Abstract: Based on the petroleum exploration, several tens oil and gas fields have been discovered in thrust fault films of forland basins, depressions and eastern slope of western area of Sichuan. According to types of source rocks and trap property, combined with formations’s development of geatectonis and
geohistory of area, near 10000 meters sedimentary overlaying formation can be divided into three oil-gas bearing strata:sea facies oil bearing system;sea-land interbedding facies oil-gas bearing system and land facies oil-gas bearing system .The material bases and shape distortional embryively for each system have been formed by Emei structure (or Dongulu) movment of upper
Permian, Yinzh and yanshan cycles of Mesogoie era respectively. Three systems have been improved, destroy and organiged in varying degrees by Xishan movement of Poleogene. In this paper, three structure units distribution and exploration thoughts of each system in basin have been discussed.

Key words: fore-land basin, oil-gas bearing system, sea facies, sea-land interbedding facies, land facies