Article
Engineering, Chemical
Jiaming Chen, Yongkai Qiu, Yujing Qian, Xianglong Fang
Summary: Exploring the compressibility of deeply buried marine shale matrix and its controlling factors can help improve petroleum production efficiency. This study investigated the matrix compressibility and pore characteristics of deeply buried marine shale reservoirs using mercury intrusion porosimetry (MIP) and nitrogen adsorption/desorption isotherms. Mathematical models were established to analyze the impact of TOC, mineral components, and pore structure on matrix compressibility. The results showed that shale matrix compressibility is significant within a certain range of mercury injection pressure, and factors such as TOC content and mineral composition influence matrix compressibility through their effects on pore structure.
Article
Energy & Fuels
Quanlin Yang, Junhua Xue, Wei Li, Xuanhong Du, Qian Ma, Keliang Zhan, Zhiheng Chen
Summary: Accurate characterization of coal pore structure is essential for understanding gas storage and migration mechanisms. This study used fractal theory and the new Tait equation method to analyze MIP data of coal, finding that simultaneous interparticle void filling affects 1.9-3.4% of total intrusion volumes, while matrix compression can account for 46.72-80.41%. When combined with low pressure N2 gas adsorption, the TE method provides TPV values closer to the BJH model for pore sizes in the range of 33-320 nm, while the MC method is more suitable for correcting smaller pore sizes in MIP data.
Article
Energy & Fuels
Qiang Wei, Kaige Zheng, Baolin Hu, Xianqing Li, Songbao Feng, Wei Jiang, Wenwei Zhu, Wenqing Feng
Summary: Characterizing the pore structure and methane adsorption capacity of deep-buried coals is crucial for understanding the adsorption mechanism in deep strata. The presence of multiple pore types and microfractures in deep-buried coals was observed, with micropores contributing to a majority of the specific surface area. The measured methane adsorption capacity was found to be closely correlated with the volume and specific surface area of micropores, indicating that the adsorption process primarily involves micropore filling.
Article
Engineering, Chemical
Sandong Zhou, Dameng Liu, Zuleima T. Karpyn, Yidong Cai, Yanbin Yao
Summary: The study introduces the concept of dual compressibility to characterize coal pore compressibility, revealing that high pore compressibility significantly impacts storage and transport capacity. A new model is proposed for estimating coal permeability based on mercury porosimetry data.
TRANSPORT IN POROUS MEDIA
(2021)
Article
Construction & Building Technology
Ai Zhang, Yong Ge, Wencui Yang, Guangzhi Wang
Summary: This study investigated the damage to the pore structure of cement-based materials caused by solvent-displacement-drying method. The results showed that replacing pore water with different solvents caused similar damage to the pore structure as direct-drying. The difference in pore parameters was attributed to the physical properties of solvents and their reaction with hydration products, with acetone reacting to generate a dark brown substance.
CONSTRUCTION AND BUILDING MATERIALS
(2023)
Article
Energy & Fuels
Fudong Xin, Hao Xu, Dazhen Tang, Ding Liu, Can Cao
Summary: The low coalification degree and unique properties of lignite pose challenges in physical property testing. Freeze-drying can effectively prevent the collapse of pore structure, improving test accuracy.
INTERNATIONAL JOURNAL OF COAL GEOLOGY
(2021)
Article
Geosciences, Multidisciplinary
Peiwen Jiang, Chengtao Yang, Feng Chen, Bing Li, Jiangang Ren, Jianbao Liu, Zhimin Song
Summary: This study investigates the impact of acidification on the pore structure of different rank coals. Acid treatment improves pore opening and connectivity, while having little effect on pore shape. Acidification increases porosity and total pore volume, primarily due to the formation of large mesopores and macropores. Acid treatment has a greater impact on macropores, followed by mesopores, and the least impact on micropores. The variation in specific surface area is mainly determined by micropores. Total pore volume increment is closely related to macropore volume increment, not coal maturity, suggesting that mineral content may be more important when evaluating the applicability of acidification technology.
