缝洞型储层模型AVO属性特征分析

The Characteristic Analysis of AVO Attribution for Fractured-Vuggy Reservoir Model

塔里木盆地是我国最大的含油气盆地,拥有巨大的油气资源潜力。但塔中地区奥陶系岩溶缝洞型储层埋藏深、类型复杂、储层非均质性强,所表现出的岩石地球物理特性不清楚。为了分析典型缝洞型储层模型含不同流体情形下的AVO特征,建立了过玉北1井的缝洞型储层地震地质模型,模型的3个储层段对应的孔隙度分别为10%,6%和8%,分别对应Ⅰ类储层、Ⅲ类储层和Ⅱ类储层,设计了3个储层段都充填气和3个储层段分别充填气、油、水3种不同流体时的2个模型,基于正演模拟共成像点道集记录(CMP),提取截距、梯度、纵横波反射系数及流体因子,采用AVO属性交汇分析方法,寻找油气识别的最佳属性组合,为叠前反演解释提供理论基础。

Tarim Basin is one of the largest petroliferous basins in China containing huge potential petroleum resources.But the rock geophysical characteristics of the central Tarim Basin are not clear,due to deep bury of Ordovician fractured-vuggy reservoir,its complex strata types and heterogeneity.In order to analyse AVO characteristics of typical fractured-vuggy reservoir model when filled with different fluids,we build a seismic and geological model of fractured-vuggy reservoir which passes the well YB1.The model has three reservoir sections,that isⅠclass reservoir,Ⅲ class reservoir and Ⅱclass reservoir,whose porosity is 10%,6% and 8% separately.Two models are designed,one of which is only filled with gas within 3 reservoir,and another one is filled with gas,oil and water separately within 3 reservoir.The intercept,gradient,P-reflectivity and S-reflectivity and fluid factors are extracted from the CMP gather record which is based on forward modeling.Then based on AVO attributes crossplot analysis,the optimum combination of AVO attribution is identified to recognize reservior.The result will be helpful to provide a theoretical basis for the interpretation of prestack inversion.