Fault structure and hydrocarbon prospects of the Palawan Basin on the southeastern margin of the South China Sea based on gravity, magnetic, and seismic data

Abstract

To study the structural features and hydrocarbon prospects of the Palawan Basin in the South China Sea (SCS), the authors collect and collate the existing gravity and magnetic data and obtain edge recognition information from the potential fields. Combined with the seismic profile data, this paper analyzes the features of the gravity and magnetic anomalies and the edge recognition information of the potential fields, determines the fault system, and delineates favorable areas for oil and gas exploration in the Palawan Basin. The results indicate that four main groups of faults with northeast, northwest, near east–west, and near south–north trends developed in the Palawan Basin and adjacent areas in the SCS. The northeast-trending fault is the regional fault, whereas the northwest-trending fault is the main fault. The northwest-trending fault often terminated at the northeast-trending fault, indicating that the northwest-trending fault is formed subsequently. This investigation has characterized two different types of exploration favorable areas (type I and type II) based on the characteristics observed. The most notable characteristic of these exploration favorable areas is that they are located in the high-value zones of the local anomaly of the Bouguer gravity anomaly and their development is obviously controlled by the faults. The amplitude of the gravity anomalies is higher and the gradient of the gravity anomalies is steeper, and there are oil and gas wells and fields distributed in the type I favorable areas for exploration. Compared with the type I favorable areas, the amplitude of gravity anomalies is relatively small, and the gradient of the gravity anomalies is relatively gentle, corresponding to the type II favorable areas.