Centrifugal Pump Control via Electrical Signal Modeling
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Solution Overview
Problem
Centrifugal pumps in oil and gas production face challenges in efficiently controlling fluid levels and flow rates, leading to pump-off and gas-lock conditions, which result in instability and reduced productivity, due to the non-linearity of the system and reliance on costly and unreliable down-hole sensors.
Innovation Solution
A method that estimates pump flow rate and pressure using above-ground measurements of electrical voltages and currents, eliminating the need for down-hole sensors, and employs mathematical models to calculate operating parameters, allowing for real-time closed-loop control and prevention of pump-off and gas-lock conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If down-hole sensors are used to directly measure pump operating parameters, then measurement precision is improved, but device complexity and cost increase, and reliability decreases
Solution Approach 1:
The patent uses above-ground electrical measurements as an intermediary to infer down-hole pump operating parameters. Instead of placing sensors directly in the harsh down-hole environment, the system measures electrical voltages and currents at the surface and uses mathematical models to calculate pump speed, torque, flow rate, and head pressure, thereby avoiding the reliability issues of down-hole sensors while maintaining measurement accuracy
Solution Approach 2:
The patent replaces the mechanical sensor-based measurement system with an electrical field-based measurement system. By measuring electrical parameters (voltages and currents) above ground and using mathematical models to derive mechanical pump parameters, the system eliminates the need for physical sensors in the down-hole environment, reducing complexity and improving reliability
2Stability of the object's composition
If traditional closed-loop control algorithms are used, then control stability is maintained, but response speed decreases due to system non-linearity and sensor time delays
Solution Approach 1:
The patent implements feedforward control by calculating desired pump operating parameters in advance based on measured electrical signals and mathematical models. The controller determines the required pump speed, torque, and power before actual deviations occur, allowing proactive adjustment rather than reactive correction, thereby improving response speed while maintaining stability
Solution Approach 2:
The patent combines feedforward control with feedback mechanisms by continuously monitoring electrical measurements and comparing calculated operating parameters with desired setpoints. The system adjusts pump operation based on real-time electrical signal feedback, creating a hybrid control approach that leverages both predictive and corrective actions to achieve fast and stable control
Data Source
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AI summary
A method and apparatus for determining a fluid level and/or output flow during operation of a centrifugal pump, are provided, which may be used for production of gas and/or oil from a well, and include a vector feedback model to derive values of torque and speed from signals indicative of instantaneous current and voltage drawn by the pump motor, a pump model which derives values of the fluid flow rate and the head pressure for the pump from torque and speed inputs, a pumping system model that derives, from the estimated values of the pump operating parameters, an estimated value of fluid level and other pumping system parameters. Controllers responsive to the estimated values of the pumping system parameters control the pump to maintain fluid level at the pump input, near an optimum level, or within a safe operating range and/or output flow from the pump.