Miocene Carbonate Microfacies Distribution of Tendehantu Formation, Mangkalihat Peninsula: Approach of Reservoir Potential using Outcrop Analogue
Koeshidayatullah, Ardiansyah I.; Al-Ramadan, Khalid; Cantrell, Dave L.
The origin and sedimentary evolution of the Mangkalihat Peninsula, Kalimantan (Borneo), is still debatable and has attracted the attention of many geologists and explorationists. The petroleum system of the area is believed to have good potential, because it lies between the highly productive and prospective Kutai and Tarakan basins. It consists mainly of reef-associated carbonate rocks. These carbonate rock types are the main reservoir rock types on the western-part of Indonesia. The objective of this research is to provide a detailed examination of the previously unstudied Miocene carbonate facies in this area. Based on field and petrographic analyses, this study showed that the microfacies distribution of the Tendehantu Formation consists of four microfacies as follows: 1) coralline-red algae boundstone, 2) rhodolith-bioclastic rudstone-grainstone, 3) bioclastic grainstone- mud lean packstone, and 4) foraminiferal wackestone-floatstone. The first two microfacies are considered to be deposited in the same environments, upper-middle reef front, with porosity of 10-25%. The depositional environment of microfacies 3 is suggested to be an upper fore-reef, while microfacies 4 is considered to be a lower fore-reef in the distal part of the carbonate margin, with porosities of 2-5%. These four microfacies together with mapping of the margin's morphology are used to interpret the depositional environment and construct a carbonate ramp model. The recognition of the four microfacies offers an additional tool to aid prediction of variations in reservoir potential in this area. Further seismic facies analysis is recommended to provide accurate thickness and lateral facies continuity that might not be possible to assess at the outcrop.
AAPG Search and Discovery Article #90163©2013AAPG 2013 Annual Convention and Exhibition, Pittsburgh, Pennsylvania, May 19-22, 2013