PALAEOZOIC STRUCTURES AND OIL EXPLORATION PROSPECTS IN THE EASTERN TARIM BASIN, NW CHINA

The Tabei Uplift in the northern Tarim Basin, the Tadong Depression in the eastern Tarim Basin, and the Tarim Central Uplift were formed as a result of mantle diapirism. Four stages in the geological development of this area can be recognized: an initial “embryonic” stage in the late Proterozoic; a “formational” stage in the Sinian; a “developmental” stage in the Early to mid‐Palaeozoic; and a “completion” stage in the late Palaeozoic. With long‐term Palaeozoic subsidence and well‐developed marine source rocks, the Tadong area is thought to be a promising source region for hydrocarbons. The Tabei and Central Uplifts, located respectively north and south of the Tadong Depression, are ancient, well‐preserved structures in which hydrocarbons may have accumulated, and could therefore constitute prospective areas for the location of “giant” oil‐ and gasfields in Palaeozoic sequences. Palaeozoic oil prospects have been confirmed in the Tabei area by the highly‐productive Sachan 2 well. It is expected that intensified exploration will result in the location of both oil‐ and gasfields in the Central Uplift.