Article
Geosciences, Multidisciplinary
Jian Sun, Xianming Xiao, Peng Cheng
Summary: The study investigates the pore structure characteristics of Longmaxi shale under both dry and moist conditions, finding that water mainly exists on nonmicropores surfaces, affecting shale pore structure and gas adsorption. The fractal dimension D1 is more suitable for representing shale pore heterogeneity and has a stronger predictive role in shale gas-bearing properties.
MARINE AND PETROLEUM GEOLOGY
(2021)
Article
Geosciences, Multidisciplinary
Tao Wang, Fenghua Tian, Ze Deng, Haiyan Hu
Summary: The microscopic pore characteristics of shale in marine strata in northern Yunnan and Guizhou were evaluated using FE-SEM, LT-N(2)GA, LP-CO(2)GA, and HPMA experiments. Fractal Frenkel-Halsey-Hill theory was used to analyze the fractal characteristics and discuss the adsorption pore characteristics of shale. The results showed that the shale samples had complex pore structures and open pore styles, with abundant micropores and mesopores. The fractal dimensions were positively correlated with the TOC and clay mineral contents and negatively correlated with the quartz content. Fractal analysis is helpful for understanding the pore structure and adsorption capacity of shale gas reservoirs.
FRONTIERS IN EARTH SCIENCE
(2023)
Article
Energy & Fuels
Fei Mo, Zhilin Qi, Xiaoliang Huang, Wende Yan, Shuai Wang, Yingzhong Yuan, Zhiqiang Li
Summary: This study proposed a model to calculate the diffusivity of gases in water-bearing shales. The results showed that the presence of water significantly reduced the gas diffusion in shales. In addition, factors such as temperature, pore radius, porosity, and pore wall roughness were found to affect the diffusion coefficient.
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
(2022)
Article
Energy & Fuels
Ran Li, Zhangxin Chen, Keliu Wu, Jinze Xu
Summary: Gas flow properties in nanopores are influenced by flow patterns, and slug flow pattern is a potential water-gas two phase flow pattern. The impact of water bridge on gas flow capacity is estimated using a foam apparent viscosity model. Comparison with other flow models suggests that gas molecular movement is hindered by flow space reduction and loss of gas slippage. Understanding the structure and transport of water and gas molecules is crucial for predicting shale gas production.
Article
Energy & Fuels
Kang Yang, Junping Zhou, Xuefu Xian, Yongdong Jiang, Chengpeng Zhang, Zhaohui Lu, Hong Yin
Summary: The study investigated the impact of supercritical CO2-water exposure on the adsorption characteristics of shale, revealing that increasing exposure pressure and decreasing exposure temperature resulted in a gradual decrease in CH4 and CO2 adsorption capacity in shale due to alterations in mineral composition and pore structure. The study also found that the selectivity factor of CO2 to CH4 decreased with increasing exposure pressure and decreasing temperature, indicating the feasibility of CO2-enhanced shale gas recovery and sequestration even after exposure to ScCO2-water.
Article
Multidisciplinary Sciences
Shengwei Wang, Xijian Li, Haiteng Xue, Zhonghui Shen, Liuyu Chen
Summary: This study explores the influence of shale pore parameters on permeability in different diffusion zones, finding that fractal dimension and porosity have a significant impact on permeability in the transitional diffusion zone, while porosity has no obvious effect on permeability in the Knudsen diffusion zone. The research provides valuable insights into the seepage law of shale gas and contributes to a more accurate characterization of pore structures of porous media.
ROYAL SOCIETY OPEN SCIENCE
(2021)
Article
Mathematics, Interdisciplinary Applications
Qian Zheng, Huili Wang, Xiuya Guo
Summary: This study investigates the effect of surface roughness on gas diffusion in composite materials, proposes a new model based on microstructural parameters, and analyzes the influence of relative roughness and other parameters on gas diffusion. The model shows better agreement with experimental data than empirical correlations and is believed to reveal more physical mechanisms.
FRACTALS-COMPLEX GEOMETRY PATTERNS AND SCALING IN NATURE AND SOCIETY
(2021)
Article
Energy & Fuels
Xianglu Tang, Zhenxue Jiang, Zhenglian Yuan, Yifan Jiao, Caihua Lin, Xiaoxue Liu
Summary: This study investigates the controlling effect of pore water on shale gas enrichment by systematically analyzing the characteristics of pore water in Quaternary shale in the Qaidam Basin, China. The study reveals that pore water plays a significant role in the formation, adsorption, flow, and occurrence of shale gas. This research is crucial for enhancing the geological theory of shale gas and guiding shale gas exploration.
