scholarly journals Swelling Pressure of Double-Expansive Material and Its Active Support Effect for Coal Seam Gas Drainage Borehole

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Zhiming Wang ◽  
Yuning Sun
Keyword(s):  
Coal Seam ◽  
Field Tests ◽  
Swelling Pressure ◽  
Support Effect ◽  
Coal Seam Gas ◽  
Borehole Stability ◽  
Gas Drainage ◽  
Nonlinear Fitting ◽  
Improved Stability ◽  
Drainage Borehole

To improve coal seam gas drainage performance, we developed a double-expansive (DE) material to seal the borehole. The swelling process of this material includes an initial swelling stage and a secondary swelling stage. We studied the swelling pressure properties of the DE material under four constraint conditions using a self-made swelling test device. Further, the active support effect of the DE material on the borehole was analyzed by simulating borehole stability with COMSOL Multiphysics software. The results exhibit the following: (1) The swelling pressure of the DE material exhibits time-dependent behavior, and the mathematical relationship between the swelling pressure and time can be obtained by nonlinear fitting. (2) The radial swelling potential is principally formed during the secondary swelling stage, providing the main active support on the radial constraint. (3) The active support imposed on the hole wall can prevent the extension of plastic and damage regions around the borehole, for improved stability of the gas drainage borehole. Finally, field tests demonstrate improved gas drainage performance of the borehole sealed by the DE material compared to a conventional sealing material.

Computational fluid dynamics optimization of gas drainage technology in gas-mining areas

2021 ◽  
pp. 014459872110635
Author(s):  
Wei Zhao ◽  
Wei Qin
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Coal Seam ◽  
Field Tests ◽  
Mining Area ◽  
Engineering Practice ◽  
Horizontal Distance ◽  
Gas Drainage ◽  
Working Face ◽  
Gas Seepage

Coal mining results in strata movement and surrounding rock failure. Eventually, manual mining space will be occupied by the destructed coal rock, making it difficult to conduct field tests of the coal seam to explore gas seepage and transport patterns. Therefore, computational fluid dynamics (CFD) numerical computation is an important tool for such studies. From the aspect of gas pre-drainage, for layer-through boreholes in the floor roadway of the 8,406 working face in Yangquan Mine 5 in China, reasonable layout parameters were obtained by CFD optimization. For effectively controlling the scope of boreholes along coal seam 9 in the Kaiyuan Mine, CFD computation was performed. The results revealed that the horizontal spacing between boreholes should be ≤2 m when a tri-quincuncial borehole layout is used. Optimization of the surface well position layout for the fault structure zone in the Xinjing Mine of the Yangquan mining area indicated that the horizontal distance between the surface well and the fault plane should be <150 m. From the aspect of gas drainage with mining-induced pressure relief, CFD computation was performed for pressure-relieved gas transport in the K8205 working face of Yangquan Mine 3. The results showed that forced roof caving should be used before the overhang length of hard roof reaches 25 m in the K8205 working face to avoid gas overrun. From the aspect of gas drainage from the abandoned gob, surface well control scopes at different surface well positions were computed, and an O-ring fissure zone is proposed as a reasonable scope for the surface well layout. CFD computation has been widely applied to coal and gas co-extraction in the Yangquan mining area and has played a significant role in guiding related gas drainage engineering practice.

scholarly journals Numerical investigation of flue gas injection enhanced underground coal seam gas drainage

2019 ◽  
Vol 7 (6) ◽  
pp. 3204-3219 ◽  
Author(s):  
Bingjie Huo ◽  
Xuedong Jing ◽  
Chaojun Fan ◽  
Yongliang Han
Keyword(s):  
Coal Seam ◽  
Numerical Investigation ◽  
Flue Gas ◽  
Gas Injection ◽  
Coal Seam Gas ◽  
Gas Drainage

scholarly journals Experimental and measured research on three-dimensional deformation law of gas drainage borehole in coal seam

2020 ◽  
Vol 30 (3) ◽  
pp. 397-403
Author(s):  
Hongbao Zhao ◽  
Jinyu Li ◽  
Yihong Liu ◽  
Yikuo Wang ◽  
Tao Wang ◽  
...  
Keyword(s):  
Coal Seam ◽  
Three Dimensional ◽  
Gas Drainage ◽  
Deformation Law ◽  
Drainage Borehole

N2 injection to enhance coal seam gas drainage (N2-ECGD): Insights from underground field trial investigation

Energy ◽  
2022 ◽  
Vol 239 ◽  
pp. 122247
Author(s):  
Xin Yang ◽  
Gongda Wang ◽  
Feng Du ◽  
Longzhe Jin ◽  
Haoran Gong
Keyword(s):  
Coal Seam ◽  
Field Trial ◽  
Coal Seam Gas ◽  
Gas Drainage

scholarly journals Interactions between coal seam gas drainage boreholes and the impact of such on borehole patterns

2017 ◽  
Vol 38 ◽  
pp. 597-607 ◽  
Author(s):  
Zhengdong Liu ◽  
Yuanping Cheng ◽  
Jingyu Jiang ◽  
Wei Li ◽  
Kan Jin
Keyword(s):  
Coal Seam ◽  
Coal Seam Gas ◽  
Gas Drainage ◽  
The Impact

A Stimulation and Production Experiment in a Vertical Coal Seam Gas Drainage Well

