Computation of elastic properties of 3D digital cores from the Longmaxi shale

Zhang, Wenhui; Fu, Li‐Yun; Zhang, Yan; Weijun, Jin

doi:10.1007/s11770-016-0542-4

Cited by 16 publications

(7 citation statements)

References 21 publications

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“…Due to the compact grain structure of shale, its permeability is low, which is approximately 10 −4 to 10 −3 mD (Chen et al., 2013; Li et al., 2013). Shale is characterized by low porosity/permeability, anisotropy (layered; Figure 10), and brittle (W. H. Zhang et al., 2016). For shale layers, horizontal permeability is significantly greater than vertical permeability (Du et al., 2019; S. Hu et al., 2020).…”

Section: Discussionmentioning

confidence: 99%

Anisotropy and Heterogeneity Induced by Shale in Aquifer lithology—Influence of Aquifer Shale on the Leaky Model With Tidal Response Analysis

Zhang

Zhu

et al. 2023

Water Resources Research

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Tidal and barometric water‐level responses in wells have been widely used to calculate the hydraulic properties of aquifer systems. The effect of anisotropy induced by shale content on such responses has not received significant attention. In this study, we examine how the presence of shale (anisotropy, extremely low porosity/permeability; approximately 10−4 to 10−3 mD), which occurs as interlayers in aquifers, affects the tidal responses of the leaky model. Our findings show that the number of wells with shale in the screened section of the study aquifer is limited. Here, we focus on the study of the limited number of wells in the North China Platform to ensure a similar geological background for each well. Calculations indicate that wells, even with a small amount of shale (≥∼5%) in the observation aquifer, may exhibit strong anisotropy and heterogeneity, deviating from the theoretical analytical solutions obtained using isotropic and homogeneous assumption models. Generally, the higher the shale content in aquifer lithology, the greater the phase shifts deviated. Thus, theoretical ideal models with isotropic and homogeneous assumptions may only obtain a rough estimation for wells with shale in aquifer lithology, suggesting that we avoid setting observation aquifers onto shale layers.

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Section: Discussionmentioning

confidence: 99%

Anisotropy and Heterogeneity Induced by Shale in Aquifer lithology—Influence of Aquifer Shale on the Leaky Model With Tidal Response Analysis

Zhang

Zhu

et al. 2023

Water Resources Research

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“…Therefore, the mechanical parameters of uniaxial compressive strength (UCS), Young's modulus (E) or Poisson's ratio (µ) in this article will need to be considered with the above caveat in mind. The mechanical characteristics of the Longmaxi shale are related to its properties of lithology, kerogen and porosity (Zhang et al, 2016). However, as the purpose of this paper is to study changes in methane adsorption capacity before and after compressive deformation, and not the comparative mechanical properties of the Longmaxi shale, we list the mechanical parameters of the samples without further discussion (Table 2).…”

Section: Mechanical and Deformation Testingmentioning

confidence: 99%

Preliminary Experimental Study of Methane Adsorption Capacity in Shale After Brittle Deformation Under Uniaxial Compression

et al. 2021

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This paper presents a preliminary experimental study on methane adsorption capacity in shales before and after artificial deformation. The experimental results are based on uniaxial compression and methane isothermal adsorption tests on different shale samples from the Silurian Longmaxi Formation, Daozhen County, South China. Two sets of similar cylindrical samples were drilled from the each same bulk sample, one set was subjected to a uniaxial compressive simulation test and then crushed as artificial deformed shale sample, the other set was directly crushed as the original undeformed shale sample. And then we conducted a comparative experimental study of the methane adsorption capacity of original undeformed and artificially deformed shales. The uniaxial compression simulation results show that the failure mode of all samples displayed brittle deformation. The methane isothermal adsorption results show that the organic matter content is the main controlling factor of shale methane adsorption capacity. However, the comparative results also show that the compression and deformation have an effect on methane adsorption capacity, with shale methane adsorption capacity decreasing by about 4.26–8.48% after uniaxial compression deformation for the all shale samples in this study.

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“…In an attempt to circumvent certain assumptions inherent in effective medium theories [16][17][18][19][20][21][22][23], numerical simulations have been extensively applied for studying the elastic properties of complex rocks. Numerical methods can be used to characterize real fractures with different shapes, sizes, partial interconnections, and intersections, as well as provide independent validation of theoretical methods and laboratory measurements as an efficient means of determining their general applicability.…”

Section: Introductionmentioning

confidence: 99%

Anisotropic Effective Elastic Properties for Multi-Dimensional Fractured Models

Jian

Cheng

2022

Applied Sciences

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The size, distribution, and orientation of fractures are generally multiscale and multi-dimensional in nature, leading to complex anisotropic characteristics. Theoretical or semi-analytical methods to determine the effective elastic properties depend on several assumptions, including the absence of the stress interaction and idealized fractures. On the basis of finite-element models, we conduct numerical oscillatory relaxation tests for determining the effective elastic properties of fractured rocks. The numerical approach for calculating equivalent stiffness tensors in two-dimensions is compared to the theoretical models for different fracture densities. Due to fracture interactions at high fracture densities, the suggested model makes a physical prediction. The effective elastic properties obtained from the application to a real fractured model, established from an outcrop, obviously disperse at different frequencies, which can be used to investigate fracture interactions and dynamic stress disturbances. The algorithm is extended to three-dimensional cases and also validated by using conventional effective medium theories. It is found that the fracture density obviously impacts the effective anisotropy properties, and the proposed method gives a reasonable prediction for high-fracture density. This work is significant because it enables the calculation of effective elastic properties of multi-dimensional fractured models and the fracture interaction mechanism.

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Computation of elastic properties of 3D digital cores from the Longmaxi shale

Cited by 16 publications

References 21 publications

Anisotropy and Heterogeneity Induced by Shale in Aquifer lithology—Influence of Aquifer Shale on the Leaky Model With Tidal Response Analysis

Anisotropy and Heterogeneity Induced by Shale in Aquifer lithology—Influence of Aquifer Shale on the Leaky Model With Tidal Response Analysis

Preliminary Experimental Study of Methane Adsorption Capacity in Shale After Brittle Deformation Under Uniaxial Compression

Anisotropic Effective Elastic Properties for Multi-Dimensional Fractured Models

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