Abstrak

Kembali

We show a case study of full-waveform inversion (FWI) applied to a regional 240-km long seismic profile (called POLCRUST-01) located in southeast Poland. The experiment is unique because it portrays different tectonic deformation styles over a relatively short distance. It was designed for deep reflection imaging, but we decided to use FWI to provide a high-resolution P-wave velocity model of the shallow (down to 3 km) subsurface. The acquisition parameters, namely the use of 10-Hz geophones and Vibroseis sweeps starting at 6 Hz, made it necessary to design a non-standard data preconditioning workflow for enhancing low frequencies including match filtering and curvelet denoising. Final model was validated using multiple procedures, such as comparison with borehole data and independently processed Kirchhoff pre-stack depth migration. Although in some deeper areas of the model we identified artefacts that are most likely a result of cycle skip, the velocity profiles from our model match the borehole check-shot data and the velocity anomalies coincide very well with the reflectivity in the migrated data. The resolution of the model allows us to delineate the internal structure of the Carpathian thrust system and presumably small natural gas reservoirs in the Miocene sediments of the Carpathian Foredeep.