Tectonic Evolution Of Sirte Basin In North Africa And Its Affation To Basin’s Petroleum Geology

The Sirte Basin is a rift system, developed in the North Africa Craton during Mesozoic and Cenozoic, and rich in oil and gas resources. This basin is one of important areas for China to carry out overseas cooperation in petroleum industry. However, foreign studies of Sirte Basin fell to two extremes: for one thing, studies on the whole basin are rough, for another thing, studies on oil fields and wells are too meticulous to show the whole features of Sirte Basin. Demostic studies are in the initial stage.The petroleum geology data of Sirte Basin was summed up and studied , and the tectonic evolution of Sirte Basin and its affation to Basin’s petroleum geology is the main topic of the study.And the petroleum geology data about Sirte Basin was collected and summed up for the topic,which include the characteristics and evolvement of structure, the development of sedimental enviroments and basin’s Petroleum features. Based on materals mentioned above, the study takes following three steps. Firstly, to study the sedimental and structural feature of Sirte Basin which are controlled by geotectonic background and tectonic events.And then to analyze the affation of sedimental and structural feature to basin’s petroleum characteristics. Finally ,to prodict promising areas on tectonic vision.This thesis has drown following conclusions: Firstly, Sirte basin’s tectonic evolution can be divided into three phases——Pre-rift phase ( Precambrian- Jurassic), Syn-rift phase (Cretaceous-Eocene) and Post-rift phase (Oligocene- Present), and now the Sirte basin is in its declining stage. Secondly, pre-rift sediments is limited but Cambro-Ordovician quartzitic sandstones and basement are one of important reservoirs; syn-rift phase is of the most importance in which basin’s main source rocks, reservoirs, seals and traps were formed; post-rift phase is crucial for the generation, transportion and preservation of basin’s hydrocarbon. Thirdly, the thesis summarize the commonality and difference on petroleum characteristics between Sirte Basin and general rift basins. Finally, based on tectonic analysis, Zella rough, Messlah High and its surrounding region, Drahra platform, west border of Waddan uplift and Sea area in the North of Sirte Basin are considered as promising areas.