Trap types and their characteristics in shallow gas reservoir in south of Song-Liao basin

Four kinds of structural traps,anticline,fault-block,fault-nose and fault-anticline,could be easily seen from bottom structure maps of 9 reflecting layers,based on geologic data and seismic cross section with high quality.As controlled by tectonic movement,fault distribution is closely related with faulted structural zone.The traps in this re-search area were mainly formed in depression-inversion period and fault-block traps provide the most primary places for hydrocarbon accumulation.As superposed traps are fa-vorable to the formation of composite petroleum accumula-tion zones,the traps preservation has direct effect on hydro-carbon preservation.Therefore,traps formed in different stages have different controlling effect on different hydrocar-bon accumulation.