The Research of Variation Regularity of Coal Bed Methane Production in CO2 Flooding

2013 ◽  
Vol 868 ◽  
pp. 677-681
Author(s):  
Yang Liu ◽  
Di Wu

CO2flooding can increase coal bed methane production rate, enhance coal bed methane recovery and store CO2into underground. It has good application prospect for CBM development. This paper analyzes the adsorption-desorption law of mixed gas in the coal during the CO2injection process, as well as the diffusion and seepage law of gas in the coal seam. The sensitivity of factors affecting coal bed methane production is studied and then the coal bed methane production under different conditions is simulated numerically. The results show that methane concentration and coals permeability are the two key factors affecting the output of coal bed gas and their influence on productivity are even more significant than injection pressure and initial pressure. The higher injection pressure, coals permeability and gas concentration, the greater amount of methane the coal reservoirs will yield. When the coals permeability and the gas concentration in coal reservoirs increase, the growth rate of methane production accelerates accordingly.

2012 ◽  
Vol 134 (3) ◽  
Author(s):  
Jerzy Stopa ◽  
Stanisław Nawrat

This paper presents an improved reservoir simulation approach to methane production in a longwall mining environment. The coal beds are naturally fractured systems with the gas adsorbed into the coal matrix. Fractures penetrating the coal matrix have limited storage capacity, but they play the role of a gas transportation system. The proposed simulation technique is based on the assumption that a mass of coal removed by mining transfers its gas to adjacent fractures. By using an ECLIPSE coal bed methane simulator, the pore volume of the matrix represents the coal volume of the simulation cell. Consequently, the exploitation of coal can be simulated by modifying the matrix pore volume over time. This paper presents theoretical backgrounds of this approach and investigates numerical effects. A case study of the Moszczenica coal mine in Poland, including computer simulations of methane production, is also reported to show that a long history of the methane and coal recovery can be reproduced using the proposed technique.


2009 ◽  
Vol 1 (1) ◽  
pp. 81-89 ◽  
Author(s):  
Wang Zuo-tang ◽  
Wang Guo-xiong ◽  
Rudolph V. ◽  
Diniz da Costa J. C. ◽  
Huang Pei-ming ◽  
...  

2011 ◽  
Vol 29 (6) ◽  
pp. 759-775 ◽  
Author(s):  
Fengde Zhou ◽  
Guangqing Yao ◽  
Zhonghua Tang ◽  
Oyinkepreye D. Orodu

Matrix compressibility, shrinkage and swelling can cause profound changes in porosity and permeability of coalbed during gas sorption and desorption. These factors affect the distribution of pressure, methane production and CO2 sequestration. This paper compares the effects of cleat compression and matrix shrinkage and swelling models with the injection of different compositional gas mixtures (CO2 and N2). It shows that well performance, pressure distribution and properties of the seam are strongly affected by matrix shrinkage and swelling. Matrix shrinkage and swelling also affects net present value of the enhanced coalbed methane recovery scheme. In order to select the best enhanced coalbed methane recovery schemes, economic evaluation and sensitivity studies are necessary.


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