Multi-thread parallel algorithm for reconstructing 3D large-scale porous structures

Ju, Yang; Huang, Yao-Hui; Zheng, Jiangtao; Xu, Qian; Xie, Heping; Zhao, Xuesheng

doi:10.1016/j.cageo.2017.01.003

Cited by 53 publications

(19 citation statements)

References 53 publications

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“…It is noteworthy that Figure b was acquired by enhancing the boundary of the gravels through image processing methods to distinguish coarse gravels from the matrix. We first converted the original CT image to the binary image by using a self‐developed image processing program (Ju et al, ; Ju, Huang, et al, ). The software, ImageJ (https://imagej.nih.gov/ij/) (Hildebrand & Rüesgsegger, ), was then employed to distinguish the gravel boundaries from the matrix by using the plugin program of the software.…”

Section: Methodsmentioning

confidence: 99%

CT Identification and Fractal Characterization of 3‐D Propagation and Distribution of Hydrofracturing Cracks in Low‐Permeability Heterogeneous Rocks

Liu

Gao

et al. 2018

JGR Solid Earth

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Understanding and characterization of the three‐dimensional (3‐D) propagation and distribution of hydrofracturing cracks in heterogeneous rock are key for enhancing the stimulation of low‐permeability petroleum reservoirs. In this study, we investigated the propagation and distribution characteristics of hydrofracturing cracks, by conducting true triaxial hydrofracturing tests and computed tomography on artificial heterogeneous rock specimens. Silica sand, Portland cement, and aedelforsite were mixed to create artificial heterogeneous rock specimens using the data of mineral compositions, coarse gravel distribution, and mechanical properties that were measured from the natural heterogeneous glutenite cores. To probe the effects of material heterogeneity on hydrofracturing cracks, the artificial homogenous specimens were created using the identical matrix compositions of the heterogeneous rock specimens and then fractured for comparison. The effects of horizontal geostress ratio on the 3‐D growth and distribution of cracks during hydrofracturing were examined. A fractal‐based method was proposed to characterize the complexity of fractures and the efficiency of hydrofracturing stimulation of heterogeneous media. The material heterogeneity and horizontal geostress ratio were found to significantly influence the 3‐D morphology, growth, and distribution of hydrofracturing cracks. A horizontal geostress ratio of 1.7 appears to be the upper limit for the occurrence of multiple cracks, and higher ratios cause a single crack perpendicular to the minimum horizontal geostress component. The fracturing efficiency is associated with not only the fractured volume but also the complexity of the crack network.

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Section: Methodsmentioning

confidence: 99%

CT Identification and Fractal Characterization of 3‐D Propagation and Distribution of Hydrofracturing Cracks in Low‐Permeability Heterogeneous Rocks

Liu

Gao

et al. 2018

JGR Solid Earth

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“…In practice, less strict constraints are applied to the inverse solution – we want to reproduce general morphological and physical properties rather than reconstruct the original (Yeong & Torquato, 1998; Gerke & Karsanina, 2015; Li and Teng et al, 2019). Although significant progress was made recently in the area of speeding up stochastic reconstructions (Havelka, Kučerová, & Sýkora, 2016; Ju et al, 2017; Karsanina & Gerke, 2018), a number of problems remain, most notably reconstructions of non‐stationary structures (Tahmasebi & Sahimi, 2015) and identification of the set of correlation functions with the necessary information content (Gommes et al, 2012a; Gommes et al, 2012b). Although the exact correlation functions set to fully describe any given soil pore structure are not known (Karsanina, Gerke, Skvortsova, & Mallants, 2015), Jiao et al (2009) provided some significant evidence that the set of CFs used in this work should be enough to provide the necessary information content.…”

