| Patents for E21B 21 - Methods or apparatus for flushing boreholes, e.g. by use of exhaust air from motor (13,780) |
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| 06/09/1987 | US4671703 Apparatus for driving pipes through the ground |
| 06/03/1987 | EP0224353A1 Method and apparatus for treating sludge streams |
| 06/02/1987 | US4670501 Drilling fluids |
| 06/02/1987 | US4670161 Cyclone separator for drilling mud additives |
| 06/02/1987 | US4670139 Drilling mud cleaning machine |
| 06/02/1987 | US4669555 Downhole circulation pump |
| 05/26/1987 | US4668251 Oil well drilling mud |
| 05/26/1987 | US4667750 Vibratory earth penetrator with synchronized air lance control |
| 05/21/1987 | WO1987003037A1 Valve for use in well bores |
| 05/21/1987 | DE3540870A1 Threaded connector or plug connector |
| 05/19/1987 | US4666471 Mud degasser |
| 05/19/1987 | US4665996 Method for reducing friction in drilling operations |
| 05/14/1987 | DE3634149A1 Pneumatic implement for working rock |
| 05/14/1987 | DE3539450A1 Drilling method for sinking earth bores, drill rods, and drill-rod joint for this |
| 05/13/1987 | EP0221053A1 Oil well safety valve for use with drill pipe |
| 05/12/1987 | US4664816 Sealing porosity in well bores |
| 05/12/1987 | US4664192 Cementing apparatus and methods |
| 05/12/1987 | CA1221603A1 Vent line system |
| 05/05/1987 | US4663366 Shear thickening composition with polycarboxylic acid |
| 05/05/1987 | US4662802 Device for effecting a seal against an underlying surface |
| 04/28/1987 | US4660596 Inside B.O.P. valve |
| 04/28/1987 | CA1221025A1 Apparatus for signalling within a borehole while drilling |
| 04/21/1987 | US4658905 Mud valve |
| 04/15/1987 | CN85107367A Well-drilling liquid |
| 04/14/1987 | US4657948 Polyallylamine or salts, naphthalene sulfonates, lignosulfonates, sulfonated aromatic vinyl polymers, crosslinking |
| 04/14/1987 | US4657092 Circulation reversing tool |
| 04/09/1987 | DE3534661A1 Drilling head, in particular for a horizontal drilling appliance |
| 04/07/1987 | US4655923 Desilter apparatus including adaptor members for accommodating connection of cyclone separators of any diameter to manifold conduits having invariant diameters |
| 04/07/1987 | US4655302 Rotating coupling |
| 04/07/1987 | US4655289 Remote control selector valve |
| 04/07/1987 | US4655247 Ball-type check valve assembly |
| 04/01/1987 | CN86106885A Air pressure impact drilling method and apparatus for same |
| 03/31/1987 | US4654150 Apparatus and method for removing combustibles from drill cuttings |
| 03/31/1987 | US4653597 Method for circulating and maintaining drilling mud in a wellbore |
| 03/31/1987 | US4653593 Control method and control device for a down-the-hole rock drill |
| 03/24/1987 | US4651836 Process for recovering methane gas from subterranean coalseams |
| 03/17/1987 | US4650153 Oil well safety valve for use with drill pipe |
| 03/17/1987 | US4650013 Chip sampler |
| 03/17/1987 | US4649655 Drilling mud dehydration system |
| 03/04/1987 | EP0212809A2 Rotary drill bit for coring holes in subsurface formations |
| 03/04/1987 | EP0126740B1 A method employed in long-hole drilling and a drill rod system |
| 03/03/1987 | US4646858 Earth boring bit with air system access |
| 03/03/1987 | US4646844 Diverter/bop system and method for a bottom supported offshore drilling rig |
| 03/03/1987 | CA1218740A1 Method and apparatus for borehole fluid influx detection |
| 02/25/1987 | EP0211112A1 Apparatus and method for real-time measurement of drilling fluid properties |
| 02/24/1987 | US4645608 Method of treating oil contaminated cuttings |
| 02/24/1987 | US4645006 Annulus access valve system |
| 02/17/1987 | US4643259 Hydraulic drill string breakdown and bleed off unit |
| 02/17/1987 | CA1218052A1 Method for improving cuttings transport in deviated wells |
| 02/12/1987 | DE3631424A1 Method of disposing of harmful substances with simultaneous energy generation |
| 02/10/1987 | CA1217761A Method employed in deep hole drilling and a drill shaft system |
