THE NEW ADVANCES IN CLASTIC DEEP-WATER FAN

Hydrocarbon reservoirs found in deep-water sandstone facies have now aroused geologists' interest in studying details of clastic deep-water fans. The research of deep-water fan has made great progress in recent years. The aim of this paper is to review and sum up a series of new advances and ideas in this field in the recent years. In general, it involves the following key points:deep-water fans can not only be formed in lowstand system tracts, but also in highstand system tracts where sediment supply is great. In some cases, submarine fans cannot be found in lowstand system tracts. Deep-water fans are mostly built by turbidite deposits, but sometimes debris flows can also generate fans. Strata successions of deep-water fans are not simply characterized by either upward-thickening or upward-coarsening cycles. Some new models have been proposed based on these views. More factors such as eustasy, basin tectonics, sedimentation rate, and type of submarine fan are considered. The models are divided into gravel-rich, sand-rich, mixed sand-mud and mud-rich categories and each one includes three types in terms of sediment sources:point sourced, line sourced and multi-sourced. These models are more comprehensive and more accurately reflect characters of deep-water fans. They are also an effective tool to predict sandbody distribution in hydrocarbon exploration.