CONTROLLING FACTORS AND CHARACTERISTIC OF RESERVOIR FRACTURES INXUJIAHE FORMATION OF DAYI AREA

The reservoirs of Xujiahe Formation in Dayi area are super tight sandstone reservoir,and the reservoirpetrophysical property is poor. The existence of fractures greatly improves the reservoir permeator. There are tectonicfractures,diagenetic fractures and abnormal high-pressure fractures in this area. There exists drilling inducedfractures in some wells. Tectonic fractures develop well among them,which is the key types of factures. The tectonicfractures of this area mainly take the form of low-angle and high-angle fractures. The distribution of fractures developmentis controlled obviously by faults. Fracture-developed zone presents zebraic distribution along east-northfault belt,where faults clip zone as well as the fracture in high-steep part of structure develop better. The controllingfactors of the fractures development mainly include tectonic stress,tectonic position,rock types,rock stratum,etc.The tectonic position and rock types are the key factors controlling the development and distribution of the fractures.