Downhole Cable Location Using Rotating Electromagnetic Interrogation
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Solution Overview
Problem
Conventional methods for locating a cable behind a downhole tubular are time-consuming, requiring stationary measurements at multiple angles at every depth, which increases completion time and cost in oil and gas exploration.
Innovation Solution
An interrogation tool with at least one electromagnetic transmitter and receiver is deployed downhole, emitting an electromagnetic field that interacts with the tubular and cable to produce a secondary field, measured from different positions, allowing for efficient cable location determination with minimal sampling, using either time domain or frequency domain approaches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional stationary measurement at multiple angles is used at every depth, then cable position detection accuracy is improved, but completion time and cost increase significantly
Solution Approach 1:
The patent applies partial action by using only two angular positions (0 degrees and 90 degrees) instead of measuring at multiple angles around the tubular. This partial sampling is sufficient to determine cable position when combined with the tool's rotation, eliminating the need for exhaustive multi-angle measurements at each depth while maintaining detection accuracy.
Solution Approach 2:
The patent transforms the static measurement approach into a dynamic one by rotating the measurement tool around the tubular during a single pass. This continuous rotation allows the tool to collect angular position data dynamically, replacing the conventional static multi-angle measurement approach and significantly reducing measurement time.
2Measurement precision
If conventional stationary measurement at multiple angles is used at every depth, then cable position detection accuracy is improved, but completion cost increases
Solution Approach 1:
The patent uses partial action by measuring at only two specific angular positions (0 and 90 degrees) rather than multiple angles. This reduced sampling strategy, when combined with tool rotation, provides sufficient data for accurate cable positioning while dramatically improving productivity and reducing completion costs.
Solution Approach 2:
The patent implements continuous useful action by rotating the measurement tool continuously during a single pass through the tubular. This continuous rotation enables uninterrupted data collection, eliminating the need for repeated stationary measurements at multiple depths and angles, thereby enhancing productivity and reducing operational costs.
3Loss of time
If minimal sampling with single measurement is used, then completion time is reduced, but cable position detection reliability may be compromised
Solution Approach 1:
The patent uses dynamic rotation of the measurement tool to compensate for minimal angular sampling. By continuously rotating during measurement, the tool captures spatial variations in the electromagnetic field, providing sufficient information for reliable cable position determination even with only two angular measurement positions.
Solution Approach 2:
The patent introduces the tool's rotational motion as an intermediary mechanism that bridges the gap between minimal angular sampling and reliable detection. The rotation serves as a mediator that provides additional spatial information, enabling accurate cable positioning despite the reduced number of measurement angles.
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 significantly reduces the time required to locate the cable, enabling faster and more cost-effective perforation operations by determining the cable's angular position at each depth with a single sampling, compared to conventional methods.
Implementation Method 1
An electromagnetic field is emitted from a position inside the tubular using a transmitter
Implementation Method 2
The secondary electromagnetic field is measured by the receiver to produce a response signal
Data Source
AI summary
Interrogation tools and methods are used to efficiently locate cable behind casing. The interrogation tool has at least one electromagnetic transmitter and receiver. An electromagnetic field is emitted from inside the tubular, whereby it interacts with the tubular and cable to produce a secondary electromagnetic field. The secondary electromagnetic field is measured by the receiver(s) from at least two different positions inside the tubular to produce corresponding response signals. The interrogation tool then compares the response signals to baseline response signals, whereby the position of the cable is determined. The electromagnetic measurements can be acquired simultaneously or sequentially.