Study on Burial History and Mesozoic Hydrocarbon Accumulation of Sugan Lake Depression on the Northern Margin of Qaidam Basin

Mesozoic oil-gas exploration of Sugan lake depression in northern margin of Qaidam Basin is low relatively. In order to understand the controlling factors and enrichment rules of reservoir formation in this depression, this paper based on analysis of single well buried history, by using thermometry of fluid inclusions in reservoirs and the fourier transform infrared spectrograph, to determine the formation time and stage of reservoir. We restore burial history and original stratigraphic thicknesses, which is 1440 m and 319 m respectively. The mean homogeneous temperature value of saline fluid inclusion coexisted with oil-bearing fluid inclusion in Middle-Jurassic Dameigou Group reservoir is 72°C. Combined with single well burial history and temperature history, the formation time of reservoir is 100 Ma, which formed in tectonic return period of Early Cretaceous. Organic inclusions at different depths have the same characteristics of fourier transform infrared spectrograph, which means the accumulation periods are uniform.