High-resolution Land Full Waveform Inversion - A Case Study on a Data Set from the Sultanate of Oman

Standard reflection-based model building for land applications is challenging due to reduced data quality, near-surface heterogeneities, and the low-fold of reflection data at shallow depths. Broadband and large offset data acquisitions have been developed with the aim of investigating full waveform inversion (FWI) as an alternative tool for velocity model building. FWI using minimally-processed refractions and diving rays provides an efficient solution to recover longer spatial wavelength details in the velocity model. In recent studies this method has been proposed as a means to guide and enhance standard reflection-based methods. Rather than follow refraction/diving ray FWI with reflection tomography, we apply FWI to conventionally-processed reflection data, and move to higher frequencies (up to 13Hz). By incorporating reflection data and higher frequencies we obtain higher resolution structural details such as channels and fault structures and obtain improved imaging results compared to those found by migration velocity analysis. We outline a refraction data preprocessing sequence tailored for data quality at low frequencies and long offsets, and describe the FWI workflow which uses both refractions/diving rays and conventionally-processed reflections. We show the resolution uplift over refraction-based FWI and compare migrated stacks generated with the standard tomography model to that generated with the high frequency FWI result.