Annular BOP Packer with Rigid Inserts for Crack Resistance
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Solution Overview
Problem
Annular blowout preventers (BOPs) face challenges in sealing effectively due to their geometry, which affects their ability to manage rapid fluid invasions during drilling operations, and existing configurations can be prone to cracking and require high pressure to maintain a seal.
Innovation Solution
The design incorporates a relatively large packer with a small donut or a one-piece assembly without a donut, featuring rigid inserts and a modified geometry that allows the packer to seal with lower pressure and resist cracking, enabling the drill string to drift within the central bore while simplifying manufacturing, installation, and maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional packer geometry is used, then the annular BOP can seal the annulus, but it requires high pressure to maintain the seal and is prone to cracking
Solution Approach 1:
The packer is divided into multiple segments that can independently deform and conform to the annulus geometry. This segmentation allows the seal to adapt to irregular surfaces without requiring excessive pressure, reducing the risk of cracking while maintaining effective sealing.
Solution Approach 2:
The packer geometry is modified with specific curvature radii and thickness variations. The first curvature radius is larger than the second curvature radius, creating an optimized stress distribution that reduces pressure requirements while preventing crack formation during actuation.
2Reliability
If a conventional packer geometry is used, then the annular BOP can seal the annulus, but the packer is prone to cracking during actuation
Solution Approach 1:
The packer incorporates specific geometric parameters including a first curvature radius larger than a second curvature radius, and controlled thickness variations. These parameter changes optimize stress distribution during actuation, preventing stress concentration that leads to cracking while maintaining sealing capability.
Solution Approach 2:
The packer is constructed as a composite structure combining elastomeric material with fabric reinforcement layers. This composite construction enhances crack resistance by distributing stresses across multiple material phases, preventing propagation of cracks during actuation.
3Reliability
If a traditional BOP assembly is used, then sealing function is provided, but the weight and complexity of the assembly is high
Solution Approach 1:
The packer design integrates multiple functions into a single component structure. The optimized geometry combines sealing surfaces, stress distribution features, and actuation interfaces in one unified design, reducing the number of separate parts and simplifying the overall assembly while maintaining reliable sealing function.
Solution Approach 2:
The design eliminates unnecessary components and simplifies the structure by removing redundant elements. The optimized packer geometry achieves sealing and stress management functions without requiring additional support structures or complex mechanisms, reducing overall assembly complexity.
4Reliability
If a conventional packer design is used, then sealing is achieved, but manufacturing and installation are more difficult
Solution Approach 1:
The packer incorporates standardized geometric parameters including specific curvature radii and thickness values that are optimized for manufacturability. These parameter choices allow the component to be produced using conventional molding and fabrication processes while achieving the required seal capability.
Solution Approach 2:
The packer design applies different geometric characteristics to different regions: a larger first curvature radius in areas requiring flexibility and a smaller second curvature radius in areas requiring structural integrity. This localized optimization maintains seal capability while simplifying manufacturing of specific sections.
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 configuration enhances the annular BOP's ability to maintain a seal with reduced pressure, improves crack resistance, and facilitates easier handling and maintenance by allowing the drill string to drift radially and axially within the central bore, while also reducing the weight and complexity of the assembly.
Implementation Method 1
enables the packer to seal with lower pressure and resist cracking
Implementation Method 2
The first curvature radius of the packer is greater than the second curvature radius, and a thickness of the packer varies along a radial direction
Data Source
AI summary
An annular blowout preventer includes a housing, an annular packer positioned within the housing, and an annular piston assembly positioned within the housing. An annular contacting surface of the annular piston is configured to contact the annular packer while the annular blowout preventer is in the open position. The annular blowout preventer also includes a plurality of inserts extending axially through the annular packer and arranged circumferentially within the annular packer. The annular piston is configured to drive the annular packer in an axial direction within the housing, thereby compressing the annular packer, causing the plurality of inserts to rotate radially inwardly, and moving the annular blowout preventer from the open position to a closed position.