Macrolithotype characteristics of coal seam and their controls on coalbed methane well productivity in the Hancheng block of the southeastern margin of Ordos Basin

2020 ◽  
pp. 1-14
Author(s):  
Tiantian Zhao ◽  
Hao Xu ◽  
Dazhen Tang ◽  
Yulong Liu
Keyword(s):  
Coal Seam ◽  
Coalbed Methane ◽  
Ordos Basin ◽  
Well Productivity ◽  
Southeastern Margin

Effect of Coal Dust on Coalbed Methane Wells Productivity

2013 ◽  
Vol 641-642 ◽  
pp. 26-29
Author(s):  
Hong Ze Ma
Keyword(s):  
Natural Gas ◽  
Coal Seam ◽  
Coalbed Methane ◽  
Coal Dust ◽  
Path Model ◽  
Well Productivity ◽  
Vertical Well ◽  
Parallel Path

CBM has the largest reserve except for conventional natural gas and is the cleanest energy. However, neither coal seam permeability nor CBM vertical well productivity has been determined when the immigration of coal dust are considered, which restricts the economic CBM exploitation. Based on coal seam characteristics, use permeability parallel path model and CBM seepage equation. The results show that with different ratio of non-clogging path and the total path, coal seam permeability and CBM vertical well productivity may either increase or decrease.

scholarly journals Geological conditions of coalbed methane accumulation in the Hancheng area, southeastern Ordos Basin, China: Implications for coalbed methane high-yield potential

2019 ◽  
Vol 37 (3) ◽  
pp. 922-944 ◽  
Author(s):  
Chen Guo ◽  
Yucheng Xia ◽  
Dongmin Ma ◽  
Xueyang Sun ◽  
Gelian Dai ◽  
...  
Keyword(s):  
Coal Seam ◽  
Coalbed Methane ◽  
Hot Spot ◽  
Ordos Basin ◽  
Yield Potential ◽  
High Yield ◽  
Tectonic Deformation ◽  
Critical Depth ◽  
Geological Conditions ◽  
High Yield Potential

The Hancheng area is a hot spot for coalbed methane exploration and exploitation in China. Structure is a key factor affecting coalbed methane accumulation and production in the Hancheng area. For a better understanding of the coalbed methane accumulation conditions and high-yield potential, this study investigates the structural patterns and evolution, the hydrogeological conditions, and the geothermal field in the coal-bearing strata in the Hancheng area. Then, the spatial distribution of the coalbed methane content and the tectonic deformation of the coal seam are evaluated. Finally, the critical depth for coalbed methane enrichment and a high-yield potential are revealed, and the favorable areas for coalbed methane development are predicted. The following conclusions are obtained: (1) Under the Yanshanian SE–NW trending maximum principle stress, the Hancheng overturned anticline was formed and subsequently subjected to uplift and erosion along its axis, which led to the NW limb of the anticline forming the current uniclinal structure of the Hancheng area; (2) Four degrees of tectonic deformation in the coal seam are identified based on structural curvature analysis. The moderately deformed area shallower than 800 m would benefit coalbed methane production with higher permeability. Most of the locations of coal and gas outburst events that occur during coal mining were distributed along the highly and very highly deformed areas; (3) The gas content gradually increases along the NW-trending inclination of the coal seam. 400 m and 800 m are discriminated as the critical depth levels for controlling coalbed methane accumulation and a high yield. Secondary biogenic methane was generated in the shallow formations; and (4) The Hancheng area is divided into four ranks for determining coalbed methane development potential. From high to low, they are ranked A, B-1, B-2, and C. Most of the high-yield wells are located in the areas ranked A and B-1.

scholarly journals Geochemical characteristics and genesis of coalbed methane in Baode area on the eastern margin of Ordos Basin

