正演模拟技术在碳酸盐岩溶洞响应特征研究中的应用

Application of forward modeling to research of carbonate cave response

在塔里木盆地奥陶系碳酸盐岩储层识别中,"串珠状"反射是十分重要的地震响应特征之一。文中利用波动方程正演模拟技术,设计了不同的溶洞模型,分析了溶洞宽度和高度变化时对"串珠状"响应特征的影响。结果表明:溶洞宽度增加时,"串珠"响应振幅增强,但响应时间长度不变;溶洞高度增加时,"串珠"振幅呈先增大后减小的趋势,且响应时间长度变长。模型正演为进一步研究溶洞的响应机理、溶洞形状与"串珠"特征的关系提供了手段,从而为碳酸盐岩储层的半定量或定量预测提供了依据。

The ＂string bead＂ reflection is one of the important seismic response features in identification of Ordovician carbonation reservoir in Tarim Basin.The mechanism of ＂string beads＂ is very complex.Base on forward modeling of wave equation,some different models are designed,and the influence of cave width and height on ＂string bead＂ characteristics is analyzed.The result shows that the amplitude of ＂string bead＂ intensifies with the cave width increasing,but the length of ＂string bead＂ do not change.The amplitude of ＂string bead＂ firstly intensifies and then decreases with the cave height increasing,and the ＂string bead＂ lengthens.Forward modeling provides approach for further study of response mechanism of cave,cave shape and ＂string bead＂ features,and criterion for semi-quantitative and quantitative forecast of carbonate reservoir.