Application of probabilistic approach to evaluate coalbed methane resources using geological data of coal basin in Indonesia

Abstract

The aim of this study is to present coalbed methane (CBM) resources with more comprehensive estimation from geological data of coal basins in Indonesia. As Indonesia has the huge amount of coal resources, CBM potential is also highly expected. However, insufficient assessments due to the lack of data in the coalbed reservoir have been done, resulting in lack of accuracy in resource estimations. In this study, volumetric and material balance analysis using Monte Carlo simulation was carried out to evaluate the CBM resources. The focus of the part include selection of parameters, determination of distribution function, generation of random numbers, and evaluation of the parameters corresponding to random numbers in Monte Carlo simulation. The coal reservoirs and CBM properties were obtained from Powder River and San Juan basins in the US, while geological and drilling data were obtained from the fields in Indonesia. As the results, the total CBM resources of Indonesian 6 target basins are evaluated to be approximately 15.10 trillion m3 and 15.27 trillion m3 as the best estimate (analog with 2P reserve) by volumetric and material balance estimation, respectively.