Downhole Tubing Cutter Hydraulic Actuation
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Solution Overview
Problem
Existing methods for separating stuck casings in wellbores often rely on dangerous explosives, and there is a need for a mechanical solution to cut the casing without getting stuck.
Innovation Solution
A downhole tubing cutter tool with a pivotably connected cutting arm, activated by a hydraulic piston system powered by an electrical motor, which allows for safe separation of the casing from within by applying hydraulic pressure to move the cutting arm between retracted and projected positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If explosives are used to cut the casing, then the casing can be separated from the lower part, but the operational safety deteriorates due to the dangerous nature of explosives
Solution Approach 1:
The patent replaces the chemical explosion system with a mechanical cutting system consisting of a cutting arm, cutting element, and hydraulic actuation system. The cutting arm is moved between retracted and extended positions by a hydraulic piston, allowing mechanical cutting of the casing without using explosives, thereby eliminating the safety hazards while maintaining cutting effectiveness
Solution Approach 2:
The patent employs a hydraulic piston system to actuate the cutting arm. Hydraulic pressure is applied to move the piston, which in turn moves the cutting arm between retracted and extended positions. This hydraulic mechanism provides controlled, reliable actuation for the mechanical cutting process, replacing the uncontrolled energy release of explosives with a controllable hydraulic system
2Object-affected harmful factors
If a mechanical cutting tool is used instead of explosives, then operational safety is improved, but the device complexity increases due to additional mechanical components
Solution Approach 1:
The cutting arm is rotatably mounted within the tool housing and can be retracted into or extended from the housing. The hydraulic piston is nested within the tool housing, with the piston rod extending to connect with the cutting arm. This nested arrangement consolidates multiple components within a compact structure, reducing overall device complexity while maintaining the mechanical cutting functionality
Solution Approach 2:
The tool housing serves multiple functions: it provides structural support, contains the hydraulic piston mechanism, and acts as the mounting structure for the rotatable cutting arm. The hydraulic system serves both to actuate the cutting arm and to provide the cutting force through the piston. This multi-functionality reduces the number of separate components needed, thereby reducing device complexity
3Productivity
If the cutting arm is made movable between retracted and projected positions, then the cutting effectiveness is improved, but the device complexity increases due to the activation assembly
Solution Approach 1:
A hydraulic piston is employed to actuate the cutting arm, providing a compact and efficient means of movement between retracted and extended positions. The hydraulic system offers controlled, high-force actuation in a space-efficient design, avoiding more complex mechanical linkage systems while achieving reliable cutting arm positioning
Solution Approach 2:
The hydraulic piston is nested within the tool housing, with its rod extending to connect with the cutting arm. The cutting arm itself is nested within the housing when retracted. This nested configuration minimizes the space required for the activation assembly and reduces the number of external components, thereby reducing overall device complexity while maintaining cutting effectiveness
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 the safe and effective separation of the upper part of the casing from the lower part without using explosives, ensuring operational safety and reliability.
Implementation Method 1
the piston member being capable of applying a projecting force on the cutting arm by applying hydraulic pressure on the first piston face
Implementation Method 2
the pump is driven by an electrical motor powered through a wireline
Data Source
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AI summary
The present invention relates to a downhole tubing cutter tool for submerging into a casing or a drill pipe in a wellbore and separating an upper part of the casing from a lower part of the casing by cutting the casing from within, the tool extending in a longitudinal direction, comprising a tool housing having a first and a second housing part, a cutting arm which is pivotably connected with the first housing part and has a cutting edge in a first end, said arm being movable between a retracted position and a projected position in relation to the tool housing, an arm activation assembly for moving the cutting arm between the retracted position and the projected position, and a rotatable shaft arranged in the second housing part and connected with the first housing part for rotating the cutting arm, wherein the arm activation assembly comprises a piston housing arranged in the first housing part and comprising a piston chamber, a piston member arranged inside the piston chamber and engaged with the cutting arm to move the cutting arm between the retracted position and the projected position, the piston member being movable in the longitudinal direction of the downhole tool and having a first piston face and a second piston face, the piston member being capable of applying a projecting force on the cutting arm by applying hydraulic pressure on the first piston face and moving the piston in a first direction. The invention also relates to downhole system comprising a downhole tubing cutter tool according to the invention, and a driving unit for moving the downhole tubing cutter tool forward in the casing.