Origin and characteristics of oil pool sequence in Ordos Basin

The Mesozoic Ordos Basin developed the special oil pool sequence, which contains lithologic oil pool, lithologic-structural combination oil pool and structural oil pool from down to up. The comprehensive analyses on the different type of reservoir-forming condition and exploration status showed that the formation of oil pool sequence was controlled by many factors including source rock, oil-gas migration, and reservoir-cap rock combination. The source rock is the main controlling factor for generation of oil pool sequence. The vertical distance between trap and source rock is the vital index, which determines oil source condition. The quality of cap rock has significance for oil pool sequence.