3D Borehole TEM Unwrapping for Negative Response Localization

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Solution Overview

Problem

The borehole transient electromagnetic method faces challenges in accurately determining the orientation and distance of anomalous bodies due to varying response curves and negative responses, which hinder effective resistivity value calculation and precise localization.

Innovation Solution

A three-dimensional unwrapping processing method transforms negative electromagnetic signals into positive responses using a roll angle transformation equation, establishing unwrapped diagrams with roll angle as the horizontal coordinate and induced electromotive force as the longitudinal coordinate, and combining this with a calibration system to ensure accurate measurement and determination of anomalous body orientation and distance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional transient electromagnetic detection is used in boreholes, then metal support interference is avoided and signal-to-noise ratio is improved, but negative response curves occur that hinder accurate resistivity calculation and anomalous body localization

Engineering Contradiction:

Improvesignal-to-noise ratioVSAvoidresistivity calculation accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent applies inversion by transforming negative response curves into positive response curves through coordinate system transformation. Specifically, when a negative response is detected at a certain roll angle, the patent inverts the angle to its supplementary angle (180° - θ) and uses the absolute value of the response, thereby converting the harmful negative signal into a useful positive signal for resistivity calculation.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent changes the parameter of roll angle to transform negative responses. By adjusting the roll angle parameter and using transformation equations, the patent converts negative electromotive force signals into positive signals, enabling accurate resistivity calculation while maintaining the reliability benefits of borehole detection.

Inventive Principle:

Principle #35Parameter changes

2Ease of operation

If only approximate angle of borehole is determined, then detection is simplified, but distance between anomalous body and borehole center cannot be determined

Engineering Contradiction:

Improvedetection complexityVSAvoidanomalous body positioning accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent transitions from two-dimensional angular detection to three-dimensional spatial analysis by introducing the roll angle dimension. This allows the system to not only determine the approximate angle of the borehole but also calculate the precise distance and orientation of anomalous bodies relative to the borehole center, achieving accurate positioning while maintaining operational simplicity through automated processing.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Adaptability or versatility

If full space response is considered, then comprehensive detection is achieved, but negative responses cause inaccurate resistivity calculation

Engineering Contradiction:

Improvedetection coverageVSAvoidresistivity value accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent converts the harmful negative responses into beneficial positive responses by applying coordinate transformation. The negative responses, which originally hindered accurate resistivity calculation, are transformed through roll angle inversion to become useful signals that maintain comprehensive detection coverage while improving measurement precision.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 enhances the accuracy of anomalous body positioning by effectively utilizing negative responses, improving the detection of anomalous bodies' orientation and distance, and resolving issues of inaccurate positioning caused by full space response.

Implementation Method 1

a secondary field induced electromotive force

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS20260029555A1Three-dimensional unwrapping processing method and system for borehole transient electromagnetic method

Publication Date: 2026.01.29 ANHUI HUIZHOU GEOLOGY SECURITY INST

AI summary

A three-dimensional unwrapping processing method for a borehole transient electromagnetic method includes: acquiring measurement information of each measuring point in a target borehole, where the measurement information includes a secondary field induced electromotive force and a roll angle; establishing, for each measuring point, an unwrapped diagram with the roll angle as a horizontal coordinate and the secondary field induced electromotive force as a longitudinal coordinate; and transforming, when an electromotive force signal in the unwrapped diagram is a negative response, the electromotive force signal into a positive response according to a transformation equation of the roll angle to acquire measurement transformation information. The processing problem of the borehole transient electromagnetic method in detecting a negative induced electromotive force response is solved, and the acquired measurement transformation information includes a negative electromotive force signal. A three-dimensional unwrapping processing system for a borehole transient electromagnetic method is also provided.