Hydrocarbon accumulation characteristics of the Neogene reservoirs in Huatugou Oilfield of Qaidam Basin

Through analyzing the main types, micro-fluorescence and thermodynamic characteristics of fluid inclusions in the Neogene reservoir of Huatugou Oilfield, the process of fluid filling into reservoirs could be divided into two stages including low-temperature and low-salinity fluid, high-temperature and high-salinity fluid. The study on the burial history and thermal history showed that hydrocarbon filling in the first stage was mainly a trace amount of immature hydrocarbon and happened at the middle Pliocene Epoch. The hydrocarbon filling in the second stage was a large scale filling of oil and gas and happened in the late Pliocene Epoch. The second episodic petroleum accumulation process lasted a short time and could be a fast and efficient petroleum-charging model.