ORDOVICIAN UNDER-SALT RESERVOIRS AND FORMING CONDITIONS OF GAS POOLS IN EASTERN ORDOS BASIN
鄂尔多斯盆地东部奥陶系盐下储层及成藏条件分析

O1m5^7, O1m5^9, the upper O1m4 member, O1m2^1 and O1m2^2 are the five reservoirs located below the salt of the Ordovician Majiagou formation in eastern Ordos basin. The porosity of these reservoirs is generally low, but they have a relatively high permeability. Observation from the under-salt exploration wells demonstrates that the under-salt dolomite take on an obvious phenomenon of hydrocarbon generation and accumulation. Carbonaceous asphalt fills the dissolved reservoirs, and there are excellent source-reservoirseal association and various types of traps. Having these geologic conditions of forming under-salt gas pools, the under-salt dolomite is a new favorable gas exploration area.