海洋可控源电磁场和地震波场联合反演方法研究

发布时间：2018-05-10 08:58

本文选题：联合反演 + 地震　；参考：《中国石油大学(华东)》2015年博士论文

【摘要】：在油气勘探和开采中,利用地球物理数据准确的估算储层参数是非常重要的。通过地震数据可以进行准确的地质构造成像以及储层孔隙度的预测,但却很难判断构造中的流体性质。与此相反,海洋可控源电磁(CSEM)方法虽然不能很好地解决地质构造问题,但电阻率对于不同流体的饱和度却非常敏感。可以看出海洋可控源电磁法和地震能够提供互补的勘探信息,因此本文开展基于储层构造约束的海洋可控源电磁场(CSEM)和地震全波形联合反演方法研究,反演得到储层的饱和度和孔隙度。海洋可控源电磁和地震方法得到的是不同物性参数的地球物理数据,联合反演时,通过岩石物理模型的建立,使二者具有相同的物性结构,由于岩石物理模型的不确定性,因此利用岩石物理实验数据的统计分析结果进行岩石物理建模研究,根据Archie公式得到了孔隙度和电阻率的关系表,归纳总结出样品纵横波速度与电阻率的线性关系式,并分析了不同压强对岩石物理模型的影响,结果表明,每一块样品随着压强的增加速度和电阻率都会增大,并且每块样品在不同压强下的速度和电阻率同样有近似的线性关系。通过岩石物理模型,建立了基于储层为目标导向的正则化因子自适应变化的海洋可控源电磁和地震联合反演目标函数,目标函数包括模型拟合项和模型约束项,提出了一种正则化因子自适应调整方法,使正则化因子只与上次反演迭代所得的目标函数值有关,并且通过引入加权因子q,控制正则化因子中拟合项和模型约束项的比重,使联合反演过程更加稳定,在目标函数中,岩石物理模型参数根据给定的判别标准进行自动选取,提高了反演精度。通过一维理论模型联合反演对比了模拟退火粒子群算法和非线性共轭梯度算法优缺点,结果表明非线性共轭梯度法可以有效的提高反演速度,因此重点研究基于非线性共轭梯度法二维联合反演,推导了地震和电磁梯度,并对测井约束和收敛标准进行了讨论,从二维理论模型反演结果可以看出联合反演结果优于单独反演,能够准确的反映储层物性,减少解的多解性,应用该方法对我国华东某区的一条电磁和地震剖面进行了联合反演,可以看出反演结果与测井数据基本吻合,说明了本文提出的海洋可控源电磁和地震联合反演方法可以更准确的确定储层参数,提高钻井成功率。
[Abstract]:In oil and gas exploration and exploitation, it is very important to use geophysical data to estimate reservoir parameters accurately. Accurate geological structure imaging and reservoir porosity prediction can be made by seismic data, but it is difficult to judge the fluid properties in the structure. On the contrary, although the ocean controllable source electromagnetic (CSEMM) method can not solve the problem of geological structure well, the resistivity is very sensitive to the saturation of different fluids. It can be seen that ocean controllable source electromagnetic method and earthquake can provide complementary exploration information. Therefore, this paper studies the joint inversion method of ocean controllable source electromagnetic field and seismic full waveform based on reservoir structure constraint. The saturation and porosity of the reservoir are obtained by inversion. The electromagnetic and seismic methods of ocean controllable source are geophysical data of different physical parameters. In the joint inversion, they have the same physical structure through the establishment of rock physical model, because of the uncertainty of rock physical model. Therefore, based on the statistical analysis of the experimental data of rock physics, the modeling of rock physics is carried out. According to the Archie formula, the relationship between porosity and resistivity is obtained, and the linear relationship between the velocity of longitudinal and shear wave and the resistivity of the sample is summarized. The influence of different pressures on the rock physical model is analyzed. The results show that the velocity and resistivity of each sample increase with the increase of pressure, and the linear relationship between the velocity and resistivity of each sample under different pressures is similar. Based on the petrophysical model, an objective function for the joint inversion of ocean controllable sources, electromagnetic and seismic, is established, which is based on the adaptive change of the regularization factor of reservoir orientation. The objective function includes the model fitting term and the model constraint term. In this paper, an adaptive regularization factor adjustment method is proposed, in which the regularization factor is only related to the objective function value obtained from the last inversion iteration, and the weight factor is introduced to control the proportion of the fitting term and the model constraint term in the regularization factor. The joint inversion process is more stable. In the objective function, the parameters of the rock physical model are automatically selected according to the given criteria, and the inversion accuracy is improved. The advantages and disadvantages of simulated annealing particle swarm optimization algorithm and nonlinear conjugate gradient algorithm are compared through one-dimensional theoretical model inversion. The results show that the nonlinear conjugate gradient method can effectively improve the inversion speed. Therefore, based on nonlinear conjugate gradient method, 2-D joint inversion, seismic and electromagnetic gradient are derived, and logging constraints and convergence criteria are discussed. From the inversion results of 2-D theoretical model, we can see that the joint inversion results are superior to the single inversion results, which can accurately reflect the reservoir physical properties and reduce the multi-solution properties of the solutions. Using this method, a joint inversion of an electromagnetic and seismic section in a certain area of East China is carried out. It can be seen that the inversion results are basically consistent with the logging data. The results show that the proposed joint inversion method of ocean controllable source electromagnetic and seismic can determine reservoir parameters more accurately and improve the success rate of drilling.
【学位授予单位】：中国石油大学(华东)
【学位级别】：博士
【学位授予年份】：2015
【分类号】：P631

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