An Integrated Approach to Uncertainty Assessment for Coalbed Methane Model
This study deals with quantitative detection of parameters uncertainty in coalbed methane (CBM) modelling, and a systematic and integrated workflow is developed to analyse the uncertainty of CBM model. In the structure modelling, the uncertainty of measure depth and coal thickness uncertainty are analysed by disturbing the structure surfaces or thickness surfaces while fixed at the well locations. In the petrophysical modelling, an analysis of the residual distribution between each correlation and its measurements is used to characterize the uncertainty in each. Sensitivity analysis is performed for the parameters such as gas content, structure surfaces, coal ply thickness, density, ash content, to evaluate the volume uncertainty. The critical sensitive attributes are used to build multiple realizations to determine P90, P50 and P10 gas volumes. The low, middle and high probabilistic geological models are achieved corresponding to the probabilistic gas volumes and are used for the next reservoir simulation and development plan design.
KeywordsUncertainty analysis Coalbed methane Geological model Sensitivity analysis Gas content
Thanks are extended to Arrow Beijing Study Center for providing the opportunity to carry out the research. Thanks are also due to a number of our colleagues for their warm help.
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