Reservoir Formation and Exploration Orientation of Deep Natural Gas in Songliao Basin

The laws of natural gas reservoir formation of Songliao Basin are summed up from the perspectives of structural evolution,features of deep fault depressions and palaeohighs,reservoir conditions,fault development,and cap conditions.Geological evaluation of zones is conducted based on the criteria for selecting geological parameters of evaluating deep gas zones of the basin.On the basis of analogic methodology,the deep gas resources of the basin is evaluated as 1116.144 billion cubic meters,which is mainly distributed in the zones of Xujiaweizi,Miaotaizi,Changling,Yingshan,and Gulong.The target of exploration for the deep gas of the basin is ultimately determined as follows:Shengping-Xingcheng structural belt of Xujiaweizi fault depression,Xuxi slope,and the slope east of Changling fault depression are strategic areas for expanding exploration;Songzhan and Fengle uplifts of Xujiaweizi fault depression as well as the central uplift of Changling fault depression are strategic areas for making breakthroughs;Yingshan-Miaotaizi and Gulong fault depressions are strategic areas for preparing for exploration.