| Patents for E21B 31 - Fishing for or freeing objects in boreholes or wells (3,788) |
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| 09/26/1989 | CA1261133A1 Use of mono- and polyalkylene glycol ethers as agents for the release of differentially stuck drill pipe |
| 09/26/1989 | CA1260692A1 Method for releasing stuck drill string |
| 09/20/1989 | CN2044640U Underground sand eliminator |
| 09/19/1989 | CA1259603A1 Mechanical jarring devices for use in drilling |
| 09/13/1989 | CN2044282U Magnetic oil jet |
| 09/12/1989 | US4865125 Hydraulic jar mechanism |
| 09/05/1989 | US4862958 Coil tubing fluid power actuating tool |
| 08/16/1989 | EP0328244A1 A drilling tool |
| 08/15/1989 | US4856582 Motorized wellbore fishing tool |
| 08/02/1989 | EP0325835A1 Mechanical latching device operated by dead weight and tension |
| 07/27/1989 | WO1989006737A1 A drilling tool |
| 07/18/1989 | US4848820 Wireline running and pulling tool |
| 07/18/1989 | US4848454 Downhole tool for use with a ball and seat traveling valve for a fluid pump |
| 07/18/1989 | CA1257701A1 Method of avoiding stuck drilling equipment |
| 07/11/1989 | US4846273 Jar mechanism accelerator |
| 07/04/1989 | US4844183 Accelerator for fishing jar with hydrostatic assist |
| 07/04/1989 | US4844157 Jar accelerator |
| 06/28/1989 | EP0321610A1 Oil well safety valve and setting and retrieving tools for such a valve |
| 06/27/1989 | US4842082 Variable outside diameter tool for use in pikewells |
| 06/21/1989 | CN2039737U Rod-shaped inner-magnet type waxing-proof device |
| 06/13/1989 | US4838594 Running and pulling tool |
| 06/07/1989 | CN2038951U Overshot |
| 06/07/1989 | CN2038950U Fishing tube for column-shaped drop in well |
| 05/31/1989 | CN2038543U Protective device for deep well |
| 05/16/1989 | US4829816 Method and apparatus for testing spotting fluids for releasing stuck drill pipe |
| 05/09/1989 | US4828026 Remotely operable downhole junk basket system |
| 05/09/1989 | US4828023 Mechanical latching device operated by dead weight and tension |
| 05/03/1989 | EP0314130A1 Accelerator for a fishing jar |
| 05/02/1989 | CA1253533A1 High-pressure sealing means for longitudinally movable parts of deep-well drilling tools |
| 04/25/1989 | US4823877 Open hole pipe recovery circulation valve |
| 04/05/1989 | CN2035379U Three-tule type strong magnetic wax-protecting device |
| 04/05/1989 | CN2035378U Mechanical wheel type well dredging machine |
| 04/04/1989 | US4817716 Pipe connector and method of applying same |
| 03/21/1989 | US4813730 Retrieval device for a well control tool |
| 03/15/1989 | CN2034194U Anti-wax, guided multi-functional connector |
| 03/08/1989 | CN2033851U Detonating device for buckle-loosening by explosion |
| 03/01/1989 | EP0304988A1 Method and apparatus for producing pressure variations in a drilling fluid |
| 03/01/1989 | CN2033441U Automatic dewaxing equipment of oil well |
| 02/28/1989 | US4807709 Fluid Powered drilling jar |
| 02/22/1989 | CN2033051U Sucker rod with righting scraper wax |
| 02/08/1989 | CN2032246U Wire arranging system with auto error complement |
| 01/31/1989 | US4801167 Downhole well fishing assembly |
| 12/20/1988 | US4791998 Method of avoiding stuck drilling equipment |
| 12/14/1988 | CN87103829A Clearing apparatus for internal surface of casing pipes |
| 11/08/1988 | CA1244401A1 Drill extractor |
| 11/02/1988 | EP0289103A2 Pipe connector and method of applying same |
| 10/25/1988 | CA1243711A1 Releasable spear for retrieving tubular members from a well bore |
| 10/19/1988 | EP0287155A2 Assembly for directional drilling of boreholes |
| 10/05/1988 | CN86209127U Magnetic salvaging apparatus |
| 09/21/1988 | CN87101747A Viscosity-decreasing and wax-coagulation-preventing device in petroleum transporting pipe |
