NMR Well Log Data Integration for Fluid Characterization
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Solution Overview
Problem
Current multi-tool log analysis techniques do not fully utilize diffusion effects on transverse relaxation time in NMR data, leading to incomplete fluid characterization in reservoir evaluation, especially in environments where conventional methods are inaccurate.
Innovation Solution
A method that integrates NMR measurements with additional well log data, expressing both in terms of subcomponents and simultaneously inverting them to yield fluid properties, including fluid volumes and viscosities, using equations that account for diffusion and relaxation times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional multi-tool log analysis techniques are used, then the analysis process is simple, but fluid characterization is incomplete and inaccurate
Solution Approach 1:
The patent combines NMR measurements with conventional well log measurements into a unified analysis framework. By merging these different measurement types and simultaneously inverting them together, the method achieves more complete fluid characterization than conventional techniques alone, resolving the contradiction between accuracy improvement and complexity increase.
Solution Approach 2:
The patent utilizes diffusion effects on transverse relaxation time as an additional parameter dimension in NMR analysis. By incorporating diffusion-weighted measurements and using diffusion coefficients as discriminating parameters, the method enhances fluid characterization accuracy, particularly for heavy oil reservoirs where conventional methods fail.
2Loss of information
If NMR measurements are used alone, then fluid characterization can be performed, but diffusion effects are not fully utilized leading to incomplete analysis
Solution Approach 1:
The patent performs preliminary expression of NMR measurements in terms of diffusion-weighted components before inversion. By pre-processing the NMR data to extract diffusion information and expressing it in a standardized form, the method ensures that diffusion effects are fully utilized in the subsequent simultaneous inversion with conventional log data.
3Measurement precision
If conventional log analysis methods are used in heavy oil reservoirs, then the process is straightforward, but estimation accuracy deteriorates
Solution Approach 1:
The patent applies diffusion-weighted NMR analysis specifically tailored for heavy oil reservoirs. By using diffusion coefficients as a key discriminating parameter and expressing NMR measurements in terms of diffusion-weighted components, the method provides locally optimized accuracy for heavy oil characterization where conventional methods are known to fail.
Data Source
AI summary
A method to determine one or more properties of a substance in a downhole region of investigation is disclosed. The method includes obtaining NMR measurements from the region of investigation, obtaining at least one additional well log measurement from the region of investigation, expressing the NMR measurements in terms of NMR subcomponents, expressing the additional well log measurement in terms of well log subcomponents, and simultaneously inverting the expressed NMR measurements and the expressed additional well log measurement for the NMR subcomponents to yield one or more properties of a substance.