Article
Geosciences, Multidisciplinary
Shuai Shi, Jinxian He, Xiaoli Zhang, Hongchen Wu, Ziqi Yu, Jian Wang, Tiantian Yang, Wei Wang
Summary: Studying the complex pore structures and fractal characteristics of gas shale is important for understanding the mechanism of shale gas accumulation and efficient development. This paper utilizes the fractal theory together with mercury intrusion porosimetry and N-2 adsorption technology to investigate the pore size distribution of shale samples. The results reveal that the most common pore types in the samples are pores between or within clay minerals, micropores and mesopores inside organic matter, and microfractures. The pores of shale samples exhibit fractal geometries, and the fractal dimension correlates positively with the corresponding pore volume.
FRONTIERS IN EARTH SCIENCE
(2022)
Article
Energy & Fuels
Ping Gao, Xianming Xiao, Dongfeng Hu, Ruobing Liu, Yidong Cai, Tao Yuan, Guangming Meng
Summary: This study investigated the water content and its distribution in the different nanopores of deep and ultra-deep shales in China. The results showed that irreducible water is the dominant form of water in ultra-deep shales, primarily occurring in clay-hosted pores and parts of organic pores. It is mainly distributed in non-micropores, especially in micropores with a diameter of 0.4-0.6 nm and mesopores with a diameter of 2-10 nm. The presence of irreducible water significantly affects the specific surface area of non-micropores, which is more pronounced in organic-rich shale samples.
Article
Energy & Fuels
Ji-Yuan Wang, Shao-Bin Guo
Summary: The relationship between hydrocarbon generation and the evolution of shale pore structure and its heterogeneity of continental shale was quantitatively studied in this research. The results show that hydrocarbon generation has different effects on pore heterogeneity of different scales, indicating the complexity of the relationship.
Article
Energy & Fuels
Jianchao Cai, Zhenhua Tian, Shangwen Zhou, Yihua Xiong, Chenhao Sun, Jianhui Zeng
Summary: This study focuses on the quantitative characterization of fluid storage and structural properties of deep Longmaxi Formation shale samples from southern Sichuan Basin. Experiments including nuclear magnetic resonance and nitrogen adsorption are conducted to analyze pore distribution complexity and pore surface irregularity, which are controlled by factors such as stratigraphic division and shale composition. The research findings suggest that the storage capacity and microstructural properties of deep shales are influenced by stratigraphic division and shale composition.
Article
Energy & Fuels
Yufei Chen, Changbao Jiang, Juliana Y. Leung, Andrew K. Wojtanowicz, Dongming Zhang
Summary: The study found that although slippage pores dominate the total volumetric contribution in Longmaxi shale, with a clear presence of adsorption pores, overall gas transport in shale is mainly controlled by seepage pores (fracture-pores), which only constitute a very small portion of the total volume.
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
(2021)
Article
Geosciences, Multidisciplinary
Sai Xu, Zhengming Yang, Songtao Wu, Lei Wang, Wei Wei, Feng Yang, Jianchao Cai
Summary: Pore structure is a critical factor influencing the physical properties of oil and gas reservoirs, and it varies greatly with the reservoir rock type. This study analyzed the pore structures of shale and sandstone using low-pressure nitrogen adsorption experiments and fractal theory. The results showed significant differences in pore shape, distribution, specific surface area, and pore size between shale and sandstone. Fractal dimensions were found to be important parameters in characterizing the pore structure. The study highlights the usefulness of fractal theory in characterizing unconventional reservoirs.
NATURAL RESOURCES RESEARCH
(2022)
Article
Geosciences, Multidisciplinary
Yuqi Huang, Jinchuan Zhang, Peng Zhang, Xuan Tang, Junwei Yang
Summary: Marine-continental transitional shale strata in China, such as the Longtan shales, have high gas potential. The fractal dimensions of different pore sizes were calculated to analyze the pore structures of the Longtan shales. The macropores (>= 100 nm) were mainly inorganic with a complex structure, while the mesopores (50-100 nm) had a slightly higher proportion of organic pores and a medium complexity. The mini-micropores were mainly organic and had complex structures and rough surfaces, and they accounted for the highest proportion of the total pores.
