Segmented Elastomeric Packer for Blowout Preventer Sealing
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Solution Overview
Problem
The sealing integrity between the elastomeric packer and the drill pipe in annular blowout preventers (BOPs) is compromised due to the extrusion of elastomeric material when the BOP is actuated, leading to reduced sealing pressure and potential fluid leaks during uncontrolled influxes in hydrocarbon drilling operations.
Innovation Solution
The annular elastomeric packer design features circumferentially spaced inserts with upper and lower flanges and a rib structure, which pivot and engage with a wear plate to apply torque, reducing radial gaps and enhancing sealing pressure by trapping elastomeric material between inserts and the drill pipe, thereby maintaining sealing integrity even under increased fluid pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an annular elastomeric packer is actuated into the closed position to seal against the drill pipe, then sealing pressure is applied to restrict fluid flow, but the elastomeric material extrudes between the packer and drill pipe reducing sealing integrity
Solution Approach 1:
The packer is segmented into multiple circumferentially spaced inserts rather than a continuous annular structure. Each insert can independently pivot and engage the drill pipe, distributing the sealing force and preventing concentrated extrusion that would occur in a continuous packer design.
Solution Approach 2:
The inserts are designed to pivot dynamically about their longitudinal axes during actuation. This dynamic movement allows the inserts to self-adjust and engage the drill pipe surface optimally, maintaining sealing pressure while accommodating variations in drill pipe position and reducing elastomeric extrusion.
2Reliability
If the elastomeric packer is constricted about the drill string to seal the wellbore, then fluid communication is restricted, but the sealing pressure decreases over time due to material flow
Solution Approach 1:
Dividing the packer into discrete inserts prevents the continuous flow of elastomeric material that occurs in traditional annular packers. The segmentation creates discrete sealing zones that maintain pressure more effectively over time by eliminating the extrusion pathway.
Solution Approach 2:
The pivot angle and engagement geometry of the inserts are optimized to maintain consistent sealing pressure. By changing the geometric parameters of the insert design, the system maintains effective sealing pressure for extended durations without the pressure decay seen in traditional designs.
3Reliability
If traditional annular packers are used, then the structure is simple and easy to manufacture, but the sealing integrity is compromised under pressure
Solution Approach 1:
While increasing structural complexity, the segmentation into inserts provides superior sealing integrity under pressure by distributing loads and preventing material extrusion. The modular insert design allows for optimized sealing surfaces and engagement geometries that traditional annular packers cannot achieve.
Solution Approach 2:
The dynamic pivoting capability of the inserts adds functional complexity but enables the packer to adapt to drill pipe variations and maintain sealing integrity under pressure conditions where static annular packers fail.
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
This design effectively restricts fluid communication and increases sealing pressure, preventing elastomeric material extrusion and ensuring reliable sealing in both open and closed positions, even under increased pressure conditions.
Implementation Method 1
an angled engagement interface is formed between the insert of the elastomeric packer and the curved surface of the wear plate... engagement between the wear plate and the insert applies a torque against the insert about the axis of rotation
Implementation Method 2
an inner surface of the elastomeric packer sealingly engages the outer surface of the tubular member and a sealing pressure applied to the outer surface of the tubular member by the inner surface of the packer is increased in response to an increase in fluid pressure in the bore of the housing
Data Source
AI summary
An annular elastomeric packer for a blowout preventer includes a plurality of circumferentially spaced inserts, wherein at least one of the plurality of inserts includes an upper flange extending between a radially inner end and a radially outer end, a lower flange extending between a radially inner end and a radially outer end, and a rib extending between the upper flange and the lower flange, wherein the upper flange includes an upper surface disposed at an acute angle relative a longitudinal axis of the elastomeric packer, and an elastomeric body coupled to the plurality of inserts and including an inner sealing surface.