Method for determining optimal oil pumping rate of beam-pumping unit

Abstract

The invention provides a method for determining the optimal oil pumping rate of a beam-pumping unit. The method comprises the steps that an inflow characteristic curve is determined; determining an outflow characteristic curve; drawing an oil well supply and discharge coordination diagram according to the inflow characteristic curve and the outflow characteristic curve; calculating the working fluid level depth; calculating a reasonable submergence degree; expressing an oil well pump plunger motion equation in a Fourier series expansion form; calculating the volume of a pump cavity between the plunger and the standing valve; calculating the volume of liquid in the pump cavity; calculating a pump fullness coefficient by combining the volume of the pump cavity and the volume of liquid in the pump cavity; determining constraint conditions; calculating each optimal coefficient of the Fourier series expansion; an optimized oil well pump plunger motion equation is determined; and the suspension point motion equation and the motor motion rate are reversely deduced through the oil well pump plunger motion equation. On the premise that the service life of an oil pumping system is not shortened, the pump efficiency and the oil pumping efficiency are improved, and the oil pumping consumption is reduced.

Description

technical field [0001] The invention belongs to the technical field of oil production, and in particular relates to a method for determining the optimal pumping rate of a beam pumping unit based on comprehensive downhole working conditions. Background technique [0002] The beam pumping unit has the advantages of simple geometric structure and reliable quality, so it has a very important position in the mechanical oil recovery of the oil field. Up to now, in my country's oilfield production, mechanical oil production wells account for 98% of all oil wells, of which beam pumping wells account for 96% of all mechanical oil production wells. With the continuous development of the oil field, the liquid supply capacity of the formation continues to decline, the liquid production volume of the oil well gradually decreases, and the problems of low efficiency of the oil production system and high energy consumption become increasingly prominent, which seriously restricts the economi...

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Problems solved by technology

[0004] In order to solve the problem of the mismatch between the plunger movement law of the oil pump and the working conditions of the oil well, and improve the oil production efficiency of the pumping well, the present invention proposes a method for determining the optimal pumping rate of the beam pumping unit based on the comprehensive working conditions downhole. method, in order to determine a reasonable relationship between supply and discharge, optimize the speed of plunger movement, and improve pump efficiency; optimize the acceleration of suspension points to reduce inertial loads;

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