Abstract:

According to geologic model of unsteady groundwater flow in heterogeneous medium and adopting the finite difference solution,the direction and strength of oil gas migration can be quantified.Tarim Basin had three main oil gas generating phases including the early Hercynian,the late Hercynian and the Himalayan phases,Modeling result suggests that,in the early Hercynain,groundwater flew from the source depression to the around areas.Tazhong,Shaya Uplifts and the south and east of Shaya Uplift are favourable for oil gas migration.As the early Hercynian movement was very strong,fossil oil pools were exposed on surface and mainly denudated;in the later Hercynian,the oil gas migrated to Tazhong and Tabei Uplifts,accumulated in Tazhong;in the Himalayan stage,because of intense surface waterfall and draining,fissil oil pools were distoried;the fullness of the pools decreased ,and pressure system was changed.

Key words: palaeohydrodynamic force, model, application, oil and gas migration, Tarim Basin