Section: Discussion and Outlookmentioning

confidence: 99%

Compressing soil structural information into parameterized correlation functions

Karsanina

Lavrukhin

Fomin

et al. 2020

European J Soil Science

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Soil structure is highly interconnected to all of its properties and functions. The structure for most soils is very complex and hierarchical in nature. Considering the fact that a truly multiscale digital 3D soil structure model for a single genetic horizon, even with the resolution not finer than 1 μm, will contain an enormous amount (approx. up to 1015 voxels or even more) of data, it is an appealing idea to compress this structural information. Effective management and pore‐scale simulations based on such datasets do not seem feasible at the moment. Another approach would be to reduce the complexity to a limited but meaningful set of characteristics/parameters, for example using universal correlation functions (CFs). In this study, we successfully compressed the soil structural information in the form of 3D binary images into a set of correlation functions, each of which is described using only six parameters. We used four different correlation functions (two‐point probability, lineal, cluster and surface‐surface functions) computed in three orthogonal directions for the pores. The methodology was applied to 16 different soil 3D images obtained using X‐ray microtomography (XCT) and segmented into pores and solids. All computed CFs were fitted using a superposition of three basis functions. In other words, we reduced 900–13003 voxel images into sets of 72 parameters. Fitting of computed correlation functions and reducing them to a number of parameters is a powerful way of compressing soil structural information. However, the analysis based on parameters alone is different from the one where correlation functions are used. This problem can be negated by uncompressing the correlation functions back from these parameters before any application. This way, correlation functions are not only a way to compress the soil structural information with minimal loss, but also may be used to solve a number of additional problems, including the comparison and differentiation of soil samples, location of elementary volumes, effective physical property prediction using machine learning, and fusion of hierarchical soil structures. Highlights The 900–13003 voxels soil XCT scans were compressed into sets of 72 parameters The use of fitted parameters alone may result in the inconsistent analysis of the soil structures Each soil structure was uniquely described by a set of directional correlation functions Correlation functions were found to be sensitive to the structural difference of all the studied soils

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“…A random sphere packing method (Ju, Huang, et al, 2017;Zheng et al, 2017) was used to generate the intergranular pores in the first step. Initially, the model was completely composed of black voxels.…”

Section: Reproduction Of the Porous Structure Model Of The Shalementioning

confidence: 99%

Pore‐Scale Modeling of Spontaneous Imbibition Behavior in a Complex Shale Porous Structure by Pseudopotential Lattice Boltzmann Method

Zheng

Wang

2018

JGR Solid Earth

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Spontaneous imbibition of fracturing fluid into shale matrix is one of the primary reasons for the low flowback rate in shale gas wells after the hydraulic fracturing. This leads to concerns of impacts on both environment and shale gas production. A direct pore‐scale simulation is crucial to gain a deep understanding of spontaneous imbibition behavior and its impacts. The porous structures in the shale matrix are characterized by not only a geometrical complexity but also a mixed wettability, which bring great challenges to simulation methods. An improved pseudo‐potential lattice Boltzmann method is proposed to simulate the spontaneous imbibition behavior in a reproduced three‐dimensional porous structure of shale. The results show that the nanoscale hydrophilic pores provide the driving force and a storage place for the residual treatment fluid. The pore size and wettability heterogeneity lead to the nonuniform menisci propagation and fracturing fluid distribution in the model. Specifically, the fracturing fluid imbibed quicker in the larger pores at the early stage and gradually migrated into the smaller pores during the process. With a limited volume of the fracturing fluid, a portion of the larger pores was finally reopened. The analysis of saturation and apparent gas permeability data during the spontaneous imbibition process showed a great recovery of the model permeability along with the reopened pores. These results provide direct evidence of the residual fracturing fluid migration pattern in the shale reservoir and its influence on shale gas production.

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Multi-thread parallel algorithm for reconstructing 3D large-scale porous structures

Cited by 53 publications

References 53 publications

CT Identification and Fractal Characterization of 3‐D Propagation and Distribution of Hydrofracturing Cracks in Low‐Permeability Heterogeneous Rocks

CT Identification and Fractal Characterization of 3‐D Propagation and Distribution of Hydrofracturing Cracks in Low‐Permeability Heterogeneous Rocks

Compressing soil structural information into parameterized correlation functions

Pore‐Scale Modeling of Spontaneous Imbibition Behavior in a Complex Shale Porous Structure by Pseudopotential Lattice Boltzmann Method

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