate the risk of jarnming against a loose rock in a bored hole.
The fittings are provided with screw threaded bores 13, 14 for engagement by the extractor 16 described below with reference to Figure 3.
The bore 14 in the male fitting 5 is counter-bored at 15 to ensure that should all or part of the male end 8 break away from the fitting 5, the extractor can engage in an adequate length of thread 13 in a female fitting into which the male end 8 is screwed without interference from an out of true thread in the fractured male end. As shown the thread in the female fitting 5 does not extend into the spigot 7.
As shown in Pigure 3, the extractor 16 has an elongate threaded member 17 attached to a boss 18 similar to the male fitting 4 whereby the extractor may be fitted ~o the end of a recovery string of drilling tubes for feeding through a hole to a lost string of other drilling tubes. The member 17 may be integral with the boss 18 but is preferably threaded and possibly pinned or otherwise fitted thereto. The elongate member is of sufficient length to pass through the tube 3 to engage the thread 1~ in the female fitting 5 should the male fitting come away from the tube at its weld 6. For use with 2 3/4" (70mm) diameter, 9 ft (2750mm) long drilling tubes, the extractor is 11 ft ~3355mm) long and its elongate member is 1 3/8" ~35mm~
in diameter. The forward end of the elongate member of the extractor is pointed at 19 to guide the tool towards the axis of a broken drilling tube in the event of the extractor reaching the tube eccentrically. A bore 20 extends along the length of the elongate member 17 to pass compressed air ;nto the recovered string o-E drilling tubes. An indication of engagement o:E the elongate member in a thread 13, l4 oE the lost equipment is provided by the compressed air working the lost drilling hammer at the far end of the lost string.
Figures 4 and 5 show a drilling hammer 21 which has been lost following fracture o:E its shock absorber 22 at 23, the shock absorber normally connecting the hammer to its drill string. In accordance with the invention the hammer has a pair of diametrically opposite bayonet fi~ting slots 24 which are complementary to 2 pair of dogs 25 provided on an extractor 26. To retrieve the hammer, the tool 26 is brought into contact with the hammer and rotated until the dogs 25 engage in the slots 24. A
counter bore 27 is provided in a boss of ~he extractor to accommodate the shock absorber. As may be seen in Figure 5 the trailing edges 28 of the slots are chamfered to obviate the accumulation of drilling debris in thc slots. For ~he same reason the slots are directed in the direction of normal hammer rotation so that debris does not accumulate at the forward end 29 of the foot of the slots.
The present invention relates to recovery of equipment lost underground during drilllng such as rock drilling, water-well drilling and oil well dri]ling. ~lerein this equipment is reEerred to as "ground drilling equipment"
Ground drilling equipment includes, Eor a typical 4" (102mm~
diameter bore hole, a "down the hole" drilling hammer with a ~" (102mm) diameter bit alld a string of 2 3/~" ~70mm) diameter drilling tubes extending down from a drilling platform to the hammer. Individual drilling tubes may be 9 ft. ~2750mm) long and consist of 1/8" (3mm) wall thickness tubing having male screw-coupling fittings at one end and female fittings at the other end.
From time to time the string breaks, generally at a weld between a fitting and the tubing, or less frequently in the middle of the tubing of a tube.
Extractors exist for recovering the equipment left down the bore hole in the event of a breakage. Conventional extractors consist of a stepped cone having a screw thread on both conical portions. When the break-age has occurred at the bottom of one drilling tube, where its tubing is welded to a fitting, the smaller conical portion engages in a central bore provided in the fitting, provided for the supply of compressed air to the hammer. ~lthough the extractor is hardenedJ its conical thread often fails to cut a thread in the fitting's central bore since the fitting is itself hardened to lengthen the life of its own thread. If the fitting is success-fully threaded~ the new thread is unlikely to extend for more than two threads on account of the taper. This length of thread may well prove insufficient to lift the weight oE the lost equipment.
If the breakage has occurred at the top of a tube or in the middle, the large diameter conical portion oE the extractor will engage the ~, tubing. There should be no problem with hardness here, but again only two threads may be cut, the tube being typically only approximately 1/8" (3mm) thick for 2 3/4" (70mm) tubing.
The ob~ect o:E the invention is to improve the chances of recovering lost equipment.
According to one aspect of the invention there is provided ground drilling equipment having at least one rotatably engageable adaption which is not untilized during normal use of the equipment and which is arranged to cooperated with a complementary rotatably-engageable extractor for recovery of the equipment in the event of loss of the 0quipment.
According to a second aspect of the invention there is provided an extractor :Eor recovering ground drilling equipment in accordance with the first aspect of the invention, the extractor having a rotatably engageable adaption complementary to the adaption of the drilling equipment and means including a boss for coupling the extractor to a string of drilling tubes.
