Analysis of advancing speed effect in gas safety extraction channels and pressure-relief gas extraction

Zhao, Pengxiang; Zhuo, Risheng; Li, Shugang; Shu, Chi‐Min; Laiwang, Bin; Jia, Yongyong; Shi, Yu; Suo, Liang

doi:10.1016/j.fuel.2019.116825

Cited by 31 publications

(22 citation statements)

References 32 publications

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“…Qu et al (2015) proposed a three-zone conceptual model comprising a fractured gas-interflow zone, a de-stressed gas-desorption zone, and a confined gas-adsorption zone in overlying strata of a longwall panel, accounting for the coupled behavior of strata deformation and gas flow. Li et al (2018) and Zhao et al (2020b) proposed the elliptic-paraboloid zone as an addition to mining-induced fracture theory and developed a simplified model of mining-induced fractures with a round-rectangle trapezoidal zone. Furthermore, Feng et al (2018) determined the gas enrichment area of fractured zone, and further calculated the gas storage space area under different advancing distance of working face.…”

Section: Introductionmentioning

confidence: 99%

RETRACTED: A new method for layout layer optimization of long horizontal borehole for gas extraction in overlying strata: a case study in Guhanshan coalmine, China

Guo

Yuan

et al. 2021

Preprint

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The large emission of pressure-relief gas in coal mining will cause atmospheric greenhouse effect. Arranging long horizontal borehole (LHB) to extract the gas is an effective solution. However, the determination of LHB layout layer in strata has a decisive effect on efficient gas extraction. A "zone-block" theoretical method for determining the LHB layout layer, in present study, was proposed by combining physical simulation test, theoretical analysis and engineering application. Three processes of the method were presented. Firstly, stable fractured subzone (SFSZ) was the optimum zone of the LHB layout based on the analysis of mining-induced fractures distribution and the borehole stability, and spatial location boundaries of the SFSZ in overlying strata were defined. Secondly, the SFSZ was divided into nine-grid blocks, the LHB layout suitability rate of each block were determined according to borehole stability rate, fracture permeability rate and gas accumulation rate. Finally, the LHB drilling could be conducted sequentially according to the layout suitability rate of each block in SFSZ. Field application results show that: the maximum and average amount of pure gas extracted through single borehole arranged in block I can reach up to 5.52 and 2.43 m3·min-1, respectively; and the pure amount in the entire extraction stage of the borehole is 2.53 and 6.69 times of boreholes arranged in blocks II and III, respectively. The proposed method can effectively determine the LHB layout layer in strata, so as to improve the gas extraction efficiency and ensure safe and green mining.

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Section: Introductionmentioning

confidence: 99%

RETRACTED: A new method for layout layer optimization of long horizontal borehole for gas extraction in overlying strata: a case study in Guhanshan coalmine, China

Guo

Yuan

et al. 2021

Preprint

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“…For mining stress relief and gas control technology, many experts have made a lot of profound researches. Zhao et al (2019Zhao et al ( , 2020aZhao et al ( , 2021 explored the influence of mining height, dip angle and advancing speed on the distribution of gas migration channels in overlying strata via laboratory similar simulation, and then proposed the evolution model of gas migration channel based on fractal dimension. Liu et al (2018b) explored the stress relief range and degree of surrounding rock in the steeply-inclined thick coal seam and put forward a design scheme of gas drainage borehole.…”

Section: Introductionmentioning

confidence: 99%

Evolution of mining stress field and the control technology of stress relief gas in close distance coal seam

Cheng

Zhao

et al. 2022

Energy Exploration & Exploitation

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The prevention and control of stress relief gas have crucial influence on safety of coal mine, it is not only the inevitable requirement of safe production, but also an effective way to realize reasonable utilization of gas. Taking the 1103 working face of the Weijiadi coal mine as the background, the mining stress field was analysed by means of numerical simulation, theoretical analysis and field practice, and the control technology of stress relief gas was studied. The results showed that scope of stress relief zone drops gradually associated with an increase of distance from the roof (or floor) to the working face. Additionally, the shape of the stress relief body exhibited a ring-shaped distribution, while four corners of the goaf roof and floor underwent high permeability zones due to a deep stress relief body, where the permeability of two corners near the transportation roadway of the floor was higher. The results provided good information for W-shaped ventilation mode with two inlets and one return which was adopted in the working face. More importantly, the optimized layout of boreholes was put forward, which eventually were useful for solving the gas overrun of the working face. The technology used in 1103 working face has an attractive and practical background with other extensive applications for the prevention and control of relief gas.

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“…In terms of extraction borehole placement and optimization, An et al studied directional boreholes for gas extraction from upper and lower adjacent beds, which broadened the areas of application of directional boreholes [16]. By conducting on-site high-level drilling field tests, Zhao et al optimized the parameters of the high-level boreholes based on specific advancing speeds, which ensured production safety and efficiency of the mining working face [17]. A dualporosity model was constructed by Si et al to describe gas migration in coal seams, and the ratio of gas diffusion and seepage was used to determine the optimal boreholes distance [18].…”

Section: Introductionmentioning

confidence: 99%

Effects of Borehole Arrangement on Methane Migration and Implications for High Efficiency Extraction in Intact and Tectonic Combined Coal Seams

Chang

Dong

2022

Geofluids

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Gas extraction by bedding boreholes is a key means to realize safe mining of coal mine and protect the environment. The traditional bedding boreholes are usually constructed in the center of the coal seam, which may not obtain a high methane extraction rate because of the existence of tectonic coal sublayer with low permeability. In this paper, the gas migration characteristics of combined coal seams composed of tectonic and intact coal sublayers are investigated, and the efficient gas extraction method is further explored. The results indicate that only 2.676 kg/m3 of gas can be extracted under the traditional bedding borehole arrangement in 300 days. The tectonic coal sublayer with low permeability restricts the gas in the intact coal sublayers to flow to the extraction boreholes, which is the main reason for the low gas extraction rate. By arranging boreholes up and down alternately with a vertical spacing of 2.74 m, the maximum gas amount of 3.526 kg/m3 can be extracted, showing an increased rate of 31.8%. The optimal vertical spacing between adjacent boreholes (VSAB) raises with the relatively increasing thickness or decreasing permeability of the tectonic coal sublayer. The optimal VSAB has a linear relationship with the thickness ratio of the tectonic coal sublayer to the combined coal seams. The optimal VSAB can be obtained referring to the numerical relationship, and then, the extraction boreholes can be dilled to achieve efficient gas extraction of combined coal seams. In engineering, the dislocation arrangement of borehole can greatly improve the gas extraction efficiency and coal mine safety.

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Analysis of advancing speed effect in gas safety extraction channels and pressure-relief gas extraction

Cited by 31 publications

References 32 publications

RETRACTED: A new method for layout layer optimization of long horizontal borehole for gas extraction in overlying strata: a case study in Guhanshan coalmine, China

RETRACTED: A new method for layout layer optimization of long horizontal borehole for gas extraction in overlying strata: a case study in Guhanshan coalmine, China

Evolution of mining stress field and the control technology of stress relief gas in close distance coal seam

Effects of Borehole Arrangement on Methane Migration and Implications for High Efficiency Extraction in Intact and Tectonic Combined Coal Seams

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