Three-dimensional quantitative fracture analysis of tight gas sandstones using industrial computed tomography

Lai, Jin; Wang, Guiwen; Fan, Zhuoying; Chen, Jing; Qin, Z.; Xiao, Chengwen; Wang, Shu-Chen; Fan, Xuqiang

doi:10.1038/s41598-017-01996-7

Cited by 43 publications

(21 citation statements)

References 56 publications

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“…The microscale structure of geomaterials contains minerals, pores, and fractures of complex shapes that evolve as a result of coupled fluid, heat, mechanics, and chemical reactions. In order to understand such dynamic multiphysics problems, in the past decade, new technologies have been developed for visualization and characterization of the multiphysics processes of geomaterials at the pore scale, microscale, and even smaller scales [16,20,31,33,38].…”

Section: Introductionmentioning

confidence: 99%

Microscale mechanical modeling of deformable geomaterials with dynamic contacts based on the numerical manifold method

Rutqvist

2020

Comput Geosci

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Micromechanical modeling of geomaterials is challenging because of the complex geometry of discontinuities and potentially large number of deformable material bodies that contact each other dynamically. In this study, we have developed a numerical approach for micromechanical analysis of deformable geomaterials with dynamic contacts. In our approach, we detect contacts among multiple blocks with arbitrary shapes, enforce different contact constraints for three different contact states of separated, bonded, and sliding, and iterate within each time step to ensure convergence of contact states. With these features, we are able to simulate the dynamic contact evolution at the microscale for realistic geomaterials having arbitrary shapes of grains and interfaces. We demonstrate the capability with several examples, including a rough fracture with different geometric surface asperity characteristics, settling of clay aggregates, compaction of a loosely packed sand, and failure of an intact marble sample. With our model, we are able to accurately analyze (1) large displacements and/or deformation, (2) the process of high stress accumulated at contact areas, (3) the failure of a mineral cemented rock samples under high stress, and (4) post-failure fragmentation. The analysis highlights the importance of accurately capturing (1) the sequential evolution of geomaterials responding to stress as motion, deformation, and high stress; (2) large geometric features outside the norms (such as large asperities and sharp corners) as such features can dominate the micromechanical behavior; and (3) different mechanical behavior between loosely packed and tightly packed granular systems.

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Section: Introductionmentioning

confidence: 99%

Microscale mechanical modeling of deformable geomaterials with dynamic contacts based on the numerical manifold method

Rutqvist

2020

Comput Geosci

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“…In this interpretation, the void volume reflects bulk structural decomposition, while the void surface area quantifies the continuity of the pellet, as reported in previous analyses of fatigue driven mechanical failure. [ 40–42 ] For both cells void volume and void surface area increase monotonically with cycling, reflecting the irreversible mechanical decomposition of the pellet. The enhanced mechanical stability afforded by the solvate is evident, as the interlayer cell demonstrates substantially lower void volume and surface area even after nearly twice the cycling time.…”

Section: Resultsmentioning

confidence: 99%

Direct Observation of Interfacial Mechanical Failure in Thiophosphate Solid Electrolytes with Operando X‐Ray Tomography

