苏北盐城凹陷复合含油气系统

苏北盐城凹陷含油气系统可划分为上、下2个复合含油气系统。上复合含油气系统，即Pz、K2p、K2t(生)-K2t、E1f1(储)一E1f1 E1f2(盖)，古生界、中生界浦口组和泰州组为烃源岩层，泰州组和阜宁组一段为储集层，阜宁组一段顶部至二段暗色泥岩为区域盖层，油气沿深大断裂运移，油气成藏关键时刻在古近纪晚期至新近纪早期，有利勘探区在深大断裂附近的中、新生界发育地区；下复合含油气系统，即Pz、K2p(生)-Pz、K2p(储)-K2p3 K2p4(盖)，油气通过断层或不整合运移，油气大量生成的关键时刻为古近纪早期，该系统中气藏分布在古生界被中生界覆盖地区。

The Composite Petroleum Systems of Yancheng Sag in Subei Basin

The Yancheng sag is situated in the Subei basin and includes two composite petroleum systems,namely the upper system and the lower one.The upper composite petroleum system consists of Pz,K_2p and K_2t as source rocks,K_2t and E_1f_1 as reservoir,and E_1f_1+E_1f_2 as capping.In this system,hydrocarbon source beds are the Paleozoic,the Pukou and Taizhou Formations of Mesozoic.Reservoirs are the Taizhou Formation and the first member of Funing Formation.A regional muddy capping bed is the second member for several times.Critical moments are Eocene and Miocene.The most favorable regions ought to be the Mesozoic and Cenozoic formations near the deep faults and fractures.However,the lower composite petroleum system consists of Pz and K_2p as source,Pz and K_2p as reservoirs,and K_2p_3+K_2p_4 as capping.Faults or disconformities act as the passages of natural gas.Critical moment is Paleogene.In the lower system,the favorable regions ought to be Paleozoic and Mesozoic formations covered with the Mesozoic regional capping rock.