Gas Lift Compressor Control for Minimum Production Pressure
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Solution Overview
Problem
The oil and gas industry faces challenges in managing gas injection rates during gas lift operations, as over-injection increases friction and reduces fluid flow, while under-injection fails to lift liquids to the surface, leading to fluid buildup and reduced production. Existing methods lack the ability to continuously adjust gas injection rates in response to changing production pressures.
Innovation Solution
A method and improved compressor system that incrementally adjust gas injection rates to identify the minimum production pressure required to lift fluids, using the Hunt Mode and Critical Rate Mode to dynamically manage gas injection, incorporating programmable logic and sensors to monitor and adjust production pressures, and a computer server to calculate optimal gas injection rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gas injection rate is increased to ensure lifting of liquids to the surface, then liquid lifting is improved, but friction during production increases and fluid flow from formation into the well decreases
Solution Approach 1:
The system dynamically adjusts the gas injection rate based on real-time monitoring of production pressure and fluid flow conditions. Rather than using a fixed injection rate, the system continuously optimizes the gas injection rate to match changing well conditions, thereby maintaining reliable liquid lifting while minimizing friction and preserving fluid flow from the formation.
Solution Approach 2:
The system implements a feedback mechanism where production pressure and fluid flow rates are continuously monitored and used to adjust the gas injection rate. This closed-loop control ensures that the gas injection rate is optimized in real-time to achieve reliable liquid lifting without excessive friction, thus resolving the contradiction between lifting reliability and fluid flow productivity.
2Productivity
If gas injection rate is decreased to reduce friction, then fluid flow from formation is improved, but liquids fail to lift to the surface and fluid buildup occurs
Solution Approach 1:
The system dynamically adjusts the gas injection rate based on real-time monitoring of production pressure and fluid flow conditions. Rather than using a fixed low injection rate, the system continuously optimizes the gas injection rate to match changing well conditions, thereby maintaining fluid flow productivity while ensuring sufficient gas injection to lift liquids to the surface and prevent fluid buildup.
Solution Approach 2:
The system implements a feedback mechanism where production pressure and fluid flow rates are continuously monitored and used to adjust the gas injection rate. This closed-loop control ensures that the gas injection rate is optimized in real-time to achieve both high fluid flow rates and reliable liquid lifting, preventing the fluid buildup that occurs with under-injection.
3Ease of operation
If fixed gas injection rate is used to simplify operations, then operational complexity is reduced, but system cannot compensate for changes in production pressure
Solution Approach 1:
The system is designed to automatically adjust the gas injection rate based on real-time well conditions without requiring manual intervention. The control system self-regulates by monitoring production pressure and fluid flow rates, and automatically modifies the gas injection rate to compensate for pressure changes, thereby maintaining both operational simplicity and adaptability to changing conditions.
Solution Approach 2:
The system dynamically changes the gas injection rate parameter in response to varying production pressure conditions. By automatically adjusting this key parameter based on real-time monitoring, the system maintains adaptability to pressure changes while keeping operations simple through automated control rather than manual adjustment.
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 allows for continuous optimization of gas injection rates, reducing friction and maintaining efficient well production by identifying the minimum gas injection rate necessary to unload all fluids from the well, thereby improving operational efficiency and preventing liquid loading.
Implementation Method 1
The use of injected gas, commonly known as gas lift, to aid in the production of liquids from a well
Implementation Method 2
continuing to produce liquids from the well during the first incremental period while monitoring production pressure within the well
Data Source
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AI summary
Disclosed is a compressor system suitable for carrying out artificial gas lift operations at an oil or gas well. Also disclosed is a method for controlling the compressor system. The methods disclosed provide the well operator with the ability to identify and maintain gas injection rates which result in the minimum production pressure. The minimum production pressure will be determined either by a bottom hole sensor or a casing pressure sensor located at the surface or any convenient location capable of monitoring pressure at the wellhead.