Multi-frequency Dielectric Borehole Imager for Anisotropy
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Solution Overview
Problem
Current borehole imaging tools fail to accurately characterize the anisotropy of subterranean formations due to low resolution resistivity measurements, which are isotropic and do not account for intrinsic and structural anisotropy, limiting the characterization of petrophysical parameters and conditions downhole.
Innovation Solution
The development of multi-frequency dielectric borehole imaging tools and methods that use sensor arrays with transmitters and receivers to measure dielectric constants and resistivity at various frequencies, providing detailed images of petrophysical parameters like water saturation, porosity, and cementation exponent, and enabling anisotropic inversion to capture the orientation-dependent properties of formations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If resistivity logging tools are used to measure formation resistivity, then electrical resistivity data can be obtained, but the measurement resolution is insufficient to detect intrinsic anisotropy at the scale of inches or centimeters
Solution Approach 1:
The tool divides the measurement function into multiple discrete sensor elements arranged in arrays around the borehole. Multiple transmitter and receiver pairs are segmented and positioned at different azimuthal locations to capture directional resistivity variations, enabling intrinsic anisotropy detection through spatial segmentation of measurement capabilities
Solution Approach 2:
The invention transitions from conventional single-point or limited-point resistivity measurements to multi-dimensional imaging by arranging sensors in three-dimensional arrays around the borehole. This adds azimuthal and radial dimensions to measurements, creating a spatial map of resistivity that reveals intrinsic anisotropy patterns not visible in traditional one-dimensional log data
2Adaptability or versatility
If conventional borehole imagers are used, then isotropic resistivity images can be produced, but they cannot characterize the anisotropic properties of formations
Solution Approach 1:
The logging tool is designed with multi-functional sensor arrays that can measure resistivity in multiple directions and orientations simultaneously. The same physical sensor array performs both conventional isotropic resistivity imaging and advanced anisotropic characterization, making the tool universally applicable to various formation types and measurement objectives without requiring separate specialized tools
Solution Approach 2:
The system measures resistivity parameters at multiple orientations and azimuthal angles, then uses inversion algorithms to derive anisotropic formation parameters such as horizontal and vertical resistivity components. By changing the measurement parameters from single-value isotropic resistivity to multi-component anisotropic resistivity tensors, the system accurately characterizes formation anisotropy
3Loss of information
If additional sensor arrays and multi-frequency measurements are implemented, then detailed petrophysical parameter images can be produced, but the device complexity increases
Solution Approach 1:
The invention combines multiple measurement functions into a single integrated logging tool. Resistivity sensors, dielectric sensors, and other measurement systems are merged into one tool assembly that can simultaneously or sequentially acquire multiple types of data. This consolidation reduces the need for multiple separate tools and minimizes overall system complexity while maximizing information retrieval
Solution Approach 2:
The system replaces complex mechanical measurement approaches with electromagnetic field-based measurements. Instead of physical contact or mechanical probing methods, the tool uses electromagnetic waves to probe formation properties, enabling non-contact, multi-parameter measurements through field interactions rather than mechanical systems
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
These tools produce high-resolution images that better characterize the anisotropy of formations, improving petrophysical and geological interpretation, optimizing well placement, and enhancing hydrocarbon production by accurately capturing azimuthal anomalies and structural features.
Implementation Method 1
sensor arrays with transmitters and receivers to measure dielectric constants and resistivity at various frequencies
Implementation Method 2
multi-frequency dielectric borehole imaging tools and methods that use sensor arrays with transmitters and receivers to measure dielectric constants
Data Source
AI summary
Systems, methods and devices for dielectric borehole imagery are disclosed. Systems may include one or more transmitters that induce, at azimuthally-spaced positions on a borehole wall, a plurality of fields having components in non-coplanar directions within a formation; one or more directionally sensitive receivers that sense the components caused by each of the one or more transmitters; and a controller that processes signals received from the one or more directionally sensitive inductive sensors to provide a set of measurements representative of dielectric parameters at two or more azimuthal positions within the borehole.