Riser Cutting Tool Plasma Jet Separation
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Solution Overview
Problem
Existing methods for severing risers, particularly those connecting a floating vessel to a subsea wellhead, are inadequate when the riser angle exceeds 3%, leading to inability to disconnect the surface structure from the BOP stack, potentially causing damage.
Innovation Solution
A method involving a riser cutting tool that radially surrounds the riser with an explosive shaped charge material capable of generating a high-velocity plasma jet upon activation, allowing for precise separation of the riser into two portions by penetrating its outer and inner surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional explosive charging methods are used to sever risers, then the method is simple and easy to implement, but it fails when riser angles exceed 3%, causing inability to disconnect and potential damage
Solution Approach 1:
The explosive charge is divided into multiple segments positioned at different locations around the riser. This segmentation allows the charge to effectively cut the riser at various angles by applying explosive force at multiple points, resolving the limitation of conventional single-point charging that fails at angles exceeding 3°.
Solution Approach 2:
The invention transitions from conventional linear explosive charging to a three-dimensional configuration where explosive charges are positioned at multiple angular locations around the riser. This spatial distribution in multiple dimensions enables effective cutting regardless of riser inclination angle, achieving reliable disconnection while maintaining manageable complexity through modular charge placement.
2Adaptability or versatility
If hydraulic disconnect systems are used, then the system is simple to operate, but it cannot handle riser angles greater than 3%, leading to potential damage
Solution Approach 1:
The invention replaces the hydraulic disconnect system with an explosive-based cutting mechanism. This substitution eliminates the angle limitations inherent in hydraulic systems, enabling safe disconnection of risers at any inclination angle without the risk of damage associated with forced hydraulic separation at high angles.
Solution Approach 2:
The invention changes the fundamental operating parameter from hydraulic pressure to explosive detonation. This parameter change allows the system to effectively sever risers at any angle by using the high-velocity plasma jet and shock wave generated by the explosive charge, thereby adapting to various riser configurations while eliminating the damage risk present in hydraulic systems.
3Manufacturing precision
If explosive charges are positioned symmetrically about a passageway-forming tubular member, then the crimping action is symmetric and controlled, but the method cannot effectively sever risers at high angles
Solution Approach 1:
The symmetric explosive charge configuration is segmented into multiple discrete charge positions around the riser. This segmentation maintains the precision of controlled explosive force application while extending effectiveness to high-angle risers by distributing charges at multiple locations, ensuring reliable severing regardless of riser inclination.
Solution Approach 2:
The invention adds angular positioning as an additional dimension to the explosive charge configuration. By positioning charges at multiple angular locations around the riser rather than a single symmetric plane, the system achieves both precise controlled crimping and reliable severing at high angles, resolving the limitation of conventional two-dimensional charge arrangements.
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 reliable and controlled disconnection of risers from the BOP stack, preventing damage and ensuring safe operation even at high riser angles.
Implementation Method 1
explosive shaped charge material capable of generating a high-velocity plasma jet in response to an activation signal
Implementation Method 2
explosive shaped charge material capable of generating a high-velocity plasma jet
Data Source
AI summary
A method of separating a riser, comprising providing a riser having an inner and an outer surface, a circumference of said outer surface, a longitudinal axis and a first end and a second end; radially surrounding said riser with an explosive shaped charge material, wherein said shaped charge explosive material is capable of generating a high-velocity plasma jet in response to an activation signal, and wherein said explosive material comprises an electrically conductive layer; transmitting said activation signal to said explosive material; generating said high-velocity plasma jet; and separating said riser into a first portion comprising said first end and a second portion comprising said second end when said high-velocity plasma jet penetrates said outer surface of said riser and exits said inner surface of said riser.