| 02/10/1987 | CA1217759A Drilling equipment |
| 02/03/1987 | US4640372 Diverter including apparatus for breaking up large pieces of formation carried to the surface by the drilling mud |
| 02/03/1987 | CA1217325A1 Thixotropic cements for combating lost circulation problems |
| 02/03/1987 | CA1217322A1 Method of preventing loss of an oil base drilling fluid during the drilling of an oil or gas well into a subterranean formation |
| 01/29/1987 | WO1987000572A1 Drop ball sub-assembly for a down-hole device |
| 01/27/1987 | US4639258 Filtration of cuttings from drilling muds |
| 01/21/1987 | EP0209343A2 Method of avoiding a drill string becoming stuck during drilling |
| 01/17/1987 | CN85101523A Single stroke slurry renew system and method thereof |
| 01/14/1987 | CN86104849A Process for avoiding the equipment of well-drilling to block up in the well |
| 01/13/1987 | US4636308 Shale shakers, hydrocyclones |
| 01/13/1987 | US4635735 Method and apparatus for the continuous analysis of drilling mud |
| 01/13/1987 | US4635726 Method for controlling lost circulation of drilling fluids with water absorbent polymers |
| 01/13/1987 | US4635718 Continuous obstruction monitor for well logging tools |
| 01/13/1987 | CA1216515A1 Diverter/bop system and method for a bottom supported offshore drilling rig |
| 01/07/1987 | CN85105339A Polymeric compositions and methods of using them |
| 01/06/1987 | US4634535 Drilling mud cleaning method and apparatus |
| 01/06/1987 | US4633958 Downhole fluid supercharger |
| 01/06/1987 | US4633950 Method for controlling lost circulation of drilling fluids with hydrocarbon absorbent polymers |
| 12/30/1986 | US4632193 In-hole motor with bit clutch and circulation sub |
| 12/30/1986 | EP0205430A1 Method for inner cleaning of a core bit with reversed fluid flushing and a core bit herefor |
| 12/30/1986 | EP0128216B1 Flow diverter seal |
| 12/23/1986 | US4631137 Bentonite mixed with addition polymers |
| 12/23/1986 | US4630691 Annulus bypass peripheral nozzle jet pump pressure differential drilling tool and method for well drilling |
| 12/23/1986 | US4630675 Drilling choke pressure limiting control system |
| 12/23/1986 | CA1215640A1 Pneumatic transfer of solids into wells |
| 12/17/1986 | EP0205297A2 Improvements in down-hole blow-out preventers |
| 12/17/1986 | CN86103916A Means and devicd for prudent penetration of a casing through sensible overburden or sensible structures |
| 12/16/1986 | US4630244 Rotary acting shear valve for drilling fluid telemetry systems |
| 12/16/1986 | US4629575 Well drilling and production fluids employing parenchymal cell cellulose |
| 12/16/1986 | US4628996 Full opening check valve |
| 12/10/1986 | EP0204677A2 Device for prudent penetration of a casing through sensible overburden or sensible structures |
| 12/10/1986 | EP0204358A2 Process for the preparation of an aqueous solution of a heteropolysaccharide |
| 12/10/1986 | EP0204243A2 Rock Drills |
| 12/09/1986 | CA1214930A1 Process for containment of liquids as solids or semisolids |
| 12/02/1986 | US4626135 Marine riser well control method and apparatus |
| 12/02/1986 | US4625814 Percussive drill rod system |
| 12/02/1986 | US4625762 Auto-fill flow valve |
| 12/02/1986 | US4625755 Kelly mud saver valve sub |
| 11/25/1986 | US4624330 Rotary drill bit with strainer element |
| 11/25/1986 | US4624327 Method for combined jet and mechanical drilling |
| 11/25/1986 | US4624316 Super seal valve with mechanically retained seal |
| 11/18/1986 | US4622993 Well pipe float valve |
| 11/12/1986 | CA1213879A Drifting equipment |
| 11/11/1986 | US4621655 Marine riser fill-up valve |
| 11/06/1986 | WO1986006454A1 Oil well safety valve for use with drill pipe |
| 11/05/1986 | EP0200418A2 Drilling cuttings treatment |
| 10/29/1986 | EP0199669A2 Choke valve especially used in oil and gas wells |
| 10/29/1986 | EP0198853A1 Marine riser well control method and apparatus. |
| 10/28/1986 | US4619772 Method and material for increasing viscosity and controlling of oil well drilling and work-over fluids |