APPLICATION OF 3D SEISMIC INTERPRETATION TO THE DEEPWATER CHANNEL SYSTEM ON THE NORTHERN CONTINENTAL MARGIN OF SOUTH CHINA SEA

The Northern continental margin of South China Sea bears great potential of oil and gas resources, and has been the hotspots of deep-water petroleum exploration for decades. Based on the high-resolution 3D seismic data from the region, we used in this paper a series of seismic sedimentology techniques, including seismic facies analysis, 3D seismic slice technique, attribute computation between horizons and 3D visualization technology for integrated researches.Two sets of deep-water channel systems in the Late Cenozoic of the Baiyun Sagare are recognized. They are the early channel system formed in the Early Middle Miocene and the late channel system formed later since the middle Middle Miocene. The early channel system is a point-source single channel filled with channel axis infilling, levee and mass transportation deposits. According to seismic facies, the early channel system consists of two sets of sediments:1) the sediments of stage I is characterized by strong downward erosion and "V" shaped bottom boundary and 2) the sediments of stage Ⅱ characterized by weak erosion and "U" shaped bottom boundary. The late channel system is composed of series of sub-parallel channels along the slope formed up to the present. The system consists of the sediments formed in four stages:stage I (13.8-12.5 Ma), stage Ⅱ (12.5-10.5 Ma), stage Ⅲ (10.5-5.5 Ma) and stage IV (5.5-0 Ma).The channel system in the Baiyun Sag shows good depositional differentiation and has big potential for oil exploration. The early channel system with upper deep-water deposits could form a reservoir-seal assemblage in the deep-water area. And the late channel system is of significance for the formation of enriched gas hydrate reservoirs.