东营凹陷南坡西段红层地球物理特征及储层预测

在孔一段一沙四段下亚段沉积时期,东营凹陷南坡发育以漫湖相为主的红色碎屑岩沉积,紫红色泥岩与砂岩互层分布,并穿插多期火成岩,给红层的储层预测带来了较大困难。根据红层的地震、地质特征,对钻井揭示红层的岩性、物性、电性及速度特征等进行统计,对研究区孔一段上亚段的岩性组合及其地震反射特征进行了研究。结果表明,孔一段上亚段上部砂岩相对不发育,为泥岩与火成岩组合,强振幅反射主要对应火成岩与泥岩的界面;下部发育砂、泥岩互层穿插火成岩组合,中一高频、中一弱振幅反射主要对应砂岩与泥岩、砂岩与火成岩的界面。进而分析了对砂岩敏感的地震属性,并利用测井约束波阻抗反演与自然伽马反演相结合,较好地实现了对研究区红层储层的预测。

Geophysical and reservoir feature of redbed,south slope of Dongying depression

At the sedimentary period of the first member of Kongdian formation（Ek₁） and the lower submember of fourth member of Shahejie formation（Es₄^x）,the red clastic rocks sediments,which mainly belong to sheetflood lake facies,are consisted of purple mudstone interbed sandstone and many phases igneous bodies in south slope of Dongying depression.And,it is very difficult to predict the red beds reservoir distribution.The author investigated the lithologic association and the seismic reflection characters of the upper submember of Ek₁,studied the red beds lithology,physical properties,electrical properties and velocity characters.The study shows that the mudstone and igneous rocks developed in the top of upper submember of Ek₁,and the strong amplitude reflection refers to the interface between igneous rock and mudstone.In the bottom of upper submember of Ek₁,there develops sandstone interbedded mudstone and igneous rocks.Both the difference between sandstone and mudstone and the difference between sandstone and igneous rock result in the same seismic reflection characters including the middle-high frequency and middle-weak amplitude. This paper analyzed the seismic attributes distinguishing sandstone from seismic reflection.It also indicated that the combination the acoustic impedance inversion constrained by logging data with GR inversion can predict the red beds reservoir distribution effectively.