Dynamic Variable Orifice for Subsea BOP Pressure Spike Mitigation
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Solution Overview
Problem
Subsea and offshore BOP control systems face pressure spikes during testing and operation, which can damage equipment and disrupt operations due to high hydraulic fluid velocities and system energy levels, necessitating a mechanism to mitigate these spikes.
Innovation Solution
A dynamic variable orifice that adjusts its opening area based on fluid pressure and flow conditions to gradually dampen pressure spikes, maintaining a pressure balance and preventing damage to downstream components while allowing operational fluid flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hydraulic control valves are rapidly opened or closed to meet faster BOP closing times, then productivity and response speed are improved, but pressure spikes are generated that can damage equipment and reduce reliability
Solution Approach 1:
The dynamic variable orifice is pre-configured with a restricted minimum flow area that acts as a cushioning mechanism before pressure spikes occur. This restricted orifice gradually opens in response to pressure increases, providing progressive dampening that protects downstream equipment from damage while allowing rapid BOP operation when needed
2Reliability
If a restricted orifice is used to dampen pressure spikes, then reliability is improved, but fluid flow restriction increases which could slow down BOP operation
Solution Approach 1:
The orifice transitions from a static restricted opening to a dynamic variable opening that automatically adjusts its flow area based on real-time pressure conditions. The orifice gradually opens as pressure increases, providing progressive dampening while maintaining high flow capacity during normal operation, thus resolving the contradiction between pressure spike mitigation and fluid flow rate
3Reliability
If a pressure relief mechanism is added to mitigate pressure spikes, then reliability is improved, but device complexity increases
Solution Approach 1:
The dynamic variable orifice is designed as a self-regulating device that automatically responds to pressure changes without external control signals or complex logic systems. The orifice area varies dynamically based solely on the pressure differential across it, providing pressure spike mitigation through inherent hydrodynamic principles rather than complex control mechanisms
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 dynamic variable orifice effectively reduces or eliminates pressure spikes, enhancing the reliability and efficiency of BOP control systems by protecting valves and preventing downtime from flow line and valve damage.
Implementation Method 1
the dynamic variable orifice changes to intermediate flow areas and to a maximum flow area based only on the fluid pressure at the inlet side of the device
Implementation Method 2
The opening area through the dynamic variable orifice changes gradually based on the pressure and flow conditions at the inlet thereof, but rapidly enough to ameliorate a pressure spike and reduce or eliminate the pressure spike at locations downstream
Data Source
AI summary
A dynamic variable orifice includes a housing within which are located a rotor having at least one opening extending therethrough, and at least one seat ring, having an opening therethrough, biased thereagainst. In response to a pressure spike occurring at the inlet of the dynamic variable orifice, the rotor moves axially and rotationally in the housing, to selectively align the opening in the rotor with the opening in the seat ring.