Updating velocity models for complex pre-salt targets in Santos basin

Barragan, Sergio; Donno, Daniela; Jouno, Florian; Martinez, Adriano; Khalil, A.

doi:10.22564/16cisbgf2019.164

Cited by 1 publication

(1 citation statement)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The issues are associated with the complex geometry of the overlying thick layer of salt, the deep carbonate reservoirs and an ultra-deep water layer which exceeds 2 km . The requirement to improve seismic imaging and reservoir characterization in ultra-deep water regions has encouraged using new seismic data acquisition technologies, such as the oceanbottom-node (OBN) acquisition, together with robust techniques associated with full-waveform inversion (FWI) (Barragan et al, 2019, Cypriano et al, 2019, Thedy et al, 2015, Wang et al, 2019.…”

Section: Introductionmentioning

confidence: 99%

Target-oriented refraction waveform inversion: A Brazilian pre-salt case study

Felipe

Capuzzo

Luiz

et al. 2022

Preprint

View full text Add to dashboard Cite

The ocean-bottom-node (OBN) technology has been increasingly used to characterize the Brazilian pre-salt reservoirs. The independence between the geometries of seismic sources and receivers, enabled by an OBN survey, permits designing wide-aperture acquisition geometries that favour the recording of refracted waves from ultra-deep reservoirs. In this context, we present a target-oriented full-waveform inversion (FWI) methodology to evaluate the inversion of refracted waves simulated using a realistic velocity model inspired by typical Brazilian pre-salt oil fields. In our tests we compare three acquisition geometries, using the same node configuration on the seabed, but different source geometries: (i) circular shot geometry, (ii) conventional OBN geometry, (iii) long-offset OBN geometry. We perform a wavepath analysis to investigate the illumination of the target region promoted by the refracted waves of a circular shot OBN survey. The wavepath analysis suggests that Brazilian pre-salt reservoirs may be well illuminated using the much fewer source points in a circular shot acquisition geometry. The FWI results with synthetic data show that refracted waves bring important information from the ultra-deep reservoirs which are indispensable for obtaining a reliable final velocity model. We show that adding a low-cost circle shot geometry to a conventional OBN survey delivers improvements from the long-offset data that are comparable to those obtained from the much more expensive long-offset OBN geometry. Furthermore, these results suggest that the long-offset and multi-azimuth dataset has great potential to improve the reservoir characterization in deep-water exploration marine settings.

show abstract

Section: Introductionmentioning

confidence: 99%