ESP Motor Current Analysis for Sensorless Gas Lock Prevention
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Solution Overview
Problem
The presence of gas in wells designed for liquid hydrocarbon production interferes with the operation of electric submersible pumps (ESPs), leading to reduced production efficiency, equipment wear, and potential gas lock conditions, which can result in premature pump failure.
Innovation Solution
A method that measures the electrical current provided to a downhole ESP motor, calculates a Gas Production Index (GPI) based on signature analysis of the motor current data, and adjusts the motor speed to control the relative gas production level, thereby preventing excessive gas interference and gas lock scenarios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If gas lock recovery mode is triggered to clear gas from the pump, then gas interference is reduced, but liquid production rate decreases and equipment operates longer under suboptimal conditions
Solution Approach 1:
The system performs preliminary detection of gas conditions through motor current signature analysis and takes preventive action by adjusting motor speed before gas lock fully develops, avoiding the need for reactive gas lock recovery modes that reduce production
Solution Approach 2:
The system continuously monitors motor current signatures and provides real-time feedback on gas conditions, enabling dynamic adjustment of motor speed to maintain optimal production while preventing harmful gas accumulation
2Loss of information
If downhole instrumentation is deployed to monitor pump conditions, then real-time data is obtained, but the instrumentation is subjected to extreme conditions leading to failure and increased maintenance
Solution Approach 1:
The ESP motor serves dual purposes: as the pumping actuator and as a sensor through its current signature analysis, eliminating the need for separate downhole instrumentation and reducing failure points
Solution Approach 2:
The motor current acts as an intermediary that indirectly measures downhole conditions without requiring physical sensors in the harsh environment, transferring measurement function from vulnerable sensors to the robust motor
3Productivity
If motor speed is increased to maintain liquid production in the presence of gas, then production efficiency is maintained, but equipment wear increases
Solution Approach 1:
The system dynamically adjusts motor speed based on real-time gas conditions detected through current signature analysis, optimizing the balance between maintaining production and minimizing equipment stress
Solution Approach 2:
The system changes operational parameters (motor speed) in response to detected gas conditions, adapting the pumping regime to maintain production while reducing equipment wear under gas interference
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables proactive and continuous management of gas production in ESPs, reducing equipment wear, maintaining production efficiency, and preventing gas lock conditions, all without the need for additional downhole sensors.
Implementation Method 1
measuring data describing an electrical current provided to a downhole electrical submersible pump motor; calculating a Gas Production Index value indicating a relative gas production level of the well based on a signature analysis of the measured motor current data
Implementation Method 2
adjusting a speed of the motor to control the relative gas production level by actuating a variable-frequency drive that modifies electrical power signals provided to the motor
Data Source
AI summary
Measuring and actively managing gas production in a downhole electrical submersible pump, such as for liquid hydrocarbon well production. A controller monitors pump motor electrical current data and performs a motor current signature analysis to calculate a Gas Production Index (GPI) value indicating a relative amount of gas being produced by the well at a particular time. The controller then responsively uses the calculated present GPI value as a synthetic process variable in a closed control loop, by dynamically adjusting the pump motor speed to achieve a target amount of liberated gas as estimated by a future GPI value.