Progressing Cavity Pump Control Using PID Algorithm and Fillage
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Solution Overview
Problem
Existing positive displacement pump systems, particularly progressive cavity pumps, face challenges with high installation costs, reduced accuracy, and limited long-term reliability due to the need for subsurface sensors for monitoring and control, which are costly and unreliable.
Innovation Solution
A pump control system using a proportional-integral-differential (PID) based algorithm that calculates theoretical fluid flow rates and pump fillage, adjusting pump speed to optimize production and minimize wear without requiring subsurface sensors, utilizing surface sensors and well operator-provided data to refine calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If subsurface sensors are deployed to monitor and control pump operations, then real-time downhole parameter measurement is achieved, but installation costs increase and long-term reliability decreases
Solution Approach 1:
The patent introduces an intermediary approach by using surface-level measurements and calculations to infer downhole conditions. Instead of placing sensors directly in the challenging subsurface environment, the system uses readily available surface data (fluid flow rate, pump speed) combined with pump performance curves to calculate and infer downhole parameters such as cavity fillage, thereby avoiding the reliability issues of subsurface sensor deployment while still achieving the measurement objective
2Measurement precision
If subsurface sensors are deployed to monitor and control pump operations, then real-time downhole parameter measurement is achieved, but installation costs increase
Solution Approach 1:
The patent extracts the measurement function from the subsurface environment and relocates it to the surface level. By taking out the sensing requirement from the difficult-to-access downhole environment and performing calculations using surface-available data, the system eliminates the need for expensive subsurface sensor installation while maintaining the capability to monitor and control pump operations based on inferred downhole conditions
3Productivity
If pump speed is increased to optimize fluid production, then productivity increases, but pump wear increases
Solution Approach 1:
The patent implements a feedback control mechanism that continuously monitors inferred downhole conditions (specifically cavity fillage) and adjusts pump speed accordingly. The system calculates the desired pump speed based on maintaining optimal cavity fillage levels, which prevents excessive wear while maximizing fluid production. This closed-loop feedback ensures the pump operates in the optimal performance window, balancing productivity with equipment longevity
Data Source
AI summary
System/method for real-time monitoring and control of pump operations at a well provide a pump control system that uses pump fillage with a proportional-integral-differential (PID) based algorithm to control positive displacement pump operations. The pump control system/method obtains measured or inferred pump speed from available pump speed data and, using certain pump characteristics provided by the well operator, calculates a theoretical fluid flow rate based on the pump speed. The pump control system/method thereafter compares the calculated theoretical fluid flow rate to a measured or observed fluid flow rate to calculate a pump fillage. The calculated pump fillage is then provided as a process input to the PID based algorithm along with a desired pump fillage from the well operator. The PID based algorithm processes the calculated pump fillage and the desired pump fillage using tuning parameters to determine an optimum pump speed based on the desired pump fillage.