海洋可控源电磁与地震资料构造联合反演方法研究

发布时间：2018-03-23 15:45

本文选题：联合反演　切入点：海洋可控源电磁反演　出处：《中国海洋大学》2015年博士论文

【摘要】：联合反演方法从不同的地球物理资料出发研究同一地质现象,降低了单一地球物理资料反演方法局限性和反演问题多解性的影响,并使反演结果更真实可靠。地震勘探方法分辨率高,能精细刻画地层和地下构造特征,却难以识别流体界面,如油和水的分界面。海洋可控源电磁法(CSEM)纵向分辨率相对较低,但是该方法对油气藏电性差异敏感,可有效识别高阻油气藏。结合这两种地球物理方法的优势,实现海洋电磁和地震资料联合反演,可进一步提高油气藏的识别能力。在前人研究基础上,本文从海洋CSEM数值模拟方法和地震声波方程正演及波形反演方法着手,并以此为基础对海洋CSEM与地震联合反演技术进行研究,主要研究内容和成果如下：(1)层状各向同性介质电磁场解析表达式的推导基于Schelkunoff位函数理论,推导了电偶源激励下层状各向同性介质电磁场在波数域和空间域的拟解析表达式；根据电磁场叠加原理,采用高斯积分法求解有限长度源下电磁场；使用方位角和倾角将任意方向有限长度源分解为三个坐标轴方向等效源并求出其对应的电磁场,根据电磁场叠加原理,可求得任意方向有限长度源激励下的电磁场。(2)海洋CSEM一维反演在电偶源激励下层状各向同性介质中电磁场拟解析表达式基础上,推导了电磁场对地层电阻率的偏导数,并实现海洋CSEM一维高斯-牛顿反演和BFGS(Broyden, Fletcher, Goldfarb, and Shanno)反演。进一步推导了电磁场对发射源导航参数(方位角,倾角,水平位置)的偏导数；对雅可比矩阵进行SVD分解,通过特征参数分析(Eigenparameter Analysis)方法发现,发射源导航参数与地下电阻率参数在反演过程中是可以解耦的；在此基础上,实现了海洋CSEM发射源导航参数和地下电阻率同步联合反演。(3)交错网格有限差分海洋CSEM二维和三维正演基于交错网格有限差分理论,对双旋度电场方程进行离散并采用delta函数对源进行离散,使用总场方法实现海洋CSEM三维正演；在三维正演基础上,对走向方向做傅立叶变换,得到二维情况下双旋度电场方程的有限差分离散形式,使用总场方法实现海洋CSEM二维正演。(4)声波方程一维和二维有限差分正演和全波形反演采用PML (Perfectly Matched Layer)边界条件,实现声波方程一维和二维有限差分正演,在正演基础上,实现地震一维和二维全波形反演。反演方法采用修正的高斯-牛顿法,对海森矩阵做对角化处理,在保持高斯-牛顿法快速收敛的同时,克服其在极值点附近不稳定现象,使得模型扰动量变化趋于稳定：采用频率加权处理,压制占主导地位的高频信息,以避免反演陷入局部极小。(5)海洋CSEM与地震资料联合反演使用构造耦合泛函实现了海洋CSEM与地震资料一维和二维联合反演,其中海洋CSEM与地震一维联合反演使用JTV (Joint Total Variation)耦合泛函,而二维联合反演使用JTV耦合函数和交叉梯度(Cross-gradient)耦合泛函。海洋CSEM反演采用高斯-牛顿法,反演收敛快,成像精度高;地震反演为基于声波方程的全波形反演,反演方法为修正的高斯-牛顿方法,反演稳定并保持较快收敛速度。理论模型测试结果表明,电磁和地震资料联合反演可极大提高电磁方法成像能力,有效圈出油气藏边界;同时,根据油气藏电性差异,区分其物性特征。
[Abstract]:Study on the same geological phenomenon from the point of view of different geophysical data inversion, reduces the inversion method of single geophysical data and the limitations of the inverse problems of multiple solutions of the impact, and make the inversion results more reliable. High resolution seismic exploration method, can fine description of strata and underground structures, it is difficult to identify the fluid interface. Such as oil and water interface. The marine controlled source electromagnetic method (CSEM) vertical resolution is relatively low, but the method of oil and gas electric difference sensitive, can effectively identify high resistivity reservoir. The combination of these two kinds of geophysical method advantage, marine electromagnetic inversion and seismic data can be further improved oil and gas reservoir recognition. On the basis of previous studies, this paper from the marine CSEM numerical simulation method and seismic wave equation forward and waveform inversion method, and on the basis of CSEM in the ocean and land Research on seismic inversion technology, the main research contents and results are as follows: (1) the derivation of layered isotropic electromagnetic field analytical expression of Schelkunoff function is derived based on the theory of electric dipole excitation in layered isotropic electromagnetic field in the quasi analytical expressions of the wavenumber domain and spatial domain; electromagnetic field according to the superposition principle, using Gauss integral method finite length source electromagnetic field; using azimuth and inclination angle to any direction of finite length source is decomposed into three axes equivalent source and calculate the corresponding electromagnetic field, electromagnetic field according to the superposition principle, the electromagnetic field can be obtained in any direction finite length source excitation. (2) CSEM