影响岩溶缝洞体地震反射特征的关键因素分析

岩溶缝洞体是目前塔里木盆地碳酸盐岩储层中最重要的钻探目标, 对缝洞体反射特征的研究一直是地震勘探的重点, 但早期研究往往只关注单一因素对地震反射特征的影响。本文基于声波方程数值模拟, 全面探讨了缝洞体的位置、形态、物性、内部结构等多种因素对地震反射特征的影响; 明确了缝洞体的反射振幅主要受其宽度、总孔隙度和内部结构等三方面因素的综合影响; 认为应用现行技术很难将这些因素的影响区分开, 直接研究缝洞体的容积是储层定量描述的现实途径。

Key influence factors of Karst fracture-cave bodies on reflection characteristics

The Karst fracture-cave body (FCB) is the most important drilling target in Tarim carbonates. The influence of the FCB on reflection characteristics merits great efforts of research. The early research efforts usually focused on a single factor influence. Using numerical simulation based on acoustic wave equation, we discuss in this article many influence factors including location, shape, porosity, inner structure, etc. It is confirmed that the main influence factors on reflection amplitude are FCB's width, total porosity, and inner structure. Therefore, it is believed that quantitative reservoir characterization and porosity volume calculation are more practical than separate estimations of the porosity and the bulk volume.