A Case Study on the Gas Drainage Optimization Based on the Effective Borehole Spacing in Sima Coal Mine

Ji, Ming; Sun, Zhongguang; Sun, Wei

doi:10.1155/2021/5510566

Cited by 6 publications

(1 citation statement)

References 14 publications

(16 reference statements)

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“…(1) Reasonable Borehole Spacing in a Fully Pressure-Relief Zone. To determine reasonable borehole spacing in the fully pressure-relief zone (see Figure 10), according to the literature [24], five cases of gas extraction with borehole spacing being 20 m, 25 m, 30 m, 35 m, and 40 m are simulated, respectively. The gas pressure-time curves for monitoring point under varying borehole spacings are given in Figure 20.…”

Section: Reasonable Borehole Spacing In Different Pressure Relief Zonesmentioning

confidence: 99%

Numerical Assessment on Unloading Disturbance and Gas Extraction in Remote Distance Protective Layer Mining

et al. 2022

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Protective layer mining could not only significantly alter geostress but also increase the permeability of protected layer, which is beneficial for the coal gas extraction rate and ensures coal mining safety. However, due to unique geologic conditions, remote distance protective layer mining has its own characteristics. To investigate characteristic changes caused by remote distance protective layer mining, a suitable mathematical model that considered disturbance of unloading mining and solid-gas coupling effects during gas extraction was developed. The established mathematical model was implemented by combining FLAC3D and COMSOL programs to study characteristic changes during remote distance protective layer mining of Chajiaotan coal mine. Numerical simulation results of unloading disturbance mining indicated that the protected layer would experience a process of stress loading, stress unloading, stress recovery, and stress stability as the working face of protective layer advanced; unloading disturbance has a greater influence on coal permeability than gas pressure; gas extraction measure should be further adopted to decrease gas pressure. Numerical comparisons of gas pressure distribution in the original protected layer and unloading protected layer revealed that gas extraction after unloading disturbance can reduce gas pressure more effectively, and appropriate borehole spacings in the fully pressure-relief and nonfully pressure-relief zones are 30 m and 5 m, respectively. The layout of field boreholes for gas extraction was designed according to numerical results. The results of site investigation showed that numerical simulation results of relative expansion deformation and gas extraction radii agree well with the results of site observation, demonstrating reliability of the mathematical model and its implementation. The proposed mathematical model is promising for assessing unloading disturbance and gas extraction in remote distance protective layer mining.

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Section: Reasonable Borehole Spacing In Different Pressure Relief Zonesmentioning

confidence: 99%

Numerical Assessment on Unloading Disturbance and Gas Extraction in Remote Distance Protective Layer Mining

et al. 2022

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Effect of proppant distribution in hydraulic fractures on coalbed methane extraction

Li,

Huang,

Zheng

et al. 2023

Results in Engineering

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Coalbed Methane Industry Development Framework and Its Limiting Factors in China

2022

Geofluids

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The current average daily gas production of single coalbed methane (CBM) wells in China is less than 1,300 m3. The low production rate of CBM wells dramatically limits the sustainable development of the CBM industry in China. To promote CBM industry development, three universal geological factors, i.e., gas sources, channels, and driving force of the low production wells are analyzed, considering the various and complicated geological conditions of CBM reservoirs in China. Additionally, we find that the growth in proven CBM reserves should be greatly promoted as the CBM proven rate is only less than 3% by the end of 2020. The widespread CBM extraction mode based on depressurization via dewatering generates very limited effects in coal seams with notable deformation, high in situ stress, or little water. Therefore, a specific design of CBM development modes is proposed, according to the applicable geological conditions of different CBM development modes. It covers depressurization via dewatering, depressurization via stress release, and coal and CBM comining. Moreover, the regional governments play a key role in the development of the regional CBM industry, and favorable policies should be formulated to promote the multipoint development conditions across China. This study is concluded to provide a recommended development framework involving sustainable CBM production in China and its development processes.

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A Case Study on the Gas Drainage Optimization Based on the Effective Borehole Spacing in Sima Coal Mine

Cited by 6 publications

References 14 publications

Numerical Assessment on Unloading Disturbance and Gas Extraction in Remote Distance Protective Layer Mining

Numerical Assessment on Unloading Disturbance and Gas Extraction in Remote Distance Protective Layer Mining

Effect of proppant distribution in hydraulic fractures on coalbed methane extraction

Coalbed Methane Industry Development Framework and Its Limiting Factors in China

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