FRONTIERS IN EARTH SCIENCE
(2023)
Article
Engineering, Environmental
Xianwei Zhang, Gang Wang, Xinyu Liu, Yiqing Xu, Lingwei Kong
Summary: This study investigates the pore characteristics of natural marine clay and its relationship with macroscopic performance using various techniques. The results show that the clay has a randomly oriented open-flocculated structure and contains ink-bottle pores. This study enhances the understanding of the pore characteristics of natural structured clays.
BULLETIN OF ENGINEERING GEOLOGY AND THE ENVIRONMENT
(2022)
Article
Construction & Building Technology
Jiajia Liu, Jianmin Hu, Mengqi Shen, Ming Yang, Yingxiang Fang
Summary: The study revealed that high-rank coals with different bedding angles have developed small pores, with the influence on fracture proportion being minimal, while the effect is greater on the proportion of microholes, medium holes, and large holes, demonstrating a certain pattern.
ADVANCES IN CIVIL ENGINEERING
(2021)
Article
Construction & Building Technology
Jing Cao, Fangyi Liu, Siyang Huang, Cheng Kong, Huafeng Sun, Yue Gao, Fuhua Liu, Jianyun Li, Guoshou Liu
Summary: This study investigates the impact of soil containing humic acid (HA) on the strength of cement-soil through unconfined compressive strength (UCS) tests and microscopic experiments. The results indicate that the addition of HA decreases the strength of cement-soil and alters the failure mode to plastic failure.
ADVANCES IN CIVIL ENGINEERING
(2022)
Article
Chemistry, Multidisciplinary
Honggao Xie, Xijian Li, Feng Xue, Hao Sui, Jiajia Zhao, Junjie Cai, Cong Feng
Summary: Experiments on corrosion reactions of pulverized coal with monomeric and polymeric acid solutions reveal that the corrosion effects of monomeric acids in descending order are HF, HCl, and CH3COOH. Acidization of coal samples increases the porosity and transforms certain pores, resulting in changes in gas adsorption capacity.
Article
Geosciences, Multidisciplinary
Haiqi Li, Zijun Feng, Chao Zhang, Peng Zhao
Summary: This paper investigates the pore structure characteristics of low-rank coalbed methane (CBM) resources and proposes a new method of pore size classification. The relationship between pyrolysis temperature and matrix compressibility is also analyzed, highlighting the significant effect of transition pores on matrix compressibility.
NATURAL RESOURCES RESEARCH
(2022)
Article
Geosciences, Multidisciplinary
Shasha Zhang, Huan Liu, Zhehui Jin, Caifang Wu
Summary: This study investigated the pore heterogeneity of coal using different methods and analyzed the multifractal characteristics of coal pore structures. The results revealed that the heterogeneity and complexity of pore structures increase with the coalification degree.
NATURAL RESOURCES RESEARCH
(2021)
Article
Chemistry, Multidisciplinary
Yanhai Chang, Kun Zhang, Yipeng Zhang
Summary: The permeability of rocks, especially coal, is important in geological applications. Previous permeability models for coal have limitations in accuracy. This study modifies the Purcell model to improve its predictive capability for coal permeability. A new model based on NMR data is developed, providing high accuracy for field permeability estimation.
Article
Green & Sustainable Science & Technology
Jun Xu, Yali Li, Lingchao Lu, Xin Cheng, Laibo Li
Summary: The heavy use of marine concrete consumes a large amount of cement, leading to increased CO2 emission. This study aimed to improve the mechanical performance and durability of marine concrete by introducing colloidal nano-silica (CNS) and epoxy silane modified colloidal nano-silica (M-CNS) to High Sulfate Resistance Portland cement. The results showed that the addition of M-CNS enhanced the workability, mechanical properties, and durability of marine cement samples, reducing the chloride diffusion coefficient and porosity, and increasing compressive strength.
