Features of Gravity Anomalies and Their Oil-Gas Geological Significance in the Cuu Long Basin

Abstract

This study uses data from the global satellite gravity model SDUST2021GRA and associated processing algorithms (upward continuation and tilt angle of the horizontal gradient) in delineating structural features and hydrocarbon distribution in the Cuu Long Basin (CLB). The gravity anomalies in the CLB are characterized by blocky development in the Northeast - Southwest (NE - SW) and North - South (N - S) direction. According to the changes in amplitudes, the regional gravity anomalies can be classified into four distinct zones. Analysis of gravity data in the CLB indicates that: three main sets of faults are developed in the region, namely, the NE - SW, N - S and NW - ES trending faults. NE - SW trending faults are distributed in a wide range, and they are main faults in the region. They are followed by N - S trending faults, while there are a small number of nearly NW - ES trending faults. Large - scale faults are mainly margin controlling faults for the boundary of the basin and uplifts . Through analysis of gravity anomaly characteristics, combined with location of oil/gas fields, the results show that oil/gas fields in the CLB are mainly located within zones of negative residual gravity anomalies. This approach provides a cost - effective tool for preliminary hydrocarbon exploration and structural evaluation in offshore basins.