Downhole Tester Valve Rapid Nitrogen Charging Mechanism
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Solution Overview
Problem
Downhole tester valves used in well testing operations face uncertainty and impossibility in closure during the time delay between opening and fully charging the nitrogen biasing source, leading to unreliable valve closure.
Innovation Solution
A downhole tester valve design with a housing and mandrel assembly that includes an operating fluid chamber, a biasing fluid chamber, and a power fluid chamber, where annulus pressure pressurizes the operating fluid to shift the valve assembly from closed to open, and a bypass passageway is opened to charge the biasing fluid, enabling immediate closure upon pressure reduction, utilizing a piston assembly with a collet and snap sleeve mechanism and check valves for precise control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fluid metering section is used to charge the nitrogen biasing source, then the nitrogen can be fully charged, but a time delay occurs during which valve closure is uncertain or impossible
Solution Approach 1:
The patent removes the fluid metering section from the system entirely. Instead of using a metering section to control nitrogen charging, the invention uses a direct communication pathway between the annulus and the nitrogen chamber through a packer and port system, eliminating the time delay inherent in metering-based charging while maintaining reliable valve closure capability
Solution Approach 2:
The patent establishes preliminary communication pathways and pressure equalization mechanisms that allow the nitrogen biasing source to be charged immediately when annulus pressure increases, without waiting for a metering process. The packer and port system are pre-configured to enable rapid nitrogen charging as soon as pressure conditions are met, eliminating the sequential delay
2Ease of operation
If the annulus pressure is increased to open the ball valve assembly, then the valve opens for flow testing, but the nitrogen charging time causes closure uncertainty
Solution Approach 1:
The patent merges the valve opening operation and nitrogen charging process into a single simultaneous action. When annulus pressure increases to open the ball valve, the same pressure increase automatically charges the nitrogen biasing source through the packer and port system, eliminating the sequential timing issue where closure reliability was compromised during the charging delay
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
Ensures reliable and immediate closure of the valve assembly by rapidly charging the biasing fluid, eliminating the uncertainty and impossibility of closure during the time delay, enhancing the operational reliability of downhole tester valves.
Implementation Method 1
annulus pressure entering the power fluid chamber pressurizes operating fluid in the operating fluid chamber which acts on the piston assembly to shift the valve assembly from the closed position to the open position
Data Source
AI summary
A downhole tester valve (100) includes a housing assembly (106) and a mandrel assembly (172, 174) that define therebetween an operating fluid chamber (176), a biasing fluid chamber (184) and a power fluid chamber (180). A valve assembly (126) disposed within the housing assembly (106) is operable between open and closed positions. A piston assembly (146) is operably associated with the valve assembly (126) such that annulus pressure entering the power fluid chamber (180) pressurizes operating fluid in the operating fluid chamber (176) which acts on the piston assembly (146) to shift the valve assembly (126) from the closed position to the open position and such that predetermined travel of the piston assembly (146) opens a bypass passageway (162) for the pressurized operating fluid to charge biasing fluid in the biasing fluid chamber (184), thereby enabling closure of the valve assembly (126) upon reducing annulus pressure by a predetermined amount.