| Patents for E21B 21 - Methods or apparatus for flushing boreholes, e.g. by use of exhaust air from motor (13,780) |
|---|
| 12/08/1981 | US4305110 Mud separator valve apparatus |
| 12/08/1981 | US4304609 Drill cuttings treatment apparatus and method |
| 12/08/1981 | US4304309 Surface drilling apparatus |
| 12/01/1981 | US4303100 Kelly valve |
| 12/01/1981 | CA1113418A1 Apparatus and method for removing hydrocarbons from drill cuttings |
| 11/24/1981 | US4301868 Method using hydrocarbon foams as well stimulants |
| 11/24/1981 | CA1113081A1 Positioning deflection wedges |
| 11/17/1981 | US4300642 Device for reaming and collecting dust, for a drilling apparatus |
| 11/17/1981 | US4300636 Constant bottom contact tool |
| 11/17/1981 | CA1112516A1 Drilling fluid processing system |
| 11/12/1981 | WO1981003143A1 Blender apparatus |
| 11/11/1981 | EP0039597A2 Drilling a borehole from an offshore platform |
| 11/10/1981 | US4299123 Sonic gas detector for rotary drilling system |
| 11/03/1981 | US4298078 Method of inhibiting sticking of well string |
| 11/03/1981 | US4298077 Circulation valve for in-hole motors |
| 11/03/1981 | US4298073 Drill head |
| 11/03/1981 | US4297880 Downhole pressure measurements of drilling mud |
| 10/27/1981 | US4297225 Dehydration of muds using a revolving cone |
| 10/27/1981 | US4296970 Hydraulic mining tool apparatus |
| 10/27/1981 | US4296823 Cable tool with circulating drill stem |
| 10/27/1981 | US4296822 Multipurpose fluid flow assisted downhole tool |
| 10/20/1981 | US4295534 Well boring rigs and spoil handling conveyor apparatus therefor |
| 10/20/1981 | US4295529 Blow-out preventor |
| 10/20/1981 | US4295366 Drilling fluid circulating and monitoring system and method |
| 10/20/1981 | US4295361 Drill pipe tester with automatic fill-up |
| 10/14/1981 | EP0037804A2 Rock drilling apparatus |
| 10/13/1981 | US4294593 Drilling mud degasser apparatus and system |
| 10/13/1981 | US4294492 Caliper seal assembly |
| 10/13/1981 | US4294317 Drillhead unit |
| 10/13/1981 | US4294314 Inside blowout preventer well tool |
| 10/13/1981 | CA1110613A1 Blades stabiliser with a minimum of one venturi effect spacing, particularly for use with an earth boring machine |
| 10/13/1981 | CA1110612A1 Method of caisson placement |
| 10/06/1981 | US4293427 (meth)acrylamide-(meth)acrylamidosulfonic acid copolymer optionally crosslinked |
| 10/06/1981 | US4293163 Valve for closing the fluid passage of a well bore tubular member with balanced operating arrangement |
| 10/06/1981 | US4293048 Jet dual bit |
| 10/06/1981 | US4292988 Soft shock pressure plug |
| 09/29/1981 | US4291772 Drilling fluid bypass for marine riser |
| 09/29/1981 | US4291762 Apparatus for rapidly attaching an inside blowout preventer sub to a drill pipe |
| 09/29/1981 | US4291723 Fluid pressure actuated by-pass and relief valve |
| 09/29/1981 | US4291722 Drill string safety and kill valve |
| 09/22/1981 | US4290305 Drilling fluid circulating and monitoring system and method |
| 09/15/1981 | US4289610 Apparatus for pumping and conditioning drilling fluid |
| 09/08/1981 | US4288582 Aqueous drilling fluid additive, composition and process |
| 09/08/1981 | US4287957 Cooling a drilling tool component with a separate flow stream of reduced-temperature gaseous drilling fluid |
| 09/01/1981 | US4286664 Positive seal float collar |
| 09/01/1981 | US4286659 Ball valve safety screen |
| 08/25/1981 | US4285601 Drilling mud mixer |
| 08/25/1981 | US4285408 Reverse circulating tool |
| 08/25/1981 | CA1107713A1 Apparatus and method for detecting abnormal drilling conditions |
| 08/25/1981 | CA1107638A1 Well collar or shoe and cementing/drilling process |
| 08/18/1981 | US4284422 Industrial vacuum cleaner |