1996 ◽  
Author(s):  
R.G. Jeffrey ◽  
J.R. Enever ◽  
J.H. Wood ◽  
J.P. Connors ◽  
S.K. Choi ◽  
...  
Keyword(s):  
Coal Seam ◽  
Coal Seam Gas ◽  
Gas Drainage ◽  
Production Experiment

Applications of Indirect Hydraulic Fracturing to Improve Coal Seam Gas Drainage for the Surat and Bowen Basins, Australia

2021 ◽  
Author(s):  
Raymond Leslie Johnson ◽  
Honja Miharisoa Ramanandraibe ◽  
Ayrton Ribeiro ◽  
Matthew Ramsay ◽  
Kaa Tipene ◽  
...  
Keyword(s):  
Coal Seam ◽  
Hydraulic Fracturing ◽  
Coal Seam Gas ◽  
Gas Drainage

scholarly journals Speculum Observation and Trajectory Measurement in Gas Extraction Drilling: A Case Study of Changling Coal Mine

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Enbiao Zhao ◽  
Kangnan Li ◽  
Xin Yang ◽  
Nan Deng
Keyword(s):  
Coal Seam ◽  
Coal Mine ◽  
Efficient Production ◽  
Drilling Process ◽  
Coal Seams ◽  
Adjacent Layer ◽  
Gas Drainage ◽  
High Level ◽  
Trajectory Measurement ◽  
Drainage Borehole

Coal will still be China’s basic energy for quite a long time. With the increase of mining depth, gas content and pressure also increase. The problems of gas emission and overrun affect the safety and efficient production of coal resource to a certain extent. In this work, the field test of gas drainage borehole peeping and trajectory measurement in coal seam of Changling coal mine are carried out. These coal seams include C5b coal seam, upper adjacent C5a coal seam, C6a coal seams, C6c in lower adjacent strata, and C5b coal seam in high-level borehole. The view of gas drainage borehole peeping and trajectory measurement in the working seam, upper adjacent layer, lower adjacent layer, and high position are obtained. It is found that the hole collapses at the position of about 20 m in both adjacent strata and high-level boreholes, and there are a lot of cracks in the high-level boreholes before 12 m. The deviation distance of high-level borehole is large, and the actual vertical deviation of upper adjacent layer is small. Finally, the strategies to prevent the deviation of drilling construction are put forward. It includes four aspects: ensuring the reliability of drilling equipment, reasonably controlling the drilling length, standardizing the drilling, and reasonably selecting the drilling process parameters.

scholarly journals Analysis of Coal Seam Gas Emission Based on Mine Gas Drainage Statistics

2019 ◽  
Vol 384 ◽  
pp. 012163
Author(s):  
Jufeng Zhang ◽  
Xuguang Li ◽  
Fengfeng Yang ◽  
Tai Xu ◽  
Chao Zheng ◽  
...  
Keyword(s):  
Coal Seam ◽  
Coal Seam Gas ◽  
Gas Emission ◽  
Gas Drainage ◽  
Mine Gas

scholarly journals Influence of polycrystalline diamond compact bit geometric parameters on drilling performance during gas drainage borehole in soft coal seam

2018 ◽  
Vol 10 (1) ◽  
pp. 168781401775066
Author(s):  
Xiaoming Han ◽  
Qiangqiang Zhang ◽  
Shifeng Wang ◽  
Jialiang Li ◽  
Detuo Chen
Keyword(s):  
Coal Seam ◽  
Polycrystalline Diamond ◽  
Rake Angle ◽  
Gas Drainage ◽  
Drilling Performance ◽  
Soft Coal ◽  
Feeding Resistance ◽  
Soft Coal Seam ◽  
Diamond Bit ◽  
Drainage Borehole

Polycrystalline diamond compact bit is the main rock-breaking tool of gas drainage borehole. In order to investigate the influence of geometric parameters of polycrystalline diamond bit on its drilling performance, the integrated force model of polycrystalline diamond bit pressed into rock was established. The stress analysis results show that the tooth rake angle, pressing depth, and horizontal tangential displacement are the main factors to influence the normal load and the axial load of polycrystalline diamond bit. There is an optimal tooth rake angle value of polycrystalline diamond bit cutter when it is used in the soft coal seam. The drilling experiment system was built to verify the drilling performance of drill bits with different geometric structure and different tooth rake angle through drilling the soft coal wall. The experiment results show that the drilling torque and feeding resistance of polycrystalline diamond bit are higher than that of the wing bit at the beginning of drilling the soft coal wall. With the increase in the drilling depth, the feeding resistance of wing bit will increase to exceed that of the polycrystalline diamond bit. So the polycrystalline diamond bits should be selected to drill the gas drainage borehole in soft coal seam. The polycrystalline diamond bit with bigger tooth rake angle cannot cut and break the coal rock effectively, which will reduce the drilling efficiency and the feeding speed. When the tooth rake angle is smaller, polycrystalline diamond bit cannot cut in coal wall effectively, which will increase the feeding resistance. So the polycrystalline diamond bit with tooth rake angle of 15°–20° is suitable for the gas drainage borehole in soft coal seam. With the increase in the rotary speed of polycrystalline diamond bit, the cutting thickness of coal rock decreases and the horizontal tangential displacement increases. When the rotary speed of polycrystalline diamond bit is 290 r/min, the mean drilling torque and mean feeding resistance of polycrystalline diamond bit reach the minimum. Therefore, in order to reach the optimum drilling performance, the working parameters of low drilling pressure and high rotary speed are usually selected during the actual gas drainage borehole in soft coal seam.

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