Avizo Software for Geology

Pore space within shale rocks is very thin and measured in the micron or nanometer scale. To capture a representative region for measurement, plasma focused ion beam milling (PFIB-SEM) can be used to capture 3D regions considered large compared to conventional electron microscopy. Large, high-resolution volumes help disentangle the organic matrix and porosity from the shale.

Avizo Software can reconstruct FIB-SEM stacks of images into a volume. The image processing tools align data and remove artifacts, such as curtaining. The visualization engine provides stunning visuals of the data in 3D, color mapping volumes of interest.

Avizo Software also helps with data segmentation and analysis. To isolate the organic matrix, a combination of thresholding, top-hat, and marker-based watershed are employed when contrast is excellent. Deep learning methods are used for challenging samples with charging artifacts or heterogeneous features.

Ultimately, a volume fraction can be calculated to inform a larger study of the potential for extraction from the shale formation. In the shale example pictured here, the organic matrix was 2.80% of the sample.

Rock imaging provides a digital twin for understanding pore space geometry and organics in oil- and gas-bearing rock and shale. The heterogeneity of real samples benefits from deriving representative elementary volumes from real microscopy data.

Using multiple imaging technologies combines the strengths of multiple systems. In this example, high-resolution FIB-SEM imaging of a mudstone shale was registered in Avizo Software with a corresponding region in micro-CT of the same sample. When combined with other techniques like optical thin sections, this method permits high-resolution pore and organic phase measurements scaled to a large field of view.

In this study, an Avizo Software segmentation of FIB-SEM data uncovered that the organic matrix was 16.5% and porosity was 4.8% percent. The micro-CT data alone was not able to see micro- and nano-porosity, illustrating the value of multiscale, multimodal microscopy for oil extraction.

Well logs corresponding to drilled cores provide a common source of direct evidence to evaluate the potential oil or gas yield from a geological formation. Both hydraulic fracturing and traditional oil pumping benefit from careful study of these logs by petrophysicists and geologists.

Direct study of drilled cores can complement well bore sensor logs. As the samples are precious and expensive to obtain, non-destructive imaging with CT and MRI is preferred. CT is not usually sensitive to elemental contrast, but with a dual energy CT (DECT) study, Avizo Software can be used to infer the materials from a database relevant to the sample.

For example, in this rock core imaged at two peak X-ray energies, the DECT method in Avizo Software was used to infer the majority rock type and density for every millimeter along the core's length.

Carbon capture promises to help abate carbon released from burning traditional fossil fuels, but the technique faces technical and logistical challenges. It is not fully understood is how much material a previously extracted oil field can retain.

Researchers can emulate the conditions of carbon capture with rock samples in a lab environment by repeatedly flooding the sample with, for example, oil, brine used in hydraulic fracturing, and concentrated carbon dioxide.

By modelling the pore space directly from micro-CT imaging data, researchers were able to realistically measure oil-wet rock pore flooding dynamics in Avizo Software. Non-destructive imaging and re-imaging provided direct evidence of lowered ganglion connectivity and residual carbon storage—two desirable outcomes for carbon capture.

A proposed solution for reducing the carbon footprint of industrialization is to store some of that carbon as CO₂ in the same reservoirs initially used for oil production. Simply pumping materials into the ground may not be as effective as desired due to the gaseous CO₂ escaping the reservoir system over time.

By conducting flooding experiments of carbonate rocks with micro-CT, Avizo Software can be used to locate and measure disconnected ganglia that should be capable of long-term CO₂ retention.

In this study, a barrier region was identified that retains the non-wetting phase behind it. This promoted early disconnection and is thought to enhance CO₂ trapping efficiency. Studies like these are essential for realizing the capabilities or limitations of this climate change mitigation tool.

Modern devices such as batteries and semiconductors rely on rare earth elements and other minerals that are not common in the Earth's economically minable materials. Heterogenous samples that contain compound grains are then interesting as they may contain trace elements that can then be targeted for mining.

Various types of spectroscopy are commonly employed to understand the composition of unknown samples. Recently, spectroscopy has been more commonly extended to a raster pattern to produce an image based on the spectroscopic method. These layered and dense images can be studied in Avizo Software as multi-channel fields.

For example, a laser ablation laser ionization time of flight mass spectroscopy (LALI TOF-MS) investigation of a complex grain in a core plug is shown here. Individual maps of minerals are combined for co-visualization and pattern detection in a way that isolated images or spectrograms may not reveal.

As an alternative to traditional mining like blasting or digging, in situ blasting can break up material into fine particles without as greatly introducing safety concerns of ground-pressure control. Later, leaching solutions are applied to the top of a blasted ore deposit and collected through a network of pipes through the force of gravity. Collectively, this approach reduces costs for extracting certain targets such as low-grade ore deposits.

Because blasting creates a range of particle sizes and distributions, it is useful to study how leaching fluid can filter around and through a variety of particle compositions. Micro-CT imaging and Avizo Software can be used to extract a pore network model that is used to determine the tortuosity and relative permeability of the sample along the direction of fluid flow.

In this example, six samples with different particle size distributions had a pore network model extracted from segmentation data produced in Avizo Software. A high concentration of fine particles reduced permeability and network connectivity.

Avizo Software provides tools for processing and analyzing complex 2D and 3D imaging datasets that help geologists and paraphysicists extract quantitative information about rock structure, mineral composition, and pore systems for geological interpretation. Key functions include:

• 3D visualization of rock microstructures, pores, fractures, and mineral phases
• Quantitative measurement of porosity, grain size, mineral fractions, and connectivity
• Segmentation of minerals and pore space using image processing and machine learning tools
• Pore network and fracture analysis for structural and fluid-flow studies
• Multiscale analysis from thin sections to core-scale CT data
• Support for digital rock physics and transport property modeling
• Characterization of sedimentary textures, deformation features, and diagenetic structures
• Reproducible workflows for consistent and comparable geological analysis