in the marine electric dipole excitation of quasi one-dimensional inversion the electromagnetic field in layered isotropic medium is derived based on the analytical expression, the partial derivative of electromagnetic field on the resistivity of the formation, and the realization of a marine CSEM Victoria Gauss Newton inversion and BFGS (Broyden, Fletcher, Goldfarb, and, Shanno) inversion. Further deduced the electromagnetic field on the emission source of navigation parameters (azimuth, inclination, horizontal position) of the partial derivative of the Jacobi matrix; SVD decomposition, the characteristic parameter analysis (Eigenparameter Analysis) found that the emission source and the navigation parameters the resistivity parameters can be decoupled in the inversion process; on this basis, the CSEM emission source marine navigation parameters and underground resistivity. (3) synchronous joint inversion of staggered grid finite difference ocean CSEM 2D and 3D forward staggered grid finite difference based on the theory of double curl equation was discrete and the electric field the delta function was used to discrete the source, using the field method of marine CSEM 3D modeling; in 3D forward on the basis of the direction of Fu Liye transform, obtain the two-dimensional case of double The finite difference equation of the discrete curl field form, using field method to realize marine CSEM 2D forward. (4) the acoustic wave equation and two-dimensional finite difference modeling and full waveform inversion using PML (Perfectly Matched Layer) implementation of boundary conditions, the acoustic wave equation and two-dimensional finite difference forward, forward basis on the realization of seismic and two-dimensional full waveform inversion. The inversion method using the modified Gauss Newton method for diagonalization of the Hessian matrix, while maintaining the Gauss Newton method with fast convergence at the same time, to overcome the unstable phenomenon near the extreme points, which makes the model perturbation tends to be stable by using a frequency weighted processing, pressing high frequency information of the dominant, in order to avoid the inversion of a local minimum. (5) the joint inversion of marine CSEM and seismic data using structural coupling functional to achieve the ocean CSEM and the one-dimensional and two-dimensional joint anti seismic data Play, one marine CSEM and one-dimensional seismic joint inversion using JTV (Joint Total Variation) and functional coupling, two-dimensional joint inversion using JTV coupling function and cross functional gradient (Cross-gradient) coupling. Marine CSEM inversion using Gauss Newton method, inversion of quick convergence and high precision imaging; seismic inversion and full waveform inversion of acoustic wave equation based on the inversion method for the modified Gauss Newton method, inversion stability and faster convergence rate. The test results show that the theoretical model, the joint inversion of electromagnetic and seismic data can greatly improve the ability of electromagnetic imaging method, the effective boundary circle of oil and gas reservoir; at the same time, according to the difference between the oil and gas reservoirs, according to its physical characteristics.

【学位授予单位】：中国海洋大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：P631.325;P631.46

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