| 08/18/1981 | US4284136 Positioning deflection wedges |
| 08/12/1981 | EP0033654A2 Rotary drill bits and method of use |
| 08/11/1981 | US4282939 Method and apparatus for compensating well control instrumentation for the effects of vessel heave |
| 08/11/1981 | US4282928 Method for controlling permeability of subterranean formations |
| 08/04/1981 | US4281678 Throttling mud choke apparatus |
| 07/28/1981 | US4280524 Apparatus and method for closing a failed open fluid pressure actuated relief valve |
| 07/28/1981 | CA1105921A1 Choke for controlling the flow of drilling mud |
| 07/21/1981 | CA1105348A1 Oil base fluids with organophilic clays having enhanced dispersibility |
| 07/07/1981 | US4276945 Mud return line connector apparatus |
| 07/07/1981 | US4276931 Junk basket |
| 06/30/1981 | US4276003 Reciprocating piston pump system with screw drive |
| 06/30/1981 | US4275926 Down hole pump with bottom receptor |
| 06/30/1981 | US4275795 Fluid pressure actuated by-pass and relief valve |
| 06/23/1981 | US4274963 Solids and liquid separating apparatus |
| 06/23/1981 | US4274497 Skirted hammer sub for dual tube drilling |
| 06/23/1981 | US4274283 Apparatus and method for measuring fluid gel strength |
| 06/23/1981 | CA1103655A1 No translation available |
| 06/23/1981 | CA1103654A1 No translation available |
| 06/16/1981 | US4273212 Oil and gas well kick detector |
| 06/16/1981 | US4273193 Process for use in degasification of subterranean mineral deposits |
| 06/09/1981 | US4272258 Through cylyndrical housing by action of auger |
| 06/09/1981 | US4271916 System for adapting top head drilling rigs for reverse circulation drilling |
| 06/02/1981 | US4270620 Constant bottom contact tool |
| 06/02/1981 | US4270569 Valve assembly for the remote control of fluid flow having an automatic time delay |
| 05/26/1981 | US4269567 Mud degasser pump |
| 05/26/1981 | US4269279 Spheroidal plastic coated magnetizable particles and their use in drilling fluids |
| 05/26/1981 | CA1101837A1 Centrifugal water-air separation in earth drilling bits |
| 05/26/1981 | CA1101830A1 Disconnectable riser for deep water operation |
| 05/19/1981 | US4268400 Aqueous drilling fluid additive, composition and process |
| 05/12/1981 | US4266620 High pressure fluid apparatus |
| 05/05/1981 | US4265321 Rock drill |
| 05/05/1981 | US4265312 Method for developing water wells |
| 05/05/1981 | CA1100480A1 Vortex type solids-liquid flow mixer |
| 04/30/1981 | WO1981001181A1 Kelly valving apparatus |
| 04/28/1981 | US4264285 Downhole cleaner assembly for cleansing lubricant of downhole turbo-machines within wells |
| 04/28/1981 | US4263936 Erosion resistant check valve assembly |
| 04/28/1981 | US4263788 Universal joint apparatus having sliding plate construction for separating thrust and torque forces |
| 04/28/1981 | CA1100034A1 Subterranean mining |
| 04/28/1981 | CA1099908A1 No translation available |
| 04/21/1981 | US4262693 Kelly valve |
| 04/16/1981 | WO1981001014A1 Device for preparation of dilution liquid for drilling muds |
| 04/08/1981 | EP0026188A1 Apparatus for well logging while drilling |
| 03/31/1981 | US4258801 Dump valve for use with downhole motor |
| 03/24/1981 | US4257442 Choke for controlling the flow of drilling mud |
| 03/24/1981 | CA1097904A1 Shale stabilizing drilling fluid |
| 03/10/1981 | US4255269 Method and apparatus for adapting the composition of a drilling fluid for use in making a hole in the earth by rotary drilling |
| 03/10/1981 | US4255068 Method and a device for undersea drilling |
| 03/10/1981 | US4254836 Methods and apparatus for controlling fluid flow |
| 03/10/1981 | CA1097329A1 Drilling method and apparatus for large diameter pipe |