| 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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| 06/10/1998 | EP0846839A2 Method and apparatus for placing and cementing casing in horizontal wells |
| 06/10/1998 | CN2283722Y Drilling fluid swirl de-mud apparatus with mushroom swirler assembly |
| 06/09/1998 | US5762143 System and method for placement and retrieval of a subsurface diverting tool used in drilling and completing wells |
| 06/04/1998 | WO1998012413A3 Wellbore milling system |
| 05/28/1998 | WO1998022689A2 Whipstock |
| 05/28/1998 | WO1998022552A1 Multiphase lubricant concentrates for use in water based systems in the field of exploratory soil drilling |
| 05/28/1998 | CA2271733A1 Multiphase lubricant concentrates for use in water based systems in the field of exploratory soil drilling |
| 05/26/1998 | US5755892 Waste disposal of contaminated drill cuttings from geological drilling using drilling fluid systems containing mineral oil |
| 05/26/1998 | CA2221435A1 One-trip whipstock setting and squeezing method |
| 05/20/1998 | EP0841982A1 Improvements in or relating to ultrasonic processors |
| 05/20/1998 | DE19647565A1 Mehrphasige Schmiermittelkonzentrate für den Einsatz in wasserbasierten Systemen aus dem Bereich der Erdreicherbohrung A multiphase lubricant concentrates for use in water-based systems in the field of Erdreicherbohrung |
| 05/12/1998 | US5749422 Enhanced gas or oil recovery |
| 05/07/1998 | WO1998019040A1 Recovery of gas from drilling fluid returns in underbalanced drilling |
| 05/07/1998 | WO1998018882A1 Process for the facilitated waste disposal of working substances based on water-in-oil invert emulsions |
| 05/07/1998 | WO1998018881A1 Enhanced multicomponent mixtures for soil decomposition |
| 05/07/1998 | DE19643840A1 Verbesserte Mehrkomponentengemische für den Erdreichaufschluß Improved multi-component mixtures for geological exploration |
| 05/07/1998 | CA2271040A1 A process for the simplified disposal of working fluids based on w/o invert emulsions |
| 05/07/1998 | CA2270716A1 Improved multicomponent mixtures for use in geological exploration |
| 05/06/1998 | EP0839619A1 Core drill |
| 05/06/1998 | EP0839255A1 Safeguarded method and apparatus for fluid communication using coiled tubing, with application to drill stem testing |
| 04/29/1998 | EP0837978A1 Single trip whipstock assembly |
| 04/28/1998 | US5744428 Controlling permeability of walls when drilling through geological formations |
| 04/28/1998 | US5743331 Wellbore milling system |
| 04/23/1998 | WO1998016717A1 Oil and gas well cuttings disposal system with continuous vacuum operation for sequentially filling disposal tanks |
| 04/23/1998 | WO1998016716A1 Continuous circulation drilling method |
| 04/23/1998 | WO1998016712A1 Apparatus and method for drilling boreholes |
| 04/23/1998 | DE19745766A1 Sludge preparation station for tunnelling machine whose working tip consists of compressed sludge |
| 04/22/1998 | CN1038153C Method of increasing viscosity of anion polyacrylamide solution |
| 04/21/1998 | US5740871 Flow diverter ring for a rotary drill bit and method |
| 04/16/1998 | WO1998015711A1 Inflatable plug with anchoring means |
| 04/16/1998 | CA2240001A1 Inflatable plug with anchoring means |
| 04/14/1998 | US5738336 Oilfield valve |
| 04/14/1998 | US5738178 Method and apparatus for navigational drilling with a downhole motor employing independent drill string and bottomhole assembly rotary orientation and rotation |
| 04/09/1998 | WO1998014688A1 Method and multi-purpose apparatus for dispensing and circulating fluid in wellbore casing |
| 04/09/1998 | WO1998014687A1 Novel method of drilling well bores |
| 04/07/1998 | US5735348 Fill-up and circulating tool |
| 04/07/1998 | CA2030694C Functional fluids |
| 04/01/1998 | EP0832344A2 Down hole hammer assembly |
| 04/01/1998 | CN2277453Y Telescopic continuous flushing device |
| 03/31/1998 | US5734988 Method and apparatus for the injection disposal of solid and liquid waste materials into subpressured earth formations penetrated by a borehole |
| 03/31/1998 | US5732775 Duplex assembly for use with drill pipe |
| 03/26/1998 | WO1998012413A2 Wellbore milling system |
| 03/26/1998 | WO1998012412A1 Drill shank for a drill drive |
| 03/26/1998 | WO1998012410A1 Coupling piece for use at simultaneous earth and/or rock drilling with an upper rotary percussion device and a lower percussion device |
