STUDY OF NEOGENE SESIMIC AND SEDIMENTARY FACIES IN THE HYDRATE SURVEY AREA OF SHENHU REGION ON THE NORTH MARGIN OF SOUTH CHINA SEA

According to the tectonic movement and global sea level changes in the South China Sea since Late Miocene, combining with seismic reflection terminating features, the Neogene in the hydrate survey area of the Shenhu region were subdivided into eight sequences. Following the principles of the "external shape and internal structure",i.e. the external geometry and the internal structure of the seismic reflection, plus seismic physical attributes, such as amplitude, frequency and consistence, six categories of seismic facies,i.e.the filled, mound, sheet, lens, flat, wedge-like shapes respectively and a total of 19 kinds of seismic subfacies were identified in the studying area. Sedimentary facies were interpreted from seismic facies based on the relationship between the seismic reflection parameters and sedimentary architecture as well as the single well log facies.Four maps of third-order sequences after T₂ were compiled.Compared with the drilling data for gas hydrate,it is revealed that the gas hydrates are mainly enriched in slump deposits.