Research Of Well Log Guided Velocity Interpolation For FWI

Full waveform inversion(FWI)is a hot technique for modeling a high-resolution subsurface velocity model.FWI can use full wave information to invert a accurate velocity model for reverse time migration(RTM),thus RTM can process complex structure.So FWI and RTM are the most promising technique for imaging complex structure.But the success of FWI still faces a lot of problem,and the great dependence of a good velocity model is one of them.When the initial velocity model is far away from the true velocity model,FWI can rarely converge to the ideal velocity model.In order to solve the problem,this paper proposes a method for building a good initial velocity model that can put into the FWI framework for inverting a perfect velocity model.This paper use well log velocity and the geological structural as prior information together to interpolate a velocity model for FWI through the way of regularization.In order to obtain the geological structure of subsurface reflectors,this paper firstly uses RTM with a given smoothed velocity model to image the geological structure,then uses plane-wave destruction filters to get the local slop from the RTM image as the prior information.This paper uses a relatively simple layered model and a more complicated marmousi velocity model to demonstrate the effectiveness and applicability of the proposed method.This paper starts from a very smooth velocity model and then get the RTM image and the local slop,finally FWI uses the interpolated velocity as initial velocity and can obtain a nearly perfect result.And the comparison to the traditional FWI approach also shows the advantage of the well log interpolated velocity guided by geological structure.