According to a third aspect of the invention there is provided a method of recovering ground drilling equipment consisting in feeding an extractor of the second aspect of the inVentiOJI to lost drilling equipment of the first aspect, the extractor being coupled to a recovery string of drilling tubes, engaging the rotatably engageable adaption of the lost drilling equipment with the complementary rotatably-engageable adaptiosl of the extractor and withdrawing the recovery string of drilling tubes, the extractor and the lost drilling equipment.
For recovering a string of drilling tubes, the extractor comprises an elongate screw threaded member and a boss from which the threaded member extends. Preferably, the boss is adapted to be connected to a recovery string by means of a female thread.
, 5~3 For recovery with this extractor, the dri]ling tubes are provided with a female thread ln the central bores of the fittings, the thread being complementary to that of the elongate threaded member. Although it is possible for the thread to be included in only one of the male and female fittings, the o~her being bored out to pass the elongate member of the extractor, it is preferred that both fittings of a drilling tube are provided with the female thread. Further, it is preferred that the male fittings are counter-bored along the axial extent of their male threads, to allow engagement of the extractor in an adjacent female fitting where a male thread has broken off.
Preferably the elongate member is of sufficient length to pass through the full length of one tube. This enables the fitting at the far end of a broken tube to be engaged when the fitting at the near end has broken off.
The end of the elongate member remote from the boss is preferably pointed to provide self-centering when a fitting is engaged. Preferably the elongate member has an axial compressed air bore. An indication of whether the extractor has engaged the lost equipment can be gained by passing air through the extractor. If it has engaged, the hammer will start operating.
To further improve the drilling tube fittings and the extractor, it is proposed that the spanner flats thereon should be shallower than the ; 20 presently used flats which are machined to the extent of defining a square which is continuous in cross-section across the fittings. Further it is proposed that the flats at right angles to each other sllould be longitud-ina~ly spaced. }lowever, conventional square section flats may be used.
It is envisaged that normally the invention will be employed in respect of drilling tubes in the range of diameters 2 1/2" (64mm) to 5 l/2"
(1285mm) but it may also be employed for larger range of drilling tubes for example l l/2" ~38mm) to 8" ~20~0mm).
Ano~her equlpment breakage which can occur is fai.lure of the shock absorber in the hammer. The shock absorber connects th~ hammer to the drilling string with the result that the hammer is lost down the hole i.f the shock absorber breaks.
For recovery of the hammer, it is pre-ferably providecl with a pair of bayonet fitti.ng slots and an extractor is provided with a complementary pair of ba~onet fitting dogs.
Preferably the bayonet slots are directed in ~he normal direction of rotation i.e. clockwise, and the trailing edges of the slots are chamfered to keep the slots clear of drilling debris.
To help understanding of the invention, various embodiments thereo:E will now be described with reference to the accompanying drawings in which:
Figure 1 is a side view of a conventional extractor;
Figure 2 is a side view - partly sectioned - of a drilling tube in accordance wi.th the invention;
Figure 3 is a side view of a drilling tube e~tractor i.n accordance with the invention;
Figure 4 is a side view of a hammer having a broken shock absorber and of a hammer extrac~or in accordance with the invention; and Figure 5 is a plan view on line V-V in Figure 4.
The drilling tube 3 shown in Figure 2 has an upper female screw-coupling fitting 4 and a lower male screw-coupling fitting 5 j~. both fittings being welded to tubing at weld 6 and having spigots 7 that extend into the tubing. It is at either of of the we~ds 6 that the tube is most likely to fail. The male fitting ~ has a male screw threaded end 8 adapted to screw in~o ,.
~ ' ..
the fcmale screw threaded socket 9 of another tube. The fittings are hardened to prolong the life of the threads at 8,9. The threads may be of standard Whitworth profile or rope threads for example and may be tapered.
To facilitate unscrewing oE joined male and female fittings they are provided with spanner f]ats 10 which do not extend across as much of the width of the fittings as they might to obviate the risk of jarnming against a loose rock in a bored hole.
The fittings are provided with screw threaded bores 13, 14 for engagement by the extractor 16 described below with reference to Figure 3.
The bore 14 in the male fitting 5 is counter-bored at 15 to ensure that should all or part of the male end 8 break away from the fitting 5, the extractor can engage in an adequate length of thread 13 in a female fitting into which the male end 8 is screwed without interference from an out of true thread in the fractured male end. As shown the thread in the female fitting 5 does not extend into the spigot 7.
