Hongwei Zhang^1,2, Zhijun Wan³, Yixin Zhao^1,2, Yuan Zhang³, Yulong Chen^2,*, Junhui Wang^3,*, Jingyi Cheng³

CMES-Computer Modeling in Engineering & Sciences, Vol.126, No.2, pp. 443-455, 2021, DOI:10.32604/cmes.2021.013179

Abstract In the enhanced geothermal system (EGS), the injected fluid will induce shear sliding of rock fractures (i.e., hydroshearing), which consequently, would increase the fracture aperture and improve the heat transfer efficiency of the geothermal reservoir. In this study, theoretical analysis, experimental research and numerical simulation were performed to uncover the permeability and heat transfer enhancement mechanism of the Hot-Dry-Rock (HDR) mass under the impact of shearing. By conducting the direct shear test with the fractured rock samples, the evolution process of fracture aperture during the shearing tests was observed, during which process, cubic law was adopted to depict the rock… More >

JiangtaoLi^1,2,*

Intelligent Automation & Soft Computing, Vol.26, No.5, pp. 1047-1061, 2020, DOI:10.32604/iasc.2020.010136

Abstract In view of poor permeability of coal seam and soft coal quality in China's coal mining area, a point hydraulic fracturing method suitable for the occurrence characteristics of coal seam is put forward based on the characteristics of coal seam hydraulic fracturing and the field practical experience of coal seam hydraulic fracturing for many years. A theoretical and mathematical model of hydraulic fracturing is established. Based on the large-scale finite element software ABAQUS, numerical simulation of two dimensional and three dimensional hydraulic fracturing is carried out, and the fracture propagation law and its parameter sensitivity of coal seam point hydraulic… More >

Junhui Wang¹, Wanzi Yan¹, Zhijun Wan^1,*, Yi Wang^2,*, Jiakun Lv¹, Aiping Zhou³

CMES-Computer Modeling in Engineering & Sciences, Vol.125, No.3, pp. 1135-1157, 2020, DOI:10.32604/cmes.2020.014313

Abstract Precise recovery of Coalbed Methane (CBM) based on transparent reconstruction of geological conditions is a branch of intelligent mining. The process of permeability reconstruction, ranging from data perception to real-time data visualization, is applicable to disaster risk warning and intelligent decision-making on gas drainage. In this study, a machine learning method integrating the Random Forest (RF) and the Genetic Algorithm (GA) was established for permeability prediction in the Xishan Coalfield based on Uniaxial Compressive Strength (UCS), effective stress, temperature and gas pressure. A total of 50 sets of data collected by a self-developed apparatus were used to generate datasets for… More >

Xiaolei Man^1,*, Ganggang Sha², Shuigen Hu¹, Hui Bao¹, Guangying Liu¹

Structural Durability & Health Monitoring, Vol.14, No.4, pp. 339-353, 2020, DOI:10.32604/sdhm.2020.013001

Abstract Geotubes are heterogeneous structures composed of filling sand and bag material, and its permeability characteristics are different from that of filling sand. The uncertainty of geotubes permeability characteristics results in the failure of seepage analysis of geotube dams, which restricts the safety assessment of the dams. As the basis of the study on the seepage mechanism of the geotubes, the influence of particle grading on permeability coefficient of filling sand and sand covered with geotextiles were explored by the permeability tests of filling sand with different particle grading under the condition of sand covered with or without geotextiles. And the… More >

Lei Guo^1,2,3, Zi Guan¹, Lixia Guo^1,2,3,*, Weiping Shen¹, Zhilong Xue¹, Pingping Chen¹, Mingru Li¹

Journal of Renewable Materials, Vol.8, No.12, pp. 1711-1727, 2020, DOI:10.32604/jrm.2020.013415

Abstract A recycled aggregate (RA) was prepared by crushing and sieving demolished discarded concrete pavements and was subsequently tested and analyzed to determine its various physical properties. On this basis, pervious concrete (PC) mix proportions were designed. Coarse RA particles with sizes of 5–10 and 10–20 mm were selected. Concrete specimens were prepared with a water–cement ratio of 0.3, an aggregate–cement ratio of 4.5, the substitute rates of RA with 0, 25%, 50%, 75% and a single-/double-gap-graded RA mix (mass ratio of particles with sizes of 5–10 mm to particles with sizes of 10–20 mm: 1:1, 1:2, 2:1, 2:3 and 3:2).… More >

