Rock Flow Simulation Calibration Using Pore-Scale 3D Velocity Maps
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Solution Overview
Problem
Existing direct flow simulations in rock samples overpredict large axial velocities and underpredict low axial velocities, and current MRI methods provide spatial resolutions that are too coarse for capturing pore-scale information, leading to inaccurate simulations and limited sample processing due to time and expense.
Innovation Solution
A method involving 3D spatially-resolved fluid velocity mapping using pulsed field gradient nuclear magnetic resonance imaging (PFG NMR) and compressed sensing (CS) to generate high-resolution fluid flow maps, which are then compared with direct flow simulations to calibrate the simulations accurately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional MRI methods are used to characterize fluid flow, then the measurement process is non-invasive and provides spatially-resolved data, but the spatial resolution is too coarse (hundreds of microns) to capture pore-scale information
Solution Approach 1:
The patent applies compressed sensing theory to change the acquisition parameters of MRI scans. By using undersampled k-space data with specific sampling patterns and reconstruction algorithms, the system achieves high spatial resolution (sub-10 micron) flow field measurements at pore scale while maintaining acceptable acquisition times. This parameter change in the imaging approach resolves the contradiction between resolution and time.
2Productivity
If direct flow simulations are performed to predict fluid flow and transport, then computational results can be obtained quickly for decision-making, but the simulations overpredict large axial velocities and underpredict low axial velocities without calibration
Solution Approach 1:
The patent establishes a feedback loop where high-resolution flow-MRI measurements of actual fluid flow are used to calibrate and validate direct flow simulations. The simulation results are compared with experimental MRI data, and the simulation parameters are adjusted accordingly. This feedback mechanism enables the simulations to maintain their speed advantage while achieving accurate velocity predictions across the full range of flow conditions.
3Measurement precision
If laboratory tests for fluid flow factors are conducted to obtain accurate data, then measurement precision is improved, but the process requires substantial time and is expensive, limiting the number of samples that can be processed
Solution Approach 1:
The patent creates a virtual copy of the physical rock sample through high-resolution 3D imaging (micro-CT) that captures the complete pore structure. This digital twin allows multiple flow simulations to be performed on the same sample without conducting additional physical tests. The imaging and simulation approach replaces multiple expensive laboratory flow tests with a single imaging procedure followed by computational analysis, dramatically increasing the number of samples that can be processed while maintaining measurement precision.
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
Enhances the accuracy of direct flow simulations by providing quantitative, non-invasive measurements of fluid flow at the pore scale, enabling better decision-making for hydrocarbon recovery, carbon capture, and geothermal heat extraction.
Implementation Method 1
generating a 3D spatially-resolved fluid velocity map for one or more fluid phases at a pore-scale resolution using pulsed field gradient nuclear magnetic resonance imaging
Data Source
AI summary
A method for calibrating a direct flow simulation of a rock sample involves providing a 3D image of a rock sample and generating a segmented structural image of the rock sample from the 3D image by selecting voxels to represent either a pore space or a solid material. Fluid flow is simulated on the segmented structural image with a direct flow simulation. A 3D spatially-resolved fluid velocity map is generated for one or more fluid phases at a pore-scale resolution using pulsed field gradient nuclear magnetic resonance imaging. The simulated fluid flow and the 3D spatially-resolved fluid velocity map are compared to calibrate the direct flow simulation across the rock sample.