| 摘要 |
<p>Method and apparatus for pumping production fluid up a production tube from a well. A hydraulic actuator unit, (100, 160, 200) with its own hydraulic fluid incorporates pressure sensing valves (40, 42, 54, 76, 141, 228, 236, 238) to move a hydraulic piston (117, 126, 173, 175, 222, 264, 266, 268, 502, 504, 506, 522, 526) through a power stroke and a resetting stroke. A power transmission tube (135, 167, 208, 352, 528) having its own power fluid transfers pressure from the hydraulic actuator to a downhole piston assembly (206, 350, 400, 500) to pump the production fluid directly up the production tube (120, 304, 352, 408, 520, 574, 578) during a power stroke. The static head of the production fluid in the production tube (120, 304, 352, 408, 520, 574, 578) resets the downhole piston assembly (206, 350, 400, 500) during the resetting stroke. The pressure sensing valves (40, 42, 54, 76, 141, 228, 236, 238) enable the hydraulic piston to extend its power stroke a sufficient distance to pressurize the power transmission fluid and move the downhole piston assembly (206, 350, 400, 500) through its entire production stroke independent of the compressibility of the power transmission fluid. The present invention is applicable for single and multiple well installation.</p> |
