| 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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| 03/03/1981 | US4253530 Method and system for circulating a gas bubble from a well |
| 02/17/1981 | US4250974 Apparatus and method for detecting abnormal drilling conditions |
| 02/17/1981 | US4250972 Pneumatic ram boring device |
| 02/17/1981 | US4250966 Insertion type cementing baffle |
| 02/10/1981 | US4249611 Marine conductor string provided with a connector and a connector for use in such a marine conductor string |
| 02/10/1981 | CA1095501A1 Flow control valve for rock bits |
| 02/03/1981 | US4248264 Internal mud saver valve |
| 02/03/1981 | CA1095093A1 Method and device for breaking a hard compact material |
| 01/28/1981 | EP0022865A1 Hydraulically-driven downhole drill |
| 01/27/1981 | US4247403 Method of sealing pores, and lost circulation additive therefor |
| 01/27/1981 | US4247312 Drilling fluid circulation system |
| 01/27/1981 | US4246975 Wellbore drilling technique using eccentric tool joints to mitigate pressure-differential sticking |
| 01/20/1981 | US4245710 Centrifugal water-air separation in earth drilling bits |
| 01/20/1981 | US4245708 Blade stabilizer provided with at least one fluid passage having a venturi effect, in particular for use in combination with a drill bit |
| 01/20/1981 | US4245672 Sealing valve for sludge scavenging system |
| 01/20/1981 | CA1093806A1 Biodegradable foaming agent in drilling and workover operations |
| 01/13/1981 | US4244431 Drilling apparatus with dual drill pipe and cross-over |
| 01/06/1981 | US4243252 Dual concentric pipe joint |
| 01/06/1981 | US4243113 Drilling head of a rotary impact drill |
| 01/06/1981 | CA1092855A1 Method and apparatus for measuring volume and density of fluids by a drilling fluid system |
| 12/30/1980 | US4242146 Absorption, compaction |
| 12/30/1980 | US4241797 Impact tool for dislodging stuck drill bits |
| 12/16/1980 | US4239396 Method and apparatus for blending liquids and solids |
| 12/11/1980 | WO1980002719A1 Method of separating weighting material from drilling mud |
| 12/11/1980 | WO1980002718A1 Method of drilling productive stratum |
| 12/11/1980 | WO1980002717A1 Method and device for earth-rock probing and rock drilling by a percussion drill |
| 12/11/1980 | WO1980002716A1 Device for rectification of drilling mud |
| 12/09/1980 | US4237977 Removal of water from gas well borehole with solid foaming agent |
| 12/09/1980 | CA1091083A1 Thickening compositions containing xanthan gum, guar gum and starch |
| 11/25/1980 | US4235552 Fluid mixing system |
| 11/18/1980 | US4234421 Land restoration following oil-well drilling |
| 11/18/1980 | US4234413 Method and apparatus for self-cleaning drilling mud separation system |
| 11/18/1980 | US4234047 Disconnectable riser for deep water operation |
| 11/04/1980 | US4231436 Marine riser insert sleeves |
| 10/15/1980 | EP0017518A1 Rotary drilling machine and drilling method using this machine |
| 10/14/1980 | US4227583 Method and apparatus for sinking shafts |
| 10/14/1980 | CA1087640A1 Surface drilling apparatus |
| 10/07/1980 | US4226726 Desilter |
| 10/07/1980 | US4226447 Swivel apparatus |
| 10/07/1980 | CA1087165A1 Means for drilling |
| 10/02/1980 | WO1980002053A1 Method of continuous logging of borehole |
| 10/02/1980 | WO1980002052A1 Method for determining the depth of occurrence of chemically aggressive stratum |
| 10/02/1980 | WO1980002051A1 Apparatus for well logging while drilling |
| 10/02/1980 | WO1980002050A1 Method for determining the depth of occurrence of fluid saturated stratum and the type of fluid |
| 10/02/1980 | WO1980002049A1 Method and device for filling up the borehole |
| 10/02/1980 | WO1980002048A1 Device for electrophoretic rectification of drilling mud |
| 10/02/1980 | WO1980002047A1 Method and device for separating the solid phase from the drilling mud |
| 10/02/1980 | WO1980002046A1 Method and device for processing the drilling mud |
| 10/02/1980 | WO1980002045A1 Device for electrokinetic separation of the drilling mud into liquid and solid phases |
