Study of high-quality sandstone in Early Miocene sequence of Beikang-Zengmu Basin, the Southern South China Sea

With the increase in difficulties in global oil-gas exploration, the research and characterization of high-quality sandstone reservoirs have become the hot and difficult point in oil-gas exploration, especially in the area of deep water. So far, a large number of high-quality sandstone reservoirs have been found in the Beikang-Zengmu Basin in the southern South China Sea, and there is huge amount of oil-gas resources occurred. The Beikang-Zengmu Basin was in the stage of continental drifting in Early Miocene (about 23-16 Ma), suffering large scale of thermal subsidence and deposition of large-scale sandstone systems of delta-deep water fan systems. The sandstone deposited in the Beikang-Zengmu Basin is characterized by high abundance, strong variation, wide distribution and multi-stages of deposition, and the physical properties of the sandstone are controlled by sedimentary environment and tectonic factors. So far, limited surveys have been carried out due to complicated international environment that leads to limited data availability. Comparing to the northern continental margin basin of the South China Sea, it is more difficult to make sand bodies prediction. In this paper, based on the seismic response characteristics of the high-quality sandstone established by seismic waveform analysis, we selected some key seismic profiles to delineate the typical sandstone formations in the Early Miocene sequence of the basin, and then, delineating and depicting the spatial distribution of the sandstone. Finally, a depositional model was established for the sandy sedimentary system from deltas to deep-water fans in the Early Miocene sequence of Beikang-Zengmu Basin.