An experimental investigation of the effect of acid stimulation on gas extraction from coal
Source abstract
Abstract
This study presents a novel method of acid stimulation to improve the permeability of coal seams and promote gas extraction. The mineral composition and pore structure characteristics of coal, before and after acidification, were studied using x-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The XRD images suggest that the main mineral present in coal before acidification was kaolinite. The minerals that fill the pores and fractures in coal decrease or even disappear after acidification. Furthermore, SEM images indicate that acidification increases the number and width of fracture and increases the connectivity of the fracture system. The mechanism of acid stimulation has been studied by investigating the permeability and porosity of coal. The results demonstrate that the permeability and porosity of coal show an overall increasing trend with an increase in the duration of acidification. To replicate the practical conditions in coal mines, the effects of confining pressure and temperature on permeability and porosity, with the synergistic effect of acidification, were studied for three different coal samples. The permeability of coal shows an overall decreasing trend with increasing confining pressures at constant temperatures, and the permeability first increases and then decreases with increasing temperatures at constant confining pressures. The trends in permeability and porosity are approximately consistent. The results are important for enhancing permeability and, therefore, gas extraction from coal.
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Research context
OpenAlex topics: Coal Properties and Utilization · Rock Mechanics and Modeling · Hydrocarbon exploration and reservoir analysis
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
Affiliations
College of Safety Science and Engineering, Liaoning Technical University 1 , Fuxin 123000, China
Key Laboratory of Mine Thermodynamic Disasters and Control of Ministry of Education 2 , Fuxin 123000, China
Postdoctoral Research Workstation, Yangquan Coal Industry (Group) Co., Ltd. 3 , Yangquan, Shanxi 045000, China
School of Mining Engineering, Liaoning Shihua University 4 , Fushun 123006, China
Funding
Ministry of Science and Technology of the People’s Republic of China · Department of Education of Liaoning Province · National Natural Science Foundation of China
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