Pressure-Sensitive Wellhead Choke for Intermittent Marginal Production
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Solution Overview
Problem
Mature oil and gas fields experience productivity decline due to reservoir pressure depletion, with existing technologies like downhole chokes requiring high gas pressure and lacking surface-mounted or intermittent operation solutions for marginal wells.
Innovation Solution
A pressure-sensitive device with high-pressure and low-pressure bellows, installed in the wellhead choke box, that automates oil or gas production by opening and closing based on wellhead and flow line pressures, allowing for intermittent or continuous production without human intervention and power supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a downhole choke is installed at the bottom of the well to extend reservoir production, then a higher gas-to-liquid ratio is obtained and flowing pressure gradient is reduced, but high gas pressure supply is required and the device cannot operate intermittently or be installed at the surface
Solution Approach 1:
The invention inverts the conventional approach by moving the choke device from downhole installation to surface-mounted installation in the wellhead choke box. This inversion eliminates the need for high gas pressure supply and enables intermittent operation while maintaining the ability to control flow and extend reservoir production.
Solution Approach 2:
The device uses self-regulating pressure-sensitive bellows that automatically open and close based on wellhead and flow line pressure differentials without requiring external control systems, power supply, or human intervention. This self-service mechanism enables intermittent operation and eliminates the need for complex control infrastructure.
2Productivity
If a downhole choke is used to extend production, then reservoir pressure depletion is mitigated, but the device requires continuous high gas pressure and cannot sustain marginal production intermittently
Solution Approach 1:
The pressure-sensitive bellows mechanism automatically responds to wellhead and flow line pressure changes, opening when wellhead pressure exceeds flow line pressure by a differential amount, and closing when pressures equalize. This self-regulating system sustains marginal production intermittently without requiring continuous high gas pressure supply or external energy input.
3Ease of operation
If surface-mounted tools are used for marginal wells, then installation flexibility is improved, but existing tools lack intermittent operation capability and automated pressure-based control
Solution Approach 1:
The device incorporates pressure-sensitive bellows that automatically sense wellhead and flow line pressure differentials and mechanically actuate the choke opening and closing without electronics, power supply, or human intervention. This provides both surface-mounted installation flexibility and fully automated pressure-based control for intermittent operation.
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
The device effectively recovers hydrocarbon production from closed-in wells, sustains marginal oil production, and reduces downtime by harnessing well energy to optimize pressure restoration, suitable for remote and hard-to-access locations, both onshore and offshore.
Implementation Method 1
The bellows are pressure sensitive and will automatically open when the wellhead pressure exceeds the flow line pressure by a predetermined pressure differential
Implementation Method 2
The bellows are biased to be in a closed position
Data Source
AI summary
Devices that can be used to recover hydrocarbon production from closed-in oil wells capable of building up wellhead pressure and/or to sustain marginal oil production in oil wells are disclosed. Production in oil and natural gas producing wells in mature fields that have the ability to build up wellhead pressure and where the depletion of reservoir pressure has caused low or zero productivity may be automated. The devices include at least two bellows that facilitate their operation. The bellows may close the well to build up pressure in the wellhead and open the well to flow line pressure.