Frequency conversion hydraulic well pumping unit for reducing installation power

Abstract

The invention discloses a frequency conversion hydraulic pumping unit with reduced installed power. Including mechanical system, hydraulic system, detection and control system composed of AC vector frequency converter and controller. The variable voltage and frequency conversion technology is used to control the speed of the three-phase AC asynchronous motor, thereby controlling the output flow of the quantitative hydraulic pump, and driving the hydraulic cylinder to control the operating speed of the pumping unit. At the same time, the installed power of the pumping unit is reduced by using the balance method of the counterweight of the accumulator, and the potential energy of the downstroke of the pumping unit can be effectively used, so the energy-saving effect is very obvious. The pumping unit adopts digital frequency conversion control technology, which can make the operating speed curve of the pumping unit reach the best ideal state, so that the efficiency of the pumping unit system can reach the highest. The variable frequency hydraulic pumping unit has continuous stepless speed regulation and stroke adjustment functions, and has multiple strong self-protection functions such as overload, load break, overcurrent, and instantaneous stall.

Description

[0001] Technology area [0002] The invention relates to a device for extracting fluid from a well, in particular to a frequency conversion hydraulic pumping unit with reduced installed power. Background technique [0003] Rod pumping unit is a kind of mechanical pumping equipment commonly used in oilfield development at present, which is divided into beam pumping unit and beamless pumping unit. Beam pumping units have been widely used in oil fields due to their durability, reliable components, and easy maintenance. However, during the long-term use of the beam pumping unit, many problems have been exposed: [0004] 1) Large installed power, high energy consumption and low efficiency [0005] The pumping unit is bulky, complex in structure and large in installed power. At present, the average installed capacity of a pumping unit in onshore oilfields is above 32.6KW, and the annual power consumption of rod pumping units in onshore oilfields in my country is about 6.76 billio...

AI Technical Summary

Problems solved by technology

Due to its huge balance weight, reducer, four-link mechanism and belt drive, it consumes a lot of energy during operation

In addition, the motor cannot automatically adjust its output power according to the load change of the pumping unit’s up and down strokes, so the system efficiency of the pumping unit is very low, only about 26%

[0006] 2) It is impossible to realize automatic control according to the requirements of complex and changeable oil well conditions

In recent years, as my country's oilfields increasingly need long-stroke, low-stroke pumping units to increase fluid production, people have studied a variety of energy-saving hydraulic pumping units, which are improving oil pumping Some progress has been made in improving the efficiency of the pumping unit, but because the designed hydraulic system is only based on how to recover the energy of the downstroke of the pumping unit, it has not fully utilized the power of the motor and hydraulic pump. At the same time, the self-adaptive ability of the pumping unit is poor, resulting in low system efficiency, and the energy-saving effect of the pumping unit is not obvious, so it has not been effectively promoted

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