FRONTIERS IN EARTH SCIENCE
(2023)
Review
Chemistry, Multidisciplinary
Ruijie Yang, Yingying Fan, Yuefeng Zhang, Liang Mei, Rongshu Zhu, Jiaqian Qin, Jinguang Hu, Zhangxing Chen, Yun Hau Ng, Damien Voiry, Shuang Li, Qingye Lu, Qian Wang, Jimmy C. C. Yu, Zhiyuan Zeng
Summary: This review provides a tutorial-style overview of the application of two-dimensional transition metal dichalcogenides (TMDs) in photocatalysis. It highlights the unique electronic, optical, and chemical properties of TMDs that make them promising materials for effectively utilizing light and catalyzing redox reactions.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Thermodynamics
Nanlin Zhang, Zhangxin Chen, Zhifeng Luo, Pingli Liu, Weiyu Chen, Fushen Liu
Summary: The success of self-propping phase-transition fracturing (SPF) technology depends on accurate temperature distribution calculations and the use of reaction heat models.
Article
Energy & Fuels
Maojie Chai, Zhangxin Chen, Hossein Nourozieh, Min Yang
Summary: Transitioning from fossil fuels to renewable energy is crucial in addressing climate change, and hydrogen storage using the concept of 'power to gas' could provide a solution to the fluctuating renewable energy generation and demand. Aquifers offer a possibility for safe, cost-effective, and environmentally friendly long-term hydrogen storage, but further research is needed to understand their trapping mechanisms and improve hydrogen recovery. This study explores the underground interactions of hydrogen with rock or fluid and integrates multiple cycles and cushion gas injection to enhance hydrogen recovery.
Article
Mathematics, Applied
Jing Wen, Zhangxing Chen, Yinnian He
Summary: This paper investigates a method of gradient-divergence stabilization in discontinuous Galerkin methods for a coupled Stokes and Darcy problem. The method penalizes the jumps of normal velocities over facets of the triangulation to improve the accuracy of velocity and mass conservation. The paper proves the existence, uniqueness, and stability of the solution, and demonstrates the convergence of the method with an analogue of gradient-divergence stabilization.
COMPUTERS & MATHEMATICS WITH APPLICATIONS
(2023)
Article
Thermodynamics
Min Yang, Yishan Liu, Ning Lu, Maojie Chai, Sen Wang, Qihong Feng, Zhangxin Chen
Summary: A calibration workflow was proposed to investigate the oxidation behavior and establish a reaction kinetics model. Based on the integration of RTO and CT results, a comprehensive reaction kinetics model was developed to predict the ISC performance within a wide temperature range. The proposed workflow helps upscale the oxidation behavior from a RTO experiment to a CT test and provides benchmarks for field operations.
Article
Thermodynamics
Chao Tang, Wen Zhou, Zhangxin Chen, Jiabao Wei
Summary: Shale gas is an important unconventional fossil fuel resource. Carbon capture and sequestration in shale gas reservoirs, known as CO2-EGR, can sequester 45%-60% of injected CO2 in the shale reservoir while providing 10%-15% incremental gas recovery. Factors such as formation temperature, mean pore size, and injection rate greatly impact the feasibility of CO2-EGR.
Article
Thermodynamics
Mohammadali Ahmadi, Qingfeng Hou, Yuanyuan Wang, Xuantong Lei, Benjieming Liu, Zhangxin Chen
Summary: CO2/N2 switchable surfactants have attracted attention in enhanced oil recovery due to their environmental and economic benefits. This study evaluated the performance of different surfactant mixtures in water/dodecane systems and investigated the effects of molecular structure and surfactant concentration on emulsification and demulsification processes triggered by CO2/N2 injection.
Article
Geosciences, Multidisciplinary
Qiyang Gou, Shang Xu, Fang Hao, Liang Zhang, Zhangxing Chen, Nan Bai
Summary: This study systematically analyzed the complex mineral composition and multiple pore structure of a typical carbonate-rich shale from the Paleogene Xin'gouzui Formation in the Jianghan Basin. The results showed that there are noticeable differences in pore sizes between the mixed shale and dolomitic shale, which are the main lithofacies types in the study area. The difference in pore structure is closely associated with mineral composition, and a storage space development model for different lithofacies shales was established.
