A transient electromagnetic vector finite-element forward-modeling method based on 3D anisotropic resistivity constrained by well-logging and seismic data is developed. This method integrates detailed stratigraphic division provided by well-logging data and structural information from seismic interpretation to establish a structural model that reflects the actual geologic conditions. Based on the structural model, a kriging interpolation method is applied to the logging resistivity data to obtain the anisotropic resistivity distribution information of each layer in the reservoir, thereby establishing a 3D anisotropic resistivity model. To ensure the smoothness of the model, we use a variogram function based on a spherical model to fit the discrete interpolation points. After the resistivity model is spatially discretized by locally refined unstructured tetrahedral meshes and temporally discretized by a nonuniform time step, the large sparse matrix equation is solved using the PARDISO direct solver to obtain the forward response. We apply this method to layered models of isotropic and vertical transversely isotropic (VTI) media and verify the accuracy of the forward simulation method by comparative analysis with quasi-analytical solutions. Doubling the nonuniform time step in our forward simulations does not affect the accuracy of the solution. Applying our method to China’s D oilfield, the electromagnetic response at observation points generally matches traditional methods well. Comparative analysis of the forward results between our method and the model without geologic data or homogeneous resistivity shows that we achieve better fitting with the field measurement data and provide more detailed electrical properties.

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