| Patents for E21B 34 - Valve arrangements for boreholes or wells (14,685) |
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| 08/02/1988 | US4760879 Choke and kill control system |
| 07/14/1988 | WO1988005110A1 Method and device for taking measurements and/or carrying out interventions in a well subjected to a hydraulic compression |
| 07/13/1988 | CN87205306U Balanced type high-pressure valve set |
| 07/12/1988 | US4756372 Tool for closing a well tubing |
| 07/12/1988 | US4756364 Packer bypass |
| 07/05/1988 | US4754813 Tree capless cone seal manifold |
| 07/05/1988 | US4754811 Controlled retracting gasifying agent injection point process for UCG sites |
| 06/28/1988 | US4753292 Method of well testing |
| 06/28/1988 | US4753291 Modular wireline tool connector with swivel coupling |
| 06/28/1988 | CA1238573A1 Valves |
| 06/21/1988 | CA1238269A1 Subsurface safety valve with lock-open system |
| 06/16/1988 | WO1988004382A1 Shut down valve for use in a subwater position |
| 06/16/1988 | DE3641103A1 Killing valve for an output well |
| 06/15/1988 | EP0271297A2 Packer bypass |
| 06/07/1988 | US4749044 Apparatus for washover featuring controllable circulating valve |
| 06/07/1988 | US4749043 Subsurface safety valves and seals |
| 06/07/1988 | US4749036 Dual bore well treating tool |
| 05/25/1988 | EP0268521A1 Lock valve |
| 05/24/1988 | US4745974 Well tool lock mandrel and handling tools therefor |
| 05/24/1988 | CA1237068A1 Well tool with improved valve support structure |
| 05/18/1988 | EP0267638A1 Oil well safety valve adapted to artificial lifting |
| 05/18/1988 | CN86106661A Functional mechanisms of a drilling tool for core-taking with rope |
| 05/17/1988 | CA1236769A1 Downhole tool with compressible well fluid chamber |
| 05/17/1988 | CA1236768A1 Downhole tool with compression chamber |
| 05/11/1988 | EP0267096A1 Tool for the measurement of the pressure in an oil well |
| 05/10/1988 | US4743033 Dynamic seal assembly for piston and cylinder operating in subterranean wells |
| 05/10/1988 | CA1236550A1 Well valve control system |
| 05/03/1988 | CA1236002A1 Bottom hole sampler and safety valve and valve therefor |
| 04/26/1988 | CA1235653A1 Well safety and kill valve |
| 04/19/1988 | US4738431 Ball valve structure |
| 04/12/1988 | US4736798 Rapid cycle annulus pressure responsive tester valve |
| 04/12/1988 | US4736791 Subsurface device actuator requiring minimum power |
| 04/05/1988 | US4735229 Wear monitoring construction for erosive/corrosive flow conducting devices |
| 03/30/1988 | EP0261287A1 Fluid pressure actuated downhole apparatus |
| 03/30/1988 | CN87102522A Anti-lifting safety device by interlocking the anti-gush device and the broke of a drilling machine |
| 03/29/1988 | US4733723 Gravel pack assembly |
| 03/29/1988 | CA1234540A1 Drill pipe inside blowout preventer |
| 03/22/1988 | US4732364 Wear resistant diamond cladding |
| 03/22/1988 | US4732214 Subsea production test valve assembly |
| 03/22/1988 | US4732211 Annulus pressure operated vent assembly |
| 03/08/1988 | US4729433 Safety valve for oil-wells and installation tool for the valve |
| 03/08/1988 | US4729432 Activation mechanism for differential fill floating equipment |
| 03/08/1988 | CA1233744A1 Tubing drain valve |
| 03/02/1988 | CN87205931U Level-pressure contant current device for capillary tube |
| 03/01/1988 | US4727939 Tool for closing a production column in a well |
| 03/01/1988 | US4727901 Ball valve |
| 02/24/1988 | EP0256727A2 Apparatus for perforating a well casing |
| 02/24/1988 | EP0256178A1 Method and apparatus for controlling borehole pressure in perforating wells |
| 02/23/1988 | US4726424 Well apparatus |
| 02/23/1988 | US4726422 Annular safety assembly for an oil well, especially a double production zone well |