As shown in Pigure 3, the extractor 16 has an elongate threaded member 17 attached to a boss 18 similar to the male fitting 4 whereby the extractor may be fitted ~o the end of a recovery string of drilling tubes for feeding through a hole to a lost string of other drilling tubes. The member 17 may be integral with the boss 18 but is preferably threaded and possibly pinned or otherwise fitted thereto. The elongate member is of sufficient length to pass through the tube 3 to engage the thread 1~ in the female fitting 5 should the male fitting come away from the tube at its weld 6. For use with 2 3/4" (70mm) diameter, 9 ft (2750mm) long drilling tubes, the extractor is 11 ft ~3355mm) long and its elongate member is 1 3/8" ~35mm~
in diameter. The forward end of the elongate member of the extractor is pointed at 19 to guide the tool towards the axis of a broken drilling tube in the event of the extractor reaching the tube eccentrically. A bore 20 extends along the length of the elongate member 17 to pass compressed air ;nto the recovered string o-E drilling tubes. An indication of engagement o:E the elongate member in a thread 13, l4 oE the lost equipment is provided by the compressed air working the lost drilling hammer at the far end of the lost string.
Figures 4 and 5 show a drilling hammer 21 which has been lost following fracture o:E its shock absorber 22 at 23, the shock absorber normally connecting the hammer to its drill string. In accordance with the invention the hammer has a pair of diametrically opposite bayonet fi~ting slots 24 which are complementary to 2 pair of dogs 25 provided on an extractor 26. To retrieve the hammer, the tool 26 is brought into contact with the hammer and rotated until the dogs 25 engage in the slots 24. A
counter bore 27 is provided in a boss of ~he extractor to accommodate the shock absorber. As may be seen in Figure 5 the trailing edges 28 of the slots are chamfered to obviate the accumulation of drilling debris in thc slots. For ~he same reason the slots are directed in the direction of normal hammer rotation so that debris does not accumulate at the forward end 29 of the foot of the slots.
Claims (2)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. Ground drilling equipment comprising a drilling tube;
a male screw-coupling fitting at one end of the tube; a first screw-threaded bore in the male screw-coupling fitting; a female screw-coupling fitting at the other end of the tube; a second screw-threaded bore in the female screw-coupling fitting, said screw threaded bores being such as to co operate with a complemen-tary screw-threaded extractor; and a counter-bore extending along the axial extent of the male thread of said male fitting.
a male screw-coupling fitting at one end of the tube; a first screw-threaded bore in the male screw-coupling fitting; a female screw-coupling fitting at the other end of the tube; a second screw-threaded bore in the female screw-coupling fitting, said screw threaded bores being such as to co operate with a complemen-tary screw-threaded extractor; and a counter-bore extending along the axial extent of the male thread of said male fitting.
2. Ground drilling equipment as claimed in claim 1 where-in said screw-coupling fittings are provided with spanner flats.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB7930563 | 1979-09-04 | ||
| GB7930563 | 1979-09-04 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1194858A true CA1194858A (en) | 1985-10-08 |
Family
ID=10507588
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000358939A Expired CA1194858A (en) | 1979-09-04 | 1980-08-25 | Recovery of ground drilling equipment |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0025650A1 (en) |
| AU (1) | AU549216B2 (en) |
| CA (1) | CA1194858A (en) |
| ZA (1) | ZA805223B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106759338B (en) * | 2017-01-23 | 2022-09-30 | 北京健安诚岩土工程有限公司 | Broken rod drilling device for threaded connection rod piece and construction method of broken rod drilling device |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1469493A (en) * | 1921-10-29 | 1923-10-02 | Charles H Brown | Fishing tool |
| US1521482A (en) * | 1924-02-05 | 1924-12-30 | Hampton A Steele | Tool joint |
| US2647008A (en) * | 1950-08-10 | 1953-07-28 | Tri State Oil Tool Company Inc | Retrieving arrangement for well drilling operations |
| US2751019A (en) * | 1954-02-23 | 1956-06-19 | Baker Oil Tools Inc | Apparatus for disengaging threaded joints |
| US2947362A (en) * | 1956-09-06 | 1960-08-02 | Houston Oil Field Mat Co Inc | Fishing tool |
| US3211484A (en) * | 1962-11-02 | 1965-10-12 | Sandvikens Jernverks Ab | Extension rod for drill rods |
| US3667252A (en) * | 1970-11-02 | 1972-06-06 | Nelson Arthur J | Coupling for drill string |
| US3737189A (en) * | 1971-12-23 | 1973-06-05 | Cities Service Oil Co | Reversible tie-back tool |
-
1980
- 1980-08-21 EP EP80302905A patent/EP0025650A1/en not_active Withdrawn
- 1980-08-25 CA CA000358939A patent/CA1194858A/en not_active Expired
- 1980-08-25 ZA ZA00805223A patent/ZA805223B/en unknown
- 1980-08-28 AU AU61820/80A patent/AU549216B2/en not_active Ceased
Also Published As
| Publication number | Publication date |
|---|---|
| AU549216B2 (en) | 1986-01-23 |
| EP0025650A1 (en) | 1981-03-25 |
| AU6182080A (en) | 1981-03-12 |
| ZA805223B (en) | 1981-08-26 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |