Retrievable Subsea Hydraulic Dump Valve for Rapid Well Shutdown
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Solution Overview
Problem
Subsea oil and gas production systems face challenges in quickly closing critical safety valves during loss of communication between the surface facility and subsea wells due to friction losses in long hydraulic supply lines, leading to potential safety and financial risks.
Innovation Solution
A retrievable and retrofittable subsea hydraulic dump valve assembly that converts existing Low Pressure A and Low Pressure B hydraulic supply lines into a primary and pilot line, respectively, allowing for rapid depressurization and closure of critical control valves by venting hydraulic fluid locally, reducing the time required to shut in wells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If long hydraulic supply lines are used to connect surface facility to subsea wells, then the subsea wells can be positioned further away from the surface facility, but the time required to close critical safety valves increases due to friction losses in the hydraulic supply lines
Solution Approach 1:
The hydraulic system is segmented into two separate lines: a long hydraulic supply line for normal operation and a short pilot line for emergency valve closure. The pilot line is positioned close to the subsea well, eliminating friction losses associated with long lines, while the supply line maintains flexibility for well placement.
Solution Approach 2:
A pilot line acts as an intermediary between the surface facility and the subsea well's hydraulic system. By transmitting pressure changes through this short line to activate local dump valves, the system achieves rapid valve closure without requiring fast pressure transmission through the entire length of the supply line.
2Reliability
If hydraulic pressure is exhausted through long supply lines back to the surface facility to close valves, then valve closure is achieved, but the closure time exceeds regulatory maximum closure times
Solution Approach 1:
The hydraulic pressure exhaustion function is extracted from the remote surface facility and relocated to the local subsea well site through dump valves. These valves are positioned near the actuators and exhaust pressure locally, eliminating the time delay associated with pressure transmission and exhaustion through long supply lines.
Solution Approach 2:
The subsea well's hydraulic system performs its own pressure exhaustion function through locally positioned dump valves. When a loss of communication occurs, the system automatically exhausts hydraulic pressure from the actuators through these local valves, enabling self-contained emergency valve closure without relying on remote surface facility intervention.
3Loss of time
If a retrievable and retrofittable dump valve assembly is installed, then quick valve closure is achieved, but the system complexity increases
Solution Approach 1:
The dump valve assembly is merged with the existing hydraulic distribution manifold at the subsea well. By integrating the dump valves and associated components into the existing manifold structure, the system achieves rapid valve closure capability without adding separate, complex systems. The assembly utilizes existing hydraulic connections and infrastructure.
Solution Approach 2:
The hydraulic distribution manifold serves multiple functions: it distributes hydraulic pressure to control valves during normal operation and simultaneously serves as the mounting platform for dump valves during emergency closure. This multi-functionality reduces the need for additional dedicated components and simplifies the overall system architecture.
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
Enables quick closure of critical control valves within regulatory timeframes, minimizing disruption and risk, while being easily installable with minimal capital costs and disruption to existing systems, and compatible with existing multi-quick coupler plates.
Implementation Method 1
at least one hydraulic selector valve including a solenoid
Implementation Method 2
a spring. The hydraulic selector valve converts the first hydraulic pressure supply line into a primary hydraulic pressure supply line and the second hydraulic pressure supply line into a pilot line and the backup hydraulic pressure supply line
Implementation Method 3
The second hydraulic pressure supply line channels a second flow of hydraulic fluid to the solenoid to reconfigure the hydraulic selector valve between a first operating configuration and a second operating configuration
Data Source
AI summary
A retrievable and retrofittable subsea hydraulic dump valve assembly for a subsea oil and gas production system including at least one hydraulic selector valve including a solenoid and a spring. The hydraulic selector valve converts a first hydraulic pressure supply line into a primary hydraulic pressure supply line and a second hydraulic pressure supply line into a pilot line and a backup hydraulic pressure supply line. In a first operating configuration the hydraulic selector valve channels a first flow of hydraulic fluid from the first hydraulic pressure supply line to the critical control valve actuators to maintain the critical control valve actuators in the open configuration. In a second operating configuration the hydraulic selector valve channels the flow of hydraulic fluid to the subsea environment at a local venting location to reconfigure the critical control valve actuators into a closed configuration.