Abstract: The Ordovician reservoir in Tahe oilfield is a karst-type carbonate reservoir formed by multi-stage tectonics and karstification. Its crack-cavity system is controlled by the karstification which is restricted by the palaeogeomorphology. Because Tahe oilfield is of deepburied feature and few well data, it is insufficient to describe the karst palaeogeomorphology of it in detail. This paper adopts error simulation method combined with the seismic and the drilling data to reconstruct it and develop the karst palaeogeomorphology model of early Hercynian orogeny in Tahe oilfield, based on two isochronal boundaries and studies in sequence stratigraphy. Finally, the karst highland and the karst slope are recognized, and the secondary pores-developed blocks are predicted.

Key words: Tahe oilfield, carbonate rock, karst, palaeogeomorphology, model