Characteristics of Sedimentary Facies in Cretaceous Jiufotang Formation in Songnan Area

Cretaceous Jiufotang Formation in Songnan Area was the main oil and gas reservoir development staged in the basement faults with intense activity.To clarify the hydrocarbon potential of Jiufotang Formation,based on the research of well logging,core and seismic section from the studied area,nearshore subaqueous fan facies,fan delta facies,delta facies,turbidite fan facies,lacustrine facies were found out,of which the near-shore subaqueous fan facies and fan delta facies were mainly distributed in the steep slope zones of the faulted basin.The delta facies was mainly developed in the gentle slope belt and lacustrine facies was organized around the fan delta and delta facies and in the central zone of the deep area.From the margin to the centre of the depression,the sedimentary facies is gradually turned from near-shore subaqueous fan,fan delta or delta facies to lacustrine facies.