To research the deep-rooted fault system in Dachuanzhong area of Sichuan Basin

2D seismic data of 21 000 km and 3D seismic data of 3 000 km

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were interpreted applying the integrated seismic interpretation technique.Three characteristics of the deep-rooted faults were revealed.The deep-rooted faults control the tectonic deformation of the seals.They cut downward into the basement and upward into the Feixianguan Formation and are associated with flower-shaped faults.The deep faults and the shallow ones have distinct characteristics

with the former being high in angle and dominated by strike-slip faults while the latter being relatively low in angle and dominated by reverse faults.A total of 172 faults were interpreted in Dachuanzhong area and their lateral extensions range from 3 to 79 km.The areal distribution of deep faults shows distinct zonation.The first zone is Weiyuan-Ziyang-Suining-Dazu area where the faults are NE-trending or nearly EW-trending.The second is Bazhong-Yilong-Guang'an area where the faults are NW-trending or nearly EW-trending.The third is Pingchang-Dazhou area where the faults are SN-trending.The deep faults control the sedimentary faces belts and the distribution of favorable sedimentary body

communicate the low porosity and tight reservoirs

effectively improve the reservoir properties and increase oil and gas production capacity.They also control the formation of local structural traps and can act as effective migration pathways for hydrocarbons from source rocks to reservoirs and control hydrocarbon accumulation of allogenic source systems.