| 02/18/1988 | DE3627627A1 Injection packer |
| 02/16/1988 | US4724908 To be positioned in a well drilling string above a drill bit |
| 02/16/1988 | CA1232835A1 Well test apparatus and methods |
| 02/09/1988 | US4723606 Surface controlled subsurface safety valve |
| 02/02/1988 | US4722400 Mechanically actuated subsurface injection tool |
| 02/02/1988 | US4722399 Self closing equalizing valve for a subsurface well safety valve |
| 02/02/1988 | US4722393 Latch assembly for well tools |
| 02/02/1988 | US4722392 Multiple position service seal unit with positive position indicating means |
| 01/26/1988 | US4721162 Fluid level controlled safety valve |
| 01/26/1988 | US4721132 Subsea flowline quick disconnect coupling |
| 01/26/1988 | CA1231891A1 Apparatus and method for inserting flow control means into a well casing |
| 01/20/1988 | CN87206291U Isotope underwell releasing instrument |
| 01/14/1988 | WO1988000275A1 Cement control valve device |
| 01/12/1988 | US4718494 Methods and apparatus for selectively controlling fluid communication between a pipe string and a well bore annulus |
| 01/12/1988 | US4718488 Pump-out plug system for a well conduit |
| 01/12/1988 | CA1231302A1 Downhole flapper valve |
| 01/07/1988 | EP0251872A1 Well head with flow control means for landfill gas recovery |
| 01/05/1988 | US4716970 Oil or gas well workover technique |
| 01/05/1988 | US4716969 Hydraulic valve actuating means for subsurface safety valve |
| 01/05/1988 | US4716968 Double seated well valve |
| 12/29/1987 | CA1230824A1 Well tool with selective bypass functions |
| 12/23/1987 | EP0250144A2 Tubing tester valve |
| 12/22/1987 | US4714233 Adapter bracket for making a valve fire safe |
| 12/22/1987 | US4714116 Downhole safety valve operable by differential pressure |
| 12/22/1987 | CA1230544A1 Weight actuated tubing valve |
| 12/15/1987 | US4712613 Down-hole blow-out preventers |
| 12/08/1987 | US4711305 Multi-mode testing tool and method of testing |
| 12/01/1987 | US4710063 Non-return valve for bore hole sleeves |
| 12/01/1987 | US4709900 Choke valve especially used in oil and gas wells |
| 12/01/1987 | US4709762 Variable fluid passageway for a well tool |
| 12/01/1987 | US4709760 For an oil or gas well casing |
| 11/24/1987 | US4708163 For installation within a well flow conductor |
| 11/19/1987 | EP0246024A2 Rapid cycle annulus pressure responsive tester valve |
| 11/17/1987 | US4706933 Oil and gas well safety valve |
| 11/17/1987 | CA1229242A1 Drill stem testing apparatus with multiple pressure sensing ports |
| 11/10/1987 | US4705109 Controlled retracting gasifying agent injection point process for UCG sites |
| 11/10/1987 | CA1229042A1 Safety valve for oil well |
| 11/10/1987 | CA1229041A2 Multi-mode testing tool for use in a well bore |
| 11/10/1987 | CA1229040A2 Displacement valve for use in displacing fluid in a downhole tool |
| 11/10/1987 | CA1229039A2 Indexing assembly for a downhole tool |
| 11/10/1987 | CA1229038A2 Operating assembly for a downhole tool |
| 11/10/1987 | CA1229037A2 Ratchet assembly for transmitting movement in a downhole tool |
| 11/04/1987 | EP0244068A1 Ball valve for undersea pipelines |
| 11/03/1987 | US4703807 In a well |
| 11/03/1987 | US4703805 Equalizing means for a subsurface well safety valve |
| 11/03/1987 | CA1228802A2 Operating assembly for a downhole tool |
| 11/03/1987 | CA1228801A2 Method of operating a multi-mode downhole tool |
| 11/03/1987 | CA1228800A1 Tool for use in a testing string disposed in a well bore |
| 10/27/1987 | CA1228582A1 Subsea gate valve actuator with external manual override and drift adjustment |
| 10/27/1987 | CA1228532A2 Method of operating a multi-mode downhole tool |