Publications

Kutai basin is the second largest Tertiary basin that produced oil and gas in Indonesia, with proven reserve more than 11 BBOE (Corutney, et al., 1997). More than 85% reserve is located in the Middle Miocene sediment.There are two different data used in this research: outcrop data located at Loa Janan, Samarinda Seberang, East Kalimantan and well data from Intan field, located at the center of modern Mahakam Delta (Figure 1 and 2).The outcrop data will be used as an analog to the subsurface data to understand the lateral stratigraphy distribution and reservoir characterization. The startigraphy succession and stacking pattern in the subsurface has the similarity to the outcrop sediments at the same age in the Mahakam Delta (Samson et al., 2005 op cit Cibaj, 2007).There are five distinct facies associations classification: (1) tidal influenced distributary channel, (2) flood plain deposit, (3) distributary mouth bar, (4) deltafront mud, and (5) prodelta mud. Seven deltaic cycles are recognized and represents high-frequency parasequence cycles. Stacking pattern of parasequence sets in the lower and middle part of the outcrop interval differ the system track. The lower section shows retrogradational parasequence set that represents TST and the above parasequence set shows progradational parasequence set that represents HST. The last section shows aggradational parasequence set that represents LST. The isopach map shows that the distributary channel shows elongated distribution with W - E trend and distributary mouth bar shows lobate distribution. Petrography analysis shows that pore type of this deltaic deposit is predominantly intergranular (primer) porosity that is cemented by ferro oxide and carbonate cement. Maximum value of distributary channel effective porosity is along channel axis. The effective porosity is up to 27% and porosity from petrography analysis ranges 20 - 25%. Maximum value of distributary mouth bar effective porosity is at the top of the bar. The value up to 25% and the porosity from petrography analysis ranges 10 - 20%.