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

In order to study the structural features and hydrocarbon prospects of the Palawan basin in the South China Sea (SCS), the authors collected and collated the existing gravity and magnetic data, and obtained edge recognition information from potential. Combined with the seismic profile data, this paper analyzed the features of the gravity and magnetic anomalies and the edge recognition information of the potential fields, determined the fault system, and delineated favorable areas for oil and gas exploration in the Palawan basin. The results showed that four main groups of faults with NE, NW, near EW, and near SN trends developed in the Palawan basin and adjacent areas in the SCS. The NE-trending fault was the regional fault, while the NW-trending fault was the main fault. The NW-trending fault often terminated at the NE-trending fault, indicating that the NW-trending fault was formed later. This investigation has characterized two different types (Type I and Type II) of exploration favorable areas based on characteristics observed. The most notable characteristic of these exploration favorable areas was that they were located in the high value zones of the local anomaly of Bouguer gravity anomaly, and their development was obviously controlled by the faults. The amplitude of gravity anomalies was higher and the gradient of the gravity anomalies was steeper, and there were oil and gas wells and fields distributed in Type I favorable areas for exploration. Compared with Type I favorable areas, the amplitude of gravity anomalies was relatively small and the gradient of the gravity anomalies was relatively gentle corresponding to Type II favorable areas.