彭阳-三岔地区上三叠统延长组成藏期次分析

Analysis of Hydrocarbon Accumulation Period in Upper Triassic Yanchang Formation of Pengyang-Sancha Region

采用储层油气包襄体的宿主矿物生成期次与两相包裹体均一温度分布特征相结合的研究方法．分析鄂尔多斯盆地西南缘彭阳-三岔地区上三叠统延长组成藏期次，认为延长组砂岩储层中发育三期烃类充注作用．其中第一期和第二期烃类充注与石油成藏有关；结合烃源岩埋藏史和热演化史分析成果，指出了本区延长组第一次石油成藏时间为下白垩统志丹组沉积早期，第二次石油成藏时间为旱白垩世晚期；区内现今的石油储量主要是发生于早白垩世晚期的第二次石油充注成藏的结果，喜马拉雅期发生改造调整。

The oil accumulation period-times of Upper Triassic Yanchang Formation in Pengyang - Sancha region of the southwestern margin of Ordos Basin are analyzed by adopting a combination of research methods of generation period of the host minerals in oil/gas inclusions of the reservoir and homogenization temperature distribution characteristics of the two- phase fluid inclusion. It is considered that the three-stage hydrocarbon filling is developed in the sandstone reservoirs of Yanchang Formation, of which the first and second hydrocarbon-filling is related to nil accumulation and reserving. With combination of analysis results of souree rock burial history and thermal evolution history, the authors point out that the first time period of oil accumulation in the Yanchang Formation of this region was the early sedimentary stage of Lower Cretaceous Zhidan Formation, and the second time was the late stage of Early Cretaceous. Nowadays the region＇s oil reserves are mainly the result of the second petroleum filling into accumulation and reserving happened in the early Late Cretaceous, with the transformation and adjustment in the Himalayan Age.