Publications

“DR” area is located in the most prolific Basin in Indonesia, Central Sumatra Basin. In this location, Bangko Formation has been reevaluated using modern concept and facies model. In this study, 2 core wells and 134 well logs were examined. The method consists of several step (1) core analysis, (2) electrofacies calibration, (3) Hi-resolution sequence stratigraphy correlation, (4) Facies mapping in the Bangko Formation. Core analysis reveals evidence to approve the tidal control: tidal bundles, mud drapes, heterolithic stratification, glauconite, hummocky and through cross bed, wavy and lenticuler sedimentary structure and fluid mud existence within the conglomerate thalweg deposit. Ichnofacies analysis was firstly used in the area and it is give significant result in appearance of Zoophycos, Cruziana, and Skolithos that shows progradation trend in the stratigraphic record. Highresolution sequence stratigraphy correlation within the area result in lateral geometry of depositional facies of the area, they are the Tidal Channel, Tidar Bar, Subtidal Bar, and Shelf Ridges, also accompanied mudstone and siltstone as local seal of the Prodelta, Delta Front and Tidal Flat facies. The facies maps revealing the geometry of the delta itself, it is having funnel shape channel geometry bounded by tidal point bar and tidal flat facies. This channel is prograding and has Tidal Bars on top of it, which were the series of the Channel-Bar-Tidal Flat succession. This bars are built by control of tide and have elongate shape parallel to the sedimentation direction. These data and interpretation are used to build the model of tide dominated delta at Early Miocene age. This comprehensive study offering another reference * Gadjah Mada University ** Chevron Pacific Indonesia to approach the Bangko succession as deposit of sand-rich tropic tide dominated delta in Central Sumatra Basin.