Sedimentary Evolution And Reservoir Characteristics Of Reef Carbonate In Dongsha Massif Of Pearl River Mouth Basin, South China Sea

Hydrocarbon resource distributing in the organic reef areas all over the world is so rich that it is estimated that it will exceed 5 billion tons of oil. With continuous development of the oil exploration and production, hydrocarbon resource in bioherm reservoirs will increase greatly. The recent oil exploration situation of bioherm reservoirs in the world is reviewed. South China Sea is the largest marginal sea in China and various kinds of organic reefs existed and buried in it. The peculiar geological conditions and the favorable bioherm reservoir conditions contribute to a good prospect for oil exploration.The South China Sea is the biggest marginal sea in the West Pacific and its evolutionary process supply proper growing environment to the reef. Dongsha massif was the shallow water and far from provenance supply area in the Miocene,its temperature, salinity and water depth were fit for the reef growth.According to the multidisciplinary analysis of seismic data interpretation, well logging and core data,conbining to the relative sea level curve of variation,we hold the point that plent of reef developed in Dongsha Massif,and their growth was correspondent to the relative sea level curve of variation and areal structure evolution period. The relative sea level cycling variation and the complicated structure evolution made reef in the study area had good poroperm characteristics,and became potential gas and oil reservoir. According to the relative sea level curve of variation, the development of reefs evolution is divided into four stages: sea-level slow rise stage; Sea-level rise fast stage; Sea level remained stable - sea-level drop stage; A new round of transgression process. The reservoir types of LH11-1-1A Wells included interparticle pore, intracrystal pore, intercrystal pore,moldic pore and crack, etc.