Annular BOP Packing Unit with Sealing Compound for Irregular Tubing
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Solution Overview
Problem
Annular blowout preventers are ineffective in sealing irregularly shaped production tubing during well control events, as traditional ram packers and annular BOPs fail to fill crevices and gaps around bundled control lines and cables, leading to damage and loss.
Innovation Solution
An annular blowout preventer with a packing unit that includes a packer body and an internal chamber filled with a sealing compound, where the compound is expelled and constricts around the tubing upon actuation, using a combination of materials with varying rigidity to create a seal around tools with irregular profiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional ram packers and annular BOPs are used to seal irregularly shaped production tubing, then the sealing effectiveness deteriorates because they cannot fill crevices and gaps around bundled control lines and cables
Solution Approach 1:
The packing unit combines a rigid packer body made of one material with a compliant sealing compound made of a different material. The rigid body provides structural support and initial constriction, while the compliant compound flows into and fills crevices and gaps around irregular tool profiles, achieving both structural integrity and adaptive sealing effectiveness.
Solution Approach 2:
The sealing compound changes its physical state from a more rigid form within the internal chamber to a compliant, flowable state when expelled. This parameter change allows the material to adapt to irregular surfaces and fill gaps, transforming the packing unit's ability to seal around tools with non-uniform outer profiles.
2Reliability
If blind shear ram is actuated to seal the well, then the well control is achieved, but the production tubing and bundled control lines are sheared and dropped into the well causing damage
Solution Approach 1:
The invention replaces the cutting/shearing mechanism of blind shear rams with a constricting sealing mechanism. Instead of severing the production tubing to achieve well control, the dual-material packing unit constricts around the tubing and uses the compliant sealing compound to fill gaps and create a seal, preventing fluid flow without causing mechanical damage to the tubing or bundled control lines.
3Strength
If the packer body is made from rigid material, then the structural strength is improved, but the ability to fill crevices and conform to irregular surfaces deteriorates
Solution Approach 1:
The packing unit employs a composite structure where the packer body is made from rigid material providing structural strength and mechanical support, while the sealing compound is made from compliant material that can deform and flow. This composite approach allows the rigid packer body to maintain structural integrity during actuation while the compliant compound conforms to irregular tool surfaces and fills crevices.
Solution Approach 2:
Different regions of the packing unit have different material properties optimized for their specific functions. The packer body uses rigid material for structural support and force transmission, while the sealing compound uses compliant material for surface conformity and gap filling. This local differentiation of material quality resolves the contradiction between overall strength and local adaptability.
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 effectively seals irregularly shaped pipes and tools by filling crevices and gaps, preventing damage and ensuring well control integrity during completions and production stages.
Implementation Method 1
The internal chamber is filled with a sealing compound. The packing unit further includes a channel in fluid communication with the chamber and a separation between the channel and the opening. At least a portion of the fluid is expelled through the separation and into the opening when the packing unit is compressed.
Implementation Method 2
The packer body is fabricated from a first material. The packing unit further includes a second material disposed between the packer body and the opening, the second material being less rigid than the first material. The packer body and the second material constrict the opening when the annular blowout preventer is actuated.
Data Source
AI summary
An annular blowout preventer includes a body, a piston disposed within the body, and a packing unit disposed adjacent the piston. The packing unit includes an packer body surrounding an opening. The packer body is fabricated from a first material. The packing unit further includes a second material disposed between the packer body and the opening, the second material being less rigid than the first material. The packer body and the second material constrict the opening when the annular blowout preventer is actuated. The second material creates a seal around a tool disposed within the opening. The second material fills in one or more crevices or recesses on an outer perimeter of the tool.