Double acting pump
The basic type of hydraulic piston pump, the promotion area accounts for 80% to 90%. The structural feature is that the reversing slide valve is located between the upper and lower plungers. The upper and lower plungers are both hydraulic motor plungers and deep well pump plungers. The connecting surfaces of the two plungers and the plunger rod are alternately acted The other end of the plunger alternately discharges the well fluid in the cylinder out of the pump. The plunger rod is always under tension, the force is in good condition, and a larger stroke can be designed. When the reversing valve is in the lower limit position, the high-pressure power fluid enters the lower cavity of the upper cylinder through the flow channel to push the plunger assembly upward, and the well fluid in the upper cavity is discharged to the annular space of the tubing casing through the upper discharge valve. At the same time, the well fluid enters the lower cavity of the lower cylinder through the fixed valve and the suction valve, and the depleted power fluid in the upper cavity of the lower cylinder is discharged to the annular space of the tubing casing through the flow passage. When the plunger group moves to the upper limit position, the high-pressure power fluid acts on the lower end of the reversing spool valve through the reversing groove at the lower part of the tie rod, and the area difference between the two ends of the spool valve generates an upward thrust, which causes the spool valve to change direction. The high-pressure power fluid enters the upper cavity of the lower cylinder through the reversing slide valve hole and the flow channel, and the depleted power fluid in the lower cavity of the upper cylinder is discharged to the annular space of the tubing casing through the flow channel. When the plunger assembly moves down to approach the lower limit position, the reversing valve groove on the upper part of the tie rod connects the hole with the drain hole, so that the lower cavity of the reversing slide valve is connected to the low pressure. The reversing valve moves downward under the action of high and low pressure difference, and the plunger group reversing operation, repeating this cycle, continuously lifting the well fluid to the surface
Single-acting pump
Partially modified on the basis of double-acting pump. The structural feature is that the diameter of the upper plunger in the plunger group is smaller than the diameter of the lower plunger, and is designed to a certain ratio to balance the load and working pressure of the up and down stroke. There is only one set of suction and discharge valves, which are arranged at one end of the large-diameter plunger. The working principle is similar to that of a double-acting pump. The characteristic is to significantly reduce the pump pressure ratio and wellhead working pressure; the same wellhead working pressure, the pump's lifting capacity is significantly improved, but the pump displacement is also reduced accordingly. It is suitable for oil wells with low liquid level and small production.
Double pump end pump
On the basis of the double-acting pump, a pump end plunger is added. Both the upper stroke and the lower stroke are driven by a hydraulic motor to drive the two pump end plungers, and the displacement of the pump is greatly improved. It is suitable for large production oil wells.
Double liquid motor pump
On the basis of the double-acting pump, a hydraulic motor plunger is added. Both the upstroke and the downstroke are driven by two hydraulic motors to drive a pump end plunger, and the pump head is greatly improved. It is suitable for deep well pumping.
