Downhole Tool Positioning via Magnetic Field Indication
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Solution Overview
Problem
Current methods for locating downhole apparatuses in pressure-containing systems, such as oil and gas wells, face challenges due to accumulated errors from friction wheel measurements, leading to uncertainty in tool positioning, potentially resulting in tool failure or damage during deployment and retrieval.
Innovation Solution
A magnetic field-based system is employed, where a magnetic device generates a field within the wellbore's pressure cavity, and a magnetic field indicator external to the cavity monitors the presence and magnitude of the field to determine the apparatus's location, leveraging differences in magnetic properties between the apparatus, conveyance means, and pressure barrier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If friction wheel measurement is used to track conveyance means movement, then depth measurement is provided, but accumulated errors lead to uncertainty in tool positioning
Solution Approach 1:
A magnetic field indicator acts as an intermediary reference system between the surface equipment and the downhole tool. The indicator provides a magnetic field that can be detected by the tool, creating a reliable reference point that does not accumulate errors like the friction wheel system. This intermediary magnetic reference allows for accurate positioning verification without being affected by the cumulative measurement errors of the mechanical friction wheel.
Solution Approach 2:
The patent replaces the mechanical friction wheel measurement system with a magnetic field-based positioning system. Instead of relying on mechanical rotation and friction to measure depth, the system uses magnetic field detection to determine tool position. This substitution eliminates the accumulated errors inherent in mechanical measurement systems while providing continuous, accurate positioning data.
2Loss of information
If friction wheel is used as sole means of locating downhole tool, then location tracking is provided, but errors accumulate leading to uncertainty of hundreds of feet
Solution Approach 1:
The magnetic field indicator serves as an intermediary reference that provides accurate location information independent of the friction wheel system. By detecting the magnetic field strength and characteristics, the tool can determine its precise location relative to the indicator, preventing the accumulation of location errors that would otherwise reach hundreds of feet.
Solution Approach 2:
The magnetic field indicator provides continuous feedback to the downhole tool about its position. This feedback mechanism allows the system to constantly verify and correct the tool's location, preventing error accumulation. The tool receives real-time magnetic field data and can adjust its position understanding accordingly, maintaining precision throughout the operation.
3Productivity
If tool is pulled up at high speed based on friction wheel measurements, then retrieval efficiency is improved, but tool may be pulled into sealing means causing failure
Solution Approach 1:
The magnetic field indicator provides real-time feedback on the tool's position relative to the BOP stack and sealing means. This feedback allows operators to monitor the tool's approach to critical zones and adjust retrieval speed accordingly, preventing the tool from being pulled into the sealing means even during high-speed operations.
Solution Approach 2:
The magnetic field indicator is positioned and configured in advance to provide warning signals before the tool reaches critical positions near the sealing means. This preliminary indication allows operators to take preventive action, such as reducing speed or preparing for controlled deployment, before the tool enters the dangerous zone, thereby maintaining both speed and safety.
4Device complexity
If pressure deployment is performed without precise magnetic field-based location, then deployment complexity is reduced, but precision relative to BOP rams is insufficient
Solution Approach 1:
The magnetic field indicator acts as a simple yet effective intermediary reference system that provides precise positioning information without adding significant complexity to the deployment system. The magnetic field naturally penetrates the pressure boundary, providing continuous position data that helps operators achieve precise alignment with the BOP rams while maintaining relatively simple system architecture.
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 system provides precise location information, reducing the risk of tool failure and damage by accurately tracking the downhole apparatus's position, even in high-pressure environments, and compensating for measurement errors.
Implementation Method 1
a magnetic device for generating a magnetic field in the pressure cavity
Implementation Method 2
a magnetic field indicator disposed external to the pressure cavity, the magnetic field indicator responsive to the magnetic field in the pressure cavity
Data Source
AI summary
A system for locating a downhole apparatus comprises a wellbore having an interior pressure cavity, wherein the apparatus is disposed in the pressure cavity, a magnetic device for generating a magnetic field in the pressure cavity, and a magnetic field indicator disposed external to the pressure cavity, the magnetic field indicator responsive to the magnetic field in the pressure cavity, wherein the magnetic field is indicative of a position of the apparatus in the pressure cavity.