Pyrotechnic Wellbore Tubular Cutter Using High-Pressure Jet
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Solution Overview
Problem
Conventional devices for cutting wellbore tubulars in oil or gas wells either rely on mechanical cutters that are inefficient or explosive charges that can be hazardous and lack precision, failing to provide a reliable and efficient method for severing tubing.
Innovation Solution
A pyrotechnic tubular cutter device with a charge assembly that uses energetic materials and a unique liner configuration to form a circumferential cut, allowing for precise severing of wellbore tubulars by generating a high-pressure cutting jet that separates the tubing into two sections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If mechanical cutters are used to cut tubing, then the cutting can be performed mechanically, but the cutting efficiency is poor and the process is time-consuming
Solution Approach 1:
The patent replaces the mechanical cutter system with a pyrotechnic charge assembly that uses chemical energy conversion. The energetic material converts chemical energy to thermal and mechanical energy, creating a high-pressure jet that cuts through the tubular much faster than mechanical means, directly resolving the efficiency and time loss contradiction.
Solution Approach 2:
The invention changes the cutting mechanism from mechanical force to high-pressure jet formed by energetic material combustion. This parameter change in the cutting method enables rapid penetration through the tubular wall, dramatically improving productivity while reducing cutting time.
2Productivity
If explosive charges are used to sever tubing, then the cutting speed is fast, but the precision and control of the cut are poor
Solution Approach 1:
The patent employs a liner with specific geometric configuration (conical or frustoconical shape) that concentrates the explosive energy into a focused high-pressure jet at a specific location. This local concentration of energy ensures precise cutting at the desired position while maintaining fast cutting speed, resolving the contradiction between speed and precision.
Solution Approach 2:
The liner acts as an intermediary between the energetic material and the tubular to be cut. It shapes and directs the high-pressure jet to achieve precise circumferential cutting, transforming the uncontrolled explosive force into a controlled cutting mechanism that maintains both speed and precision.
3Reliability
If conventional explosive charges are used, then the tubing can be severed, but the operation is hazardous and lacks control
Solution Approach 1:
The patent converts the potentially hazardous explosive energy into a controlled beneficial cutting mechanism. The energetic material's rapid energy release is channeled through the liner geometry to create a focused high-pressure jet that cuts the tubular reliably, transforming the harmful explosive force into a controlled and reliable severing operation.
Solution Approach 2:
The charge assembly is segmented into distinct functional components: the energetic material for energy release and the liner for jet formation and direction. This segmentation allows independent optimization of each component, improving overall reliability while maintaining safety through controlled energy release.
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 enables efficient and precise severing of wellbore tubulars, offering improved performance over mechanical and explosive methods by creating a consistent and controlled circumferential cut, suitable for various wellbore applications including offshore and subsea environments.
Implementation Method 1
The charge assembly includes an upper portion and a lower portion that cooperate to form a circumferential gap between the charge assembly and the tubular. The initiator is configured to detonate the energetic material to form a high-pressure jet that penetrates through the tubular.
Implementation Method 2
The liners are configured to define a circumferential gap between the liners and the tubular. The gap is sized such that the high-pressure gas formed by the detonated energetic material flows into the circumferential gap to form a substantially contiguously circumferential penetration of the tubular.
Data Source
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AI summary
An apparatus and a method for cutting a wellbore tubular are described herein. The apparatus and the method may include an upper section and a lower section mating at a juncture plane defined by a plane transverse to the longitudinal axis of the wellbore tubular. Each section may include a support plate having a passage, a liner positioned adjacent to the support plate, and an energetic material disposed between the support plate and the liner. An initiator having a shaft may be positioned in the passages of the upper section and the lower section.