DocumentCode :
3268725
Title :
Material balance method for calculating the reserves of unsaturated coal-bed methane reservoirs
Author :
Hu Suming ; Li Xiangfang ; Hu Xiaohu ; Wei Chenji
Author_Institution :
Coll. of Pet. Eng., China Univ. of Pet.(Beijing), Beijing, China
fYear :
2011
fDate :
15-17 April 2011
Firstpage :
4268
Lastpage :
4271
Abstract :
Traditional material balance methods for calculating coal-bed methane reserves did not consider whether the coal seam was saturated or not; actually, they were only applicable for the saturated ones. Therefore, a material balance method applicable for unsaturated coal seams has been developed in this paper. In the derivation, the initial gas content is expressed as a Langmuir´s equation with respect to the critical desorption pressure, rather than the initial reservoir pressure. Finally, a linear material balance equation of the pseudo average reservoir pressure vs. cumulative produced gas is obtained, whose intercept on horizontal axis yields the initial gas reserves, and intercept on vertical axis gives the pseudo critical desorption pressure, instead of the pseudo initial reservoir pressure. By using this method to evaluate a simulated reservoir, its reserves can be obtained with an error less than 0.35%, which indicates the method is reliable when the average reservoir pressure, initial cleat porosity, Langmuir´s volume and Langmuir´s pressure are accurate.
Keywords :
chemical engineering; coal; desorption; hydrocarbon reservoirs; organic compounds; porosity; Langmuir equation; Langmuir pressure; Langmuir volume; cleat porosity; critical desorption pressure; cumulative produced gas; initial gas content; linear material balance equation; pseudo average reservoir pressure; pseudo critical desorption pressure; unsaturated coal bed methane reservoir; unsaturated coal seam; Coal; Equations; Materials; Mathematical model; Petroleum; Reservoirs; USA Councils; coal-bed methane; gas content; material balance; reserves; unsaturated;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Electric Information and Control Engineering (ICEICE), 2011 International Conference on
Conference_Location :
Wuhan
Print_ISBN :
978-1-4244-8036-4
Type :
conf
DOI :
10.1109/ICEICE.2011.5777030
Filename :
5777030
Link To Document :
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