Kinetic BOP Ram Gate-Piston Coupling for Fast Wellbore Shearing
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Solution Overview
Problem
Hydraulically actuated rams in blowout preventers require significant hydraulic force, are susceptible to failure due to damaged hydraulic lines, and face challenges with erosion and difficulty in cutting through drill strings and off-center pipe strings.
Innovation Solution
A pyrotechnically actuated kinetic BOP ram system with a piston and gate assembly, utilizing a pyrotechnic gas pressure to accelerate the gate and piston, transferring kinetic energy to close the wellbore and cut through obstructions, with a coupling mechanism to withstand large and abrupt forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydraulically actuated rams are used to close the BOP, then the wellbore can be closed, but a large amount of hydraulic force is required and hydraulic lines are needed which are susceptible to damage
Solution Approach 1:
The patent replaces the hydraulic actuation system with a pyrotechnic gas pressure system. The pyrotechnic charge generates gas pressure that directly accelerates the piston and gate assembly, eliminating the need for hydraulic lines and external pressure sources. This substitution improves reliability by removing vulnerable hydraulic connections while maintaining the closing function.
Solution Approach 2:
The patent introduces a pyrotechnic charge as an intermediary energy source between the control system and the gate assembly. The pyrotechnic charge converts chemical energy to gas pressure, which then accelerates the piston and gate. This intermediary eliminates the need for direct hydraulic connection while providing sufficient force for closing and shearing operations.
2Speed
If hydraulically actuated rams are used, then the wellbore can be closed, but erosion of cutting and sealing surfaces occurs due to relatively slow closing speed
Solution Approach 1:
The patent employs a two-phase action sequence: first, the pyrotechnic charge accelerates the gate to high speed for rapid closing; second, the gate's kinetic energy completes the shearing action. This periodic acceleration followed by kinetic energy utilization achieves both high closing speed and effective shearing while minimizing erosion time.
Solution Approach 2:
The patent transitions from static or slow hydraulic actuation to dynamic pyrotechnic acceleration. The gas pressure system provides rapid, high-energy acceleration of the gate assembly, increasing closing speed from hydraulic timescales to pyrotechnic timescales, thereby reducing exposure time to erosive wellbore fluids.
3Force
If hydraulically actuated rams are used, then the wellbore can be closed, but significant hydraulic force is required to move the rams against wellbore pressure
Solution Approach 1:
The patent changes the energy delivery parameter from gradual hydraulic pressure buildup to instantaneous pyrotechnic gas pressure release. The pyrotechnic charge delivers a rapid, high-magnitude force impulse that overcomes wellbore pressure and inertial forces more efficiently than gradual hydraulic pressurization, reducing total energy requirement.
Solution Approach 2:
The patent uses the gate's mass and the pyrotechnic acceleration to build kinetic energy before the gate encounters wellbore pressure and obstructions. This preliminary acceleration allows the gate to overcome resistance forces more efficiently, as the kinetic energy is already stored in the moving mass rather than requiring continuous force application.
4Strength
If kinetic energy is used to shear obstructions, then cutting capability is improved, but the coupling between piston and gate must withstand very large and abrupt forces
Solution Approach 1:
The patent incorporates an energy absorbing element in the coupling between piston and gate that is pre-configured to deform under high load. This element provides progressive resistance during the shearing operation and absorbs the abrupt stopping force when the gate contacts the obstruction, protecting the coupling from catastrophic failure while maintaining cutting capability.
5Adaptability or versatility
If shear rams are used to cut through drill string, then the wellbore can be closed, but difficulty arises in cutting through tool joints, drill collars, large diameter tubulars and off center pipe strings under heavy compression
Solution Approach 1:
The patent uses dynamic pyrotechnic acceleration to deliver a high-velocity impact to the obstructions rather than slow, continuous hydraulic force. This dynamic approach allows the gate to overcome the compressive pre-stress in tubulars and tool joints by delivering force faster than the obstruction can elastically deform or resist, enabling cutting of previously difficult-to-shear materials.
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 system effectively closes the wellbore and shears obstructions using pyrotechnic gas pressure, reducing the need for hydraulic lines and minimizing erosion, while ensuring reliable operation under heavy loads.
Implementation Method 1
A pyrotechnic gas pressure operated BOP ram system with a piston and gate assembly, utilizing a pyrotechnic gas pressure to accelerate the gate and piston
Implementation Method 2
such acceleration is transferred to a gate or similar closure element whereby kinetic energy of the gate may be used to shear any devices disposed in a BOP housing through bore
Data Source
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AI summary
A ram for a blowout preventer has a pressure chamber having a piston movably disposed therein, and a charge disposed at one end of the pressure chamber. A gate is coupled to the piston on a side opposed to the charge. The gate is arranged to move across a through bore in a housing disposed at an opposed end of the pressure chamber. A coupling between the piston and the gate has sufficient strength to transfer kinetic energy of the gate to the piston.