A new technology to enhance gas drainage in the composite coal seam with tectonic coal sublayer

Zhang, Rong; Wang, Ping; Cheng, Yuanping; Shu, Longyong; Liu, Yinfu; Zhang, Zhiyang; Zhang, Hongxing; Wang, Liang

doi:10.1016/j.jngse.2022.104760

Cited by 10 publications

(3 citation statements)

References 31 publications

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“…Li et al [24] embarked on a study to evaluate the outcomes of gas extraction processes. Through the lens of numerical simulations, Zhang et al [25] scrutinized the stress alterations and the likelihood of damage failure, attributing these phenomena to the scouring of coal and the geometric configurations of boreholes. Utilizing Fluent software, Xu et al [26] undertook an analysis and simulation of disparate gas extraction effects under varied stratifications and negative pressure conditions across different roadway levels, subsequently optimizing the technological parameters pertinent to these environments.…”

Section: Introductionmentioning

confidence: 99%

Optimizing Borehole Diameter for Maximum Gas Extraction Efficiency in Coal Seams

Zhang,

Tan,

Zhang

et al. 2024

ATG

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In mines characterized by high gas concentrations, the process of extracting natural resources frequently precipitates coal and gas outbursts, positioning borehole gas extraction as a pivotal preventative strategy. Investigations aimed at identifying an optimal borehole diameter for gas extraction were undertaken within the Puxi Mine, entailing the drilling of boreholes across a spectrum of diameters and subsequent comparative analysis of the resultant data. This study meticulously evaluated the influence of seven distinct borehole diameters on gas concentration and pure flow rate, per unit length of coal hole and per unit of applied negative pressure. It was discerned that boreholes with larger diameters significantly enhance gas extraction efficacy. Specifically, boreholes of 113mm and 94mm diameters were noted for their exceptional performance, delivering pure flow rates of gas at 0.0215 m³/min and 0.0428 m³/min, respectively. Through a detailed examination of borehole diameters that presented considerable advantages, notably 113mm, 105mm, and 94mm, it was ascertained that the 94mm borehole diameter achieved the highest utilization efficiency, registering a gas pure flow rate of 1.62 × 10 −4 m 3 /min per unit diameter. Consequently, this diameter was identified as the most advantageous for gas extraction purposes. The insights garnered from this investigation are instrumental for the selection of borehole diameters tailored to gas extraction in coal seams of varying thicknesses, and they significantly contribute to the formulation of rationalized gas extraction methodologies.

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Section: Introductionmentioning

confidence: 99%

Optimizing Borehole Diameter for Maximum Gas Extraction Efficiency in Coal Seams

Zhang,

Tan,

Zhang

et al. 2024

ATG

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“…Among them, coal structure is one of the key geological factors affecting coalbed methane production. − Some scholars have conducted in-depth studies on the classification and identification of coal structure, − but the influence of coal structure on hydraulic fracturing is relatively general. In general, undeformed coal and cataclastic coal are suitable for conventional hydraulic fracturing technology, and their effect is better . On the contrary, the reconstruction effect of granulated coal and mylonitized coal is worse .…”

Section: Introductionmentioning

confidence: 99%

“…In general, undeformed coal and cataclastic coal are suitable for conventional hydraulic fracturing technology, and their effect is better. 19 On the contrary, the reconstruction effect of granulated coal and mylonitized coal is worse. 20 The influence of coal structure on hydraulic fracturing is mainly manifested in the following two aspects: (1) When the geo-stress is the same, the more serious the coal structure’s broken degree is, the less likely it is to form a new fracture at the end of crack, and the fracture extension length is shorter.…”

Section: Introductionmentioning

confidence: 99%

Experimental Studies on the Crack Initiation and Propagation of Hydraulic Fracturing with Different Coal Structure Combinations

Liu,

Shu,

Wang

et al. 2023

ACS Omega

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Coal structure is one of the key geological factors that affects the effect of coal reservoir stimulation. Based on the geological spatial combination characteristics, thickness, and proportion of different coal structures, the coal reservoir is divided into different coal structure combination types. The hydraulic fracturing device is used to carry out indoor fracturing experiments and dissect the crack initiation and expansion characteristics with different coal structure combinations. The results show that the coal structure combination is of the binary type (undeformed coal + granulated coal or cataclastic coal + granulated coal), and the undeformed coal (cataclastic coal) can overcome the tensile strength and minimum principal stress when it is driven by the high-pressure fluid. The undeformed coal (cataclastic coal) ruptures and forms longitudinal cracks. The increasing proportion of granulated coal inhibits crack expansion and promotes the transverse deformation of coal. The interface contact point between the undeformed coal (cataclastic coal) and granulated coal easily fractures along the cross section of the specimen. When the coal structure combination is the triplex type (undeformed coal + granulated coal + cataclastic coal or cataclastic coal + granulated coal + cataclastic coal), the undeformed coal or cataclastic coal is transformed. The forming fractures in the undeformed coal (cataclastic coal) can cut through the soft coal when the thickness of the undeformed coal (cataclastic coal) is large and the thickness of granulated coal is thin. On the contrary, it is not easy to cut through. When the coal structure combination is granulated coal + cataclastic coal + granulated coal, the cataclastic coal fails under shear stress and forms the crack along the cross section of the coal sample. The granulated coal inhibits the crack expansion at both ends. The research results have an important indicative significance for further understanding the fracture initiation and propagation mechanism of hydraulic fracturing with complex coal structures in coal reservoirs.

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Ultrasonic-Induced Changes in Nanopores: Molecular Insights into Effects on CH4/CO2 Adsorption in Coal

Wang,

Yang,

Yang

et al. 2024

Nat Resour Res

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A new technology to enhance gas drainage in the composite coal seam with tectonic coal sublayer

Cited by 10 publications

References 31 publications

Optimizing Borehole Diameter for Maximum Gas Extraction Efficiency in Coal Seams

Optimizing Borehole Diameter for Maximum Gas Extraction Efficiency in Coal Seams

Experimental Studies on the Crack Initiation and Propagation of Hydraulic Fracturing with Different Coal Structure Combinations

Ultrasonic-Induced Changes in Nanopores: Molecular Insights into Effects on CH4/CO2 Adsorption in Coal

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