Oil-gas migration and distribution mechanism of Lunguxi buried hill in Tarim Basin

The subtle reservoir of carbonate rock in Lunguxi buried hill is a dissolution fissure-cave reservoir distributed along the top of Ordovician unconformity where oil-gas distribution is uncontrolled by local structural high. The main pathway of fluid migration in the buried hill is a complex 3D network system formed by dissolution fissure-hole-cave staggered, incised and connected mutually and distributed mainly in the section within 160 meters of depth below the top of buried hill. Oil-gas migration occurred along the path with the least resistance in dissolution fissure-cave system under the drive of buoyancy. Three factors dominate the process of oil-gas migration and accumulation. First, development of fissure-hole-cave controls the forming of subtle trap and the spatial distribution of fluid transport channels. Second, structural pattern controls the regional final direction and local tropism of oil-gas migration. The last, the space configuration among structural pattern, fluid transportation channel and oil source dominates the spatial distribution of oil-gas migration pathway. So the favorable belt for oil and gas accumulation of Lunguxi buried hill can be predicted and evaluated by synthetic analysis based on multiple factors.