Abstract:

Lianglitage Formation of Upper Ordovician is made up of microcrystalline limestone and shale ribbon-bearing limestone which generated in the platform facies and the marginal facies of platform. The types of reservoir include fissure, fissure-hole and fissure-carven. The factors controlling the growth of reservoirs mainly include the content of CaCO₃ of Lianglitage Formation, the rifting in early stage, the palaeokarst and sedimentary facies; there were two periods of palaeokarst in Lianglitage Formation between the wedgeout of Lianglitage Formation and the onlap border  of Sangtamu Formation, so the region can be regarded as the middling region for the growth of reservoir，blocking out the region of 912 km² that is favorable to the growth of reservoir of Lianglitage Formation.The result provides a theoretical base for the oil breakout of Upper Ordovician and the extension of main force pay formation in the south of Tahe oilfield.

Key words: reservoir characteristics, Lianglitage Formation, karstification, Tahe oilfield