Quantifying and Controller Determination of Shale Matrix Compressibility: Implications for Pore Structure and Gas Flow Behavior Analyses

Zhang, Jinming; Hou, Xiaowei; Zhou, Guan-Qun; Wang, Yingjin; Chen, Luwang; Fang, Huihuang; Zheng, Chunshan

doi:10.1007/s11053-023-10245-w

Cited by 5 publications

(4 citation statements)

References 60 publications

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“…18 change of pore structure during matrix compression can be solved by using the fractal theory. 20 The high-temperature and high-pressure effects caused by magma intrusion can increase the degree of metamorphism of coal seams, change the coal quality, and alter the pore and fissure structure of coal seams. 21,22 The mechanism of geochemical and petrographic response to magmatic heat in Pennsylvanian coals of the Illinois Basin was evaluated by previous authors, who showed a decrease in volatiles, N, S, and O and an increase in fixed carbon, C, and ash content in the coals.…”

Section: Introductionmentioning

confidence: 99%

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Response of Coal Nanopores and Their Complexity to Igneous Intrusion

Liu,

Zhu,

et al. 2024

Energy Fuels

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The pore structure of coal seams and its complexity have an important effect on the storage of methane and other gases, and magmatic thermal action has a significant effect on the pore characteristics of coal seams. Understanding the impact of magmatic action on the pore structure of coal seams and their complexity is crucial for the evaluation of unconventional gas reservoirs. The pore structure of 22 samples from the Zhuxianzhuang coal mine in Huaibei was investigated using mercury injection capillary pressure (MICP), field emission scanning electron microscopy (FE-SEM), and other experiments, and the Menger sponge model and multiple fractal method were used to study the nonhomogeneity of magmatism in the pores of coal samples. The results show that (1) under the influence of magmatism, the pore volume (PV) and specific surface area (SSA) of the coal samples generally show an increasing trend. ( 2) Magmatism can have a certain influence on the pore complexity by affecting the content of H element in coal samples. The higher the H content of coal samples, the weaker the pore complexity and the stronger the overall pore connectivity. (3) Igneous intrusion can induce coal transformation, and the pore structure of coal samples can change significantly during coalification. Semigraphitized coals have greater pore complexity and poorer connectivity than anthracite/altered anthracite.

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Section: Introductionmentioning

confidence: 99%

“…Some scholars have also used fractal theory to solve the effect of moisture on the pore structure of shale . Meanwhile, the change of pore structure during matrix compression can be solved by using the fractal theory …”

Section: Introductionmentioning

confidence: 99%

Response of Coal Nanopores and Their Complexity to Igneous Intrusion

Liu,

Zhu,

et al. 2024

Energy Fuels

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“…Pore heterogeneity significantly impacts the storage conditions and flow behaviors of oil and gas . Shale oil and gas recovery would alter the reservoir pressure, inducing response in matrix volumes and pore structures, which in turn determines the matrix permeability and seepage capacity of shale reservoirs. ,− The volumetric response in the shale matrix is not directly accessible but can be estimated through matrix compressibility. − Matrix compressibility serves not only to predict dynamic permeability during extraction but is also closely associated with shale oil and gas production and CO 2 -EO/GR effectiveness . Thus, matrix compressibility and pore heterogeneity are the critical properties of shale reservoirs, yet limited attention has been paid to their quantitative characterization and geological governing factors.…”

