Exploring the Thin Talangakar Formation Sandstone Using Integrated Seismic Multi-Attribute Analysis and Spectral Decomposition in Kuang Area, South Sumatra Basin

Abstract

Abstract

The Kuang area, which is located in a marginal area of the South Sumatra Basin, contains relatively thin Talangakar Formation sediments compared to the overall thickness in the basin. This thin indicates that the condition of the area during Talangakar Formation deposition was a stable pre-Tertiary basement high. Of seven exploration wells within the study area, only one well has a hydrocarbon accumulation in the Talangakar Formation sandstone. The main issue with exploration targeting Talangakar Formation sandstone in the study area is the sandstone reservoir distribution. This study describes the distribution of sandstone members within Oligocene-Miocene Talangakar Formation and their depositional environment system.

A multi-attribute seismic analysis was conducted to build a pseudo gamma-ray cube for the delineation of Talangakar Formation sandstone distribution within recently acquired 355 km² of 3D seismic data. Multi-attribute seismic training using a step-wise algorithm reveals the best correlation combination of transform using four operators and five attributes. To overcome the issue of thin reservoir thickness, spectral decomposition was conducted as an additional static analysis to resolve the details of sandstone distribution. The resulting spectral decomposition maps at 25 Hz confirmed the sandstone distribution trend of the predicted gamma-ray maps. Both spectral decomposition and predicted gamma-ray maps show that most of the exploration wells penetrated out of good sandstone reservoir.

The geological interpretation was undertaken through an integrated analysis of paleogeography, well data, pseudo gamma ray and spectral decomposition maps. The major sedimentation direction of the Talangakar Formation in the area is to the southwest with transgression phase to the northeast. The depositional environment of the lower member was identified as a fluvio-deltaic system along a NE-SW direction with a channel pattern in the eastern part. The upper member has a NW-SE sandstone pattern sedimented in a shallow marine depositional system. The study result answers the failure of most exploration wells and describes the potential of the Talangakar Formation sandstone in the area. Some new prospects can be identified from a combination of well-developed sandstone areas and structural-stratigraphic traps.

AAPG Datapages/Search and Discovery Article #90260 © 2016 AAPG/SEG International Conference & Exhibition, Cancun, Mexico, September 6-9, 2016