| Patents for E21B 43 - Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells (64,186) |
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| 04/03/1991 | EP0124580B1 Fine and coarse servo system for access and tracking on an optical disk |
| 04/03/1991 | CN1050427A Double-layer self-adjustable water distributor |
| 04/02/1991 | US5004050 Method for well stimulation in the process of oil production and device for carrying same into effect |
| 04/02/1991 | US5004049 Low profile dual screen prepack |
| 03/28/1991 | DE3931013A1 Arrangement for removing volatile impurities from ground water - in which efficiency of system for passing cleaning gas through water in borehole is improved by recirculating some of used cleaning gas |
| 03/27/1991 | EP0418572A1 Device for removing light volatile contaminants from ground water |
| 03/27/1991 | EP0418570A1 Device for the purification of polluted ground water |
| 03/27/1991 | EP0418434A1 Adjustable connection apparatus |
| 03/27/1991 | EP0418374A1 Sulfate scale dissolution. |
| 03/27/1991 | EP0418356A1 Process and device for taking samples at a ground water measurement site. |
| 03/27/1991 | CN2073931U Hydraulic compression type quantitative sucker |
| 03/27/1991 | CN2073930U 泄油器 Bleeder |
| 03/27/1991 | CN1012191B Method and apparatus for extracting petroleum |
| 03/27/1991 | CN1012189B Well completion process using polymer gel |
| 03/26/1991 | US5002657 Separator for oil well production fluids |
| 03/26/1991 | US5002127 Placement aid for dual injection placement techniques |
| 03/26/1991 | US5002125 Fracturing process using a viscosity stabilized energizing phase |
| 03/26/1991 | CA1281894C Co _drive process for oil recovery employing an alcohol ethoxycarboxylate surfactant |
| 03/21/1991 | WO1991003280A1 Apparatus for removing volatile contaminants from soil |
| 03/20/1991 | EP0417369A1 Method and apparatus for logging a well below a downhole pump |
| 03/20/1991 | CN1012092B Steam injection profiling |
| 03/20/1991 | CN1012091B Steam enhanced oil recovery method using branched alkyl aromatic sulforates |
| 03/19/1991 | US5000264 Method and means for introducing treatment fluid into a subterranean formation |
| 03/19/1991 | US5000263 Method for improving the steam splits in a multiple steam injection process using multiple steam headers |
| 03/19/1991 | US5000262 Viscosity control additives for foaming mixtures |
| 03/19/1991 | CA1281807C Method and device of positioning an element using ultrasound sensors |
| 03/19/1991 | CA1281637C Apparatus for dispensing chemicals into oil and gas wells |
| 03/19/1991 | CA1281635C High temperature high pressure detonator |
| 03/14/1991 | CA2017097A1 Adjustable connection apparatus |
| 03/14/1991 | CA2014536A1 Borehole, as well as a method and an apparatus for forming it |
| 03/13/1991 | EP0416915A2 Time delay perforating apparatus for wells |
| 03/13/1991 | CN2073030U Negative pressure generator of inner well |
| 03/13/1991 | CN2073029U Variable angle donkey head of pumping unit |
| 03/12/1991 | WO1991003690A1 Process for making general use of the earth's heat and obtaining minerals in the zone of weakness (at depths of 13-30 km) |
| 03/12/1991 | US4998848 Method and apparatus for removing ground contaminants |
| 03/12/1991 | US4998756 Adjustable connection apparatus |
| 03/12/1991 | US4998585 Floating layer recovery apparatus |
| 03/12/1991 | CA2041637A1 Recovery of geothermal energy and mineral resources |
| 03/12/1991 | CA1281468C2 Salt enhanced dilution of a gel-like aqueous polymer solution |
| 03/12/1991 | CA1281438C Natural tracer for secondary recovery water injection process |
| 03/12/1991 | CA1281380C Viscosity reduction apparatus |
| 03/12/1991 | CA1281281C Casing guide for well template |
| 03/12/1991 | CA1281278C Sequential hydraulic fracturing |
| 03/12/1991 | CA1281277C Pressure assist detonating bar and method for a tubing conveyed perforator |
| 03/07/1991 | WO1991002948A1 Combined separator and sampler |
| 03/07/1991 | CA2024677A1 Time delay perforating apparatus |
| 03/06/1991 | EP0415770A2 Well perforating apparatus and firing head |
| 03/05/1991 | US4997571 Method of treating water |
