| There are nine depressions and forty-four drilled wells in Lin Qing sag that has an area of 5910 square kilometers and has been explored for more than forty years. Only two oil wells were found in the Eogene system indicates that petroleum entrapment in this area is complicated. Following the principle of from source to entrapment, the entrapment of De Nan depression is focused in this dissertation. Under the guide of the theory of dynamic system of entrapment, the main methods applied here are multidisciplinary analysis and comprehensive study. The characteristics of compaction curves, the evolution of organic matter, the direction of migration and assignment, conduit system, fluid potential are studied It is concluded that the low maturity of the source of the Eogene age is the main factor to control the entrapment. It controls the direction of the primary migration, confines the location of mature source rock and the special carrier rock, controls the time of expulsion and the amount of petroleum, therefore; the effective traps should be near to oil kitchen and on the pathways of migration. This thesis begins with the partition of dynamic system of entrapment, emphasizes the study on entrapment and process, then makes sure the effective dynamic system of entrapment, favorable direction of migration and conduit system and dissects the present reservoir and structural style, finally points out the likely models of entrapment. The main achievements can be summarized as followings:1. By studying the material conditions of entrapment, it is conclude that De Nan depression is a low-mature oil kitchen, that main source rock of Sha San member is partly mature.2.The undercompaction starts at the depth of 1300 to 1500 meter. And there are three types of undercompaction , local undercompaction, normal undercompaction and undercompaction, in Lin Qing area. Four undercompaction zones are divided on the undercompaction curves of shale in the Eogene system of De Nan depression. The distribution of the undercompaction is related to sedimentary velocity and the distribution of impermeable shale vertically and laterally. The genesis of undercopaction is different for each zone. The zones, which are related to Sha Yi and Sha San members, are caused by the distribution and evolution of shale. The zone related to Sha Er member is more related to sedimentary velocity.3. Three dynamic systems of entrapment are divided in the Eogene of De Nan depression in terms of stratigraphic, tectonic characteristic and the vertical distribution of abnormal formation pressure.4. It is concluded that the Es3 is a main member to accommodate the oil expelled from the source rock of the Es3 member, that two assignment units of the type I are prospective areas where faulted reservoirs, fracture reservoirs, lithologic deposits may well be founded. The depth of threshold is among 2600-2800 meter and that of expulsion is around 3100-3400 meter, so the source rock of Sha Er member is totally immature and that of Sha San member is partly mature.5. The fractures of marlite, sandstone, faults and the disconformity between Sha San member and Sha Er member are three main conduit systems. For this low maturity of the oil kitchen, The fractures of marlite that coexist with source rock might as well be an important bridge to link oil kitchen and reservoir.6. It is indicated that the fractures of marlite are next to De Nan fault zone on the slice of seismic coherence. De Nan fault zone is controlled by De Nan fracture system, which is broom-like and is composed by faults No.l, No.2 and No.3 from north to south.7. The source rock in De Nan depression has the characteristics of a short period of expulsion, early tectonic ceasing, short migration distance, therefore; the most favorable places for entrapment is near oil kitchen and on the pathways of migration.8. It is concluded that three entrapment models likely exist, a model on the steep slope, a model on the gentle slope and a model on the horst between the two dep...
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