Subsea Annulus Vent Valve for Flood Isolation in Flexible Pipe
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Solution Overview
Problem
Flexible pipes used in subsea oil and gas transportation face challenges in maintaining a continuous vent path between segments, leading to potential pipe rupture due to increased annulus pressure and flooding, which can result in system-wide flooding and significant downtime.
Innovation Solution
A valve system with a slidable member and biasing element that connects and disconnects fluid communication regions between flexible pipe segments based on environmental pressure, ensuring a continuous vent path while isolating flooded segments to prevent system-wide flooding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a continuous vent path is provided between multiple segments of flexible pipe body, then annulus pressure is reduced and gas venting is improved, but the risk of system-wide flooding increases when one segment floods
Solution Approach 1:
The flexible pipe system is divided into multiple segments with individual annulus regions. Each segment can be independently vented or isolated through its own valve assembly, allowing the vent path to be segmented rather than continuous throughout the entire pipe system. This enables localized flooding containment while maintaining venting capability in non-flooded segments.
Solution Approach 2:
Valve assemblies act as intermediary devices between adjacent annulus regions. These valves can selectively open or close to control fluid communication between segments, serving as mediators that allow venting when needed while blocking flood propagation when a segment becomes compromised.
2Reliability
If annulus pressure is continuously monitored and vented, then pipe rupture is prevented, but system complexity and operational requirements increase
Solution Approach 1:
The valve assemblies are designed to automatically respond to pressure differential conditions between the annulus region and外部环境. When annulus pressure exceeds external pressure, the valve automatically opens to vent gas, and when pressures equalize or reverse, the valve closes. This self-regulating mechanism eliminates the need for complex external monitoring and control systems.
Solution Approach 2:
The venting mechanism utilizes pneumatic pressure differentials to automatically control valve operation. The valve responds to pressure conditions within the annulus region without requiring mechanical actuators, electrical controls, or complex sensing systems, thereby reducing overall system complexity while maintaining effective pressure management.
3Adaptability or versatility
If flexible pipe operates at extreme depths and temperatures, then subsea resource extraction capability is enhanced, but pipe blockage risk from fluid cooling increases
Solution Approach 1:
Gas accumulations that could cause blockages in the bore are extracted from the fluid stream and diverted into the annulus region through the valve assembly. This separates the gas phase from the production fluid, preventing blockage formation while allowing continuous operation at extreme depths where temperature-induced cooling and condensation are concerns.
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 solution provides a continuous vent path that reduces annulus pressure and prevents system-wide flooding by isolating flooded segments, thus enhancing the reliability and safety of subsea flexible pipe systems.
Implementation Method 1
at least one biasing element locatable proximate to at least one of the open channel end or closed channel end, for biasing the slidable body towards the open channel end
Implementation Method 2
the slidable member is slidable along a longitudinal axis of the channel responsive to a local environmental pressure provided at the open channel end
Data Source
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AI summary
A method and apparatus for selective connection of a first fluid communication region to a further fluid communication region at a subsea location and a flexible pipe are disclosed. The apparatus comprises a valve body that includes a primary passageway extending from a first port of the valve body, and connectable to a first fluid communication region, to a further port of the valve body, connectable to a further fluid communication region, the valve body comprising a channel intersecting the primary passageway and extending between an open channel end and a closed channel end; at least one slidable member comprising a slidable body locatable in the channel and comprising a slidable member fluid passage extending through or around the slidable body; and at least one biasing element locatable proximate to at least one of the open channel end or closed channel end, for biasing the slidable body towards the open channel end; wherein the slidable member is slidable along a longitudinal axis of the channel responsive to a local environmental pressure provided at the open channel end.