Madsen

Bassett

et al. 2020

Adv Materials Inter

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at larger scales (electric vehicle or gridscale energy storage) has been hampered by insufficient energy densities, prohibitive material costs, and safety concerns. [2] While significant progress has been made in the development of high energy density battery materials, the implementation of these materials in practical systems without sacrificing cell longevity or safety remains a pressing scientific challenge. One of the best studied approaches to improve the energy density of LIBs is to replace existing graphitic anodes (372 mA h g −1 capacity) with metallic lithium (3860 mA h g −1 capacity). [3] Unfortunately, uneven lithium plating and stripping in conventional organic liquid electrolytes promotes the growth of lithium dendrites, accelerating the formation of internal short-circuits. Additionally, the low thermal stability of electrolyte solvents (often mixtures of cyclic and linear carbonates) incurs exothermic decomposition of the electrolyte in the event of cell failure, often resulting in catastrophic thermal runaway. [4-6] While many approaches have been explored to address these issues, one of the most promising options is the elimination of the liquid electrolyte in favor of a solid electrolyte. [7] Transitioning from conventional liquid electrolytes to Li +conducting solid electrolytes (SEs) presents two primary advantages. The high mechanical rigidity of inorganic SEs may act to suppress the formation of dendrites at lithium anodes, reducing the possibility of internal short circuits. [8] Additionally, the negligible flammability of most SEs dramatically lowers the risk of uncontrolled thermal runaway in the event of cell failure. [9,10] These potential benefits motivate the search for materials with sufficiently high ionic conductivities to serve as replacements for their liquid counterparts. Among the known SE formulations, the thiophosphate class of superionic conductors exhibit exceptionally fast lithium transport at room temperature. [11] Specifically, Li 10 GeP 2 S 12 (LGPS) demonstrates an ionic conductivity of ≈10 mS cm −1 , comparable to conductivities achievable in conventional liquid electrolytes. [12] Despite the favorable ionic conductivity of LGPS, its poor chemical and electrochemical stabilities remain key challenges for practical application. The narrow window of electrochemical stability of LGPS and many other thiophosphate

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“…Electrical image logging tools that can evaluate the role of fractures in reservoir performance include the formation micro-imager (FMI) (Serra 1989;Schlumberger 2003) and the electrical micro-imager (EMI) (Halliburton 1996). As a result, fracture diagnosis remains merely qualitative, unless these tools are used to determine reservoir porosity and permeability (Aghli et al 2016;Hornby et al 1992;Lai et al 2017a;Martinez et al 2002). Most previous studies have focused on image logs for the identification of features in reservoir rocks (Khoshbakht et al 2009;Miller et al 2003;Zazoun 2013).…”

Section: Edited By Jie Hao and Xiu-qiu Pengmentioning

confidence: 99%

Reservoir heterogeneity and fracture parameter determination using electrical image logs and petrophysical data (a case study, carbonate Asmari Formation, Zagros Basin, SW Iran)

2019

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Assessment of reservoir and fracture parameters is necessary to optimize oil production, especially in heterogeneous reservoirs. Core and image logs are regarded as two of the best methods for this aim. However, due to core limitations, using image log is considered as the best method. This study aims to use electrical image logs in the carbonate Asmari Formation reservoir in Zagros Basin, SW Iran, in order to evaluate natural fractures, porosity system, permeability profile and heterogeneity index and accordingly compare the results with core and well data. The results indicated that the electrical image logs are reliable for evaluating fracture and reservoir parameters, when there is no core available for a well. Based on the results from formation micro-imager (FMI) and electrical micro-imager (EMI), Asmari was recognized as a completely fractured reservoir in studied field and the reservoir parameters are mainly controlled by fractures. Furthermore, core and image logs indicated that the secondary porosity varies from 0% to 10%. The permeability indicator indicates that zones 3 and 5 have higher permeability index. Image log permeability index shows a very reasonable permeability profile after scaling against core and modular dynamics tester mobility, mud loss and production index which vary between 1 and 1000 md. In addition, no relationship was observed between core porosity and permeability, while the permeability relied heavily on fracture aperture. Therefore, fracture aperture was considered as the most important parameter for the determination of permeability. Sudden changes were also observed at zones 1-1 and 5 in the permeability trend, due to the high fracture aperture. It can be concluded that the electrical image logs (FMI and EMI) are usable for evaluating both reservoir and fracture parameters in wells with no core data in the Zagros Basin, SW Iran.

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Three-dimensional quantitative fracture analysis of tight gas sandstones using industrial computed tomography

Cited by 43 publications

References 56 publications

Microscale mechanical modeling of deformable geomaterials with dynamic contacts based on the numerical manifold method

Microscale mechanical modeling of deformable geomaterials with dynamic contacts based on the numerical manifold method

Direct Observation of Interfacial Mechanical Failure in Thiophosphate Solid Electrolytes with Operando X‐Ray Tomography

Reservoir heterogeneity and fracture parameter determination using electrical image logs and petrophysical data (a case study, carbonate Asmari Formation, Zagros Basin, SW Iran)

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