Play Analysis & Potential Exploration Opportunities of the Ombilin Basin, West Sumatera

Abstrak

The Ombilin Basin is located next to Indonesia's most prolific oil-producing basin: The Central Sumatra Basin (CSB), i.e. Minas Field, 8 BBOE (Greaser et al., 1996). An earlier study by PT Rizki Bukit Barisan revealed that this basin potentially holds up to 600 MMBOE of oil and gas. Based on the physiography of Sumatra Island, the Ombilin Basin was classified as a Tertiary intermontane basin (Koesoemadinata and Matasak, 1981). The basin is situated within the continental crust along the Sumatra Fault Zone (SFZ), surrounded by a more recent magmatic arc. The magmatic arc, however, did not necessarily affect the basin's geothermal gradient (Koning, 1985). These complexities make the basin modelling process even more problematic, considering the already complex tectonostratigraphy and leaking faults. Therefore, a deep understanding of structurally related sedimentary processes and in-depth fault seal analysis are important.
The objective of this study is to analyse on more play concepts that have not been the focus of the previous exploration to expand the knowledge to unlock exploration possibilities within the basin. Using the new drilled wells combined with the surface oil seep and newly processed seismic, a new perspective in hope to find more resources within this basin can be reinforced. Using the integration of Basin Modelling and Advanced Seismic Processing, 12 prospects within 4 formation intervals were identified. Monte Carlo simulation was also applied to understand the impact of uncertainty-related information to help de-risk all the potential prospect so that all available resources can be used effectively.
Furthermore, the study documents new methods of exploration in Intermontane basin, this will enable readers to learn and as a guide for designing a future exploration and development in an Intermontane basin, not only but especially in Indonesia.