Double provenance depositional model and exploration prospect in the deep-water area of Qiongdongnan Basin

Abstract

Based on the newly collected seismic data and the provenance supply mode, the depositional sequence, provenance features, and oil-gas exploration prospects were analyzed. The study area has the typical double-layer geologic structure of rift-depression and has double provenance supply in the north and south. The provenance supply in rifting period was mainly from the southern Xisha Uplift and the southwestern Indo-China Peninsula and was also from the northern South China Block; whereas the provenance supply in post-rifting period was mainly from Indo-China Peninsula. In the rifting period, the southern sediment formed a large-scale progradation body in Lingshui Formation and encountered the subsea apron formed by the northern provenance in the central depression; in the post-rifting period, the large-scale turbidite channel developed in Sanya Formation, the large-scale reef developed in the southeast of the study area in Meishan Formation in the depositional stage, and the large-scale incised valleys developed in Huangliu Formation in the late depositional stage. In the Late Quaternary Period, the northern provenance and southern provenance joined in the deep-water area of Qiongdongnan Basin. The seismic data and basin modeling indicate that the reservoirs of subsea apron and sand-rich turbidite channel above the hydrocarbon-generating sag can be the good exploration targets in the deep-water area.