基于AVO反演的溶蚀孔洞型碳酸盐岩储层预测

Caved carbonate reservoir prediction based on AVO inversion

在塔里木盆地溶蚀孔洞型碳酸盐岩储层预测中,基于叠后资料以"串珠状"强反射为目标的传统手段难以弄清溶洞内充填状况,也无法识别不具"串珠状"反射特征的"内幕低阻抗"储层。本文以塔中45、中古21和轮古34三个井区为例,基于地震资料保幅处理和岩石物理分析,应用AVO反演预测了溶蚀孔洞型碳酸盐岩储层。相比传统叠后方法,AVO反演不仅能够分辨溶洞储层,而且能进一步判断其内部充填情况。此外,AVO反演还能识别不具"串珠状"强反射特征的"内幕低阻抗"储层。统计表明,AVO反演预测的结果与实际三个井区内全部33口井的吻合程度达91.3%。

Conventional methods are used for caved carbonate reservoir prediction on bead-like strong reflections of post-stack section in the Tarim Basin.However,the filling substances of caves cannot be distinguished,and the internal weak impedance reservoir without bead-like reflection is also neglected using these conventional methods.Based on seismic amplitude-preserved processing and rock physics analysis,pre-stack inversion is employed in this paper for caved carbonate reservoir prediction in Wells TZ45,ZG21and LG34zones.Comparing with conventional post-stack methods,AVO inversion can not only distinguish resolvable dissolution caves,but also predict the filling substances.Moreover,it can characterize the distribution of internal weak impedance reservoir without bead-like reflection.In practice,the coincidence of AVO inversion prediction with the drilling results of 33 wells in the zones is up to 91.3%.