Subsea Control Pod Redundancy for API 16D Compliance
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Solution Overview
Problem
Subsea wellhead assemblies face significant downtime and costly repairs due to the failure of a single control pod, which is common in redundant systems, leading to non-compliance with API Spec 16D and substantial revenue loss, especially in deep water operations.
Innovation Solution
Incorporating a third redundant control pod in the subsea control system, which is functionally identical to the existing two, to provide additional redundancy and ensure continuous operation even if one control pod fails, thereby maintaining compliance with API Spec 16D and reducing downtime and costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two control pods are used for redundancy, then reliability is improved, but system failure rate increases and downtime occurs when one pod fails
Solution Approach 1:
The control system is segmented into three independent control pods instead of two, allowing the system to maintain functionality even when one pod fails. Each pod operates independently, and the loss of one segment does not compromise the entire system's operational status.
Solution Approach 2:
The patent applies local quality by enhancing specific critical components (control pods) with additional redundancy. Rather than uniformly increasing system complexity throughout, the solution specifically targets the control pod subsystem with an extra unit to provide localized reliability improvement where it is most needed.
2Reliability
If two control pods are used for redundancy, then reliability is improved, but system complexity increases
Solution Approach 1:
The solution uses copying by creating a third control pod that is essentially a duplicate of the existing two pods. This identical copy provides redundancy without introducing new complex functionalities, thereby increasing reliability while minimizing the increase in system complexity.
Solution Approach 2:
Each control pod is designed to be universal and multi-functional, capable of performing all necessary control functions independently. This universality means that adding a third pod does not require additional specialized components or complex integration, as the third pod can assume any control function needed by the system.
3Productivity
If control pod fails, then API Spec 16D compliance is lost, but operational continuity is maintained with two pods
Solution Approach 1:
The system performs preliminary action by pre-configuring three control pods instead of the minimum two required by API Spec 16D. This advance preparation ensures that even if one pod fails, the system maintains at least two functional pods, thereby preemptively maintaining both operational continuity and regulatory compliance.
Data Source
AI summary
A blowout preventer system includes a blowout preventer stack having hydraulic components. The blowout preventer stack is coupled to a lower marine riser package that includes additional hydraulic components. The lower marine riser package includes control pods that enable redundant control of the hydraulic components of the blowout preventer stack and the additional hydraulic components of the lower marine riser package. These control pods include frames, valves, and stack stingers that facilitate connection of the control pods to hydraulic components of the blowout preventer stack, but do not include riser stingers that facilitate communication of control fluid to the additional hydraulic components of the lower marine riser package. The stack stingers extend through central apertures of bottom plates of the control pod frames and facilitate communication of control fluid from the valves to the hydraulic components of the blowout preventer stack. Additional systems, devices, and methods are also disclosed.