Abstract: The Karst system in Maokou formation (P) is classified into three different types,intra-formation paleokarstYangxin surface paleokarst,and fissure-cavern system karat. The lasttype is formed in intra-formation paleokarst£¬Yangxin surface paleokarst and fracture area£¬and during being transformed many times by underwater. It provides effective pore space for oil/gas accumulation and migration pathway, and controls the gas-water distribution in Maokou formation£¬in the area under study. The inhomogeneous develo}ent of the karat leads to forming a lot of vertical reservoir bebs and lots of lateral fissure-cavern systems. The relationship between gas and Water is complex,so there is no common watergas contact in the area. There is natural gas producing in the trap,and also good gas indication out of the trap.

Key words: 0il/gas accumulationiKarst 0il/gas distribution