Geophysical Identification Characteristics And Genetic Mechanism Of Shallow Water Flow In Deepwater Basin Of Northern South China Sea

The oil and gas resources in deep-water basin of northern South China Sea has become a hotspot in the field of oil and gas exploration in our country.However,deepwater geohazards,such as shallow water flow,shallow gas,submarine landslides and gas hydrate decomposition et al.,are the important factors for oil and gas exploration in deep-water basin.Shallow water flow is a common deep-water geohazards in deepwater drilling,it will cause leakages,blowouts,platform instability and collapse.Therefore,geohazards prediction and avoidance in deep-water oil and gas exploration is imperative.Using the Well-logging data of the ODP Leg 184 Site 1144,1146,1148,the IODP Leg 349 Site U1431,U1432,U1433,U1435 and Well X1 in deep-water basin of northern South China Sea,to research the geophysical identification and formation mechanisms of overpressure and shallow water flow combine with seismic profiles.In order to obtain the reliable results of calculated overpressure,we research the affect factors of normal compaction sediments in deep-water basin of South China Sea.Analyze the relationships between the normal compaction and the sediments contents,deposition rates,burial depth et al.in deep-water basin of South China Sea.Reveal a primary variation discipline of the coefficients of normal compaction and mudline porosity in different depth in deep-water basin of South China Sea.Calculate the overpressure in Wells by fitted normal compaction coefficient which is reliable.Analyze the geophysical characteristics and formation mechanisms of overpressure in deep-water basin of northern South China Sea.Predict the overpressured shallow water flow sands in deep-water basin of northern South China Sea based on the overpressure prediction and analysis.Analyze the geophysical characteristics of shallow water flow sands with seismic profiles across the overpressured shallow water flow sands.Analyze the formation mechanisms of shallow water flow sands in deep-water basin of northern South China Sea according to the regional geological setting,Well-logging data and seismic profiles.Offer some methods for prediction and prevention from deep-water geohazards in deep-water drilling of shallow water flow.