RESERVOIR MODELLING AND COALBED METHANE RESERVE ESTIMATION IN SANGATTA AREA, KUTAI BASIN, EAST KALIMANTAN

• Main Author: Rajasanegara, Bintang
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/44222
• Institution: Institut Teknologi Bandung

Coalbed Methane is one type of unconventional hydrocarbon with a large and prospective volumetric potential for next development stage to contribute for high energy demand in Indonesia. Kutai Basin is one of Tertiary basin which is coal-rich as stored in Balikpapan Formation. Coal in Balikpapan Formation characterized by fluvio-deltaic deposit during post inversion phase in Middle Miocene. The aim of this study is to determine the coal reservoir property including depositional environment and distribution trend of reservoir, calculate coal bulk volume and coalbed methane volume, determine aquifer system distribution and its impacts to coalbed methane reservoir. Data used in this study consists of well data including wireline log data, biostratigraphy report, core and sidewall core description and laboratory analysis data; 2D seismic line data, and borehole section data. Coal analysis utilized by core and sidewall core description data guided with maceral composition and biostratigraphy report reveals that coal seam is delta plain deposit. Depositional facies point out more detail deltaic environment which categorized as tide-dominated delta and come up with seven lithofacieses (Cb, Ssc, Shb, Ssf, Shc, Shl dan Ssw) as it indicates 4 facies association called marsh, tidal channel, tidal mixed flat and intertidal bars. Coal rank analysis exhibits bituminous – high volatile C bituminous and prospectively generate coalbed methane biogenic type. Petrophysical analysis could deliver proximate curve data in uncored interval with no laboratory data. This analysis brings out occupied by wireline log data and modified Kim equation. Facies and coal-proximate properties model show the reservoir distribution and its proximate property following facies trend of tide-dominated delta. Aquifer distribution in study area also exhibit similar trend with facies and it generates two aquifer bed which is directly affected the coalbed methane reservoir particularly in interseam U4-U3 and interseam U2-U1 layer. Volumetric calculation yields 868,958 acre.ft of coal bulk volume and 93,26 BcF of coalbed methane gas volume.