Article
Geosciences, Multidisciplinary
Dameng Liu, Qifeng Jia, Yidong Cai, Changjin Gao, Feng Qiu, Zheng Zhao, Siyu Chen
Summary: Coalbed methane (CBM) recovery in the Qinshui Basin can be supported by the abundant coal-bearing rocks and favorable geological conditions. This study comprehensively investigates various aspects of geological and reservoir characteristics to gain insights into CBM exploration and exploitation.
Article
Geosciences, Multidisciplinary
Changjiang Ji, Guofu Li, Haijin Hao, Zhimin Song, Dingding Guo
Summary: This study investigates the pore structure and its impact on reservoir characteristics in high rank coals from Sihe and Zhaozhuang blocks in the southern Qinshui Basin. The results show that the variations in gas production are mainly caused by the anomalies in pore morphology and pore structure characteristics of the coal reservoir.
FRONTIERS IN EARTH SCIENCE
(2022)
Article
Chemistry, Multidisciplinary
Yafei Zhang, Bin Sun, Zhiyu Deng, Weiwei Chao, Xinyang Men
Summary: In situ stress has a crucial impact on coal permeability and CBM productivity, with more prominent effects at greater depths. The study finds that as depth increases, the magnitude and gradient of in situ stress also increase, but decrease beyond a certain depth. Coal permeability gradually decreases with depth. Hydraulic fracturing is necessary for deep coal seams, but the current techniques lack adaptation to different stress regimes and permeability at various depths.
Article
Geochemistry & Geophysics
Hao Lu, Hongming Tang, Meng Wang, Xin Li, Liehui Zhang, Qiang Wang, Yulong Zhao, Feng Zhao, Jijia Liao
Summary: The complexity of pore types in the Middle East's Cretaceous carbonate reservoir poses challenges in characterizing and predicting its petrophysical properties accurately. By classifying the pore structure and establishing new permeability models based on identified pore structure types, this study provides valuable insights for enhancing oil recovery in the area.
Article
Energy & Fuels
Yuejian Lu, Dameng Liu, Yidong Cai, Changjing Gao, Qifeng Jia, Yingfang Zhou
Summary: This study investigates the wettability of 17 different rank coals and finds a negative correlation between wettability and coal surface roughness and adhesive force. Line tension has the most significant impact on droplets smaller than 10 nanometers, while it can be neglected in the wetting process in micropores and mesopores.
Review
Geosciences, Multidisciplinary
Qifeng Jia, Dameng Liu, Yidong Cai, Xianglong Fang, Lijing Li
Summary: The study reviewed recent progress on the petrophysics characteristics of coalbed methane (CBM), focusing on pore-fracture structure, permeability, reservoir heterogeneity, and controlling factors. The characterization of pore-fracture has evolved from qualitative to advanced quantitative methods using high-precision experimental instruments. The effects of acoustic field can increase permeability of coal reservoirs by over 10%, while tectonic stress is crucial in determining permeability and reservoir heterogeneity increases with tectonic deformation and stress field enhancement.
FRONTIERS OF EARTH SCIENCE
(2021)
Article
Chemistry, Multidisciplinary
Sen Deng, Xijian Li, Bize Xu
Summary: This study evaluated the effects of coal reservoir modification on gas desorption using molecular dynamics simulations and neural networks. The results showed a correlation between coal pore size and methane adsorption and an inverse relationship between coal pore size and methane adsorption capacity and energy. The different methane-repelling properties of CO2, N2, and H2O are due to their different diffusion capabilities. The best reservoir reforming effect can be achieved by setting the pressure ratio of CO2 to N2 to 3.4:6.6.
Article
Geosciences, Multidisciplinary
Xiaowei Hou, Yang Wang, Yanming Zhu, Jie Xiang
Summary: The study investigated the pore structure of continuous unconventional reservoirs (CURs) in coal measures in the Qinshui Basin, China. Results showed that coals have high porosity and permeability mainly from micropores, while shales have low porosity and permeability with a predominance of macropores and mesopores, and sandstones have mainly macropores. Micropores significantly impact gas adsorption in CURs, while macropores are essential for gas seepage. Effective porosity plays a significant role in the permeability of CURs.
FRONTIERS OF EARTH SCIENCE
(2021)
Article
Geosciences, Multidisciplinary
Yuehua Hou, Dongna Liu, Fenghua Zhao, Linhua Zhong, N. Nnachi Emmanuel, Qi Zhang
Summary: The main purpose of this study was to investigate the geological characteristics affecting coalbed methane (CBM) enrichment in the Anze area in China and predict the optimal CBM enrichment zones. The study revealed that the adsorption capacities and coal structure varied in different regions, and the degree of fracture development and reservoir fractal dimension also had an impact. Favorable reservoir conditions were found in specific areas in the northern and southern parts.
