Seismic Geomorphology of the LTAF Formation in JB Block, South Sumatra Basin

Abstract

After 15 years of exploration in the LTAF Formation at JB Block, undiscovered structural traps decrease both in size and in quantity. The stratigraphic trap has the highest potential to play more important role in the future. Guided by seismic sedimentology, seismic attributes, strata slicing, RGB frequency division, and combination technology, coupled with core, logging, and seismic data interpretation, have been integrated to investigate the seismic geomorphology, which will facilitate the discovery of stratigraphic exploration targets. The results show that the base-level rise half-cycle in the LTAF Formation consists of alluvial fan, braided river, and littoral to deep lacustrine sediments. The development of alluvial fan is mainly controlled by paleo-geomorphology, which is distributed around the paleo-highs with limited extension. Fluvial, littoral to deep lacustrine facies are developed in base-level fall half-cycle of the LTAF Formation. Fluvial facies mainly occur at the paleo-structural high and the southeast of the region of the study area. The sedimentary evolution history of this area is quite complex. The alluvial fan and braided river are largely developed at the early stage of rise half-cycle. However, alluvial fan and braided river facies are dwindled at the late stage and replaced by littoral-deep lacustrine facies. The littoral-deep lacustrine facies are well developed at the early stage of fall half-cycle, while the fluvial facies is well developed at the late stage.