Downhole Tool Selective Operation Piston Sleeve Magnet
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Solution Overview
Problem
Current techniques for abandoning a well require multiple trips to create a cement plug and remove casing, which is time-consuming and costly, and existing tools cannot selectively operate fluid pressure-activated tools without inadvertently activating secondary tools due to rotation-related issues.
Innovation Solution
A downhole tool with a piston sleeve that moves between two flow positions based on fluid pressure, held by a magnet and biased by a spring, allowing selective operation of secondary fluid pressure-activated tools by varying fluid pressure, eliminating the need for tool rotation and preventing accidental activation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a motor is used to rotate the casing cutter, then the requirement to rotate the entire drill string from surface is removed, but the cutting blades will inadvertently cut the suspended casing section below the anchor point when the gripping mechanism is used to pull a cut section of casing
Solution Approach 1:
The invention extracts the cutting function from continuous rotation by using a motor that can be selectively engaged and disengaged. The motor is taken out of constant operation and only activated when cutting is required, preventing unintended cutting during casing retrieval operations.
Solution Approach 2:
The system transitions from static rotation (entire drill string rotated from surface) to dynamic selective rotation (motor engaged only when needed). The motor provides dynamic control over the cutting operation, allowing it to be activated only when the cutting blades need to cut through casing.
2Reliability
If multiple trips are made into the well to create cement plug and remove casing, then each operation can be performed carefully and correctly, but substantial time and significant costs are incurred
Solution Approach 1:
The invention merges multiple separate operations (casing cutting, casing retrieval, and cement plug creation) into a single integrated tool assembly. The combined tool allows all these functions to be performed in one trip into the well, eliminating the need for multiple separate trips while maintaining operational reliability through coordinated design of all functions.
Solution Approach 2:
The downhole tool assembly is designed with universal multi-functionality, capable of performing cutting, gripping, and cement plug creation functions within a single tool string. This multi-functional design eliminates the need for multiple specialized trips while ensuring each function can be executed correctly.
3Productivity
If the drill string is rotated to use the combined casing cutting and pulling tool, then cutting and pulling can be achieved on a single trip, but rotation of the string may disengage the seal assembly from its running tool
Solution Approach 1:
The invention replaces the mechanical rotation system (rotating entire drill string) with a downhole motor system that provides localized rotation at the cutting tool. This substitution eliminates the need to rotate the entire drill string and seal assembly, maintaining their stable position while still enabling cutting functionality.
Solution Approach 2:
The system is segmented into independent functional modules: the seal assembly remains stationary on the drill string, while the cutting motor assembly rotates independently downhole. This segmentation allows the cutting function to be performed without moving the seal assembly, maintaining its stable connection to the running tool.
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 efficient and selective operation of fluid pressure-activated tools, reducing the need for multiple trips and preventing unintended tool activation, thereby minimizing costs and operational complexity.
Implementation Method 1
a magnet to hold the piston sleeve against the cylindrical body in the first position
Implementation Method 2
a spring to bias the piston sleeve towards the first position
Implementation Method 3
the piston sleeve being moveable by the action of fluid pressure in the bore between a first position and a second position
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
A downhole tool which allows the selective operation of a second fluid pressure activated tool below a first fluid pressure activated tool on a tool string in a well. The downhole tool has a piston sleeve moveable inside a cylindrical body between a first position in which a small flow area is provided through the tool and a second position in which a larger flow area is provided. The piston sleeve is held in the first position by a magnet and the first fluid pressure activated tool can be operated by increasing fluid pressure above the tool up to a cracking pressure level which matches the pulling strength of the magnet. Increasing fluid pressure to the cracking pressure therefore selectively moves the piston sleeve to the second position in which the second fluid pressure activated tool can be operated. The downhole tool is resettable.