Downhole Tool Magnetic Ranging for Wellbore Location
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Solution Overview
Problem
Current methods for locating adjacent wellbores during drilling operations, such as wireline tools, are inefficient and costly, providing only periodic and inaccurate data, which can lead to dangerous and costly errors, especially in high-pressure formations and U-shaped well drilling.
Innovation Solution
A method and device using a downhole tool with an insulated gap to generate an electric current and measure azimuthal magnetic fields with both internal and external magnetometers to determine the direction and distance to a conductive target, such as a casing, while drilling, allowing for continuous and accurate location without the need to remove the drill string.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If wireline tools are used for locating adjacent wellbores, then periodic location data can be obtained, but rig time increases and costs increase due to repeated trips
Solution Approach 1:
The patent replaces the mechanical wireline tool system with a magnetic field-based detection system. The downhole tool generates a magnetic field that induces currents in the adjacent wellbore casing, and these induced currents are detected by magnetometers to determine wellbore location. This substitution eliminates the need for mechanical wireline trips while maintaining location measurement capability, directly resolving the contradiction between measurement precision and time loss.
2Loss of information
If wireline magnetic ranging methods are used with periodic trips, then location information can be obtained, but continuous and timely data is unavailable leading to costly errors
Solution Approach 1:
The patent implements continuous magnetic field measurement while drilling operations proceed uninterrupted. The downhole tool continuously generates magnetic fields and the magnetometers continuously detect induced currents, providing real-time location data without stopping drilling or making trips. This continuous measurement approach ensures timely location information is always available, preventing costly errors while eliminating time losses associated with periodic wireline trips.
3Measurement precision
If multiple wireline trips are made to obtain location data, then accurate positioning can be achieved, but device complexity and operational complexity increase
Solution Approach 1:
The downhole tool performs self-service by generating its own magnetic field for detection purposes. The tool contains a current source that generates current through an insulated gap, creating a magnetic field that induces currents in the adjacent wellbore casing. The magnetometers on the tool then detect these induced currents to determine location. This self-contained system eliminates the need for external wireline equipment and complex trip operations, achieving accurate positioning while simplifying drilling operations.
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 approach enables continuous, accurate, and timely data collection, reducing rig time and costs by allowing real-time monitoring of wellbore location and formation resistivity, enhancing safety and efficiency in drilling operations.
Implementation Method 1
generating a current flowing across an insulated gap in a downhole tool positioned in the wellbore
Implementation Method 2
measuring an azimuthal magnetic field with at least one external magnetometer located proximate the exterior of the downhole tool
Data Source
AI summary
A method of locating a conductive target from a wellbore includes generating a current flowing across an insulated gap in a downhole tool positioned in the wellbore, measuring an azimuthal magnetic field with at least one external magnetometer located proximate the exterior of the downhole tool, measuring a secondary magnetic field using a magnetometer disposed inside the downhole tool, computing at least one of a direction and a distance to the conductive target.