Seismic Facies and Characteristics of Sand-body Distribution of Shahejie Formation in Beitang Sag of Huanghua Depression

Local exploration showed that Shahejie Formation was one of the important layers of oil and gas exploration in Beitang Sag.A few wells were drilled in large areas,especially in deep depressions,therefore it was very necessary to analyze the seismic facies.Based on the reliable seismic reflection marks,such as internal seismic reflection structure and external shape of Shahejie Formation in Beitang Sag,and in combination with its reflection parameters including amplitude,continuity,frequency and so on,the seismic facies was analyzed,and six seismic facies were identified,including mat-shaped facies,moundy facies,down-cutting filling facies,lenticular facies,wedge-shaped and foreset facies.In combination with the regional drilling data and structural background,the areal distribution characteristics of seismic facies were analyzed,the seismic facies was transfered into sedimentary one.The result shows that three sedimentary facies are developed in the area,which include lacustrine,fan delta and turbidite facies.It provides an important basis for studying the distribution of sand bodies.