Optical Sensor Gas-Liquid Level Control for Subsea Pumps
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Solution Overview
Problem
Current methods for controlling the gas-liquid interface in subsea oilfield exploitation are inadequate, leading to inefficient fluid production and increased risk of pump failure due to gas lock conditions, and require oversized pressure vessels for accurate measurement.
Innovation Solution
A system and method using sensors to measure fluid properties like density or capacitance to regulate the flow rate of electrical submersible pumps, ensuring optimal gas-liquid separation by adjusting pump speed or flow rate based on gas content, thereby maintaining a stable gas-liquid level and maximizing fluid production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pressure transducers are used to infer gas-liquid interface level based on fluid pressures, then measurement can be achieved, but oversized and more expensive pressure vessels are required to achieve the needed resolution
Solution Approach 1:
The patent replaces the mechanical pressure transducer method with an optical sensor system. Optical sensors measure fluid properties (density, gas content) directly through light transmission or scattering, eliminating the need for large pressure vessels and multiple height-differenced transducers. This substitution of measurement methodology resolves the contradiction by achieving high measurement precision without requiring oversized vessels.
Solution Approach 2:
The patent changes the measurement parameter from pressure (which requires large vessel height differential) to optical properties like light transmission or scattering (which can be measured with small vessel dimensions). By changing the physical parameter being measured, the system achieves the same measurement resolution with much smaller vessels, resolving the size-resolution contradiction.
2Reliability
If manual control of production rate is used to control gas-liquid interface, then pump operation can be stabilized, but production efficiency is reduced due to trial and error adjustments
Solution Approach 1:
The patent implements a feedback control system where optical sensors continuously monitor fluid properties (gas content, density) and feed this information to a controller that automatically adjusts pump speed. This closed-loop feedback eliminates the need for manual trial-and-error adjustments, maintaining stable pump operation while maximizing production efficiency through continuous optimization based on real-time fluid conditions.
Solution Approach 2:
The system enables self-service control where the pump automatically regulates its own operation based on real-time fluid conditions. The controller adjusts pump speed autonomously in response to sensor measurements, eliminating the need for manual intervention and optimizing production efficiency while maintaining operational stability.
3Productivity
If high production rate is maintained without gas lock, then maximum fluid production is achieved, but pump overheating and premature failure risk increases
Solution Approach 1:
The patent uses optical sensors to continuously monitor fluid gas content and feeds this information to the controller, which adjusts pump speed to maintain optimal operating conditions. This feedback mechanism prevents gas lock and overheating by detecting fluid conditions before they cause damage, allowing high production rates to be maintained safely without increasing pump failure risk.
Solution Approach 2:
The system takes preliminary action by continuously monitoring fluid properties and adjusting pump speed in advance to prevent gas lock and overheating conditions. By detecting gas content and fluid density before they reach critical levels, the controller proactively adjusts operation to avoid pump damage, enabling high production rates with reduced failure risk.
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 efficient fluid production by maintaining a low gas-liquid level, reducing the risk of pump failure, and allowing for the use of smaller, more cost-effective vessels while ensuring high-quality gas separation.
Implementation Method 1
The sensor measures the relative proportion of gas in the liquid by the change in the property being measured
Implementation Method 2
The sensor may comprise a fluid property measurement device that detects a property, such as density or capacitance, of the fluid being produced
Data Source
AI summary
An electrical submersible pump that regulates pump flow rate based on sensor measurements of the fluid is disclosed. The sensor measures a property of the fluid being processed. The sensor may be located at the intake, discharge or other area of the pump. The sensor measures the relative proportion of gas in the pumped liquid. The pump flow rate is adjusted to maintain a desired level for the gas in a production environment. The pump may be used to operate and control a seabed gas-liquid separation and centrifugal pump system.