BOP Seal Inserts with Interlocking Tips for Extrusion Control
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Solution Overview
Problem
Current wellbore sealing techniques, including blowout preventers (BOPs), face challenges in effectively sealing wellbores under high pressure and accommodating various pipe diameters, leading to potential leakage and environmental risks.
Innovation Solution
The use of inserts with upper and lower bodies having extended tips and tip receptacles, positioned in an elliptical array within a seal assembly of a BOP, which restrict extrusion and provide interlocking engagement for enhanced sealing, including recesses and ledges for slidable movement, and scallops for conforming to different pipe diameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional sealing techniques are used in BOPs, then the device structure is simple, but the sealing reliability under high pressure is insufficient
Solution Approach 1:
The seal assembly is divided into multiple inserts (typically 3-5 inserts arranged in a circle), each with upper and lower bodies forming separate sealing chambers. This segmentation allows each insert to independently maintain sealing pressure and prevents catastrophic failure across the entire seal, thereby improving reliability while distributing structural complexity across modular components.
Solution Approach 2:
The inserts are positioned within the seal assembly in a nested configuration where multiple sealing elements are contained within the overall BOP structure. The upper and lower bodies of each insert create nested sealing chambers that contain seals, improving reliability through layered containment while managing device complexity through hierarchical organization.
2Reliability
If inserts are positioned close together to reduce extrusion gaps, then sealing reliability improves, but the inserts cannot accommodate various pipe diameters
Solution Approach 1:
The inserts are designed with movable upper and lower bodies that can slide relative to each other along the axial direction. This dynamic configuration allows the inserts to adjust their position and spacing to accommodate different pipe diameters while maintaining small extrusion gaps for reliable sealing. The ledges and recesses enable controlled movement while preserving the sealing geometry.
Solution Approach 2:
The insert assembly allows for changes in geometric parameters (spacing between inserts, position of upper and lower bodies) to adapt to different pipe diameters. By modifying these parameters through the slidable mechanism, the system maintains reliable sealing with small extrusion gaps across various pipe sizes, resolving the contradiction between reliability and adaptability.
3Reliability
If inserts are made fixed to prevent movement, then extrusion gaps are reduced, but the seals cannot accommodate pressure variations
Solution Approach 1:
The upper and lower bodies of each insert are designed to slide relative to each other in response to pressure variations. This dynamic adjustment allows the insert assembly to accommodate pressure changes while maintaining fixed positioning relative to the pipe, preventing extrusion gaps. The ledges and recesses guide this movement to preserve sealing integrity under varying pressure conditions.
Solution Approach 2:
The insert assembly automatically adjusts its configuration in response to pressure variations without external intervention. The slidable upper and lower bodies self-regulate their position based on pressure differential, maintaining optimal sealing geometry and preventing extrusion gaps across different operating conditions, thereby achieving both reliability and pressure accommodation.
Data Source
Figure 1
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Figure 3A~3B
AI summary
Methods and apparatuses for sealing a wellbore are provided. A seal assembly carried by a pair of opposing ram blocks of a blowout preventer is provided. The seal assembly includes a pair of seals carried by the pair of opposing ram blocks and a plurality of inserts carried by the pair of seals. The inserts include an upper body and a lower body with a rib therebetween. The upper and lower bodies each have an extended tip on a seal end thereof and a tip receptacle on a leading face thereof for receiving the extended tip. The extended tips are positionable in the tip receptacle of an adjacent inserts whereby an extrusion of a seal therebetween is restricted.