| 10/02/1980 | WO1980002044A1 Method of separation of solid phase in the drilling mud |
| 10/02/1980 | WO1980002043A1 Device for degassing the drilling mud |
| 10/02/1980 | WO1980002042A1 Device for electrokinetic separation of drilling mud |
| 10/02/1980 | WO1980002041A1 Method of separation of solid phase in the drilling mud |
| 10/02/1980 | WO1980002040A1 Method of controlling the quality of drilling mud |
| 10/02/1980 | WO1980002039A1 Method of control of process of dispersion of solid phase in a liquid phase |
| 10/02/1980 | WO1980002038A1 Method of maintaining preset parameters of drilling mud |
| 10/02/1980 | WO1980001996A1 Device for rectification of drilling mud |
| 10/02/1980 | WO1980001994A1 Device for preparation of drilling mud |
| 10/02/1980 | WO1980001993A1 Method and device for preparation of drilling mud |
| 10/01/1980 | EP0016304A1 Choke for controlling the flow of drilling mud |
| 09/30/1980 | US4224989 Method of dynamically killing a well blowout |
| 09/30/1980 | US4224988 Device for and method of sensing conditions in a well bore |
| 09/23/1980 | US4223748 Method of collecting dust during rock drilling and a dust collecting suction system for a rock drilling apparatus |
| 09/23/1980 | US4223747 Drilling using reverse circulation |
| 09/23/1980 | CA1086239A1 Method and apparatus for the degasification of fluids |
| 09/16/1980 | US4222988 Heater to vaporize, mill to shear |
| 09/16/1980 | US4222444 Method of well fluid leak prevention |
| 09/16/1980 | CA1085598A1 Method of reducing drag and rotating torque in the rotary drilling of oil and gas wells |
| 09/09/1980 | US4221503 Drilling method and apparatus for large diameter pipe |
| 09/02/1980 | US4220207 Seafloor diverter |
| 09/02/1980 | US4220176 Methods and apparatus for controlling fluid flow |
| 08/26/1980 | US4219087 Enlarged bore hole drilling method |
| 08/26/1980 | CA1084251A1 Drilling fluid lubricant |
| 08/26/1980 | CA1084250A1 Controlling corrosion in gas-containing aqueous drilling fluid |
| 08/19/1980 | US4217965 Cottonseed hulls, bentonite, and surfactant to seal porous formations |
| 08/19/1980 | US4217709 Submarine sand sampler |
| 08/12/1980 | US4217208 Method for separating solid lubricating material from drill cuttings |
| 08/12/1980 | US4216836 Process and system for recovering solid particulate additives from a drilling fluid |
| 08/05/1980 | US4215753 Drilling fluid cooling system |
| 07/29/1980 | US4214879 Degassing apparatus |
| 07/24/1980 | WO1980001499A1 Method of regeneration of drilling mud |
| 07/24/1980 | WO1980001498A1 Method and device for separating the solid phase in a drilling mud |
| 07/24/1980 | WO1980001497A1 Device for dispersing and homogenizing drilling mud |
| 07/24/1980 | WO1980001496A1 Method for controlling a drilling mud dispersing process |
| 07/24/1980 | WO1980001495A1 Method and device for preparing a drilling mud |
| 07/24/1980 | WO1980001469A1 Method and device for preparing a drilling mud |
| 07/22/1980 | US4213740 Oilfield pump stroke monitor |
| 07/22/1980 | US4213508 Downhole fire control |
| 07/15/1980 | CA1081685A1 Nutating drill bit |
| 07/01/1980 | US4210208 Subsea choke and riser pressure equalization system |
| 06/26/1980 | WO1980001300A1 Hydraulically-driven downhole drill |
| 06/17/1980 | US4208285 Drill cuttings disposal system with good environmental and ecological properties |
| 06/10/1980 | US4207017 Earthen tank and liner |
| 06/03/1980 | CA1078817A1 Check valve for rock drill |
| 05/27/1980 | US4204715 Method and device for breaking a hard compact material |
| 05/27/1980 | CA1078369A1 Device whereby a duct in a deep bore hole is supported and moved up or down by reaction against the bore hole surface |
| 04/29/1980 | US4200160 Sweep pickup for a big hole bit |
| 04/29/1980 | CA1076552A1 Process and installation for drilling holes in the earth's crust under freezing conditions |
| 04/17/1980 | WO1980000726A1 Method and device for control of structure-mechanical properties of drilling mud |
| 04/08/1980 | US4196783 Device for boring |