非单一岩性地层中的弱反射

Weak reflection from multi-lithologic formation,

弱反射是地震剖面上常见的一种反射特征,在岩性预测中,一般都解释成单一岩性。根据辽东湾的勘探实例证明,弱反射不只是反映单一名性,也可以在非单一岩性地层中出现,即在薄互层和反射系数很小的厚层砂泥岩地层中产生。笔者利用地质模型论证了它们的形成条件和判别方法,并指出在陆相沉积盆地地层中利用弱反射结构判别岩性,不能简单地运用一两种模式,必须结合本地区的沉积、构造特点,采用多种地震信息进行综合分析。

Weak reflection is a reflection phenomenon we can often see in seismic section. The weak reflection is usually considered to come from single-lithologic formation in predicting lithology. The seismic example in Liaodong bay has shown that weak reflection can mirror single-lithologic formation, or multi-lithologic formations: the formation that is composed of thin interbeds,and the formation consisting of thick sandstone and mudstone layers which have very low reflection coefficients. With the use of geological model, the author expounds how the weak reflections occur and how they can be distinguished. It is emphasized that the lithology of weak reflection configuration in continental sedimentary basin is determined not only by consulting some interpretation patterns but also by performing com- prehensive analysis of various seismic informations,sedimentary feature and structural feature in the area.