Method and system for determining an electric submersible direct drive screw pump

Abstract

The invention provides a determination method of an electric submersible direct-driven screw pump and a system. The determination method comprises the following steps: a rotor and a stator of a screwpump are manufactured according to selected material formulas of the screw pump; a per-rotation displacement value of the screw pump and a no-load operation torque of the screw pump placed in an experimental oil well are obtained; lifting pressure is gradually applied to an output end of the screw pump, and pressure operation torques of the screw pump corresponding to each lifting pressure are generated; lifting torques corresponding to each lifting pressure are generated according to each lifting pressure, the no-load operation torques and the per-rotation displacement value; and the qualification of the performances of the screw pump is judged according to the pump efficiency of the screw pump, the displacement of the screw pump and the ratios of the pressure operation torques to the corresponding lifting torques. The determination method achieves the prominent effects of guiding the design and the manufacturing of the screw pump, meeting high-speed operation demands of an underground driven screw pump, solving the power torque limiting problem of an underground driving motor and prolonging the service life of the screw pump.

Description

technical field [0001] The invention relates to the technical field of oil extraction machinery, in particular to a method and system for determining an electric submersible direct-drive screw pump. Background technique [0002] The traditional screw pump is driven by the surface device through the sucker rod. The power of the ground motor is not limited by the size and can reach tens of kilowatts. However, it is limited by the sucker rod. The speed of the screw pump is generally between 70 and 150rpm. At low speed, in order to maintain high pump efficiency and lifting capacity, the interference of the stator and rotor of the screw pump is relatively large, generally between 0.1 and 0.3 mm. , causing the frictional torque between the stator and the rotor to increase. Since the power is transmitted from the wellhead of thousands of meters through the sucker rod, the larger torque will cause the sucker rod to bend and aggravate the wear of the rod and tube. [0003] At presen...

AI Technical Summary

Problems solved by technology

In the research and field test, it was found that the screw pump could not start due to the swelling problem. The main reason was that the performance of the screw pump was not accurately tested during the test of the screw pump, which did not match the downhole drive motor.

JB / T 8091-2014 screw pump test method is a measurement method for a single parameter of a screw pump, which can draw the performance curve of the screw pump, but it cannot meet the specific needs of driving the screw pump downhole

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