Publications

Batu Ayau Formation is an Eocene Coal bearing formations in Upper Kutai Basin that has good coal bed methane (CBM) potential. Due to its coal quality, high gas content is expected in this formation. The objective of this study is to determine depositional environment and to evaluate coal bed methane potential in Upper Kutai Basin. Three different data were used to determine depositional environment, outcrop data located at Laham area in West Kutai Regency, coal proximate analysis, and biostratigraphy analysis to determine paleoenvironment Batu Ayau Formation. All data are used to understand the vertical stratigraphic succession and lateral distribution of Batu Ayau formation. CBM evaluation and Kim’s Formula (1977) are used to estimate gas content. Outcrop data analyses have resulted in five distinct facies associations’ classification: (1) Tidal Fluvial Channel/Intertidal Channel, (2) Floodplain/Marshes/Swamps deposit, (3) Crevasse Splays, (4) Intertidal Deposit, and (5) Marginal to Shallow Marine. This facies associations combined with biostratigraphy analysis showed depositional environment Fluvio-Tidal Environment in Lower to middle part and Marginal to Shallow Marine in Upper part. Coal characteristics in this formation are black, banded bright, black streak, hard, brittle-concoidal, fractured. The proximate analysis from several coal sample shows inherent moisture (IM) 2.84 %, ash 7.34 %, volatile matter (VM) 39.75 %, fixed carbon (FC) 50.06%, calorific value (CV) 7408 cal/gram (adb), Ro 0.65%, maceral composition is dominated by vitrinite (87.1%), is classified as High Volatile C Bituminus (ASTM standard). The Batu Ayau Formation is interpreted to be deposited in a tidal environment with influence of fluvial in lower part and wave in upper part. Gas content estimation of Eocene coal Batu Ayau Formation using Kim’s Formula (1977) based on the proximate data taken at depth 300 -1500 m is 240.91 – 376.75 scf/ton shows this formation has good potential for CBM development potential. The main challenge is to find the potential area with the thickest coal distribution.