Wenbei Bi¹, Zengfeng Yan^1,*, Huan Zhao¹, Lixin Sun², Xudong Wang^3,4, Zhengmo Zhang³

Journal of Renewable Materials, Vol.8, No.12, pp. 1691-1710, 2020, DOI:10.32604/jrm.2020.012808

Abstract Murals in Mogao Grottoes consist of three parts: support layer, earthen plasters and paint layer. The earthen plasters play a key role in the preservation of murals. It is a mixture of Dengban soil, sand, and plant fiber. Two different natural fibers, hemp fiber and cotton fiber, were reinforced to earthen plasters in the same percentage to evaluate the influence on hygrothermal performance. The two types of earthen plasters were studied: one containing hemp fiber in the fine plaster (HFP) and the other containing cotton fiber in the fine plaster (CFP). Specific heat capacity, dry thermal conductivity, water vapor permeability,… More >

Yang Ming^1,2,3, Ping Chen^1,2,3,*, Yuanhao Wang^1,2,3,*, Ling Li^1,2,3, Xuandong Chen^1,2,3, Pengliang Sun^1,2,3,4

Journal of Renewable Materials, Vol.8, No.12, pp. 1647-1655, 2020, DOI:10.32604/jrm.2020.011929

Abstract In order to increase use ratio of steel slag solid waste, the concrete containing steel slag powder and zeolite powder as admixtures was prepared by using the orthogonal test method. The effects of water-binder ratio, sand ratio, steel slag powder content and zeolite powder on working properties, mechanical strength and chloride ion permeability of the concrete was studied. It was found that the early strength of the concrete had a decrease with the mixing of steel slag and zeolite powders, but its later strength approached to pure concrete. Moreover, the physical filling and pozzolanic activity of the admixtures increased the… More >

Yibo Zhao^1,2

Intelligent Automation & Soft Computing, Vol.25, No.4, pp. 835-845, 2019, DOI:10.31209/2019.100000087

Abstract In this paper, a new model is proposed to predict the permeability of porous media. This model introduces the Euler-Poincaré Characteristic (Euler Number), a parameter that reflects the connectivity of porous media. Using fractal and percolation theory, we establish a permeability model as a function of critical radius, porosity and Euler number. In order to relate the result to the Euler number, we introduce the Connectivity Function to calculate the critical aperture in the percolation theory, then calculate the percolation threshold value, and establish the relationship between the percolation threshold and the Euler number. The validity of the model is… More >

Ganggang Hou¹, Tongjing Liu^{1, *}, Xinyu Yuan¹, Jirui Hou¹, Pengxiang Diwu²

CMES-Computer Modeling in Engineering & Sciences, Vol.123, No.3, pp. 1223-1246, 2020, DOI:10.32604/cmes.2020.09008

Abstract CO₂ flooding has been widely studied and applied to improve oil recovery from low permeability reservoirs. Both the experimental results and the oilfield production data indicate that produced oil components (POC) will vary during CO₂ flooding in low permeability reservoirs. However, the present researches fail to explain the variation reason and rule. In this study, the physical model of the POC variation during CO₂ flooding in low permeability reservoir was established, and the variation reason and rule were defined. To verify the correctness of the physical model, the interaction rule of the oil-CO₂ system was studied by related experiments. The… More >

Jing Sun^1,2,3,*, Dehua Liu^1,2,3, Xiang Zhu^1,2,3, Wenjun Huang^1,2,3, Liang Cheng^1,2,3

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.3, pp. 425-440, 2020, DOI:10.32604/fdmp.2020.08531

Abstract Low permeability tight sandstone reservoirs have a high filtrational resistance and a very low fluid flow rate. As a result, the propagation speed of the formation pressure is low and fluid flow behaves as a non-Darcy flow, which typically displays a highly non-linear behavior. In this paper, the characteristics and mechanism of pressure propagation in this kind of reservoir are revealed through a laboratory pressure propagation experiment and through data from an actual tight reservoir development. The main performance mechanism is as follows: A new pressure cage concept is proposed based on the pressure variation characteristics of the laboratory experiments.… More >