地震资料约束下大地电磁资料反演

MAGNETOTELLURIC DATA INVERSION WITH SEISMIC DATA CONSTRAINT

应用地震资料约束下大地电磁资料反演古潜山或基底内部结构的新方法．首先利用地 震及井资料,反演得到古潜山或基底之上各层的厚度及电阻率,建立了古潜山或基底以上的 地电模型;并利用大地电磁一维反演资料,建立了古潜山或基底及其以下的地电模型．在初 始模型建立的基础上,应用高效快速的二维大地电磁正演算法—模式匹配方法,进行正演计 算．利用共扼梯度迭代方法,进行正反演迭代计算．通过对胜利油田南北618剖面反演,基 底以上在地震资料没有显示的构造信息,在反演结果中得到了较好地反映．

In the paper we present a new method to inverse the interior structure in the basement or ancient hidden hill by using magnetotelluric （MT） data with seismic data constraint. We first obtain the thickness and resistivity of each layer over the basement or buried hill by the inversion of seismic and log data and create a geoelectrical model for the layers above the basement or buried hill. Then with the reference to the inversion of 1-D MT data, a geoelectrical model for the layers below the basement or buried hill is created. On the basis of the above initial model, we present an effective and practical forward method, i. e. , a model-matched approach to conduct forward arithmetic. Finally, by the method of conjugate gradient iteration, a forward and backward iterative calculation is made. Taking No. 618 profile of the Shengli Oil Field as an example, the tectonic information that is unreflective in the seismic data below the basement is better reflected in the inversion result.