The Numerical Simulation Of Multicomponent Induction Logging Based On ADI-FDTD Algorithm

In this paper，we systematically and deeply study multicomponent inductionlogging response in anisotropic formation（borehole）based on3D alternating directionimplicit finite difference time domain.Firstly, we discrete formation model with Cartesian grid and define themedium parameters based on the location of grid. We define equivalent mediumparameters with volume weighted average method for grids that cross severalmedium. Secondly we deduce the iterative algorithm of electromagnetic fieldcomponents based on the ADI-FDTD algorithm in calculation region.To reducecalculation region and to improve calculation efficiency,we set Perfectly matchedlayer with complex frequency shifted to absorb the outward wave and deduce theiterative algorithm of electromagnetic field components in absorbing boundarycondition region. Finally we found3dimensional Numerical simulation algorithmbased on ADI-FDTD,and we solve tri-diagonal matrix equations of component of theelectric field with chase method and we use Explicit Finite Difference Method to getthe Iterative solutions of component of the magnetic field and we transformelectromagnetic field component in Time domain into electromagnetic fieldcomponent in the frequency domain by FFT,then we get the time domain responsecurve of apparent formation conductivity.we systematically study logging response based on Formation Parameter and instrument parameters.