A shallow velocity model building using full-waveform inversion on 3D onshore dataset

Abstract

Full Waveform Inversion (FWI) can provide a reliable velocity model, which is necessary to make more accurate seismic images, thus, to locate low relief reservoirs. And its successful implementation depends on the quality of low-frequency components of seismic data and the existence of a good starting velocity model. However, low-frequency components of a 3D land dataset used in this study are dominated by noises and a legacy velocity model in the survey area is not existed. To overcome these problems, a two-stage FWI workflow has been implemented to obtain a credible shallow velocity model on the 3D land dataset. As a first stage of this strategy, we update velocity model to minimize time difference of the first arrivals between field and synthetic data. At the second stage, we perform traveltime-oriented FWI to update the model by minimizing phase differences of diving and refracted events between field and modeled data. We verified the proposed workflow by analyzing QC results.