JOURNAL OF CLEANER PRODUCTION
(2023)
Article
Geosciences, Multidisciplinary
Dameng Liu, Lijing Li, Zheng Zhao, Wei Chen, Yidong Cai, Yongkai Qiu, Yingfang Zhou
Summary: This study investigated the acoustic response of gas and/or water saturated coal rock and found that coal type and gas-water saturation affect the acoustic response of coalbed methane formations. The acoustic velocity, relative anisotropy, and their growth rates increase with increasing vitrinite reflectance, density, and water saturation.
FRONTIERS OF EARTH SCIENCE
(2023)
Article
Engineering, Environmental
Qifeng Jia, Dameng Liu, Yidong Cai, Yanbin Yao, Yuejian Lu, Yingfang Zhou
Summary: The swelling strain caused by methane adsorption in coal affects reservoir permeability, and the interaction between different scales of coal pores and adsorption behavior was investigated. Larger coal particle size leads to smaller temperature variation during adsorption and more capillary condensation of methane. Higher temperature results in more concentrated distribution of adhesion in coal.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Engineering, Environmental
Hao Wu, Yanbin Yao, Dameng Liu
Summary: This study investigated the water vapor sorption behavior in different maturity coal samples and identified two types of water adsorption mechanisms: attachment to oxygen functional groups and pore filling in hydrophilic and hydrophobic pores, respectively. The differences in water adsorption characteristics were found to be influenced by pore volume and the proportion of hydrophilic pores. The results also showed that water adsorption on methane adsorption in coal was attributed to the amount and proportion of hydrophilic pores.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Thermodynamics
Fengrui Sun, Dameng Liu, Yidong Cai, Yongkai Qiu
Summary: In this paper, the coupling control mechanism of coal rank-pressure on gas occurrence is studied, and a novel concept of surface control field is proposed. The influence mechanism of coal rank on methane adsorption capacity is revealed, and the difference of energy conversion mechanism between adsorption and desorption processes is clarified. A new concept of adsorption potential is also proposed based on the coal rank-pressure linkage model of energy conversion.
Article
Energy & Fuels
Yuejian Lu, Dameng Liu, Yidong Cai, Yingfang Zhou
Summary: Multiphase flow in coal significantly affects the movement and accumulation of fluids, and plays a vital role in predicting coal permeability during coalbed methane production. Fractures play a decisive role in CBM transport after hydraulic fracturing. A multiscale pore network model was built based on FIB-SEM images, and a novel fracture-pore network model (F-PNM) was proposed to study the effect of fracture density, fracture developing direction, and wettability on multiphase flow. The results showed that F-PNM permeability increases with fracture density, decreases with increasing angle between fracture and flow direction, and wettability has a measurable impact on gas relative permeability.
Article
Engineering, Environmental
Sijian Zheng, Yanbin Yao, Dameng Liu, Shuxun Sang, Shiqi Liu, Meng Wang, Xiaozhi Zhou, Ran Wang, Sijie Han, Tong Liu
Summary: This article proposed an innovative methodology to quantitatively characterize the multiphase water in coals, applicable to both water-saturated and sub-saturated coals, by combining theory and experiment.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Energy & Fuels
Yong Liu, Yanbin Yao, Dameng Liu, Chi Zhang
Summary: Forced imbibition in shale reservoirs is crucial for efficient recovery of shale gas, but it can also lead to low flowback efficiency and reservoir damages. This study investigated imbibition behaviors in Longmaxi shales under four different boundary conditions using nuclear magnetic resonance technology. The results showed that the shale bedding structure is the key factor determining the imbibition dynamics and patterns under different boundary conditions.
Article
Energy & Fuels
Zihao Wang, Yidong Cai, Dameng Liu, Feng Qiu, Fengrui Sun, Yingfang Zhou
Summary: The structure of coal plays a crucial role in the exploration and development of coalbed methane. Traditional coal core observations are not applicable in unexplored coal seams without CBM wells and are time-consuming. Geophysical-logging interpretation of the coal structure is more efficient and economical, but improvement is needed in qualitative methods. Machine learning methods, including MLR, RF, and DNN, proved to be effective in identifying the coal structure accurately and efficiently.
