Carboniferous sedimentary facies of Kolzhan area in Pre-Caspian Basin

Kolzhan area is located in Biykzhol relief,southeast of Astrakhan-Aktyubinsk uplift in Pre-Caspian Basin,and Kungurian salt of Lower Permian is developed widely here.The whole profile is divided into 2 hydrocarbon-bearing series by salt sediments,one is dominated by clastic rocks and another is dominated by carbonate rocks.Carboniferous formation is one of the main hydrocarbon-bearing formations beneath the salt sediments.According to the analysis of cuttings well K as well as the logging data,Carboniferous sedimentary characteristics are analyzed and sedimentary facies are classified and described.Three types of sedimentary facies are developed in Carboniferous formation of well K,including deep-water turbidite fan,slope and platform facies.Deep-water turbidite fan is further divided into inner,middle and outer fan,and platform facies is divided into interbank sag and platform shoal.Using drilling results of well K and regional data,early and late Carboniferous sedimentary facies distribution is predicted initially in Kolzhan area.