| 摘要 |
A downhole pump includes a pump barrel defining a pumping chamber having a first end and a second end, a first one-way valve positioned at the first end of the pumping chamber, a second one-way valve positioned at the second end of the pumping chamber and a plunger movable disposed in the pumping chamber. The first one-way valve is operable to permit a flow of fluid out of the first end of the pumping chamber, while the second one-way valve is operable to permit a flow of fluid out of the second end of the pumping chamber. The plunger has first and second ends facing the first and second ends of said pumping chamber respectively. The pumping chamber has an inlet adapted to be in flow communication with a production zone. The plunger is movable in the pumping chamber between at least a first position and a second position. The second end of the plunger is positioned on a first side of the inlet when the plunger is in the first position such that the inlet is in flow communication with the second end of the pumping chamber. |
