Research On Phase State Distribution Rule And Its Genesis Of Oil And Gas In Lunnan Area

Lunnan area is one of the earliest places where petroleum exploration obtained breaks in Tarim Basin. And it is the area, which has the most complicated distribution of petroleum phase states. The origin mechanism of various distributions of petroleum phase state has been studied by many researchers from different aspects. But because Lunnan oil field has characteristics of multi-hydrocarbon source kitchens, mutiple stages of accumulation and several structure movement's reconstruction, if the distribution of petroleum phase state is explained by using single method or aspect, the explanation will be not symbol with actual geological situation. And if it is explained by many factors, the conclusion often will be diversificate.So, the author thought the main controlling factors of the petroleum phase state distribution need to be clear firstly, and all of other factors should be considered simultaneously. Three main controlling factors, including source rock, petroleum accumulation and structure movement, have been determined. Looking analsis of three main controlling factors as the master line, geological structure, oil component, type, homogenization temperatures and component of fluid inclusions and vitrinite reflectance of bitumen in reservoir were analyzed. All analysis mentioned above makes the result symbol with actual geological situation and having powerful proof of geo-chemistry. Following are main innovative achievements and conclusions:1) The author maps the petroleum phase state in the Lunnan area at first time. Based on the geological and geochemistry analysis, two stages of petroleum accumulation have been proposed. During the later Hercynian, the petroleum accumulation scale was determinated and the petroleum phase state was enriched during the later Himalayan.2) Three main controlling factors of petroleum phase state have been proposed. The characteristics of petroleum phase state were controlled by the source rock, the distribution was controlled by the petroleum accumulation factor and the structure changed the petroleum phase state at last.3) The origin model of petroleum phase and petroleum accumulation model,which has characteristics of differential accumulation mainly in flat and migration fractionation mainly in vertical, has been proposed in Lunnan oil and gas field. Through generalized analysis of pooling process and phase state distribution rule ofoil and gas, new exploration area has been proposed.