Borehole Image Log Anisotropy Determination Method
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Solution Overview
Problem
Current methods for determining anisotropy, dip, and azimuth in oilfield operations face challenges in accurately combining data from multiple measurements and scales, particularly in reservoir engineering, where high economic and environmental costs are associated with well testing, and existing logging techniques struggle to detect thin laminations and honor petrophysical spatial relationships.
Innovation Solution
An up-scaling method that uses image data from logging tools to determine anisotropy, dip, and azimuth by selecting data points along a borehole, interpolating planes, and calculating resistivity anisotropy coefficients, allowing for the determination of anisotropy tensors and minimizing anisotropy coefficients, which can be applied to various rock properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If visual inspection and correlation methods are used to process measurement data, then the process is simple and easy to implement, but the accuracy of determining anisotropy, dip, and azimuth is insufficient and cannot accurately combine data from multiple measurements and scales
Solution Approach 1:
The patent transforms the problem from visual inspection to automated parameter extraction by changing the processing approach from qualitative to quantitative. It uses image log data to calculate specific parameters (anisotropy coefficients, dip angles, azimuth angles) through mathematical relationships, thereby improving measurement precision while maintaining reasonable complexity through systematic computation.
Solution Approach 2:
The patent replaces the manual visual inspection and correlation method with an automated computational system. Instead of human experts visually analyzing data patterns, the system uses algorithms to automatically extract features from image log data, calculate anisotropy tensors, and determine geological parameters, thereby improving accuracy while managing complexity through automation.
2Measurement precision
If well testing is performed to predict well producibility, then accurate production predictions can be obtained, but high economic and environmental costs are incurred
Solution Approach 1:
The patent creates a virtual model of formation properties by extracting anisotropy, dip, and azimuth parameters from image log data. This virtual representation allows for production predictions to be made without physical well testing, thereby reducing costs while maintaining prediction accuracy through sophisticated data analysis and modeling.
Solution Approach 2:
The patent performs preliminary analysis of formation properties using image log data before actual production begins. By determining anisotropy tensors and geological parameters in advance, the system enables accurate producibility predictions without requiring subsequent well testing, thus avoiding the high costs associated with post-drilling testing.
3Measurement precision
If traditional logging techniques are used to measure formation properties, then the measurement process is straightforward, but thin laminations cannot be detected and petrophysical spatial relationships are not honored
Solution Approach 1:
The patent transitions from traditional one-dimensional log data to two-dimensional image log data. This dimensional enhancement allows for the detection of thin laminations and complex spatial relationships that cannot be resolved with conventional logging techniques. The image data provides additional spatial information that enables more accurate characterization of formation anisotropy and geological structure.
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 effectively combines different types of data, reduces the need for costly well testing, and provides accurate geological information by determining anisotropy, dip, and azimuth, enhancing the characterization of geological formations and optimizing production.
Implementation Method 1
One popular logging method utilizes nuclear magnetic resonance ('NMR') measurements. The NMR measurements are based on the fact that when an assembly of magnetic moments, such as those of hydrogen nuclei, are exposed to a static magnetic field, they tend to align along the direction of the magnetic field, resulting in bulk magnetization.
Data Source
AI summary
A method of determining anisotropy in a borehole is disclosed. An array of measurements along the borehole is obtained and a first depth in the borehole is selected. An arbitrary plane oriented with respect to the borehole at the first depth is designated and an anisotropy for the first depth with respect to the arbitrary plane is determined. The arbitrary plane is repositioned at the first depth and an anisotropy for different positions of the arbitrary plane at the first depth is determined. A minimum anisotropy coefficient with respect to the arbitrary plane at the first depth is identified based on anisotropy for different positions of the arbitrary plane. An anisotropy tensor for the first depth is then identified.