Characteristics and genesis of submarine pockmarks -- A case from the Niger Delta

Based on the high-resolution three-dimensional seismic data of about 1300 km² acquired from the Niger Delta Basin of the Gulf of Guinea in West Africa, studied in this paper are the temporal and spatial distribution patterns of pockmarks, the relationship between pockmarks and sea bottom channels, and the genesis of various types of pockmarks. Through the fine interpretation of the target horizon and the extraction of various seismic attributes, there have found 75 pockmarks in the northwest of the study area, 56 pockmarks found above channels, and 62 pockmarks distributed in other parts of the study area. There are three types of pockmarks, such as pockmarks in belts, complex pockmarks and isolated pockmarks. The causes and distribution patterns of pockmarks are affected by the erosion and cutting of buried channel sections. The corresponding turbidity channels in the stratum below the pockmarks produce fluids. The upward migration of fluids causes the stratum to be discontinuous, which in turn affects the stratum and distribution of pockmarks. According to the stratigraphic characteristics and filling mode, the genesis of pockmarks is classified into ancient channel genesis and fault genesis.