Wellhead BOP Extended Ram Sealing Central Bore
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Solution Overview
Problem
Existing wellhead blowout preventers (BOPs) face challenges in sealing effectively against both the polish rod and the central bore, especially under harsh chemical conditions, where elastomeric materials degrade quickly, and there is a need for a solution that can eliminate the need for multiple valves and BOPs in a wellhead stack.
Innovation Solution
A production BOP design featuring a housing with intersecting horizontal ram bores and a central bore, where the rams are equipped with thermoplastic or elastomeric seals that can seal against the polish rod and, when it is not present, seal the central bore, allowing for a single unit to replace multiple valves and BOPs, with enhanced sealing capabilities using thermoplastic materials resistant to chemical degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If elastomeric materials are used for sealing in the BOP, then sealing effectiveness is achieved, but the materials degrade quickly under harsh chemical conditions
Solution Approach 1:
The patent changes the material parameter from elastomeric to thermoplastic seals, which fundamentally alters the chemical resistance properties while maintaining sealing functionality. This material substitution resolves the contradiction by selecting a material that does not degrade under harsh chemical conditions, thereby extending service life while preserving sealing effectiveness.
Solution Approach 2:
The patent employs composite sealing structures combining thermoplastic materials with reinforced constructions. The thermoplastic seals are integrated with supporting structures and positioning mechanisms, creating a composite system that maintains sealing effectiveness while providing enhanced durability and chemical resistance.
2Reliability
If multiple valves and BOPs are used in the wellhead stack, then sealing coverage is comprehensive, but device complexity increases
Solution Approach 1:
The patent designs a universal BOP unit that performs multiple sealing functions within a single component. The ram structure is configured to seal against both the polish rod and the central bore, eliminating the need for separate sealing devices. This multi-functionality approach maintains comprehensive sealing coverage while significantly reducing the number of components in the wellhead stack.
Solution Approach 2:
The patent merges the sealing functions against the polish rod and the central bore into a single integrated BOP unit. The ram assembly combines both sealing interfaces in one structure, consolidating what would traditionally require multiple separate valves and BOPs into one unified component, thereby reducing overall system complexity.
3Reliability
If the ram structure is extended to seal the central bore, then sealing capability is improved, but the length of the moving object increases
Solution Approach 1:
The patent segments the sealing function into distinct zones within the ram structure. The ram is designed with different sections: a front sealing portion for the polish rod and an extended central bore sealing section. This segmentation allows the sealing capability to be distributed across specific regions rather than requiring the entire ram to be excessively long, optimizing the balance between sealing capability and component length.
Solution Approach 2:
The patent addresses the central bore sealing requirement by extending the ram in a different dimensional orientation. Instead of increasing the overall length proportionally, the extended sealing section is positioned strategically to engage with the central bore sealing surfaces, achieving effective sealing with minimal additional length by utilizing spatial arrangement.
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 reliable sealing against both the polish rod and the central bore under high pressure and chemical exposure, extending the lifespan of seals and reducing the need for multiple wellhead components, thus enhancing operational efficiency and reliability.
Implementation Method 1
The rubber surfaces of their inner portions seal against the sealing surfaces
Implementation Method 2
the ram ends compress together to form a solid block
Implementation Method 3
The ribs function to reinforce the elastomer layer against upward extrusion. Comparative pressure tests have shown that a ribbed ram is able to contain several times the pressure that a non ribbed ram could contain, before the seal was lost
Implementation Method 4
the vertical end face of the core inner portion is indented, for example with a plurality of spaced apart transverse grooves or dimples or a single cavity, so that the base of the elastomer layer projects into these indentations. As a result, increased face surface area is provided to bond with the elastomer
Data Source
AI summary
A blowout preventer (BOP) is provided in which one of the BOP rams is formed with an extended central bore sealing section to seal across the central bore in a central bore closing position when the polish rod is not present. The ram bores of the BOP are sized to accommodate this extended central bore sealing section in any of the open, sealing or central bore closing positions. The front ends of the BOP rams may be adapted to carry elastomeric or thermoplastic seals to seal against the polish rod or against each other. The central bore seals for the extended central bore sealing section may be formed with elastomeric or thermoplastic seals. In the case of thermoplastic seals, the rams and ram bores are adapted to ensure that the thermoplastic seals are compressed outwardly, to seal the ram bores, or are lifted upwardly, to seal the central bore.