Dual Parallel Wellhead for High-Pressure Gas Storage Maintenance
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Solution Overview
Problem
High-pressure gas storage in deep caverns requires equipment rated for extreme pressure conditions, and existing systems lack efficient methods for on-line maintenance and testing of emergency control valves without interrupting gas or liquid flow.
Innovation Solution
A storage wellhead design with dual fluidically parallel gas and liquid passages allows for on-line maintenance and testing, utilizing hydraulically operated and manually operated valves that meet API standards for pressures up to 8000 psig, ensuring continuous flow and safety through redundant valve systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If single gas passage and liquid passage are used in existing high-pressure gas storage systems, then equipment structure is simple, but maintenance and testing of emergency control valves require interruption of gas and liquid flow
Solution Approach 1:
The single gas passage and liquid passage are segmented into dual parallel passages (first and second gas passages, first and second liquid passages). This segmentation allows independent maintenance of each passage while the other remains operational, enabling on-line testing and maintenance without flow interruption.
Solution Approach 2:
Different passages are assigned different functional states (one operational, one under maintenance/testing) at the same time. The wellhead structure incorporates localized components (valves, test equipment) in specific passages to enable targeted maintenance while preserving overall system functionality.
2Productivity
If multiple flow paths are implemented to allow continuous flow, then commercial demand for continuous gas flow is met, but system complexity and equipment requirements increase
Solution Approach 1:
The flow path is segmented into parallel first and second passages for both gas and liquid. This segmentation provides redundancy and continuity - when one passage is maintained or tested, the other continues to supply gas and liquid, ensuring uninterrupted commercial operations.
Solution Approach 2:
The wellhead is designed with preliminary maintenance capability built into the structure. Test equipment and maintenance access points are pre-positioned in each passage, allowing maintenance activities to be performed in advance or concurrently with operational requirements, preventing flow interruption.
3Reliability
If emergency control valves are tested periodically as required by regulations, then safety compliance is achieved, but gas and liquid flow must be interrupted during testing
Solution Approach 1:
The testing function is segmented to occur in one passage while the other passage continues normal flow. The wellhead structure allows isolation valves to close off one passage for testing while the other passage remains open for continuous gas and liquid flow, eliminating downtime.
Solution Approach 2:
The dual parallel passage design ensures that the useful action of gas and liquid flow continues uninterrupted during valve testing. While one passage undergoes testing, the other maintains continuous flow, and the system can rapidly switch between passages to maintain ongoing operations.
Data Source
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AI summary
A storage wellhead allowing on-line system maintenance and testing is provided. Including at least two fluidically parallel gas passages adapted to allow testing or maintenance of one gas passage, while the other gas passage remains in service. The gas may be hydrogen. Also including at least two fluidically parallel liquid passages adapted to allow testing or maintenance of one liquid passage, while the other liquid passage remains in service. The liquid may be brine.