基于扰动弹性阻抗的裂缝参数反演方法  

Fracture parameter inversion based on perturbation elastic impedance

作　　者：吴国忱[1] 赵小龙 罗辑 宗兆云[1] 

机构地区：[1]中国石油大学(华东)地球科学与技术学院,山东青岛266580

出　　处：《石油地球物理勘探》2017年第2期340-349,共10页Oil Geophysical Prospecting

基　　金：国家"973"项目(2013CB228604);国家科技重大专项课题(2011ZX05030-004-002;2011ZX05019-003)联合资助

摘　　要：裂缝参数是裂缝型储层评价的重要指标,利用基于方位弹性阻抗的叠前地震反演方法可获取裂缝储层参数,而地震波方位反射系数方程是叠前方位反演的基础。为探寻稳健的裂缝参数反演方法,首先对比分析方位反射系数方程中各参数的敏感性,探讨裂缝参数反演结果不稳定的根本原因,同时发现裂缝是导致储层呈现方位差异性的主要因素;然后结合扰动反演思想,将方位各向异性弹性阻抗表示为背景介质弹性阻抗项与扰动弹性阻抗项之和,定义扰动弹性阻抗缘于储层裂缝的存在;最终构建了一种稳健的基于扰动弹性阻抗的裂缝参数反演方法。模型试算和实际资料试处理的结果均表明,利用本文方法能够得到合理的储层裂缝参数,尤其是较好地解决了裂缝参数反演不稳定的问题。Fracture parameters play a very important role in fracture reservoir evaluation. Prestrack inversion based on azimuthal elastic impedance is an efficient approach to obtain fracture parameters. Seismic azimuthal reflection coefficient equation is the basis of azimuthal prestack inversion. In order to develop a stable fracture parameter inversion method, firstly, we analyze the sensibility of each parameter in azimuthal reflection coefficient equation and discuss the primary reasons that result in the instability of fracture parameter inversion. Meanwhile, we find that fracture parameter is the basic reason why fracture reservoirs present azimuthal difference. Then, according to the thought of perturbation inversion, the azimuthal elastic impedance can be expressed as background elastic impedance term and perturbation elastic impedance term, the second term is caused by fracture parameters. Finally, we establish a stable fracture parameter inversion method based on perturbation elastic impedance. Model and real data tests show that the introduced inversion method can obtain reasonable reservoir fracture parameters, which solves the problem of the instability of fracture parameter inversion in some way. © 2017, Editorial Department OIL GEOPHYSICAL PROSPECTING. All right reserved.

关 键 词：储层裂缝参数 扰动弹性阻抗 方位反射系数 敏感性分析 

分 类 号：P631[天文地球—地质矿产勘探]