黄骅坳陷北塘凹陷沙河街组地震相及砂体展布特征

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

局部的勘探实践表明北塘凹陷沙河街组是重要的油气勘探层系。但大面积地区,尤其是深凹区钻井很少,故开展地震相分析十分必要。依据北塘凹陷沙河街组可信度较高的地震内部反射结构和外部形态,结合振幅、连续性、频率等地震反射参数,对凹陷内地震相进行了分析,共识别出6种地震相,即:席状地震相、丘形地震相、下切充填地震相、透镜状地震相、楔形地震相和前积地震相。结合钻井资料和区域构造背景,分析了地震相的平面展布特征,并把地震相转化为沉积相,结果表明发育的沉积相类型有扇三角洲相、湖泊相和浊积扇相,为该区的砂体展布及其预测提供了重要的依据。

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.