scholarly journals Coal Seam Permeability Improvement and CBM Production Enhancement by Enlarged Borehole: Mechanism and Application

2021 ◽  
Vol 118 (6) ◽  
pp. 1811-1825
Author(s):  
Xiyuan Li ◽  
Peng Chu ◽  
Zhuang Lu ◽  
Yuanyuan Liu ◽  
Zibin Zhu ◽  
...  
Keyword(s):  
Coal Seam ◽  
Cbm Production

scholarly journals Numerical analysis of drainage rate for multilayer drainage coalbed methane well group in Southern Qinshui basin

2020 ◽  
Vol 38 (5) ◽  
pp. 1535-1558
Author(s):  
Qiujia Hu ◽  
Shiqi Liu ◽  
Shuxun Sang ◽  
Huihuang Fang ◽  
Ashutosh Tripathy ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Coal Seam ◽  
Coalbed Methane ◽  
Gas Production ◽  
Hydraulic Pressure ◽  
Qinshui Basin ◽  
Well Production ◽  
Drainage Rate ◽  
Southern Qinshui Basin ◽  
Cbm Production

Multilayer drainage is one of the important technologies for coalbed methane (CBM) production in China. In this study, a multi-field fully coupled mathematical model for CBM production was established to analyze the multilayer drainage of CBM well group in southern Qinshui basin. Based on the numerical simulation results, the characteristics of CBM well production under different drainage rates and key factors influencing the CBM production were further discussed. The results show that the effect of an increased drainage rate on gas production of CBM wells and CBM recovery of No.3 coal seam is not significant. However, it significantly improved the gas production of CBM wells and CBM recovery of No.15 coal seam. After a long period of production, the CBM content in No.3 coal seam has reduced to a low level and the pressure drop potential of No.3 coal seam is insignificant, which are important reasons for the insignificant increase of CBM production even under a drainage rate of 2 to 7 times. Conversely, No.15 coal seam has larger residual CBM content and increasing the drainage rate can significantly improve the pressure drop and superimposed well interference of No.15 coal seam, which means No.15 coal seam has greater production potential than No.3 coal seam. Therefore, it is recommended to improve the gas production and CBM recovery in No.15 coal seam by increasing the drainage rate, and the average hydraulic pressure drop should be 0.018–0.031 MPa/day. The influence of effective stress is weak in No.3 and No.15 coal seam, and the coal seam permeability is largely influenced by the shrinkage of coal matrix caused by CBM desorption. This indicates the feasibility of increase in gas production from CBM wells by increasing the drainage rate.

scholarly journals Coalbed Methane Resources and Reservoir Characteristics of NO. II1 Coal Seam in the Jiaozuo Coalfield, China

2009 ◽  
Vol 27 (5) ◽  
pp. 307-332 ◽  
Author(s):  
Xiaodong Zhang ◽  
Yanhao Liu ◽  
Geoff Wang ◽  
Hao Liu
Keyword(s):  
Coal Seam ◽  
Coal Mine ◽  
Coalbed Methane ◽  
Gas Content ◽  
Burial Depth ◽  
Resource Concentration ◽  
Reservoir Evaluation ◽  
Average Value ◽  
West Part ◽  
Cbm Production

Jiaozuo coalfield is located in the northwest of Henan province, China, and close to the Southern Qinshui coal basin, the most successfully commercial CBM resource developed area in China. The No. II1 coal seam is the main economic coal seam in Jiaozuo coalfield and its average thickness exceeds 5.36m. The maximum reflectance of vitrinite (RO,max) of the No. II1 coal across the Jiaozuo is between 3.16% and 4.78%. The coalbody structure of the No. II1 coal seam changes greatly in different part and can be generally divided into 1∼3 sub-layers. The micropores in the No.II1 coal seam is the major pores, secondly are transitional pores, and then less macropores and mesopores. The No. II1 coal seam has stronger adsorption, and the reservoir natural permeability has an evident heterogeneity vary from 0.0001 to 83.71mD. High permeability region is often near fault structure or the boundary of fault block. The CBM genetic type is homologous thermal cracking gas of humic coal with high matunity. Gas content with the burial depth of 163∼1070m varies very greatly from 4.65 to 45.75m3/t, with an average value of 18.3m3/t, and gradually increases from northeast to southwest. According to the latest evaluation for CBM resource in Jiaozuo coalfield, the existing total in-place CBM resources in the No. II1 coal seam with the depth of shallower than 2000 m are close to 1.2 × 1012m3, most of them mainly distribute in the depth of 1000 ∼ 1500 m. The existing total in-place CBM resources is dominated by the inferred CBM resource reserves (more than 70%), which distribute the undrilled places with few coal geological knowledge and deeper than 1000m. The resource concentration of the No. II1 coal seam in Jiaozuo coalfield is in the range of (0.513–3.478)x108 m3/km2, with an average value of 1.805×108 m3/km2. Based on the CBM resource investigation and reservoir evaluation, the most prospective target zones for CBM production in Jiaozuo coalfield include Guhanshan coal mine, Jiulishan coal mine and the west part of Qiangnan coal district.

Phosphorus minerals in tonstein; coal seam 405 at Sośnica-Makoszowy coal mine, Upper Silesia, southern Poland

2013 ◽  
Vol 63 (2) ◽  
pp. 271-281 ◽  
Author(s):  
Magdalena Kokowska-Pawłowska ◽  
Jacek Nowak
Keyword(s):  
Trace Elements ◽  
Coal Seam ◽  
Mineral Composition ◽  
Coal Mine ◽  
Chemical Compositions ◽  
Coal Basin ◽  
Upper Silesia ◽  
Southern Poland ◽  
Basin Area

Abstract Kokowska-Pawłowska, M. and Nowak, J. 2013. Phosphorus minerals in tonstein; coal seam 405 at Sośnica- Makoszowy coal mine, Upper Silesia, southern Poland. Acta Geologica Polonica, 63 (2), 271-281. Warszawa. The paper presents results of research on tonstein, which constitutes an interburden in coal seam 405 at the Sośnica- Makoszowy coal mine, Makoszowy field (mining level 600 m), Upper Silesia, southern Poland. The mineral and chemical compositions of the tonstein differ from the typical compositions described earlier for tonsteins from Upper Silesia Coal Basin area. Additionally, minerals present in the tonsteins include kaolinite, quartz, kaolinitised biotite and feldspars. The presence of the phosphatic minerals apatite and goyazite has been recognized. The presence of gorceixite and crandallite is also possible. The contents of CaO (5.66 wt%) and P2O5 (6.2 wt%) are remarkably high. Analysis of selected trace elements demonstrated high contents of Sr (4937 ppm) and Ba (4300 ppm), related to the phosphatic minerals. On the basis of mineral composition the tonstein has been identified as a crystalline tonstein, transitional to a multiplied one.

TECHNIQUE OF EXPERIMENTAL TESTING OF THE TECHNOLOGY OF CYCLIC HYDRO IMPACT ON COAL SEAM THROUGH WELLS FROM THE SURFACE

2018 ◽  
Vol 6 (32) ◽  
pp. 17-25
Author(s):  
S.V. Slastunov ◽  
◽  
A.A. Meshkov ◽  
E.V. Mazanik ◽  
I.A. Komissarov ◽  
...  
Keyword(s):  
Coal Seam ◽  
Experimental Testing
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