Section: Introductionmentioning

confidence: 99%

Matrix Compressibility and Multifractal Nature of Nanoporous Shale

Feng,

Li,

Zhu

et al. 2024

Energy Fuels

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The abundant nanopores in shale make it an unconventional reservoir for oil and gas. Matrix compressibility and heterogeneity are crucial for fluid accumulation and migration, yet these two properties remain unclear in shale reservoirs. Herein, we investigated the matrix compressibility, multifractal properties, and their geological governing factors for nanoporous Yanchang shale from the Ordos Basin, China, utilizing petrophysical experiments, mercury injection capillary pressure (MICP), and lowpressure gas adsorption. Furthermore, a valid method was proposed to correct MICP data point by point. The results show that matrix compression in shale becomes apparent at onset pressures of 12.4−42.1 MPa during mercury injection, which can be assessed by compressibility coefficients varying within (3.85−18.77) × 10 −5 MPa −1 . Notably, the original MICP results overestimate the actual pore volumes due to the compression-induced error, within 16.19−102.95%, leading to potential misinterpretation of the pore size distributions, particularly for pores below 100 nm. Well-developed nanopores significantly contribute to the matrix compressibility. Among the shale compositions, organic matter (OM) is the primary controlling factor for matrix compressibility, with a positive effect. Ductile clay minerals promote matrix compressibility, whereas rigid brittle minerals resist matrix compression. Our findings also reveal the multifractal nature of pore structures in shale, with an upward-convex parabolic shape for multifractal singular spectra α−f(α) and an inverted "S" shape for the generalized dimension spectra q−D(q). Singularity spectrum width and Hurst exponent offer effective solutions to quantify the pore heterogeneity and connectivity. Pores over 100 nm tend to be relatively homogeneous and well-connected, while pores smaller than 100 nm increase heterogeneity and limit connectivity. OM, quartz, and easy-dissolve minerals positively impact pore heterogeneity but negatively affect connectivity. Nevertheless, clay minerals display no obvious correlation with pore heterogeneity and connectivity. This study provides valuable insights for predicting dynamic permeability and evaluation of unconventional reservoirs.

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“…Li et al [12] analyzed the microporous structure of a prominent coal seam in Guizhou, and its influence on gas flow characteristics, via a high-pressure mercury pressure experiment combined with fractal theory; they pointed out that the widely developed micropores of the prominent coal seam were an important cause of the coal seam outburst. Zhang et al [13] found that when porosity is tested using a high-pressure mercury experiment, the high pressure leads to matrix compression, and pore system redistribution increases the heterogeneity of pore structure. Yue et al [14] studied the pore structure of different types of coal using liquid nitrogen adsorption and mercury pressure.…”

Section: Introductionmentioning

confidence: 99%

Analysis of the Pore Structure and Fractal Characteristics of Coal and Gas Outburst Coal Seams Based on Matrix Compression Correction

Gao,

Cao,

Zhang

et al. 2023

Sustainability

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The comparative analysis of coal samples under different gas occurrence conditions systematically reveals the pore structure characteristics of coal and gas outburst coal seams. The functional relationship between R0,max and Kc was clarified using mathematical statistical methods, and the pore structure and fractal characteristics of coal and gas outburst coal seams were analyzed on the basis of modified mercury pressure data and fractal analysis. The results show that the functional relationship between R0,max and Kc is consistent with y = 1.59x−0.48, and when the mercury inlet pressure is 10~120 MPa, the coal sample is the most affected by the matrix compression effect. The average pore volume and average specific surface area of the outburst coal samples were 41.71% and 23.09%, which is greater than those of the non-outburst coal samples, respectively, and the specific surface area and pore volume provided by the outburst mining micropores were 46.24% and 81.67%, respectively. The fractal dimension, D, of the coal seam increased with the increase in metamorphism, and compared with low gas mines, the fractal dimension of coal samples in the coal and gas outburst mines was higher, the influence of the matrix compression effect was more obvious, and the heterogeneity was stronger.

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Quantifying and Controller Determination of Shale Matrix Compressibility: Implications for Pore Structure and Gas Flow Behavior Analyses

Cited by 5 publications

References 60 publications

Response of Coal Nanopores and Their Complexity to Igneous Intrusion

Response of Coal Nanopores and Their Complexity to Igneous Intrusion

Matrix Compressibility and Multifractal Nature of Nanoporous Shale

Analysis of the Pore Structure and Fractal Characteristics of Coal and Gas Outburst Coal Seams Based on Matrix Compression Correction

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