NATURAL RESOURCES RESEARCH
(2022)
Article
Energy & Fuels
Difei Zhao, Yinghai Guo, Geoff Wang, Xin Guan, Xueqing Zhou, Jing Liu
Summary: The influence of high-rank coal's pore characteristics on the physical properties, gas-bearing properties, and exploitation of coal reservoirs is becoming more prominent. This research analyzed the structure and fractal characteristics of reservoir pores in high-rank coal samples and established a natural classification system to describe the relationship between pore types and gas occurrence and transport mechanisms.
Article
Engineering, Chemical
Chaochao Duan, Xuehai Fu, Ze Deng, Junqiang Kang, Baoxin Zhang, Jielin Lu, Xing Hong, Ruirui Dai, Xiaogang Li
Summary: The heterogeneity of the pore structure of coal reservoirs affects the desorption and diffusion characteristics of coalbed methane. NMR and multifractal analysis were used to quantitatively evaluate the pore structure heterogeneity and determine the influencing factors in the central and eastern Qinshui Basin, where coalbed methane resources are abundant. The research results provide theoretical guidance for the subsequent exploration and development of coalbed methane in the region.
Article
Engineering, Marine
Zhongying Zhao, Lianhua Hou, Xia Luo, Yaao Chi, Zhenglian Pang, Senhu Lin, Lijun Zhang, Bo Liu
Summary: The reservoir properties of low-medium-maturity shale undergo complex changes during the in situ conversion process, including changes in mineral and maceral composition, pore structure, porosity, and permeability. This study quantitatively characterized these changes and identified mechanisms such as kerogen pyrolysis, clay-mineral transformation, unstable mineral dissolution, and thermal stress.
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2023)
Article
Chemistry, Multidisciplinary
Lin Yang, Zhengyuan Lu, Xie Tang, Ling Tang, Weiwei Zhang
Summary: The Upper Paleozoic strata in the Ordos Basin are characterized by tight sandstone gas reservoirs with strong heterogeneity and widely distributed aquifers. Traditional mud logging technology faces difficulties in effectively identifying the reservoir and fluid properties. By integrating NMR logging, regional geological characteristics, and gas test results, the reservoirs were classified to effectively identify the reservoir and fluid properties.
Article
Energy & Fuels
Bo Wang, Yanting Wu, Guofu Li, Jiaosheng Yang, Yang Zhao, Meizhu Wang, Jian Zhou, Tong Wu, Zhejun Pan
Summary: The study revealed that mineral fillings in coal beds have a significant impact on the permeability and production of coalbed methane (CBM) in China, especially in the fracture system. The influence of mineral fillings on permeability and fracture compressibility is complex, and the strong swelling strain anisotropy and low Poisson's ratio associated with mineral fillings are also noteworthy.
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
(2022)
Article
Energy & Fuels
Johan Olav Helland, Helmer Andre Friis, Mohsen Assadi, Lukasz Klimkowski, Stanislaw Nagy
Summary: This study quantifies the impact of reservoir height and permeability on the optimal production time of CO2 injection in aquifers for underground natural gas storage. By developing artificial neural networks, accurate relationships between input parameters and optimal production time can be described.
Article
Energy & Fuels
Zhigang Du, Xiaodong Zhang, Qiang Huang, Shuo Zhang, Chenlin Wang
ENERGY EXPLORATION & EXPLOITATION
(2019)
Article
Energy & Fuels
Zhigang Du, Qiang Huang, Jinjun Guo, Fuqiang Gao, Yanqiang Du
Article
Energy & Fuels
Zhigang Du, Yawen Tao, Xiaodong Zhang, Wuxiu Ding, Qiang Huang
Summary: The study shows that the development of fractures in coal affects permeability, with larger fractures leading to higher permeability. The Klinkenberg effect does not exist in ultralow-permeability coal, but significantly increases permeability in coal samples with connected fractures.
ENERGY EXPLORATION & EXPLOITATION
(2022)
Article
Energy & Fuels
Xiaodong Zhang, Shuo Zhang, Zhigang Du, Geoff G. X. Wang, Shuai Heng, Xiao Liu, Junfeng Lin
Summary: This study conducted experiments using high volatile bituminous coal to investigate the adsorption-induced deformation mechanism of confined coals with CO2 and N2, and developed a thermodynamic model based on the swelling characteristics. The results showed that the coal matrix exhibited different stages of swelling/shrinkage during the adsorption/desorption process. Furthermore, factors such as adsorbate type, chemical potential, and stress conditions were identified as key factors affecting coal swelling.
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
(2021)
Article
Geochemistry & Geophysics
Ning Li, Zhigang Du, Fuqiang Gao, Fuzhou Qi, Haiping Gao, Mingxia Li, Xiaoqiang Wang
Summary: The mechanical equation on the mechanical characteristics of rock bolt in rock mass with bedding separation is established. The mechanical characteristics of rock bolt are studied with the single and multiple bedding separation by numerical simulation. The axial force of rock bolt is mainly controlled by the side with the shorter anchoring length.