Flexible Pipe Connector With Distributing Rings for Annulus Corrosion Control
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Solution Overview
Problem
Flexible pipelines in offshore petroleum production are prone to corrosion due to corrosive gases like CO2 and H2S, which are not effectively mitigated by current connectors and circulation methods, leading to issues like stress corrosion and pitting corrosion, especially when the annulus is flooded with seawater.
Innovation Solution
A flexible pipe connector system that includes distributing rings and manifolds for forced circulation of non-corrosive fluids like N2 through the annulus, allowing for the distribution and collection of corrosion-inhibiting fluids across multiple pipe segments, with features like access hatches, removable covers, and actuation by remotely operated underwater vehicles to control fluid flow and prevent corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional flexible pipe connectors are used without integrated forced circulation system, then the pipe structure remains simple and manufacturing is easier, but corrosive gases like CO2 and H2S accumulate in the annulus causing stress corrosion and pitting corrosion
Solution Approach 1:
The distributing rings are positioned inside the connector body, nested within the existing connector structure. The rings are placed in the annulus space between the barrier and outer sheath, utilizing the existing geometric space without adding external complexity to the connector assembly.
Solution Approach 2:
The forced circulation system is divided into multiple distributing rings that can be independently positioned along the pipe length. Each ring segment handles local fluid distribution, allowing the system to be implemented in modular sections rather than requiring complete system redesign.
2Reliability
If the annulus is left without forced circulation system, then the connector design remains simple, but corrosive fluids cannot be displaced and corrosion failure mechanisms occur
Solution Approach 1:
The distributing rings are positioned inside the connector body, nested within the existing connector structure. The rings are placed in the annulus space between the barrier and outer sheath, utilizing the existing geometric space without adding external complexity to the connector assembly.
Solution Approach 2:
The distributing rings act as intermediary structures that facilitate fluid circulation between the connector and the annulus. They provide a mechanical interface that enables forced circulation without requiring direct modification of the barrier or outer sheath.
3Reliability
If distributing rings with fluidic access to annulus are installed in all connectors, then complete corrosion protection is achieved, but fluid circulation control becomes more complex and requires coordinated systems across multiple segments
Solution Approach 1:
The forced circulation system is divided into multiple distributing rings that can be independently positioned along the pipe length. Each ring segment handles local fluid distribution, allowing the system to be implemented in modular sections rather than requiring complete system redesign.
Solution Approach 2:
The system allows dynamic configuration where distributing rings can be selectively activated or deactivated based on operational needs. Fluid circulation can be controlled to flow through specific rings or multiple rings in sequence, providing flexibility in system operation and maintenance.
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 system effectively minimizes corrosive effects by circulating corrosion-inhibiting fluids through the annulus, reducing the concentration of CO2 and H2S, and preventing corrosion in the armouring of flexible pipes, even in scenarios where the annulus is flooded with seawater, thereby enhancing the integrity and longevity of the pipeline.
Implementation Method 1
A flexible pipe connector suitable for effecting control and forced circulation of corrosion-inhibiting fluids through the annulus
Data Source
AI summary
A flexible pipe connector for effecting control and forced circulation of corrosion-inhibiting fluids through an annulus between inner and outer sheaths of a flexible pipe having multiple connected segments includes an attachment mechanism for connecting to an end of a segment of flexible pipe and at least two distributing rings for distributing corrosion-inhibiting fluid. The rings are configured to be positioned in the annulus of the flexible pipe, wherein at least one distributing ring has fluidic access to the annulus of the flexible pipe. This distributing ring is configured to be connected fluidically to at least one distributing ring, in an adjacent connector, that does not have fluidic access to the annulus, A distributing ring that does not have fluidic access to the annulus of the flexible pipe is configured to be connected fluidically to at least one distributing ring, in an adjacent connector, that comprises fluidic access to the annulus.