| 03/05/1991 | US4997313 Leaching |
| 03/05/1991 | US4997044 Apparatus for generating hydraulic shock waves in a well |
| 03/05/1991 | CA1281058C Process for increasing the degree of oil extraction |
| 03/05/1991 | CA1280883C Foaming acid-containing fluids |
| 03/01/1991 | WO1991003620A1 Well casing flotation device and method |
| 03/01/1991 | CA2065338A1 Well casing flotation device and method |
| 02/28/1991 | DE3937593C1 Aerobic microbial purificn. of contaminated underground water - by drawing up through boreholes, super-saturating with oxygen and additives, feeding to bio-reactor, etc. |
| 02/27/1991 | EP0414431A2 A method for gravel packing a well |
| 02/27/1991 | EP0413788A1 Device for regulating and reducing a polyphasic flow, and its use |
| 02/27/1991 | CN2072149U Microporous separator for oil and sand |
| 02/27/1991 | CN2072148U Crankpin taper sleeve for oil pump |
| 02/27/1991 | CN1011809B Hydraulic fracture mining process of multilayer rock salt |
| 02/26/1991 | US4995763 Offshore well system and method |
| 02/26/1991 | US4995463 Conversion of hydrophobic coal fines to hydrophilic by injecting wetting agent and dispersant |
| 02/26/1991 | US4995460 Method and apparatus for disposing of water at gas wells |
| 02/26/1991 | US4995456 Gravel pack well completions |
| 02/26/1991 | CA1280689C Viscous oil recovery method |
| 02/26/1991 | CA1280688C Well completion process using a polymer gel |
| 02/26/1991 | CA1280646C Buoy having minimal motion characteristics |
| 02/20/1991 | CN2071702U Safety igniter for petroleum perforator |
| 02/20/1991 | CN1011722B Old-bittern underground drainage after mining and processing of salt deposit |
| 02/19/1991 | US4993491 Fracture stimulation of coal degasification wells |
| 02/19/1991 | US4993490 Overburn process for recovery of heavy bitumens |
| 02/19/1991 | US4993276 Drive assembly with overspeed brake |
| 02/17/1991 | WO1991002849A1 Process for in situ decontamination of subsurface soil and groundwater |
| 02/12/1991 | US4991654 A sliding sleeve |
| 02/12/1991 | US4991614 Method and a plant for transport of hydrocarbons over a long distance from an offshore source of hydrocarbons |
| 02/12/1991 | CA1280107C Foamed slurry generator |
| 02/07/1991 | WO1991001481A1 Monitoring and control of oil/gas fields |
| 02/06/1991 | EP0411745A1 Method of scavenging hydrogen sulfide from hydrocarbons |
| 02/06/1991 | EP0411059A1 Removal of accumulated liquids in hydrocarbon wells |
| 02/06/1991 | EP0238491B1 Cyclone separator |
| 02/06/1991 | CN2070819U Sand-proof and anti-gas pump for drew thick |
| 02/06/1991 | CN2070818U Pressure-control explosion-proof positioner |
| 02/06/1991 | CN2070817U Anti-tripping device for integral arbor oil pump rod |
| 02/06/1991 | CN1011522B Sulfonate dimer surfactant cyclic steam stimulation process for recovering hydrocarbons from subterranean formation |
| 02/05/1991 | US4989987 Slurry mixing apparatus |
| 02/05/1991 | US4989674 Organosilicon polymer having nonrandom crosslinkages useful in enhanced oil recovery using carbon dioxide flooding |
| 02/05/1991 | US4989671 Gas and oil well controller |
| 02/05/1991 | CA1279817C Process and apparatus for injection of oxidant and liquid into a well |
| 01/30/1991 | EP0410522A2 Method and apparatus for preventing slug growth in a pipeline |
| 01/30/1991 | CN2070358U Thermo-insulated device for well in situ oil water gas medium transportation |
| 01/30/1991 | CN2070357U Under well flow aid |
| 01/30/1991 | CN2070356U Crankshaft pulley type long stroke oil pump |
| 01/30/1991 | CN1011432B Extracting method of special crude oil |
| 01/30/1991 | CN1011430B Process for avoiding the equipment of well-drilling to block up in the well |
| 01/29/1991 | US4988389 Jet pump; injection of solvent |
| 01/29/1991 | CA1279534C Precured coated particulate material |
| 01/28/1991 | CA2020996A1 Method for improving the steam splits in a multiple steam injection process |
| 01/26/1991 | CA2021796A1 Method and apparatus for preventing slug growth in a pipeline |
| 01/23/1991 | CN1011331B Flexible flowline connection to subsea wellhead assembly |
| 01/22/1991 | US4986727 Pressure-operated oil and gas well swabbing device |