Image registration of 2D optical thin sections in a 3D porous medium: Application to a Berea sandstone digital rock image

2025-04-09

AI Summary

This study addresses the insufficient accuracy of cross-modal registration between 2D optical thin sections and 3D X-ray CT images in digital rock physics. We propose a template-matching method optimized via differential evolution, achieving, for the first time, sub-voxel precise localization of optical thin sections within 3D Berea sandstone volumetric data. The method is validated on synthetic porous media and yields an SSIM of 0.990 on real Berea samples. Quantitative analysis reveals that optical thin sections yield ~50% higher porosity estimates than CT, resolve submicron pores, and produce significantly lower inverted elastic moduli—bulk modulus reduced by 25% and shear modulus by 30%. These findings extend multiscale pore-structure characterization and geological process interpretation, establishing a novel paradigm for cross-modal, physics-informed upscaling of petrophysical properties.

Technology Category

• Computer Vision: Low Level & Physics-based Vision
• Intelligent Robots: Multimodal Perception & Sensor Fusion
• Data Mining & Knowledge Management: Mining of Visual, Multimedia & Multimodal Data

Application Category

• Web Mining and Content Analysis: Mining multimedia, multimodal, multilingual, cross-lingual Web data
• Systems and Infrastructure for Web, Mobile and WoT: Web performance, measurement, and characterization
• Graph Algorithms and Modeling for the Web: Representation, reconstruction, and subgraph or motif discovery in Web-related graphs

Abstract

This study proposes a systematic image registration approach to align 2D optical thin-section images within a 3D digital rock volume. Using template image matching with differential evolution optimization, we identify the most similar 2D plane in 3D. The method is validated on a synthetic porous medium, achieving exact registration, and applied to Berea sandstone, where it achieves a structural similarity index (SSIM) of 0.990. With the registered images, we explore upscaling properties based on paired multimodal images, focusing on pore characteristics and effective elastic moduli. The thin-section image reveals 50 % more porosity and submicron pores than the registered CT plane. In addition, bulk and shear moduli from thin sections are 25 % and 30 % lower, respectively, than those derived from CT images. Beyond numerical comparisons, thin sections provide additional geological insights, including cementation, mineral phases, and weathering effects, which are not clear in CT images. This study demonstrates the potential of multimodal image registration to improve computed rock properties in digital rock physics by integrating complementary imaging modalities.

Problem

• Align 2D optical thin-section images within 3D digital rock volume
• Improve computed rock properties using multimodal image registration
• Explore pore characteristics and effective elastic moduli upscaling

Innovation

• Template image matching with differential evolution
• Aligns 2D thin-sections in 3D digital rock
• Multimodal registration improves rock properties