Abstract:

According to evidence on truncation and hiatus in the fossil information, and the data of drilling hole from Ordovician Formation between Yijianfang and Qia'erbake in Tahe oilfield which is located in the north of Xinjiang, it is conformed that the forming of the fracture-cavity reservoir in Ordovician is affected by karsification, which is depended on the fractures. On the basis of the lately results of seismic interpretation, four faults are identified in the formation of Ordovician, which stretch to north northwest,north northeast, east-west and north-south. The growing of the faults is accompanied by fractures, and is also regarded as the path for karsification. This causes the fact that the stretch of reservoir is same to that of the fault, and thus proves that the forming of Ordovician reservoir has been controlled by the faults that developed in the middle of Caledonian.

Key words: middle Caledonian, fault, Ordovician reservior, fracture, karsification, controlling , action