Truncated Liner Jet Cutter for Complete Tubing Severance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current jet cutters used to sever tubing strings in wellbores often fail to achieve complete severance due to insufficient energy release, leading to incomplete cuts and issues like swelling or flaring, which complicate the removal process and increase time and cost.
Innovation Solution
The jet cutter design is improved by truncating the liner at and near the apex to reduce the inverse velocity gradient, increasing the jet tip velocity and energy output, thereby ensuring a more efficient and thorough cut through the tubing string.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a conventional jet cutter with a full liner is used, then the device structure is complete and simple to manufacture, but the jet tip velocity is insufficient leading to incomplete severance
Solution Approach 1:
The patent applies the extraction principle by removing the liner material from the apex region of the charged cavity. This extraction of unnecessary liner material allows the jet to achieve higher velocities by eliminating the inverse velocity gradient that occurs when liner elements near the apex collide with reduced final collapse velocity. The truncated liner design extracts only the portion of liner that would create harmful collisions, while maintaining the beneficial liner structure elsewhere.
Solution Approach 2:
The patent inverts the conventional approach by truncating the liner at the apex rather than maintaining a complete liner structure. This inversion transforms the problem of inverse velocity gradient and liner collision into a solution where the jet achieves higher tip velocities. By doing the opposite of what is conventionally done (removing liner instead of keeping it), the patent resolves the contradiction between jet velocity and manufacturing complexity.
2Reliability
If the explosive load is increased to achieve complete severance, then the cutting effectiveness is improved, but swelling or flaring at the severance point increases making removal difficult
Solution Approach 1:
The patent applies local quality by creating different liner configurations in different regions of the charged cavity. The liner is truncated at the apex region where high velocity jet formation occurs, while maintaining liner structure in other regions. This localized modification allows the jet to achieve sufficient energy for complete severance without the excessive swelling or flaring that would result from increasing the overall explosive load, thereby resolving the contradiction between severance completeness and harmful swelling.
3Power
If the liner is truncated at the apex, then the jet tip velocity and energy output increase, but the liner structure becomes more complex
Solution Approach 1:
The patent extracts only the necessary portion of liner material from the apex region, rather than redesigning the entire liner structure. This selective extraction achieves the desired increase in jet tip velocity and energy output while minimizing the added complexity. The truncated liner design removes only what is needed to eliminate the inverse velocity gradient, keeping the overall structure relatively simple and manufacturable.
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 enhanced jet cutter achieves a higher jet tip velocity and energy output, resulting in complete severance of the tubing string with reduced swelling or flaring, facilitating easier removal and reducing operational costs and time.
Implementation Method 1
The main explosive load tapers in from the top and bottom towards the middle to form an apex. The liner, being adjacent to the main explosive load, also tapers in and forms an apex. Upon initiation, a spherical wave propagates outward from the point of initiation along the axis of symmetry. This high-pressure wave moves at a very high velocity, typically around 8 kilometers per second (km/s). As the detonation wave engulfs the lined cavity, the liner material is accelerated under the high detonation pressure
Implementation Method 2
As the detonation wave engulfs the lined cavity, the liner material is accelerated under the high detonation pressure, collapsing the liner. During this process, for a typical conical liner, the liner material is driven to very violent distortions over very short time intervals (microseconds) at strain rates of 10^4 to 10^7/s. The collapse of the liner material on the centerline forces a portion of the liner to flow in the form of a jet where the jet tip velocity can travel in excess of 10 km/s
Data Source
AI summary
A method of severing a tubing string of a well system comprising: positioning a jet cutter within the tubing string, wherein the jet cutter comprises: (A) a main explosive load, wherein upon detonation or deflagration of the main explosive load, a jet propagates radially outward in a circle from an apex of the main explosive load; and (B) a liner, wherein the liner is truncated at the apex, and wherein the amount of truncation is selected such that the jet has a greater tip velocity compared to a substantially identical jet cutter without the truncated liner; and causing the main explosive load to detonate or deflagrate, wherein the tubing string of the well system is severed due to the detonation or deflagration.