Integrated Choke Kill Line Mandrel for Subsea BOP Weight Reduction
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Solution Overview
Problem
Deepwater offshore drilling operations face complexities and weight challenges due to the need for separate choke and kill connectors, hydraulic control fluid stab plates, and electrical connections between the lower marine riser package and the lower blowout preventer stack, leading to increased size, weight, and complexity of the blowout preventer stack system.
Innovation Solution
Integrating choke and kill lines, hydraulic control fluid paths, and electrical signal paths into the lower marine riser connector and the mandrel at the top of the lower blowout preventer stack, eliminating the need for independent connectors, stab plates, and reducing the moment forces and alignment requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If separate choke and kill connectors are used, then the blowout preventer stack can handle high pressure, but the system size and weight increase significantly
Solution Approach 1:
The patent integrates the choke line connector and kill line connector into a single unified connector assembly, combining multiple functions into one component. This merging reduces the overall number of separate connectors needed, thereby decreasing the blowout preventer stack weight while maintaining the required pressure handling capability through the integrated design
2Reliability
If independent hydraulic control fluid stab plates are used, then pressure control is maintained, but device complexity increases
Solution Approach 1:
The hydraulic control fluid stab plate is integrated into the connector assembly rather than being a separate component. This consolidation maintains the necessary pressure control functionality while reducing the number of independent parts, thereby decreasing overall device complexity
Solution Approach 2:
The connector assembly is designed to perform multiple functions simultaneously: mechanical connection, hydraulic control fluid transmission, and structural support. This multi-functionality eliminates the need for separate dedicated components for each function, reducing system complexity while maintaining reliability
3Reliability
If separate electrical connections are used, then signal transmission is ensured, but alignment precision requirements increase
Solution Approach 1:
Electrical connections are integrated into the connector assembly, aligned with the mechanical connection features. This integration ensures that when the mechanical connection is properly aligned, the electrical connections are automatically aligned as well, reducing the need for separate alignment procedures and decreasing manufacturing precision requirements
4Reliability
If choke and kill lines pass through external stab subs, then pressure control is achieved, but moment forces increase on the structure
Solution Approach 1:
The choke and kill line connectors are integrated into the connector assembly positioned closer to the centerline of the blowout preventer stack, rather than using external stab subs. This integration reduces the lever arm distance from the centerline, thereby reducing the moment forces exerted on the stack structure while maintaining pressure control functionality
Data Source
AI summary
In a subsea blowout preventer stack system with a lower marine riser package with a lower marine riser connector and choke and/or kill lines, and a lower blowout preventer stack with a mandrel on the upper end and choke and/or kill lines connection to choke and kill valves, a method of porting the choke, kill lines, hydraulic lines and electrical lines vertically through the wall of the lower blowout preventer stack mandrel.