黏弹性介质叠前地震反演方法

发布时间：2018-10-23 13:24

【摘要】：前人只是从理论上分析了黏弹性介质中各种波的传播特征和衰减特征,并未对黏弹性介质精确的Zoeppritz方程进行近似,无法用于实际反演;沈章洪等以完全弹性介质为背景,推导了黏弹性介质反射系数近似方程,由于该近似方程的实部为完全弹性项,虚部为黏弹性项,因此也无法用于实际资料。为此,本文以黏弹性介质为背景,推导了黏弹性介质反射系数近似公式,以此为基础,基于贝叶斯理论的叠前地震反演,将纵横波速度、密度的反演推广到纵横波速度、密度和地层品质因子(Q值)的联合反演,建立了黏弹性介质近似方程,再根据贝叶斯理论建立反演方程,最终利用共轭梯度法对方程进行求解,得到纵横波速度、密度和地层Q值。模型试算与实例分析结果表明,根据联合反演所得的纵横波速度、密度和Q值进行储层描述,可提高储层预测精度。
[Abstract]:Previous studies have only theoretically analyzed the propagation and attenuation characteristics of various waves in viscoelastic media, and have not approximated the exact Zoeppritz equation of viscoelastic media, which cannot be used for practical inversion. The approximate equation of reflection coefficient of viscoelastic medium is derived. Because the real part of the approximate equation is a complete elastic term and the imaginary part is a viscoelastic term, it can not be used for practical data. Therefore, in this paper, the approximate formula of reflection coefficient of viscoelastic medium is derived based on the Bayesian theory of prestack seismic inversion. The inversion of velocity and density of compressional and shear waves is extended to the velocity of P-S wave. The approximate equation of viscoelastic medium is established by the joint inversion of density and formation quality factor (Q value), and then the inversion equation is established according to Bayesian theory. Finally, the equation is solved by conjugate gradient method, and the velocity of compressional and shear waves is obtained. Density and formation Q value. The results of model calculation and example analysis show that reservoir prediction accuracy can be improved by using the velocity, density and Q value of P-S wave obtained from joint inversion to describe the reservoir.
【作者单位】：国土资源部海洋油气资源与环境地质重点试验室;青岛海洋科学与技术国家实验室海洋矿产资源评价与探测技术功能实验室;青岛海洋地质研究所;中国石化胜利油田分公司物探研究院;
【基金】：公益性行业科研专项(201511037) 国家自然科学基金项目(41406080)联合资助
【分类号】：P631.4

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