Magnetic Tool Position Determination in Wellbores
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Solution Overview
Problem
Determining the precise location of downhole tools in subterranean wellbores is challenging due to inaccuracies in depth reference logs and unpredictable deformations such as thermal elongation, buckling, and friction effects in tubular strings, which complicates the actuation and confirmation of tool positions.
Innovation Solution
A magnetic system is employed, featuring an array of magnets associated with a stationary component and a moveable component that changes its position relative to the stationary component, producing distinct magnetic field interference levels. A magnetic field detector is used to read these signatures, determining the operating position of the downhole tool by detecting the magnetic signature produced by the interaction between the moveable and stationary components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional depth reference logs and tubular strings are used to determine downhole tool position, then the system is simple and easy to implement, but the measurement precision deteriorates due to inaccuracies from thermal elongation, buckling, stretching, and friction effects
Solution Approach 1:
The patent replaces the mechanical depth measurement system (tubular strings and reference logs subject to thermal and mechanical deformations) with a magnetic field-based position determination system. Magnets embedded in the wellbore environment create magnetic fields that can be detected by tools, providing position information without being affected by thermal elongation, buckling, or friction effects that plague mechanical measurement systems.
Solution Approach 2:
The patent introduces magnetic fields as an intermediary medium for position determination. Instead of directly measuring mechanical depth through tubular strings, the system uses magnetic fields generated by magnets in the wellbore environment as an intermediate carrier of position information. This intermediary approach allows indirect measurement that is immune to mechanical deformations.
2Measurement precision
If magnetic field detectors are used to determine tool position, then measurement precision improves by eliminating mechanical deformation errors, but the device complexity increases due to the need for magnetic field generation and detection systems
Solution Approach 1:
The patent makes the magnetic field detection system multi-functional by embedding magnets in various wellbore components (casing, tubing, completion tools) so that the same magnetic field-based system can determine positions of different tools and confirm actuation states of various downhole devices. This universal approach justifies the added complexity by providing comprehensive position determination capabilities.
Solution Approach 2:
The system uses the wellbore environment itself (casing, tubing, completion tools) as part of the magnetic field generation system. By embedding magnets in these existing components, the system leverages the wellbore structure to create the magnetic field network, reducing the need for separate, dedicated magnetic infrastructure and thereby limiting the increase in overall system complexity.
3Reliability
If downhole tools are actuated without position confirmation, then the operation process is simple and fast, but the reliability deteriorates due to inability to verify tool position and actuation status
Solution Approach 1:
The patent implements feedback by using magnetic field detectors to read the magnetic field signatures generated by magnets associated with downhole tools after actuation. This feedback mechanism allows verification that the tool has reached the desired position and actuation state, providing reliability confirmation without requiring complex verification systems. The magnetic field signatures serve as direct feedback indicators of tool status.
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
This method allows for accurate determination of the operating position and identity of downhole tools, enabling precise positioning and actuation confirmation, even in complex well configurations like horizontal, vertical, or deviated wells, by generating unique magnetic signatures for different tool positions.
Implementation Method 1
An array of magnets is operable to produce a magnetic field. A magnetic field detector is operable to be run into the wellbore and moved relative to the downhole tool. The position of the moveable component relative to the stationary component is determined by detection of a magnetic signature produced by the moveable component and the array of magnets with the magnetic field detector.
Data Source
AI summary
A magnetic system for determining an operating position of a downhole tool. The system includes an array of magnets operable to produce a magnetic field that is operably associated with a stationary component of the downhole tool. A moveable component of the downhole tool has at least first and second positions relative to the stationary component. In the first position, the moveable component has a first degree of interference with the magnetic field. In the second position, the moveable component has a second degree of interference with the magnetic field. A magnetic field detector is operable to be run into the wellbore and moved relative to the downhole tool such that the position of the moveable component relative to the stationary component is determined by detection of a magnetic signature produced by the moveable component and the array of magnets.