Publications

The southern border of the Upper Kutai Basin is a semi-mature exploration area in Central Kalimantan which has proven producing hydrocarbons. In 1982, a significant gas and condensate accumulation was discovered in Oligocene Carbonates in Kerendan Field. Most of the seismic data in this area have poor-fair quality. So an integrated study of the surface and sub-surface was needed to get a better petroleum system component potential oversight. Surface geological mapping and measured oucrop stratigraphy were integrated with well correlations and seismic facies to obtain the depositional environments and overall stratigraphic framework. Burial history analysis from source rock maturity and petrographic analysis were conducted to understand the diagenesis or burial effects within the reservoir and source rock quality. Detailed surface structural geology investigations were integrated with image/landsat and seismic interpretations to valididate structure occurrences and possible reconstruction of the traps. Syn-rift sediments were developed during Middle to Late Eocene with terrestrial to deltaic environments A bounding fault (southern area), transitions to a marine environments which developed in a flexural margin (northern area). Post-rift sediments were developed during Early to Late Oligocene which were dominated with a marine environment, isolated reefs commonly occur in the northern area, and platform carbonates occur in the southern area. Inversion sedimentation developed in Early to Late Miocene which was dominated with deltaic sediments, where the paleo-shoreline changed from a E-W to a N-S direction. A Post-Inversion stage is developed during Plio-Pleistocene which is composed of mollasic sediments and NE-SW thrust faults. The primary source rocks are Eocene, fluvial-deltaics (Type II, III, II & III, and matured) and Oligocene marine source rocks. The best reservoirs are Miocene & Eocene fluvial deltaic sandstones and Oligocene carbonates with secondary porosity (fracture and dissolution). Regional seals are Late Oligocene offshore-bathyal shales and intra-formational seals of Eocene and Miocene deltaic sediments. The predominate traps are a combination of stratigraphy and structure which are controlled by NE-SW thrust faults or fold propagated faults