| 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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| 01/31/1989 | US4802150 Mud pressure control system with magnetic torque transfer |
| 01/31/1989 | US4802143 Alarm system for measurement while drilling oil wells |
| 01/31/1989 | US4800969 Fast descent core barrel apparatus |
| 01/24/1989 | US4799544 Drill pipes and casings utilizing multi-conduit tubulars |
| 01/17/1989 | US4798871 Compositions containing high molecular weight poly(vinylamines) for enhanced oil recovery |
| 01/17/1989 | CA1248936A1 Device for the remote actuation of an appliance associated with a duct in which an incompressible fluid circulates, particularly a device for actuating a stabilizer of a set of drill rods |
| 01/10/1989 | US4797003 Foamed slurry generator |
| 01/10/1989 | US4796704 Drop ball sub-assembly for a down-hole device |
| 01/10/1989 | CA1248564A1 Flow diverter seal |
| 01/10/1989 | CA1248443A1 Marine riser fill-up valve |
| 01/03/1989 | US4795128 Gate type kelly cock valve |
| 01/03/1989 | US4794791 Method and device for making measurements characterizing geological formations, in a horizontal borehole formed from an underground way |
| 12/29/1988 | WO1988010183A1 Treated wood fiber having hydrophobic and oleophilic properties |
| 12/27/1988 | US4793424 Self-lubricating well tools and seal elements therefor |
| 12/27/1988 | US4793423 Process for treating drilled cuttings |
| 12/21/1988 | EP0295615A1 Compositions containing high molecular weight poly (vinylamines) for enhanced oil recovery |
| 12/20/1988 | US4791999 Well drilling apparatus |
| 12/20/1988 | US4791998 Method of avoiding stuck drilling equipment |
| 12/20/1988 | CA1246855A1 Water swellable clay composition and method to maintain stability in salt contaminated water |
| 12/14/1988 | CN88212170U Dynamic-static balance combined and sealed drill tap |
| 12/13/1988 | US4790933 Dynamic filtration unit and process of use |
| 12/13/1988 | US4790396 Rotary drill bits for use in coring holes in subsurface formations |
| 12/13/1988 | US4790391 Air pressure impact drilling method and apparatus for same |
| 12/06/1988 | US4789032 Orienting and circulating sub |
| 12/06/1988 | CA1245844A1 Drilling cuttings treatment |
| 11/17/1988 | WO1988008917A1 Blowout preventer |
| 11/17/1988 | WO1988008069A3 Apparatus for use in drilling |
| 11/17/1988 | EP0233209B1 Drop ball sub-assembly for a down-hole device |
| 11/15/1988 | CA1244819A1 Drilling choke pressure limiting control system |
| 11/09/1988 | EP0290250A2 Method and apparatus for deepwater drilling |
| 11/09/1988 | EP0289673A1 Drill pipes and casings utilizing multi-conduit tubulars |
| 11/09/1988 | CN88102386A Hammer drills for making boreholes |
| 11/03/1988 | WO1988008480A1 Process for installing an underground pipe and the installation concerned |
| 10/26/1988 | EP0288180A2 Down-the-hole drill hammer |
| 10/26/1988 | EP0288106A2 Foamed slurry generator |
| 10/25/1988 | US4779688 For retaining fluids or gases in the kelly of a string of drill pipe |
| 10/20/1988 | WO1988008069A2 Apparatus for use in drilling |
| 10/20/1988 | DE3711950A1 Additive for drilling fluids, process for its preparation, and its use |
| 10/19/1988 | EP0287548A1 Apparatus for shutting off a core-barrel mounted on a drill string |
| 10/12/1988 | EP0286302A2 Top head drive assembly with axially movable quill |
| 10/11/1988 | US4777200 Polymeric compositions and methods of using them |
| 10/11/1988 | CA1242872A1 Well drilling and production fluids employing parenchymal cell cellulose |
| 10/04/1988 | US4775489 Separation into liquid phases; removal from well |
| 10/04/1988 | US4775017 Drilling using downhole drilling tools |
| 10/04/1988 | US4775015 Sliding-weight operated hole boring tool |
| 09/27/1988 | US4774007 Cleaning hydrocarbons from waste pits, pollution control |
| 09/21/1988 | EP0232268B1 Device for controlling the locking of a sampling tube |
| 09/15/1988 | DE3728269C1 Overburden drilling device |
| 09/15/1988 | DE3706755A1 Drilling head of a horizontal driving machine for controlled line-tunnel construction in the non-man-sized diameter range |
| 09/14/1988 | EP0282232A2 Monitoring drilling mud circulation |
