Electrical Submersible Pump Control for Gas Lock Avoidance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Electrical submersible pumps (ESPs) lack accurate measurement of flow rate and fluid density, leading to inefficient operation and increased risk of gas lock due to high gas content, as they typically rely on surface flow metering which differs from downhole conditions.
Innovation Solution
A system and method that includes sensors to measure current, voltage, and pressure, coupled with a processor to calculate shaft speed, fluid density, and flow rate, allowing for precise control of the ESP by adjusting motor speed based on density thresholds and efficiency curves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If surface flow metering is used to measure flow rate and density, then measurement equipment is simple, but measurement precision is poor because surface measurements differ from downhole conditions
Solution Approach 1:
The patent uses electrical parameters (current, voltage, frequency) as intermediary measurements to indirectly determine flow rate and density. Instead of directly measuring these difficult-to-obtain downhole parameters, the system measures easily obtainable electrical signals from the motor and uses computational models to derive the desired parameters, thereby achieving high measurement precision without complex downhole instrumentation.
Solution Approach 2:
The patent replaces mechanical flow measurement devices with electrical measurement and computation. Instead of using mechanical flow meters that would need to be installed downhole, the system uses electrical parameter measurements combined with motor performance models and fluid dynamics equations to calculate flow rate and density, eliminating the need for complex mechanical measurement equipment.
2Productivity
If ESP operates at high speed to maximize production, then productivity increases, but reliability decreases due to increased risk of gas lock
Solution Approach 1:
The patent implements a feedback control system that continuously monitors electrical parameters to estimate real-time flow rate and density, then adjusts motor speed accordingly. When gas content increases (indicated by decreasing density), the system reduces speed to prevent gas lock, and when liquid flow is sufficient, it increases speed to maximize production, thereby maintaining both high productivity and reliability through dynamic adaptation.
Solution Approach 2:
The patent transitions from static ESP operation at fixed speed to dynamic operation with variable speed control. The system continuously adapts motor speed based on real-time fluid conditions (density and flow rate estimates), allowing the ESP to operate optimally across varying production conditions and avoid gas lock while maximizing hydrocarbon recovery.
3Loss of information
If ESP operates without accurate fluid density measurement, then device complexity is low, but loss of information occurs leading to inefficient operation
Solution Approach 1:
The patent uses electrical parameters (current, voltage, frequency) as intermediary measurements to indirectly determine fluid density. By measuring these easily obtainable electrical signals and using motor performance models combined with fluid dynamics relationships, the system derives accurate density information without requiring complex downhole density sensors.
Solution Approach 2:
The patent enables the ESP system to self-determine fluid density using its own operational electrical parameters. The motor's electrical characteristics during operation contain information about the load, which reflects fluid density. By analyzing these self-generated electrical signals, the system obtains density information without external measurement equipment.
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
Enables accurate estimation and control of flow rate and density, optimizing ESP operation, reducing the risk of gas lock and improving hydrocarbon production by dynamically adjusting motor speed in response to fluid conditions.
Implementation Method 1
The processor is configured to calculate speed of a shaft of the electric motor based on a frequency, induced by rotation of the motor, detected in the current
Implementation Method 2
The current sensor is configured to measure a current of the electrical signal
Implementation Method 3
The voltage sensor is configured to measure a voltage of the electrical signal
Implementation Method 4
The processor may also be configured to determine a torque in the ESP based on a measured current of the electrical signal, a measured voltage of the electrical signal, a resistance of a conductor that electrically couples the ESP to the drive circuitry
Data Source
AI summary
A system, method, and computer-readable medium for determining the flow rate and fluid density in an electrical submersible pump (ESP) and controlling the ESP based on the flow rate and density. In one implementation, an ESP system includes an ESP, drive circuitry, a current sensor, a voltage sensor, and a processor. The ESP includes an electric motor. The drive circuitry is electrically coupled to the ESP and is configured to provide an electrical signal to power the ESP. The current sensor is configured to measure a current of the electrical signal. The voltage sensor is configured to measure a voltage of the electrical signal. The processor is configured to calculate speed of a shaft of the electric motor based on a frequency induced by rotation of the motor detected in the current. The processor is also configured to calculate a density of fluid in the ESP based on the speed.