2D T1/T2APP-T2APP NMR Processing for Reservoir Characterization
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Solution Overview
Problem
Current NMR imaging techniques for downhole characterization of hydrocarbon reservoirs suffer from inadequate spectral resolution and increased uncertainty due to limited data sets, leading to inaccurate porosity and movable fluid percentage measurements.
Innovation Solution
A method and apparatus for two-dimensional relaxation analysis using nuclear magnetic resonance (NMR) data, which involves varying magnetic field gradients and inter-echo times, calculating shifts in relaxation times, constructing a mathematical model, and inverting it to estimate petrophysical properties, thereby enhancing spectral resolution and reducing uncertainty.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If data are organized into groups obtained with the same magnetic field gradient and inter-echo time, then processing is simplified, but spectral resolution is inadequate and uncertainty increases
Solution Approach 1:
The patent combines multiple data groups obtained with different magnetic field gradients and inter-echo times into a unified two-dimensional inversion process. This merging of previously separate data sets allows simultaneous processing of all data, improving spectral resolution while maintaining manageable complexity through a systematic mathematical framework.
Solution Approach 2:
The patent transitions from traditional one-dimensional inversion to two-dimensional inversion by incorporating both magnetic field gradient and inter-echo time as independent dimensions. This dimensional expansion enables better spectral resolution by utilizing the additional degree of freedom in the data organization and processing.
2Ease of operation
If data groups are processed separately with two-dimensional inversion, then processing is simpler, but the amount of data per group is reduced leading to inadequate spectral resolution
Solution Approach 1:
The patent merges all data groups into a single comprehensive inversion process, utilizing the complete data set simultaneously. This approach maximizes the amount of information available for inversion, improving spectral resolution while the systematic mathematical model maintains operational simplicity.
3Quantity of substance
If vast quantities of NMR data are obtained with varying gradients and inter-echo times, then more information is available, but data organization and processing become more complex
Solution Approach 1:
The patent develops a universal two-dimensional inversion model that can process data from multiple sources (different gradients and inter-echo times) through a single unified mathematical framework. This universal approach handles vast quantities of diverse data without proportionally increasing processing complexity.
Solution Approach 2:
The patent systematically varies and utilizes multiple parameters (magnetic field gradient, inter-echo time) as independent dimensions in the inversion process. By treating these parameters as structured variables rather than uncontrolled variables, the method manages complex data sets through a organized mathematical approach.
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
The approach provides improved stability, reduced complexity, and increased spectral resolution, enabling more accurate characterization of hydrocarbon reservoirs by utilizing a generalized mathematical model that accounts for variations in magnetic field gradients and inter-echo times, resulting in better determination of petrophysical attributes like porosity and fluid percentages.
Implementation Method 1
acquiring data using nuclear magnetic resonance (NMR) measurements, the measurements performed by varying at least one of a magnetic field gradient (G) and an inter-echo time (TE)
Data Source
AI summary
A method for estimating a property of a material, the method including: acquiring data using nuclear magnetic resonance (NMR) measurements, the measurements performed by varying at least one of a magnetic field gradient (G) and an inter-echo time (TE); organizing the data according to at least one of magnetic field gradients (G) and inter-echo times (TE) used in the NMR measurements; calculating a shift of apparent transverse relaxation time (T2,app) and (longitudinal relaxation time T1)/(apparent transverse relaxation time T2,app) due to a variation of the product of G and TE; constructing a mathematical model of the NMR measurements from the shifts; and inverting the mathematical model to estimate the property.