The Mechanism And Prediction Of Deepwater Geohazard In The Northern Of South China Sea

Deepwater drilling risks have become a challenge, which constrain the development of oil and nature gas Industry and are globle problems. Drilling risks associated with shallow water flow (SWF) sands and gas hydrates have received the most attention. Using high resolution 2D seismic data, 3D seismic data and multi-beam bathymetric survey data, Both are researched on the northern of Souch China Sea(SCS).The potention SWF sands were identified according to the theory of sequence stratigraphy. These sands occur in the deepwater channel depositional system of Baiyun depression, Pearl River Basin. The characters of the SWF sands were recoginized by integration with AVA inversion, fullwave inversion and poststack inversion. The SWF sands has low density, low velocity, high poisson ratio (0.49) and high Vp/Vs (>9) value.The subsurface geohazards caused by gas hydrate dissolution were analyzed via seismic multiattribute techniques. The BSR, gas chimney and submarine slide were recoginze. gas chimney are typically circular and have a classic seismic expression on the reflected energy and similarity attributes that includes one or several of the following features: severely deteriorated data quality, near-vertical weak and/or incoherent reflections, pull-down effect. Submarine slide shows the typical geography and deformation characteristic associated with gas hydrate dissolution and the process of gas hydrate dissolution was simulated.