INTERNATIONAL JOURNAL OF COAL GEOLOGY
(2023)
Article
Geosciences, Multidisciplinary
Xianglong Fang, Dameng Liu, Yingfang Zhou, Xiaobo Liu, Yidong Cai
Summary: A systematic study was done to understand methane diffusion behavior in different rank coals. The pore structure of coals exhibited a multimodal pore size and volume distribution. Factors affecting methane diffusion in coals were analyzed, and their importance ranking was determined using gray relational analysis.
FRONTIERS OF EARTH SCIENCE
(2023)
Article
Engineering, Chemical
Xianglong Fang, Yidong Cai, Qinhong Hu, Ping Gao, Dameng Liu, Yujing Qian
Summary: Exploring the relationship between formation pressure and shale pore evolution is crucial for the development of marine shale gas accumulation theory. Experimental investigations on lowly matured marine shale were carried out to characterize the effects of formation pressure on shale pore morphology and hydrocarbon expulsion. The findings suggest that formation pressure promotes the expulsion of hydrocarbons, changes shale pore morphology, and improves pore connectivity. These results provide valuable insights into understanding the evolution of shale pore structures under different pressure conditions.
Article
Thermodynamics
Changjing Gao, Dameng Liu, Veerle Vandeginste, Yidong Cai, Fengrui Sun
Summary: This study investigates the occurrence mechanism of multiple fluids in coal reservoirs through experimental data and innovative methods. The results show that coal rank, gas composition, and adsorption heat all affect the adsorption capacity and performance.
Article
Thermodynamics
Fengrui Sun, Dameng Liu, Yidong Cai, Yongkai Qiu
Summary: It is important to study the coupling mechanism of microscale and macroscale permeabilities in coalbed methane (CBM) reservoirs for scientific and engineering purposes. This paper reveals the characteristics of the pore-fracture system of coal matrix and establishes a coupled permeability model to clarify the coal rank control mechanism on the transformation of micro-macro permeabilities. Based on a microscale gravitational field model, the influence mechanism of coal rank-pressure coupling on the slippage/diffusion/jump of adsorbed gas in the surface control field is also clarified.
Article
Energy & Fuels
Zheng Zhao, Dameng Liu, Ming Chen, Bo Wang, Junyi Sun, Lizhu Yu, Yidong Cai, Bo Zhao, Fengrui Sun
Summary: The interaction mechanism between coalbed methane (CBM) and coalbed water (CBW) in the full cycle of CBM enrichment-drainage-output was studied. It was found that CBW in the study area had higher ion concentration and relatively small Cl-Na coefficient, desulfurization coefficient, and carbonate equilibrium coefficient, making it a relatively enriched area for CBM. CBM production in high hydrodynamic areas requires greater drainage and depressurization, and has relatively lower average daily gas production. The increase in gas production during CBM drainage shows a correlation with the increase in total dissolved solids (TDS) and a decrease in Cl-Na coefficient, desulfurization coefficient, and carbonate equilibrium coefficient in the extracted water.
Article
Energy & Fuels
Yuejian Lu, Dameng Liu, Yidong Cai, Yingfang Zhou
Summary: In this study, a multiscale pore network model (PNM) and a novel discrete fracture network model (F-PNM) were constructed to investigate the effect of fracture density, fracture developing direction, and wettability on multiphase flow in coal. The results showed that the permeability of F-PNM increased with the increase of fracture density due to the predominance of snap off. The permeability decreased as the angle between the fracture and flow direction increased, with a maximum decrease of 61.8% between 0° and 15°. The wettability of coal had limited impact on its water relative permeability but had a measurable effect on gas relative permeability.
Article
Energy & Fuels
Fengrui Sun, Dameng Liu, Yidong Cai, Yongkai Qiu
Summary: This paper investigates the microscale geological control mechanism of gas transport in coalbed methane reservoirs. By establishing coupling models, the equilibrium mechanism of multilayer adsorption and surface jump, the coupling control mechanism of coal rank-pressure on gas transport, and the influence mechanism of coal rank-pressure coupling on gas transport mechanism conversion are revealed.
GAS SCIENCE AND ENGINEERING
(2023)
