Static elastic properties of Berea sandstone by means of segmentation-less digital rock physics

Digital rock physics (DRP) is an emerging technique that has rapidly become an indispensable tool to estimate elastic properties. The success of DRP mainly depends on three factors: acquiring a 3D rock structure image, accurately identifying 3D minerals, and using a proper numerical simulation method. Shales present a substantial challenge for DRP owing to their heterogeneous structure, composition, and properties from micron to centimeter scale. To obtain a sufficiently large field-of-view (FOV) image of a sample that reflects the detailed and representative internal structure and composition, we have developed a new DRP workflow to obtain large-FOV high-resolution digital rocks with 3D mineralogical information. Using the “divide-and-stitch” technique, a long shale sample is divided into several subunits, imaged separately by high-resolution X-ray microscopy (XRM), and then stitched to obtain a large-FOV 3D digital rock. An FOV of a rock cylinder (736 μm in diameter, 2358 μm in height, and 1 μm resolution) is used as an example. By correlating XRM and automated mineralogy, a large-FOV 3D mineral digital rock is obtained from a shale sample. Six mineral phases are identified and verified by automated mineralogy, and four laminae are detected according to the grain size, which offer a new perspective to study sedimentary processes and heterogeneities at the millimeter scale. The finite-difference method is used to compute the elastic properties of the large-FOV 3D mineral digital rock, and the results of Young’s modulus are within the limit of the Voigt/Reuss bounds. It also reveals that there is a difference in simulated elastic properties in the four laminae. The large-FOV 3D mineral digital rock offers the potential to explore the relationship between elastic properties and mineral phases, as well as the heterogeneities of elastic properties at the millimeter scale.

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3D Printing of True Pore-Scale Berea Sandstone and Digital Rock Verification

SPE Journal ◽

10.2118/205383-pa ◽

2021 ◽

pp. 1-6

Author(s):

Aobo Li ◽

Shuo Zhang ◽

Chicheng Xu ◽

Xiaoguang Zhao ◽

Xin Zhang

Keyword(s):

3D Printing ◽

Rock Physics ◽

Pore Scale ◽

Berea Sandstone ◽

Digital Rock Physics ◽

Digital Rock ◽

Natural Rock ◽

Internal Structures ◽

Geometric Scaling ◽

3D Printed

Summary In this study, we used two-photon polymerization 3D printing technology to successfully print the first true pore-scale rock proxy of Berea sandstone with a submicrometer resolution. Scanning electron microscope (SEM) and computed tomography (CT) images of the 3D-printed sample were compared with the digital file used for printing to verify the rock’s internal structures. Petrophysical properties were estimated with a digital rock physics (DRP) model based on the 3D-printed sample's initial pore network. The results show that our 3D-printing workflow was able to reproduce true-scale 3D porous media such as Berea sandstone with a submicrometer resolution. With a variety of materials and geometric scaling options, 3D printing of nearly identical rock proxies provides a method to conduct repeatable laboratory experiments without destroying natural rock samples. Rock proxy experiments can potentially validate numerical simulations and complement existing laboratory measurements.

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Digital rock physics and laboratory considerations on a high-porosity volcanic rock

10.5194/egusphere-egu2020-6706 ◽

2020 ◽

Author(s):

Laura L. Schepp ◽

Benedikt Ahrens ◽

Martin Balcewicz ◽

Mandy Duda ◽

Mathias Nehler ◽

...

Keyword(s):

Thermal Conductivity ◽

Elastic Properties ◽

Effective Properties ◽

Rock Physics ◽

Numerical Results ◽

High Porosity ◽

Effective Elastic Properties ◽

Digital Rock Physics ◽

Digital Rock ◽

Laboratory Investigations

Microtomographic imaging techniques and advanced numerical simulations are combined by digital rock physics (DRP) to obtain effective physical material properties. The numerical results are typically used to complement laboratory investigations with the aim to gain a deeper understanding of physical processes related to transport (e.g. permeability and thermal conductivity) and effective elastic properties (e.g. bulk and shear modulus). The present study focuses on DRP and laboratory techniques applied to a rock called reticulite, which is considered as an end-member material with respect to porosity, stiffness and brittleness of the skeleton. Classical laboratory investigations on effective properties, such as ultrasonic transmission measurements and uniaxial deformation experiments, are very difficult to perform on this class of high-porosity and brittle materials.Reticulite is a pyroclastic rock formed during intense Hawaiian fountaining events. The open honeycombed network has a porosity of more than 80 % and consists of bubbles that are supported by glassy threads. The natural mineral has a strong analogy to fabricated open-cell foams. By comparing experimental with numerical results and theoretical estimates we demonstrate the potential of digital material methodology with respect to the investigation of porosity, effective elastic properties, thermal conductivity and permeabilityWe show that the digital rock physics workflow, previously applied to conventional rock types, yields reasonable results for a high-porosity rock and can be adopted for fabricated foam-like materials. Numerically determined effective properties of reticulite are in good agreement with the experimentally determined results. Depending on the fields of application, numerical methods as well as theoretical estimates can become reasonable alternatives to laboratory methods for high porous foam-like materials.

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Effects of Pore Shape on Elastic Properties of Porous Rocks with Digital Rock Physics

10.3997/2214-4609.202011644 ◽

2020 ◽

Author(s):

Q. Liu ◽

D. Cao ◽

X. Yin ◽

Y. Xie

Keyword(s):

Elastic Properties ◽

Rock Physics ◽

Pore Shape ◽

Porous Rocks ◽

Digital Rock Physics ◽

Digital Rock

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Using digital rocks and simulations of pore-scale multiphysics to characterize a sandstone reservoir

Interpretation ◽

10.1190/int-2016-0068.1 ◽

2017 ◽

Vol 5 (1) ◽

pp. SB33-SB43

Author(s):

Madhumita Sengupta ◽

Mark G. Kittridge ◽

Jean-Pierre Blangy

Keyword(s):

Elastic Properties ◽

Computational Methods ◽

Laboratory Data ◽

Rock Physics ◽

Digital Rock Physics ◽

Reservoir Rocks ◽

Digital Rock ◽

Physical Measurements ◽

Reservoir Sandstones ◽

Sandstone Reservoir

The modeling and prediction of transport and elastic properties for sandstones are critical steps in the exploration and appraisal of hydrocarbon reservoirs, particularly in deepwater settings where seismic data are abundant and well costs are high. Reliable multiphysics modeling of reservoir rocks requires robust models that respect the underlying geologic character and microstructure of the geomaterial and honor the measured properties. We have developed a case study that integrates traditional laboratory measurements with computational methods to quantify and relate physical properties of reservoir sandstones. We evaluate the complementary use of digital rock simulations as a practical technology that adds physical insight into the development and calibration of rock-property relationships. We also determine the challenges faced while applying digital rock physics to interpret laboratory data, and the steps taken to overcome those limitations. Combining physical and computational methods, we achieve an improved understanding of the link between geologic properties (sorting, microporosity) with transport (single-phase permeability, electrical conductivity) and elastic properties (moduli). Combining physical measurements with numerical computations has enhanced our understanding of multiphysics relationships in a heterogeneous sandstone reservoir.

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