Sensitivity analysis of modeling parameters that affect the dual peaking behaviour in coalbed methane reservoirs
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Coalbed methane reservoir (CBM) performance is controlled by a complex set of reservoir, geologic, completion and operational parameters and the inter-relationships between those parameters. Therefore in order to understand and analyze CBM prospects, it is necessary to understand the following; (1) the relative importance of each parameter, (2) how they change under different constraints, and (3) what they mean as input parameters to the simulator. CBM exhibits a number of obvious differences from conventional gas reservoirs, one of which is in its modeling. This thesis includes a sensitivity study that provides a fuller understanding of the parameters involved in coalbed methane production, how coalbed methane reservoirs are modeled and the effects of the various modeling parameters on its reservoir performance. A dual porosity coalbed methane simulator is used to model primary production from a single well coal seam, for a variety of coal properties for this work. Varying different coal properties such as desorption time ( ÃÂ), initial gas adsorbed (Vi), fracture and matrix permabilities (kf and km), fracture and matrix porosity ( ÃÂf and ÃÂm), initial fracture and matrix pressure (to enable modeling of saturated and undersaturated reservoirs), we have approximated different types of coals. As part of the work, I will also investigate the modeling parameters that affect the dual peaking behavior observed during production from coalbed methane reservoirs. Generalized correlations, for a 2-D dimensional single well model are developed. The predictive equations can be used to predict the magnitude and time of peak gas rate.
Okeke, Amarachukwu Ngozi (2005). Sensitivity analysis of modeling parameters that affect the dual peaking behaviour in coalbed methane reservoirs. Master's thesis, Texas A&M University. Texas A&M University. Available electronically from