Research On The Late Oligocene-Miocene Mound-shaped Reflection Geologic Interpretation And Reef Containing Gas In Deepwater Area Of Qiongdongnan Basin

Deepwater exploration is one of the world’s three new fields petroleum exploration leading edge of this century. Deepwater area of northern South China Sea has huge oil and gas resource potential and exploration prospects, At present, the northern part of the South China Sea (fan) delta-turbidite sandstone reservoirs, The periphery of the basin south of the South China Sea has been found to have numerous reefs and large reserves of oil and gas reservoirs, Zhujiangkou Basin, northern South China Sea reef reservoirs have be found, Reef-type reservoirs and reservoir conditions due to the resource-rich, Reef and reef-type reservoir is one of the northern South China Sea deepwater exploration targets.It has been researched the deep-water area of Qiongdongnan Basin, which located in northern margin of South China Sea, has suitable environment of reef-forming during Miocene, Can form the resource-rich reef type reservoirs. seismic data throughout the basin in Qiongdongnan Basin, But the seismic line are sparse in the Miocene reef development in the southern uplift, So that affected the basin looking for reef. The study on achieves the equitime sequence stratigraphic framework is set up in the deep-water area of QiongdongnanBasin,The regional tectonic background and physical geography characteristics and the seismic facies are identified, And predecessors on the mound-shaped reflector basin based on the latest knowledge, Through the basin and three-dimensional seismic data information on hummocky reflector inside the basin geological interpretation and genetic analysis, Focus on identifying reef in the basin, Comprehensive analysis of developmental stages of combining ancient reef structure, ancient geography, ancient sedimentary facies and flow, Noted developmental characteristics and distribution of favorable areas of reef; analysised the reef reservoir conditions and Containing gas, Explore the reef exploration prospects type reservoirs.Hainan Island was the major sediment provenance during Early-Mid Miocene. Fan delta and offshore shallow sea sedimentary system distributed in the Northern uplift belt of Qiongdongnan Basin. Neritic and bathyal deposits existed along the The Central sag zone, and the abysmal deposits distributed in part of the sag. Turbidite fan deposits developed near the north side of the slope. The Southern ramp, where was a large unicline with low dip, was covered by bathyal deposits during this period. The Southern uplift belt, where was a large and flat platform, partly existed denuded zone, and offshore shallow sea sedimentary system distributed in this area during Early Miocene. The carbonate platform and carbonate slope formed widely in the Southern uplift belt during Middle Miocene. The reef grew along the platform edge in Meishan formation of Middle Miocene.early mid-Miocene Basin and southern slopes with a central depression that bathyal zone and deep-sea sediments in Qiongdongnan Basin, Meishan formation sedimentary period of large-scale development of the region showing dome reflector deposition EW banded distribution, and has a multi-stage migration feature to shallow water, deep sea and other deep stream is formed mounds and other deep plot; Southern uplift of shallow marine water environment for the development of the carbonate platform in the development of multi-platform margin carbonate reef, deep water reef migration to the direction of growth, the deep-water reef-wing direction steep reef type platform edge of the reef; Beijiao convex3D1work area late Oligocene-early Miocene uplift and erosion of the ancient district, in Sanya formation bump during the deposition of its periphery in the northern reef shallow depression phase region is advantageous reef development in the isolated bump the development of tower reef or Block reef.Deepwater area of the development of the Eocene-Yacheng formation transitional facies source rocks and Lingshui formation marine source rocks, the basin Oligocene-Miocene depression edge developmental faults, connectivity sand, broken unconformity and ancient structures ridge such as oil region ridge migration pathways, Since the late Miocene has developed thick mudstone cap, so Miocene reef with excellent reservoir conditions. By reef containing gas detection, Make the reef-type reservoir exploration potential for scientific evaluation, in the basin.