Pyrotechnic BOP Shearing Ram for Well Pressure Control
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Solution Overview
Problem
Hydraulically actuated blowout preventers require significant force to close and can fail if the hydraulic line is damaged, and pyrotechnic systems face increased energy requirements due to the presence of an isolation ring and potential debris generation.
Innovation Solution
A pyrotechnically actuated blowout preventer with a main body, an isolation ring cutter, a piston, and a gate, where a propellant charge propels the piston and gate to contact the isolation ring cutter, allowing it to move across the through bore, with an energy absorbing element and a restraint to manage kinetic energy and prevent fluid interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydraulically actuated rams are used to close the BOP, then the BOP can be closed with sufficient force, but the system becomes vulnerable to hydraulic line damage and requires large amounts of hydraulic force
Solution Approach 1:
The patent removes the hydraulic actuation system entirely and replaces it with a pyrotechnic charge system. The hydraulic line connectivity is extracted from the closure mechanism, eliminating the vulnerability to hydraulic line damage while maintaining the ability to generate sufficient closing force through chemical propulsion.
Solution Approach 2:
The patent substitutes the hydraulic mechanical system with a pyrotechnic chemical system. The hydraulic force generation mechanism is replaced by a pyrotechnic charge that produces gas pressure to propel the closure elements, eliminating the need for external hydraulic lines and reducing system complexity.
2Reliability
If pyrotechnic charges are used to actuate the BOP, then hydraulic line vulnerability is eliminated, but the shearing element requires significantly more energy to cut through the isolation ring
Solution Approach 1:
The patent incorporates a preliminary shearing element positioned to cut through the isolation ring before the main pyrotechnic charge propels the closure elements. This preliminary action removes the isolation ring barrier in advance, allowing the main charge to focus energy on closing the BOP without the additional energy burden of shearing through the isolation ring during closure.
Solution Approach 2:
The patent segments the closure operation into distinct phases: (1) preliminary shearing of the isolation ring by a dedicated shearing element, and (2) main closure action by the pyrotechnic-propelled gate and ram. This segmentation allows each phase to be optimized independently, reducing the energy requirement for the main closure operation.
3Reliability
If the isolation ring is made thick and heavy to prevent fluid entry, then sealing performance is improved, but the shearing energy requirement increases significantly
Solution Approach 1:
The patent employs a preliminary shearing element that is positioned and configured to cut through the thick isolation ring before the main closure operation. This preliminary action removes the isolation ring barrier in advance, allowing the main pyrotechnic charge to focus its energy on closing the BOP without the additional energy burden of shearing through the isolation ring during closure.
Solution Approach 2:
The preliminary shearing element acts as an intermediary component that performs the difficult task of cutting through the thick isolation ring. This dedicated shearing element is specifically designed and positioned to handle the isolation ring removal, protecting the main closure system from the high energy requirements of shearing through the isolation ring.
4Ease of operation
If hydraulic force is applied slowly to close the BOP, then the closing action is controlled, but erosion of cutting and sealing surfaces occurs in flowing wellbore conditions
Solution Approach 1:
The patent uses a pyrotechnic charge that provides a rapid, periodic impulse of force rather than slow continuous hydraulic pressure. This periodic action generates a sudden high-velocity closure event that completes the closing operation quickly, minimizing the time during which cutting and sealing surfaces are exposed to erosive wellbore flow conditions.
Solution Approach 2:
The pyrotechnic actuation system enables the closure elements to rush through the wellbore contents at high velocity. The rapid generation of gas pressure from the pyrotechnic charge propels the gate and ram through the wellbore quickly, skipping the slow, erosion-prone hydraulic closing process and completing the closure operation in a matter of seconds.
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
Enables efficient well closure without hydraulic force, reduces debris generation, and minimizes the need for a separate isolation ring, enhancing the reliability and sealing performance of the blowout preventer.
Implementation Method 1
A charge is located between the piston and an end cap. The charge is configured for activation to propel the piston and thus the gate along the passage into contact with the isolation ring cutter
Implementation Method 2
an energy absorbing element disposed in the housing proximate the main body
Data Source
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AI summary
A blowout preventer has a main body having a through bore. A housing is mounted to the main body and defines a passage connected to and transverse to the through bore. An isolation ring cutter is initially disposed around the through bore and closes the passage to fluid flow. The isolation ring cutter is movable along the passage and has an opening coincident with the through bore. A piston and gate are disposed in the passage spaced apart from the isolation ring cutter. A propellant charge is disposed between the piston and an end.