溢流相火山岩定量刻画新尝试——以渤海海域B构造为例

New attempt to quantitative characterization of effusive facies volcanic rock:a case of B structure in Bohai Sea

渤海海域B构造古近系广泛发育火山岩,分布广、厚度大的致密火山岩占据了有效的储集空间,降低了海上钻井效率,影响了井位方案的部署,有必要开展快速高效的火山岩定量刻画研究.研究区主要发育溢流相火山岩,根据溢流相火山岩表现出的特殊的地震反射特征定量刻画.溢流相火山岩地震相表现为强振幅、强连续,岩石物理特性表现为高速度、高密度,通过建立振幅类属性和已钻井信息之间的关系式定量刻画其展布特征,经验证该方法具有良好的应用效果.基于溢流相火山岩的定量研究,取得认识:研究区火山活动始于沙河街组中期,呈"点状"分布,东营组中后期活动性增强,多为连片分布特征.

In B structure of Bohai Sea,volcanic rock is extremely abundant in Paleogene. On one side,the effective reservoir space is filled by volcanic rock, which is widely distributed with great thickness. So it is unfavorable for the research and calculation of reservoir in the area. On the other side,it reduces the efficiency of well drilling and increases the cost of exploration in sea because of the overlying dense volcanic rock for Shahejie formation,which is one of the most important exploration layers. For this reason,there is an influence on the well deployment. So it is necessary to describe quantitatively the 3D distribution of the volcanic rock.From the analysis result,the volcanism is strong and regional in several periods. The formed volcanic lithofacies are various,which are mainly with the effusive facies. Based on seismic reflection characteristics,we describe quantitatively the 3D distribution of the volcanic rock. The effusive facies is widely distributed, which shows strong amplitude and relatively continuous reflection characteristic. We describe quantitatively the 3D distribution of the effusive facies by establishing the relation between amplitude attribute and lithological information. It is proved that the effect is good. The study of the quantitative distribution of the volcanic rock leads to the follows conclusion. Volcanic activity of study area may start from the middle of Shahejie formation,showing a separate distribution. The higher activity may start from the middle-later of Dongying formation,showing a widely distribution.