Adjustable Shear Thread Retaining Mechanism for Downhole Tools
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional drill stem tester valves and safety joints face challenges such as limited tension sleeve options, time-consuming installation of shear pins, and difficulties in retrieving sheared parts, which complicate deep well operations and increase safety risks.
Innovation Solution
A pressure responsive downhole tool with a shearable threaded retaining mechanism that allows for adjustable shear at any desired pressure, featuring a pin and box thread connection where the pin thread is weaker than the box thread, enabling infinite adjustment of the shear value and retention of sheared parts to prevent loss in the well.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a high value tension sleeve is selected to avoid accidental operation, then safety is improved, but the tensile rating of the workstring may be exceeded
Solution Approach 1:
The patent applies parameter changes by providing an adjustable tension sleeve mechanism that allows the shear strength parameter to be modified according to specific job requirements. The tension sleeve can be adjusted to different positions along the workstring, changing the effective shear strength to match the workstring's tensile rating, thus preventing both accidental operation and workstring failure.
2Reliability
If multiple shear pins are installed in a shear set, then the retaining mechanism is more reliable, but installation time increases significantly
Solution Approach 1:
The patent extracts the multiple shear pins from the design and replaces them with a single adjustable tension sleeve mechanism. This eliminates the need to install numerous individual shear pins while maintaining the retaining function through the adjustable sleeve that can be set to provide the desired shear strength.
3Device complexity
If conventional shear pins are used, then the retaining mechanism is simple, but sheared parts are dropped in the well making fishing operations difficult
Solution Approach 1:
The patent applies discarding and recovering by designing the tension sleeve to be retained within the tool assembly after shearing occurs. Instead of the shear pins being lost in the well, the tension sleeve remains captured by the tool housing, allowing for easier recovery operations and eliminating the need for complex fishing operations to retrieve lost parts.
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 provides a safer, more reliable, and customizable downhole tool that reduces the complexity of selecting tension sleeves and shearing pins, allowing for precise operation and efficient retrieval, thus enhancing operational safety and flexibility in deep well operations.
Implementation Method 1
a threaded shearable retaining mechanism connecting the first and second bodies to each other in a first position, the threaded shearable retaining mechanism being adapted to shear upon application of sufficient pressure
Data Source
AI summary
A pressure responsive downhole tool comprises a threaded shearable retaining mechanism which performs the tension sleeve or shear pin function. The threaded shearable retaining mechanism comprises a pin and box thread that shears upon application of a predetermined pressure which may be adjusted based upon the amount of thread engagement. The pin thread may comprise indicators to indicate which thread engagement corresponds to what shear value. A keystone thread design may be utilized such that the thread would be retained along the threaded connection and not become lost in the well. Thus, the present invention allows for each pressure responsive tool to be custom tailored for a specific job.