Gas Lift Rate Control Using Adaptive Well Test Frequency
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Solution Overview
Problem
Gas lift wells in unconventional hydrocarbon assets often operate suboptimally due to limited optimization methods, resulting in reduced production and inefficient gas allocation, particularly in offshore facilities where equipment space is limited and model-based optimization is impractical for large numbers of wells.
Innovation Solution
A method and system that determine the frequency of multi-rate well testing in gas-lifted hydrocarbon wells by monitoring performance characteristics through single-rate tests, comparing them to well models, and adjusting gas injection based on deviations, allowing for optimal gas lift rate determination only when necessary, thereby optimizing well performance without requiring extensive equipment or complex modeling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multi-rate well testing is performed frequently to optimize gas lift operations, then well performance optimization improves, but equipment availability and operational time are reduced due to limited test separators
Solution Approach 1:
The patent uses a portable, temporary testing system that can be deployed and removed as needed, rather than relying on permanent, limited test separators. The portable system includes a flow meter, pressure transducers, and data acquisition equipment that can be quickly installed and removed from the well flow line, enabling frequent testing without long-term equipment unavailability.
Solution Approach 2:
The patent extracts the essential testing functionality from the permanent test separator infrastructure and implements it as a separate, portable testing system. This allows the core measurement functions (flow rate, pressure, temperature) to be performed independently of the limited test separator resources, enabling more frequent optimization testing.
2Productivity
If model-based optimization methods are used for large numbers of wells, then optimization coverage improves, but system complexity and maintenance requirements increase
Solution Approach 1:
The patent implements an automated system that performs its own optimization calculations and adjustments without requiring external expert intervention. The data acquisition system automatically collects well performance data, compares it to target parameters, and generates optimization recommendations or automatically adjusts gas lift rates, reducing the need for complex manual model maintenance and expert analysis.
Solution Approach 2:
The patent focuses on optimizing a limited set of critical parameters (gas lift rate, flow rate, pressure, temperature) rather than maintaining complex comprehensive models. By concentrating on key performance parameters and using simplified optimization algorithms, the system achieves effective well optimization across large numbers of wells without proportionally increasing system complexity.
3Reliability
If gas lift wells operate without optimization to maintain continuous production, then operational continuity is maintained, but production efficiency and gas allocation efficiency decrease
Solution Approach 1:
The patent implements continuous monitoring of well performance parameters (flow rate, pressure, temperature) and uses this feedback to automatically adjust gas lift rates. The system compares actual performance against target parameters and makes real-time or near-real-time adjustments, maintaining both operational continuity and optimization without requiring well shutdowns or extended testing periods.
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 more efficient and cost-effective optimization of gas lift operations by reducing unnecessary testing and resource allocation, improving hydrocarbon production by ensuring optimal gas injection rates are maintained, even in large-scale unconventional well systems.
Implementation Method 1
Gas lift is a common method that is particularly suited to high-volume offshore wells. A high pressure (up to several thousand psi) gas is injected into the tubing by a casing annulus and travels to a gas lift valve.
Implementation Method 2
The gas reduces the density of the fluid column, decreasing backpressure on the producing formation. The available reservoir pressure can then force more fluid to the surface.
Data Source
AI summary
A method is provided for determining the frequency of a multi-rate well testing operation in a gas-lifted hydrocarbon well. A well performance characteristic of the well is monitored using single-rate well tests. The monitored well performance characteristic is compared to a current well model performance characteristic. If the monitored well performance characteristic differs from the current well model performance characteristic by less than a predetermined amount, an amount of gas is injected into the well based on the current well model performance characteristic. If the monitored well performance characteristic differs from the current well model performance characteristic by more than a predetermined amount, a multi-rate well test is initiated the results of the multi-rate well test are fitted to a revised well model performance characteristic, and an amount of gas is injected into the well based on the revised well model performance characteristic.