Salt Reshaping with Template-Matching Full-Waveform Inversion

Summary Subsalt imaging is an industry-level challenge that has existed for many years in the Gulf of Mexico. This is due to the irregular shape of salt bodies, combined with poor illumination below top of salt. Both correct shape of salt and kinematically correct detailed sediment velocity are required to successfully image the reservoir level below salt bodies. The conventional method in the industry is to build the model from top to bottom with flooding of sediment or salt and then delineate the salt bodies by manual interpretation. This process requires intensive labour and usually creates suboptimal subsalt images in the presence of complex salt geometries. The template-matching full-waveform inversion (TM-FWI), which minimizes both the temporal and spatial shift between observation and prediction, is designed to automate the salt velocity model building by updating both sediment and salt simultaneously. This data-driven TM-FWI workflow reveals reliable salt geometry as well as greatly reduces turnaround time for salt model building. This workflow was tested in the extremely complex Campeche region in the Southern Gulf of Mexico and the resulting image is much superior to legacy, which validated the effectiveness of the workflow proposed herein.