Acoustic Impedance Inversion Method to Determine Carbonate Reservoir Distribution of South Makassar Strait Basin Muhammad Alfan Bani Herdiaman (a*), Tumpal Bernhard Nainggolan (b), Eddy Supriyana (a)
(a) Department of Geophysics, Padjadjaran University, Jl. Raya Bandung Sumedang Km. 21, Jatinangor, 45363, Indonesia
*alfanbaniherdiaman[at]gmail.com
(b) Research Center for Geological Resources, National Research and Innovation Agency, Jl. Sangkuriang 21, Bandung, 40135, Indonesia
Abstract
The South Makassar Strait Basin is considered as a basin that has potential hydrocarbon reserves in eastern Indonesia, since it is adjacent to Sebuku Block, a giant oil and gas field. Some of the most productive hydrocarbon reservoirs have come from carbonate build-up in shallow marine, but in this area, carbonate build up has been found on deep marine. Carbonate rocks in this basin are aged from Miocene-Oligocene of Berai Formation. This study aims to obtain distribution of carbonate build-up reservoir and to prove the existence of petroleum system of South Makassar Strait Basin. Acoustic Impedance (AI) inversion method was carried out to obtain information on the distribution of carbonate reservoirs with marine 2D seismic post-stack time migration and Sultan-1 and Kris-1 wells. Target zone as carbonate reservoirs are determined at 3133-3523 m on Sultan-1 well and 3651-to 3773 m on Kris-1 well. Based on analysis, Sultan-1 well shows gas column with gas water contact but Kris-1 well shows no hydrocarbon on Berai Formation carbonate reservoirs. Both wells show the development of complex carbonate build-up in the neritic zone environment. In Oligocene period, rifting process of South Makassar Strait has stopped and has transformed into steady and calm phase. The Berai Formation model shows environmental changes laterally northwest-southeast of the platform from reef facies to the submarine basin and basinal plain facies.
