Virtual Steering Induction Logging Attenuation Phase
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing induction logging tools are unable to reliably measure attenuation and phase difference, which are crucial for determining formation dip angle and resistivity, due to the non-applicability of linear superposition principles to signal attenuation and phase differences.
Innovation Solution
A logging tool with two triads of orthogonal receivers and a triad of orthogonal transmitters is used to measure signal ratios, allowing for the determination of attenuation and phase difference through equations that enable virtual steering of measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If linear superposition is applied to manipulate coupling measurements, then measurements can be transformed to arbitrary orientations, but this principle cannot be applied to signal attenuation and phase difference measurements
Solution Approach 1:
The patent creates virtual copies of transmitter and receiver coils through mathematical transformations. By measuring actual coupling between physical coils and applying rotational transforms, the system synthesizes measurements that correspond to virtual coils at arbitrary orientations. This copying approach allows the system to achieve orientation flexibility without physically reconfiguring coils, effectively bypassing the limitation that linear superposition cannot be directly applied to attenuation and phase difference measurements.
Solution Approach 2:
The patent introduces coupling measurements as an intermediary quantity. Instead of directly manipulating attenuation and phase difference measurements (where superposition fails), the system first measures transmitter-receiver coupling, applies linear superposition to transform these coupling measurements to arbitrary orientations, and then derives the desired attenuation and phase difference from the transformed coupling measurements. This intermediary approach enables the use of superposition principles indirectly.
2Measurement precision
If multi-axial transmitter and receiver triads are used, then dip angle and strike angle measurements become possible, but the tool configuration becomes more complex
Solution Approach 1:
The patent makes the triad configuration universal by enabling measurements at any orientation through virtual steering. The same physical triad arrangement can determine dip angle, strike angle, and formation resistivity for beds at various orientations without requiring physical reconfiguration. This multi-functionality allows a single tool design to handle diverse measurement needs, reducing overall system complexity while maintaining high measurement precision.
Solution Approach 2:
The patent introduces dynamic virtual steering capability that allows the measurement orientation to be changed mathematically rather than physically. The triad configuration remains fixed physically, but the effective measurement orientation dynamically adapts to any desired direction through rotational transforms and virtual coil synthesis, enabling precise dip and strike measurements without complex mechanical adjustments.
3Device complexity
If conventional induction tools are used, then the tool structure remains simple, but reliable measurements of attenuation and phase difference cannot be obtained for virtual steering
Solution Approach 1:
The patent creates virtual receiver coils through mathematical transformations of measurements from physical receiver coils. By synthesizing signals that correspond to virtual coils at arbitrary orientations, the system obtains reliable attenuation and phase difference measurements without adding physical receivers. This copying approach maintains simple tool structure while enabling reliable steerable measurements through mathematical synthesis of the virtual coil responses.
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 allows for accurate determination of formation dip angle and resistivity, providing more reliable and compensated measurements that can be used for improved hydrocarbon reservoir evaluation and geological structure identification.
Implementation Method 1
The measurements are made by inducing electrical eddy currents to flow in the formations in response to an AC transmitter signal, and measuring the appropriate characteristics of a receiver signal generated by the formation eddy currents.
Implementation Method 2
measuring the appropriate characteristics of a receiver signal generated by the formation eddy currents
Data Source
AI summary
An apparatus and method that provide steerable measurements of attenuation and phase difference are disclosed. In a preferred embodiment, a logging tool is provided with two triads of orthogonal receivers and a triad of orthogonal transmitters. A controller in the logging tool fires selected transmitters singly and in pairs, and determines measurements of ratios between signals received by the receiver triads. The measurement of sixteen ratios is sufficient to allow determination of attenuation and phase difference that would be measured by virtually steered receivers according to equations provided herein.