Micro-CT Pore Structure Reconstruction via Soft Segmentation
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Solution Overview
Problem
Conventional micro-CT scanners have limited resolution, leading to inaccurate digital reconstruction of pore structures in unconventional reservoirs, as they cannot distinguish between partial pores and solids, resulting in errors in porosity determination.
Innovation Solution
A soft segmentation method is introduced, utilizing FIB-SEM high-resolution data to establish a relationship between grey levels in micro-CT images and actual core porosity, allowing for fractional porosity assignment to each pixel, enabling more accurate reconstruction of pore structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional micro-CT scanning with hard segmentation is used, then the scanning process is simple and fast, but the reconstruction accuracy of pore structure is poor due to inability to distinguish partial pores and solids
Solution Approach 1:
The patent divides the core sample analysis into two segments: low-resolution micro-CT scanning for overall structure and high-resolution FIB-SEM scanning for detailed pore characterization. By segmenting the analysis task and applying different techniques to different scales, the system achieves accurate pore structure reconstruction without requiring the entire system to operate at maximum complexity
Solution Approach 2:
The patent introduces FIB-SEM high-resolution scanning data as an intermediary to bridge the gap between micro-CT grey levels and actual pore structures. This intermediary provides the detailed pore information needed to calibrate and interpret the lower-resolution micro-CT data, enabling accurate reconstruction without directly observing all pore details at micro-CT resolution
2Measurement precision
If micro-CT resolution is increased to distinguish partial pores, then pore structure accuracy improves, but scanning time and data processing complexity increase significantly
Solution Approach 1:
The patent applies high-resolution FIB-SEM scanning only to selected regions of interest within the core sample, rather than scanning the entire sample at high resolution. This partial action approach provides sufficient pore structure detail for calibration while avoiding the excessive time and computational resources required for complete high-resolution scanning
Solution Approach 2:
The patent merges low-resolution micro-CT data (fast scanning) with high-resolution FIB-SEM data (accurate pore characterization) to create a hybrid reconstruction approach. This combination allows the system to achieve high porosity determination accuracy by applying detailed pore information from FIB-SEM to interpret the broader micro-CT dataset, rather than relying solely on one technique
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 improves the accuracy of digital pore structure reconstruction by allowing for fractional porosity representation, enhancing the matching degree between digital models and actual core structures, thereby improving the analysis of unconventional reservoirs.
Implementation Method 1
processing the micro-CT core sample after punching the locating holes thereon with micro-CT scanning, wherein a scanning image accuracy is CTN μm, and a scanning result is a three-dimensional pixel matrix CT_DATA
Implementation Method 2
a three-dimensional pixel block in the conventional micro-CT scanning will face three conditions
Implementation Method 3
FIB-SEM high-resolution data to establish a relationship between grey levels in micro-CT images and actual core porosity
Data Source
AI summary
A reconstruction method for a pore structure of a core with micro-CT (Computed Tomography) is provided. With utilizing a FIB-SEM (Focused Ion Beam-Scanning Electron Microscope) experiment, an actual porosity corresponding to a grey level in micro-CT results is obtained, so as to establish a relationship between the grey level of a micro-CT image and the porosity. Thereafter, according to the above relationship, a certain porosity is assigned to each pixel in the micro-CT image, so as to establish a soft segmentation method of the pore structure. The reconstruction method provided by the present invention discloses a soft segmentation method for digital reconstruction of the pore structure of the core combined with FIB-SEM data and micro-CT data, and establishes a fractional digital pore structure model of the core, which further improves a matching degree between the digital pore structure model of the core and an actual core.