Study On Sedimentary Facies And Sedimentary Environment In Mid-permian, Santanghu Basin

Santanghu Basin, in north-east of Xinjiang province, is a major sedimentary basins in western China, there is big exploration potential in oil and gas. Present study shows that mainly in the oil and gas resources deposit in Permian period, Lucaogou group and Lake group as two important oil and gas groups,are widely distributed in the basin. We study the stratum of sedimentary facies, the stratum of the distribution in plane,and sedimentary environment,It is a great significance about oil and gas exploration work in basic research of Santanghu Basin in Permian period.By collecting a lot of datas about drilling on the basin of Malang depression, Tiaohu depression and comprehensive study of Yuejin groove profiles, hold that The basin is mainly of freshwater lakes facies in Wulabo period of the Mid-permian. Lithology are gray-green siltstone of tuffaceous and brown siltstone, interbedded gray and black chert, sandstone contain the plant debris. angular unconformity with the underlying strata. lakeside phase is primary in Jingjingzigou period. characteristic of gray, dark gray mudstone, calcareous mudstone, siltstone, shale and siltstone interbedded. difference from Wulabo period is the lithology groups becomes thin. major lithology of Lucaogou group are thick dark mudstone,limestone and shale dolomite, reflecting the sedimentary sequence of semi-deep water --deep water. The distribution of Tiaohu group is similar to Lucaogou group, but the rock is different. Thick intermediate-basic volcanic rocks,volcanicrocks, sedimentary rocks distribution is less. There is sedimentary rocks in the middle of volcanicrocks. mainly of grayish green, purple mudstone, sandstone and conglomerate fine powder. article from beginning of the Tiaohu period in Permian, the lake is atrophy, north and south sides appear braided and braided river delta deposition in basin, half deep lake disappeared, only to sag in the southern edge of Tiaohu section and Malang Sag residual shallow central depression lake sediments.Through the sedimentary rock, color, biomarkers, salinity, fossils, primary sedimentary structures, carbon and oxygen isotopes, temperature and other data were integrated to determine. That: Santanghu Basin is mainly continental sedimentary environment, with a margin of lakes and coastal environment for the water medium salty lakes and terrestrial environment. Occasional short-lived transgression. in mid-permian.