Downhole Tool String Spacing for Swarf-Free Radial Machining
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Solution Overview
Problem
Existing downhole tools, such as drill bits, often break when performing radial machining operations in well tubular metal structures due to the inability to maintain a sufficient distance from the wall during drilling, leading to swarf accumulation and operational failure.
Innovation Solution
A downhole tool string design featuring a tool body with a machining tool and displacement elements that can extend radially, accompanied by distancing elements to maintain a controlled distance from the well wall, ensuring swarf removal and preventing operational failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the drill bit is extended radially to perform machining operations on the well tubular metal structure, then the operational capability is improved, but the reliability deteriorates due to breakage
Solution Approach 1:
The tool body is divided into two halves (first body half and second body half) with the machining tool on one side and displacement elements on the other, allowing independent control of machining and positioning functions. This segmentation enables the machining tool to be protected while maintaining operational capability.
Solution Approach 2:
The displacement elements are designed to be movable between retracted and projected positions, dynamically adjusting the distance between the tool body and well wall. This dynamic positioning allows the machining tool to maintain optimal working distance while preventing breakage through controlled movement.
2Productivity
If the drill bit is positioned close to the well wall for effective machining, then the productivity is improved, but harmful factors increase due to swarf accumulation
Solution Approach 1:
The distancing element acts as an intermediary between the tool body and well wall, maintaining a controlled gap that prevents direct contact while allowing effective machining. This intermediary space enables swarf to be flushed away, eliminating accumulation problems while maintaining productivity.
Solution Approach 2:
The invention introduces a radial distance dimension between the tool body and well wall, transforming the machining from direct contact to non-contact operation. This dimensional change creates space for swarf removal while maintaining machining effectiveness.
3Device complexity
If the drill bit operates without distance control from the well wall, then the device complexity is reduced, but harmful factors increase due to swarf accumulation
Solution Approach 1:
The displacement elements serve multiple functions: positioning the tool body at the correct distance, supporting the machining tool during operation, and creating space for swarf removal. This multi-functionality adds minimal complexity while effectively preventing swarf accumulation.
Solution Approach 2:
The distancing element automatically maintains the optimal gap between tool body and well wall during machining operations, self-regulating the distance without external intervention. This self-service mechanism prevents swarf accumulation while adding minimal system complexity.
Data Source
AI summary
A downhole tool string includes a tool body, an operational machining tool for performing a machining operation in a well tubular metal structure, extendable from the tool body, and first and second distancing elements extendable from the tool body The distancing elements are pivotally connected to the tool body between a retracted position and a projected position. Each distancing element is configured to abut the inner surface of the well tubular metal structure to maintain a radial distance between the tool body and the wall of the well tubular metal structure. The distancing elements are operatively connected to a common piston, and are configured to be pivotally moved from their retracted positions to their projected position by an axial movement of the common piston.