Enhanced coal bed methane (ECBM) recovery: optimization of CBM production using different injected gas composition and rate for south sumatra CBM field, IndonesiaAbdul Wahid, Fariz Adriansyah Putra, Muhamad Taufiq Hidayat and Muhammad YusufE3S Web Conf., 67 (2018) 03015DOI: https://doi.org/10.1051/e3sconf/20186703015