Abstract: The formation of Longmen mountain system is duo to the faulting-folding on the Upper Yangtz platform in late Mesozoic-Cenozoic. The western Sichuan fault-depression belongingb to the foreland basin of Longmen mountain system is a composite oil-gas province that consists of platform-type marine sediment and foreland-type continental deposit. The maturity of latest (NQ) fault-fold structure controls the development of structural traps in the foothill belt and the formation of fissured gas pools. Oil and gas accumulations on the Tianjingshan paleo-uplift formed in late Indosinian were destroyed as a result of intensive activities of the latest faulting-folding. Zhaohua area in Guangyuan county, at the NE pinching end of Tianjingshan paleo-uplift, is a favorable oil-gas accumulation belt because there developed a buried fault system and its accompanying fold group. And MianyangJiangyouAnxian area, at the SW pinching end of Tianjingshan paleo- uplift, is a favorable district to
prospect middle and shallow secondary gas-pools as where is the conjunction of NE-trending and NW-trending deep faults.

Key words: longmen mountain system, foothill belt, latest fault-fold structure, buried fault-fold belt, structural maturity