Oil Pumping Unit Electric Machine Driving Method
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Solution Overview
Problem
Conventional oil pumping units face inefficiencies when reducing the theoretical displacement of a single well, leading to increased plunger leakage and reduced motor efficiency, and wastage of resources due to limited operation modes.
Innovation Solution
An electric machine driving method and system that combines crank complete-cycle, incomplete-cycle pumping, and no-pumping operations, utilizing utility frequency and variable frequency driving modes to adjust rotating speeds and reduce the operational intensity of frequency changers, thereby improving heat dissipation and extending their service life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the working strokes are reduced to decrease the theoretical displacement of a single well, then the displacement requirement is met, but the plunger leakage rate increases and motor driving efficiency decreases
Solution Approach 1:
The patent applies dynamics by enabling the oil pumping unit to switch between different operation modes (complete-cycle and incomplete-cycle) dynamically. The crank can perform incomplete-cycle motions where it swings only to a predetermined angle less than 180 degrees, allowing the system to adapt stroke length and frequency to match desired displacement requirements while maintaining optimal operating conditions and reducing plunger leakage rates.
2Productivity
If the working strokes are reduced to decrease the theoretical displacement of a single well, then the displacement requirement is met, but the motor driving efficiency decreases
Solution Approach 1:
The system dynamically adjusts operation modes to optimize motor efficiency. By switching between complete-cycle and incomplete-cycle operations, the motor can maintain higher speeds and avoid inefficient low-speed operation, thereby improving overall driving efficiency while still achieving the required displacement reduction.
3Productivity
If the interval pumping work mode is used to reduce the theoretical displacement of a single well, then the displacement requirement is met, but manpower, material resources, and financial resources are wasted
Solution Approach 1:
The patent eliminates the need for interval shutdowns by implementing continuous operation with incomplete-cycle cranks. The oil pumping unit operates continuously without stopping between pumping intervals, maintaining continuous useful action. This removes the resource waste associated with interval pumping while still achieving the required displacement reduction through controlled stroke angles and frequencies.
4Productivity
If the variable frequency driving mode is used continuously to adjust the stroke frequency, then the desired displacement is achieved, but the operational time and intensity of frequency changers increase, reducing heat dissipation and service life
Solution Approach 1:
The system uses periodic switching between variable frequency driving mode and utility frequency driving mode. Instead of continuous variable frequency operation, the system alternates between modes based on operational requirements. During utility frequency operation, the frequency changer rests and dissipates heat, extending its service life while still achieving desired displacement control through periodic variable frequency adjustments.
Data Source
AI summary
The present invention discloses a method and a system pertaining to the field of oil production engineering. According to the method, the crank complete-cycle operation uses a utility frequency driving mode, and the crank incomplete-cycle pumping operation and the crank incomplete-cycle no-pumping, operation use a variable, frequency driving mode. The system is provided with a utility frequency loop and a variable frequency loop which are provided with a common input terminal and a common output terminal. The common input terminal of the utility frequency loop and the variable frequency loop is connected to a utility frequency power supply circuit, and the output terminal is connected to a driving electric machine of the oil pumping unit. A frequency changer is configured in the variable frequency loop. An operation control unit is further configured outside the utility frequency loop and the variable frequency loop.