| 09/13/1988 | US4770257 Method of preventing loss of drilling mud during boring a hole in the ground |
| 09/13/1988 | US4770255 Arrangement for underwater drilling of foundations |
| 09/13/1988 | CA1241944A1 Sleeved drill string coupling, especially for traversing a flow loss zone |
| 09/07/1988 | EP0280705A1 Process and device for producing drilling holes from an angled position in relation to the drilling axes. |
| 09/06/1988 | US4768598 Fluid pressure actuated bypass and pressure indicating relief valve |
| 08/30/1988 | US4767549 Alkoxylated fatty amine or quaternary ammonium salt, for plugging voids and fractures in rock |
| 08/30/1988 | CA1241463A1 Process and apparatus for handling waste from oil well operations |
| 08/23/1988 | US4765418 Borehole drill construction |
| 08/23/1988 | US4765416 Method for prudent penetration of a casing through sensible overburden or sensible structures |
| 08/23/1988 | US4765415 For increasing the drilling rate and drilling kife of a drill bit |
| 08/23/1988 | CA1240982A1 Method and system for drill stem breakout during drilling operations |
| 08/23/1988 | CA1240921A1 Diverter/bop system and method for a bottom supported offshore drilling rig |
| 08/17/1988 | EP0278671A1 Method and apparatus for measurement of fluid flow in a drilling rig return line |
| 08/17/1988 | EP0278616A2 Method of determining a safe value of density for a drilling fluid |
| 08/17/1988 | CN87215056U Packer cabable of flushing borehole |
| 08/16/1988 | US4763734 Earth drilling method and apparatus using multiple hydraulic forces |
| 08/10/1988 | EP0277861A1 Screw-type hydraulic motors |
| 08/09/1988 | US4762276 Fluid evaporation device for mud pits |
| 08/09/1988 | CA1240310A1 Apparatus and method for driving casing and conductor pipe |
| 08/03/1988 | EP0276546A1 Method and system for treating drill cuttings slurries and the like |
| 07/26/1988 | US4759406 Wireline tool connector with wellbore fluid shutoff valve |
| 07/20/1988 | EP0274523A1 Organophilic polyphenolic acid adducts. |
| 07/20/1988 | EP0131618B1 Vent line system |
| 07/05/1988 | US4754819 Method for improving cuttings transport during the rotary drilling of a wellbore |
| 07/05/1988 | US4754818 Method of measuring drill bit fluid flow |
| 07/05/1988 | US4754641 Method and apparatus for measurement of fluid flow in a drilling rig return line |
| 06/28/1988 | US4753633 Slurry separator |
| 06/23/1988 | DE3737024A1 Drilling device, in particular for core holes |
| 06/21/1988 | US4752339 Thixotropic aqueous solutions containing a divinylsulfone-crosslinked polygalactomannan gum |
| 06/14/1988 | US4750561 Gravel packing system for a production radial tube |
| 06/14/1988 | CA1238035A1 Hammer for use in a bore hole and apparatus for use therewith |
| 06/07/1988 | US4749050 Through the ground |
| 06/07/1988 | US4748849 Apparatus for dynamically measuring fluid loss characteristics |
| 06/07/1988 | CA1237658A1 Marine riser well control method and apparatus |
| 05/31/1988 | US4747961 Method and system for treating drill cutting slurries and the like |
| 05/31/1988 | CA1237421A1 Rotary drive coupling |
| 05/17/1988 | US4744426 Apparatus for reducing hydro-static pressure at the drill bit |
| 05/17/1988 | US4744420 For exacuating solids |
| 05/11/1988 | EP0266386A1 Improvements in drilling using downhole drilling tools. |
| 05/11/1988 | CN86104625A The telecontrolled operating device |
| 05/10/1988 | CA1236608A1 Materials for use in drilling fluids |
| 05/05/1988 | WO1988003222A1 Apparatus for controlling the operation of a downhole tool |
| 05/05/1988 | WO1988003220A1 A pneumatic percussion hammer |
| 04/26/1988 | US4739844 Hammer drill bit and sub-assembly |
| 04/26/1988 | US4739655 Method of automatically determining drilling fluid lag time while drilling a well |
| 04/26/1988 | CA1235653A1 Well safety and kill valve |
| 04/19/1988 | US4738727 Process for the preparation of an aqueous solution of a heteropolysaccharide |
| 04/19/1988 | CA1235379A1 Method of recovering oil from mud comprising fine- grained inorganic and/or organic particles, and oil, and water, or other evaporate liquids |
| 04/13/1988 | EP0263281A1 Pneumatic boring ram |
| 04/12/1988 | US4737295 With phosphatides |