| 03/26/1998 | DE19638464A1 Einsteckende für einen Bohrantrieb Insertion of a drill drive |
| 03/26/1998 | CA2266494A1 Coupling piece for use at simultaneous earth and/or rock drilling with an upper rotary percussion device and a lower percussion device |
| 03/25/1998 | EP0830327A1 Stable suspension of hydrocolloids |
| 03/24/1998 | US5730233 Method for detecting changes in rate of discharge of fluid from a wellbore |
| 03/24/1998 | US5730222 Downhole activated circulating sub |
| 03/24/1998 | US5729992 Refrigerant charge control system for heat pump |
| 03/18/1998 | EP0828923A2 Device for controlling the weight on an earth drill bit |
| 03/17/1998 | US5727741 Pulverizing assembly |
| 03/11/1998 | CN2276069Y Sand washing valve |
| 03/10/1998 | US5725021 System for retrieving waste drilling mud |
| 03/05/1998 | WO1998008587A1 Apparatus and method for separation of solids from liquid |
| 03/03/1998 | US5723423 Solvent soaps and methods employing same |
| 02/25/1998 | CN1174587A Method and apparatus for drilling with high-pressure, reduced solid content liquid |
| 02/24/1998 | US5720356 Method and system for drilling underbalanced radial wells utilizing a dual string technique in a live well |
| 02/18/1998 | CN2274687Y Hydraulic vortex sand remover with choked intaking pipe |
| 02/17/1998 | US5718298 Separation system and method for separating the components of a drill bore exhaust mixture |
| 02/17/1998 | US5718289 Apparatus and method for use in injecting fluids in a well |
| 02/12/1998 | WO1998005848A2 Method and apparatus for the downhole metering and control of fluids produced from wells |
| 02/12/1998 | WO1998005735A1 Invert emulsion fluids suitable for drilling |
| 02/12/1998 | WO1998005734A1 Improved oil-based drilling fluid |
| 02/12/1998 | WO1998005733A1 Improved oil-based drilling fluid |
| 02/12/1998 | DE19626589C1 Sinking boreholes in soft ground |
| 02/11/1998 | EP0823538A2 Method of stimulating a subterranean well |
| 02/11/1998 | EP0823536A2 Centralising device |
| 02/11/1998 | EP0822853A1 Shale shaker |
| 02/10/1998 | US5717131 Apparatus for testing a shear thickening plugging fluid |
| 02/10/1998 | US5715896 Method and composition for reducing torque in downhole drilling |
| 02/10/1998 | US5715895 Downhole drilling tool cooling system |
| 02/04/1998 | CN2273765Y Drilling slurry treating machine |
| 01/29/1998 | WO1998003764A1 Underground warning system for underground conduits or pipes |
| 01/28/1998 | EP0820556A2 Cementing plug |
| 01/27/1998 | US5711385 Augerless boring system |
| 01/27/1998 | CA2037048C Extension tube and internal jacketing conduit assembly |
| 01/21/1998 | EP0735919B1 Solvent soaps and methods employing same |
| 01/21/1998 | CN2272944Y Vacuum degasifier for drilling fluid |
| 01/17/1998 | CA2210458A1 Improved fluid circulation apparatus |
| 01/14/1998 | CN2272484Y Flowmeter for oil well water filling |
| 01/13/1998 | US5706905 Steerable rotary drilling systems |
| 01/08/1998 | WO1998000625A1 Drill bit with set of underreamer arms |
| 01/08/1998 | WO1998000624A1 Boring tool for reverse circulation |
| 01/07/1998 | EP0815343A1 Flow control tool |
| 01/07/1998 | EP0620892A4 Case cementing method and system. |
| 12/31/1997 | WO1997049891A1 Drill tube for forming drill strings |
| 12/31/1997 | WO1997049890A1 Method for measurement of the airflow in rock drill bits as well as measurement means for accomplishing said method |
| 12/31/1997 | WO1997049889A1 A system for directional control of drilling |
| 12/31/1997 | CA2258236A1 A system for directional control of drilling |
| 12/30/1997 | US5701963 Continuous injection of an inert gas through a drill rig for drilling into potentially hazardous areas |
| 12/24/1997 | WO1997048528A1 Dust conveying device for portable combustion motor driven rock drills |
| 12/24/1997 | WO1997048494A1 Method and apparatus for separating solids from drilling mud |
| 12/18/1997 | WO1997047853A1 Method and device for rinsing and/or cleaning delivery piping |
| 12/18/1997 | WO1997047850A1 Multi-cycle circulating sub |
| 12/16/1997 | US5697458 Drilling fluid process |
| 12/16/1997 | US5697442 Apparatus and methods for use in cementing a casing string within a well bore |
| 12/11/1997 | WO1997046790A1 Core machine |
| 12/10/1997 | CN2270114Y Drive shaft type underground flowmeter |
| 12/09/1997 | US5695014 Ram boring apparatus |