MARINE AND PETROLEUM GEOLOGY
(2023)
Review
Pathology
ZhangXing Chen, Meiyan Chen, Yuka Fu, Jingyi Zhang
Summary: Pancreatic ductal adenocarcinoma (PDAC) is a highly metastatic cancer with a high mortality rate. RAS signaling plays a key role in PDAC. Several targeted therapies have been developed, but pancreatic cancer remains challenging due to its high metastatic nature and frequent late-stage diagnosis.
PATHOLOGY RESEARCH AND PRACTICE
(2023)
Article
Energy & Fuels
Houbin Liu, Shuai Cui, Yingfeng Meng, Zhangxing Chen, Hangrui Sun
Summary: With the depletion of shallow oil and gas resources and the increase in fossil energy consumption, deep oil and gas resources have become the main driving force of economic development. However, there is little research on the rock failure law of the deep sandstone stratum. Therefore, several triaxial mechanical experiments were conducted for a batch of sandstone with similar homogeneity, and the results were used to establish a calculation model of wellbore collapse pressure in deep sandstone formation based on the variable parameter Mohr-Coulomb criterion.
GEOENERGY SCIENCE AND ENGINEERING
(2023)
Article
Energy & Fuels
Jiajia Bai, Yili Kang, Mingjun Chen, Zhangxin Chen, Lei Tao, Na Zhang, Wenyang Shi, Qingjie Zhu
Summary: Retained fracturing fluids have both negative and positive effects on methane diffusion in organic-rich shale. The entry of water into the shale pore structure leads to a decrease in methane diffusion rate in larger pores and an increase in smaller pores. The presence of water facilitates the surface diffusion of methane. These findings are significant for determining shut-in time and fracturing fluid flowback in shale gas wells.
GAS SCIENCE AND ENGINEERING
(2023)
Article
Energy & Fuels
Ran Li, Zhangxin Chen, Keliu Wu, Jinze Xu
Summary: Gas flow properties in nanopores are influenced by flow patterns, and slug flow pattern is a potential water-gas two phase flow pattern. The impact of water bridge on gas flow capacity is estimated using a foam apparent viscosity model. Comparison with other flow models suggests that gas molecular movement is hindered by flow space reduction and loss of gas slippage. Understanding the structure and transport of water and gas molecules is crucial for predicting shale gas production.
Article
Energy & Fuels
Yuting He, Zhangxin Chen, Xiaogang Li, Zhaozhong Yang, Ming Jiang, Longhai Ran
Summary: The study compared the self-supporting conductivity of fractures obtained by hydraulic fracturing, CO2 fracturing, and Sc-CO2 fracturing through laboratory experiments. It was found that fractures obtained by Sc-CO2 fracturing had higher Joint Roughness Coefficient (JRC) values compared to CO2 fracturing, while fractures obtained by hydraulic fracturing had the lowest JRC values. There was a positive correlation between the self-supporting conductivity of fractures and their JRC values. The fractures obtained by Sc-CO2 fracturing showed significant advantages in self-supporting conductivity regardless of slip displacement and closure stress, compared to hydraulic fracturing and CO2 fracturing.
GEOENERGY SCIENCE AND ENGINEERING
(2023)
Article
Energy & Fuels
Xiaohu Dong, Wenjing Xu, Huiqing Liu, Zhangxin Chen, Ning Lu, Wuchao Wang
Summary: The replacement mechanisms of CO2 in nanopores of shale oil reservoirs are discussed using static tests and molecular dynamics (MD) simulations in this study. Various molecular models of shale oil and shale rock are developed, and MD simulations are conducted to study the replacement behavior of CO2. The concept of replacement efficiency (RE) is proposed to analyze the effects of shale oil composition, porewall mineral type, and CO2 concentration. This study provides new insights into the understanding of CO2 replacement mechanisms in shale oil reservoirs, which is important for their effective and efficient development.
GEOENERGY SCIENCE AND ENGINEERING
(2023)
Article
Chemistry, Physical
Xi Cheng, Bo Liu, Heng Zhao, Hongguang Zhang, Jiu Wang, Zhangkang Li, Bei Li, Zhangxin Chen, Jinguang Hu
Summary: This study designed a catalyst with a strong interfacial effect to efficiently photorefine lignocellulosic biomass, producing hydrogen and value-added chemicals. By optimizing the interfacial effect, the catalyst achieved high photocatalytic hydrogen production in the presence of different electron donors. This research demonstrates the potential of photorefining raw biomass through the design and optimization of catalysts.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2024)