Sedimentary characteristics and potential of channel-type lithologic traps in Miocene in Enping Sag, Pearl River Mouth Basin

Commercial petrol resources have been discovered in the middle and shallow layers of Zhuyi Depression in the Pearl River Mouth Basin in recent years. Although structural traps are still the main ones, the evaluation of related lithologic targets in the paleo Pearl River delta needs to be carried out urgently. Based on high-quality well and seismic data, a fourth-order sequence framework between T50-T35 in Enping Sag is established with the upper member of Zhujiang Formation and the lower member of Hanjiang Formation (T50-T35) in Enping Sag as the main target layer, using a set of third-order sequence boundary and the maximum flooding surface as the boundary. With the constraint of high-resolution sequence stratigraphic framework, the sedimentary characteristics of distributary channel in Enping Sag are further revealed by seismic sedimentology method, and the channel sedimentary models under different sea-level backgrounds are established: the channel scale is larger in the early stage of transgression and the end of highstand, the extension distance is longer, and often developed continuously on the plane; in the late transgression and early highstand, the scale of the river channel moderate, the plane isolation is stronger, and the front edge is often transformed by waves. It is found that different types of channel sand bodies combined with specific structural background can develop "channel cutting" lithologic traps, and about the maximum flooding surface are more suitable for the development of related traps. Therefore, three favorable areas for lithologic trap: east slope of Enping A Oilfield , east slope of Enping E Oilfield and west slop of Enping G Oilfield. Two favorable exploration targets are proposed, which provided new ideas for lithologic reservoir exploration in the basin.