基于P-SV波反射系数的裂缝型致密储层流体识别  

Fluid Identification in Fractured Tight Reservoirs Based on P-SV Wave Reflection Coefficient

作　　者：窦喜英 王恩利[2] DOU Xiying;WANG Enli

机构地区：[1]兰州石化职业技术大学,兰州730060 [2]中国石油勘探开发研究院西北分院,兰州730000

出　　处：《科技创新与应用》2024年第35期1-11,共11页Technology Innovation and Application

基　　金：兰州石化职业技术大学博士基金项目(JK2021-02);2022年度甘肃省高等学校创新基金项目(2022A-213)。

摘　　要：低频条件下的等效孔隙裂缝模型更贴合实际地下裂缝型致密储层介质。借助线性滑动模型与等效孔隙裂缝介质模型的等价关系,推导出基质孔隙度、裂缝密度、填充流体与等效孔隙裂缝介质P-SV波反射系数的直接显示函数关系,并进行归一化处理后开展各向同性介质/等效孔隙裂缝介质双层模型的方位AVO特征数值模拟。模拟结果表明,3类AVO等效孔隙裂缝介质中,水饱和状态下归一化P-SV波反射系数对裂缝密度的敏感性均高于气饱和状态,2种饱和状态间的反射系数随裂缝密度变化而变化的差异从大到小依次为AVOⅢ、AVOⅡ和AVOⅠ等效孔隙裂缝介质;而基质孔隙度变化对AVOⅠ和AVOⅡ等效孔隙介质中气、水饱和状态的反射系数产生的变化差异很小,但在AVOⅢ等效孔隙裂缝介质中差异非常明显,说明基质孔隙度只对该类型介质中的流体敏感。The equivalent pore fracture model under low frequency conditions is more suitable for the actual underground fractured tight reservoir media.Based on the equivalent relationship between the linear slip model and the equivalent pore-fractured medium model,the direct explicit functional relationship between matrix porosity,fracture density,filling fluid and the P-SV wave reflection coefficient of the equivalent pore-fractured medium is derived,and then normalized,numerical simulation of azimuthal AVO characteristics of the isotropic medium/equivalent pore-fractured medium two-layer model is carried out.The simulation results show that among the three types of AVO equivalent pore fractured media,the sensitivity of normalized P-SV wave reflection coefficients to fracture density under water saturation is higher than that under gas saturation.The difference in reflection coefficients between the two saturation states with the change of fracture density is in the order of AVOⅢ,AVOⅡand AVO I equivalent pore fractured media;However,the change in matrix porosity has little difference in the reflection coefficients of gas and water saturation states in AVOⅠand AVOⅡequivalent pore media,but the difference is very obvious in AVOⅢequivalent pore fractured media,indicating that matrix porosity is only sensitive to fluids in this type of media.

关 键 词：P-SV波反射系数 方位AVO分析 裂缝密度 基质孔隙度 流体类型 

分 类 号：P618.13[天文地球—矿床学]