Surface Gas Injection Control for Intermittent Wellbore Lift
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Solution Overview
Problem
Existing gas-lift systems for wellbore injection are unable to adjust gas volumes in real-time to accommodate variations in fluid column height, leading to inefficient gas use and the need for frequent tuning of pilot valves, especially in horizontal wells that experience fluid slugging.
Innovation Solution
A gas injection optimization system that uses surface-based pressure transducers and a controller to adjust the volume of gas injected into the wellbore annulus, eliminating the need for downhole pilot valves and allowing for real-time optimization of gas flow based on differential pressure readings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If gas-lift systems use fixed-volume gas injection, then system simplicity is maintained, but gas usage efficiency deteriorates due to inability to adapt to fluid column variations
Solution Approach 1:
The system dynamically adjusts gas injection volume based on real-time differential pressure measurements. The controller modifies the injection rate to match varying fluid column heights, transitioning from fixed-volume to variable-volume injection that adapts to changing well conditions.
Solution Approach 2:
The system implements feedback control by continuously monitoring differential pressure across the fluid column and using this information to regulate gas injection volume. The controller receives pressure sensor inputs and automatically adjusts injection parameters to optimize gas lift performance.
2Measurement precision
If pilot valves are installed downhole for gas injection control, then injection precision is improved, but maintenance requirements increase due to frequent valve tuning needs
Solution Approach 1:
The system extracts the control function from downhole pilot valves and relocates it to surface-based controllers. By eliminating the need for downhole valves and moving control logic to the surface, the system maintains injection precision while removing components that require frequent maintenance and tuning.
Solution Approach 2:
The system achieves self-adjusting gas injection by using automated controllers that respond to differential pressure signals. The controller automatically modulates injection volume based on real-time conditions, eliminating the need for manual valve tuning and enabling the system to self-optimize without human intervention.
3Reliability
If gas injection volume is increased to handle fluid slugging, then production reliability is improved, but gas consumption increases reducing operational efficiency
Solution Approach 1:
The system employs periodic gas injection cycles synchronized with fluid slug formation. By injecting gas in timed intervals that match the periodic nature of slugging, the system maintains production continuity during slug events while avoiding continuous high-volume injection, thereby reducing overall gas consumption.
Solution Approach 2:
The system dynamically changes injection parameters (volume, rate, timing) based on detected fluid column conditions and slug formation. By adjusting these parameters in response to real-time differential pressure measurements, the system provides enhanced reliability during slugging while minimizing excess gas usage through precise parameter modulation.
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 system ensures optimal gas injection volumes are used, reducing the amount of gas required and eliminating the need for frequent valve adjustments, thereby improving the efficiency of gas-lift operations and addressing issues of fluid slugging in horizontal wells.
Implementation Method 1
surface-based pressure transducers and a controller to adjust the volume of gas injected into the wellbore annulus, eliminating the need for downhole pilot valves and allowing for real-time optimization of gas flow based on differential pressure readings
Implementation Method 2
Gas compression system for wellbore injection, and method for optimizing intermittent gas lift
Implementation Method 3
injection gas is being released from the storage vessel and into the annular region
Data Source
AI summary
A gas injection optimization system is provided. The optimization system is designed to control a volume of gas injected into a wellbore in connection with an intermittent gas-lift system. The system includes a gas storage vessel residing at the surface, and a series of pressure transducers. The system additionally includes a controller configured to receive pressure value signals from the transducers, and in response, send control signals that cyclically open and close a well flow control valve at the surface. When the well flow control valve is closed, compressible fluid is injected into the gas storage vessel to load the vessel. When the well flow control valve is opened, a volume of injection gas (VR) is released from the vessel and is injected into a wellbore annular region to push a volume of fluids (VS) residing in the tubing string to the surface. A method for optimizing gas injection into a wellbore in support of an intermittent gas-lift operation is also provided herein.