Research Institute of Petroleum Exploration and Production��Sino Petroleum �� Chemical Corporation��Beijing 100083��China

The effection of faults in oil �� gas accumulation was a key factor for oil �� gas exploration in Tazhong uplift and north slop area surrounded�� Based on the interpretation of the seismic data we concluded that fault systems in Tazhong uplift and its north slope area were developed in middle Caledonan�� The NW-SE compres- sion-shear faults and NNE-SSW strike-slip faults made up the fault systems�� The fault systems underwent four staged tectonic movements��including the middle Caledonan��late Caledonan��late Hercynian��and Yanshan-Her- cynian�� It is mainly developed in middle-middle Caledonan�� The faults mainly controlled the form of the structural zone and the form of the carbonate reservoirs including the Karst --��reef --and hot fluid in type�� The late move- ments of the faults provided the main oil migration pathway�� NNE faults are the long-distance migration pathway which caused the oil and gas from north depression migrate to the Tazhong uplift�� All these result in the oil reservoir distributed along the fault belts and the various oil accumulation modes��