2020 ◽  
Vol 206 ◽  
pp. 01019
Author(s):  
Weiqiang Hu ◽  
Xin Chen ◽  
Yangbing Li ◽  
Litao Ma ◽  
Wang Yuesheng ◽  
...  
Keyword(s):  
Coal Seam ◽  
Coalbed Methane ◽  
Ordos Basin ◽  
Mean Value ◽  
Geochemical Characteristics ◽  
Coal Bed ◽  
Mass Reproduction ◽  
External Water ◽  
Systematic Understanding ◽  
Exploration And Development

The degree of coalbed methane exploration and development now in Baode area is relatively low. The lack of systematic understanding of the formation of coalbed methane in this area restricts the further exploration and development of coalbed methane. Based on the comprehensive study on the geochemical characteristics of coalbed methane components, hydrocarbon isotopes, water quality detection and hydrogen oxygen isotopes in coal seam in Baode area, the origin of coalbed methane in this area is discussed. According to the research, the hydrocarbon gas in the composition of coalbed methane in Baode area is mainly CH4 and a small amount of ethane. Both of their drying coefficients are more than 0.99, so they belong to the extremely dry coal bed methane. The value of δ13C(CH4) coalbed methane is on the low side and the value of δ13C(CO2) is on the high side, the mean value of δD(CH4) is -247.5‰, which shows the characteristics of terrestrial biogas. The water produced by coal seam is weak alkaline and belongs to the NaHCO3 type of water. which is similar to the surface water ion composition, salinity , δD(H2O) and δ18O(H2O) values, indicating that the hydrodynamic conditions of the coal seam in this area are more active. There is a recharge of external water, which is benificial to the mass reproduction of CH4 producing bacteria and the formation of biogas. In this area, the coalbed methane is a mixture of thermogenic and biological genesis, mainly composed of thermogenic gases and supplemented by biogenic gases generated through carbon dioxide reduction.

scholarly journals Quantify Coal Macrolithotypes of a Whole Coal Seam: A Method Combing Multiple Geophysical Logging and Principal Component Analysis

Energies ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 213
Author(s):  
Chao Cui ◽  
Suoliang Chang ◽  
Yanbin Yao ◽  
Lutong Cao
Keyword(s):  
Principal Component Analysis ◽  
Coal Seam ◽  
Coalbed Methane ◽  
Principal Component ◽  
Component Analysis ◽  
Gas Production ◽  
Index Model ◽  
Geophysical Logging ◽  
The Relationship ◽  
Observation Results

Coal macrolithotypes control the reservoir heterogeneity, which plays a significant role in the exploration and development of coalbed methane. Traditional methods for coal macrolithotype evaluation often rely on core observation, but these techniques are non-economical and insufficient. The geophysical logging data are easily available for coalbed methane exploration; thus, it is necessary to find a relationship between core observation results and wireline logging data, and then to provide a new method to quantify coal macrolithotypes of a whole coal seam. In this study, we propose a L-Index model by combing the multiple geophysical logging data with principal component analysis, and we use the L-Index model to quantitatively evaluate the vertical and regional distributions of the macrolithotypes of No. 3 coal seam in Zhengzhuang field, southern Qinshui basin. Moreover, we also proposed a S-Index model to quantitatively evaluate the general brightness of a whole coal seam: the increase of the S-Index from 1 to 3.7, indicates decreasing brightness, i.e., from bright coal to dull coal. Finally, we discussed the relationship between S-Index and the hydro-fracturing effect. It was found that the coal seam with low S-Index values can easily form long extending fractures during hydraulic fracturing. Therefore, the lower S-Index values indicate much more favorable gas production potential in the Zhengzhuang field. This study provides a new methodology to evaluate coal macrolithotypes by using geophysical logging data.

Coalbed Methane Geostatistical Analysis: A Method for Ranking Well Productivity

1986 ◽  
Author(s):  
H.R. Pratt ◽  
E.H. Robey ◽  
R.A. Wojewodka ◽  
J.C. Mercer
Keyword(s):  
Coalbed Methane ◽  
Geostatistical Analysis ◽  
Well Productivity
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