Abstract: This paper systematically analyzed the fluid inclusion samples from outcrop of the Middle Jurassic Buqu Formation in Angdaercuo area of Qiangtang Basin using fluorescent indicator, microscopic temperature and salinity measures. Two stages of fluid inclusions were identified in calcite veins and microfractures in calcite. Aqueous inclusions indicate that homogenization temperatures are mainly 64 to 198 ℃, therein, 80 to 130 ℃ and 130 to 180 ℃ represent two large scale hydrocarbon accumulation phases: the early hydrocarbon accumulation is dominated by oil and gas; the late hydrocarbon accumulation is dominated by oil. Combined with the burial history of Qiangtang Basin, the results of this study suggest that the hydrocarbon accumulation occurred during 100 to 156 Ma (Late Jurassic to Early Cretaceous).

Key words: Qiangtang Basin, Buqu Formation, fluid inclusion, homogenization temperature, hydrocarbon migration