Petroleum Generation Kinetics Modeling And Petroleum Pool System In The Linnan Depression

The Linnan Depression is a typical fault-folded depression. It is characterized by multi-petroleum-bearing seams, widely distributed source rocks, complicated structures and variable types of petroleum pools. For these reasons, there has been no deep understanding on the petroleum generation and petroleum pool formation patterns for a long period, and lack of scientific ideas for further exploration in this depression. In this study, a combination method of petroleum geochemistry and petroleum geology has been applied to investigate the Linnan petroleum system. The following main results have been obtained:(1) The main oil source rocks are ES33-ES23 dark mudstone and their main source matter is a type of biodegraded amorphinite. The kerogens contain high contents of organic sulphur, in the range of 3.68%-7.28%. This type of source rock is characterized by an earlier oil generation model, with oil window in the range of VRo 0.50-0.90% .(2). The petroleum generation of the source rocks from the Linan Depression has covered a long period from 35 Ma up to present time. There are two petroleum generation peaks, occurring during 30-20Ma and after 10 Ma, respectively.(3). The Linnan petroleum system can be subdivided into three petroleum pool systems: the early system (formed before 20 Ma), the middle system (formed during the period of 10-20 Ma), and the late system(after 10 Ma). The hidden petroleum pools were mainly formed during the periods of the early and middle systems, and the structural petroleum pools mainly formed during the late system period.(4).The further exploration direction of the Linnan Depression should focus on hidden petroleum pools on the basis of exploration of structural petroleum pools.These results not only give a guide to the petroleum evaluation and exploration in the Linnan Depression, but also provide a case study on petroleum pool system for the petroleum-bearing basins of Tertiary age.