| 09/06/1988 | US4768588 Connector assembly for a milling tool |
| 08/30/1988 | US4767145 For engaging an internal fishing neck |
| 08/18/1988 | DE3802391A1 Device for retrieving pneumatically actuated percussion tools from boreholes |
| 08/09/1988 | US4762175 Apparatus for connecting jars to a downhole tool |
| 07/12/1988 | US4756366 Well servicing methods using a hydraulic actuated workover mast |
| 06/07/1988 | US4749044 Apparatus for washover featuring controllable circulating valve |
| 05/18/1988 | CN87208555U Finger-protective gear type fisher |
| 04/12/1988 | US4736797 Jarring system and method for use with an electric line |
| 03/30/1988 | CN87213080U Magnetized waxproof apparatus |
| 03/08/1988 | US4729433 Safety valve for oil-wells and installation tool for the valve |
| 03/02/1988 | EP0257943A2 Apparatus having a radially movable member |
| 02/23/1988 | CA1233166A1 Mechanical well jar |
| 02/23/1988 | CA1233165A1 Wireline jar |
| 02/17/1988 | CN87200965U Permanent-magnet anti-paraffin unit |
| 02/03/1988 | CN86105819A Flushing method for hydrographic and engineering geological well drilling |
| 02/02/1988 | US4722390 Adjustable collet |
| 01/20/1988 | CN87206403U Drill rod pulling machine |
| 01/13/1988 | CN87204910U Oil drilling well high field strength permanent-magnet waxproof device |
| 01/13/1988 | CN87200973U Permanent-magnet waxproof mechanism linked with sucker rod |
| 12/29/1987 | US4715454 Mechanical directional drilling jar with swivel means |
| 12/29/1987 | US4715445 For use with a well tool |
| 12/09/1987 | EP0248316A2 Mechanical directional drilling jar |
| 11/19/1987 | EP0245892A2 Apparatus for vibrating a pipe string in a borehole |
| 11/17/1987 | US4706745 Lock-down releasing spear assembly |
| 11/07/1987 | CN86206131U Magnetic fishing tool for drilling well |
| 11/03/1987 | US4703802 Cutting and recovery tool |
| 10/20/1987 | US4700775 Dual-action retrieving tool for oil well swabs |
| 09/29/1987 | US4696502 Dual string packer mill |
| 09/22/1987 | US4694917 Mechanical jarring devices for use in drilling |
| 09/15/1987 | US4693308 Tubing conveyed perforating safety anchor |
| 09/12/1987 | CN86204993U Intense magnetic anti-wax device for oil well |
| 08/25/1987 | US4688649 Mechanical drill string jar |
| 08/11/1987 | US4685520 Open hole pipe recovery circulation valve |
| 08/11/1987 | CA1225327A1 Drill string jar |
| 07/21/1987 | US4681175 For installing utility pipes in the ground |
| 07/15/1987 | EP0228844A2 Downhole retrieving mechanism |
| 07/08/1987 | CN85109237A Device and method for sectioning and recovery of seabed surface casing |
| 06/25/1987 | DE3543295A1 Fishing tool for removing iron-bearing chips from deep-drill holes |
| 06/23/1987 | US4674571 Method and apparatus for improving oil production in oil wells |
| 06/16/1987 | US4673037 Method for sonically loosening oil well liner environments |
| 05/26/1987 | US4667742 Down hole excitation system for loosening drill pipe stuck in a well |
| 05/19/1987 | US4665998 Mechanical well jar |
| 05/19/1987 | CA1221960A1 Latch-pin tripping mechanism for use in association with a mechanical drilling jar |
| 05/05/1987 | US4662460 Rotary drilling jar |
| 05/05/1987 | US4662459 Drilling system and method employing torsional sonic vibration for lubrication of journal type bit bearings |
| 05/05/1987 | US4662436 Tool for washing over, cutting and retrieving a portion of a pipe within a well bore |
| 04/21/1987 | US4658917 Enclosed jar tool |
| 04/21/1987 | US4658901 Method of and apparatus for removing stuck well pipe |
| 04/21/1987 | CA1220779A1 Single acting hydraulic fishing jar |
| 03/11/1987 | EP0213798A2 Packer retrieval assembly |