2D Digital Rock Imaging for Permeability Estimation
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Solution Overview
Problem
Current digital rock physics methods are inefficient for estimating rock properties like absolute permeability, relative permeability, formation factor, elasticity, and capillary pressure, especially when dealing with small-scale rock samples such as drill cuttings, as they require 3D volume analysis which is time-consuming and costly, and often not feasible due to size constraints.
Innovation Solution
A method utilizing 2D digital images of rock samples, obtained through scanning systems like FIB-SEM, x-ray tomography, or microtomography, to estimate rock properties by segmenting the images into pore space and mineral matrix, applying transforms like the Kozeny-Carman equation to calculate permeability, and using porosity and specific surface area estimates directly from 2D images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If 3D volume analysis is used to estimate rock properties, then measurement precision is improved, but productivity deteriorates due to time-consuming and costly scanning processes
Solution Approach 1:
The patent creates a digital copy (2D image representation) of the rock sample that preserves the essential pore space geometry information needed for permeability estimation. Instead of requiring a complete 3D digital model, the invention uses 2D images as a simplified copy that contains sufficient information when processed through the transform relationship, thereby reducing scanning time while maintaining adequate measurement precision.
Solution Approach 2:
The patent transforms the problem from 3D space to 2D space by developing a transform relationship that estimates permeability from 2D image data. This dimensionality reduction allows standard 2D imaging techniques to be used instead of time-consuming 3D scanning, while the mathematical transform preserves the necessary geometric information for accurate permeability estimation.
2Measurement precision
If 3D volume analysis is used to estimate rock properties, then measurement precision is improved, but device complexity increases due to specialized scanning equipment requirements
Solution Approach 1:
The invention uses 2D images as a simplified digital copy of the rock sample that can be obtained with standard imaging equipment rather than complex 3D scanning systems. The transform relationship extracts permeability information from this 2D copy, eliminating the need for specialized 3D volume scanning devices while maintaining adequate measurement precision.
Solution Approach 2:
The patent extracts only the essential information needed for permeability estimation from the rock sample image, rather than capturing complete 3D volumetric data. By taking out only the critical pore space geometry information visible in 2D and using a transform relationship to estimate permeability, the invention eliminates the need for complex 3D scanning equipment.
3Adaptability or versatility
If small rock samples like drill cuttings are analyzed, then adaptability is improved, but measurement precision deteriorates due to insufficient sample size for 3D scanning
Solution Approach 1:
The patent enables analysis of small samples by transitioning from 3D to 2D analysis. Small drill cuttings that are too small for adequate 3D scanning can be imaged in 2D, and the transform relationship extracts sufficient geometric information to estimate permeability with acceptable precision. This dimensionality change makes the method adaptable to small samples while preserving measurement capability.
Solution Approach 2:
The invention creates a 2D digital copy of small rock samples that preserves the pore space geometry information necessary for permeability estimation. This 2D copy approach allows even tiny drill cuttings to be analyzed effectively, as the essential information is captured in the 2D image without requiring the sample to be large enough for 3D scanning.
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 approach allows for rapid and cost-effective estimation of rock properties without the need for 3D imaging, providing accurate permeability bounds and enabling efficient characterization of rock samples, especially in hydrocarbon reservoir development.
Implementation Method 1
scanning systems like FIB-SEM, x-ray tomography, or microtomography
Implementation Method 2
scanning systems like FIB-SEM, x-ray tomography, or microtomography
Implementation Method 3
segmenting the images into pore space and mineral matrix
Data Source
AI summary
A method is provided for efficiently characterizing rock traversed while drilling a borehole for hydrocarbon reservoir development. A rock sample can be obtained having a provenance of collection linked to a specific region of the borehole, which is scanned to obtain a 2D digital image that is segmented to pixels characterized as pore space and as mineral matrix and defining a boundary between them. A transform relationship, for example, a form of the Kozeny-Carman equation adapted for application to a 2D segmented image environment, can be applied to calculate the estimated value for a target rock property, which can be absolute permeability, relative permeability, formation factor, elasticity, bulk modulus, shear modulus, compressional velocity, shear velocity, electrical resistivity, or capillary pressure, and the estimated value is used to characterize the rock at that region of the borehole. This affords an opportunity to quickly and efficiently develop massive data directly characterizing extended regions of rock, whether traversed by the borehole in this or a related well. Computerized systems, computer readable media, and programs for performing the methods are also provided.