Finite difference modeling to evaluate the improvements associated with a multicomponent towed streamer measurement in Espirito Santo basin offshore Brazil Franck Le Diagon, Yazil Abbas, Tim Bunting, Juliana dos Santos, and Carlos Montana, Schlumberger; Adelson de Oliveira, Gilberto de Lima, Lucas Balancin, Gustavo Basta Silva, Filipe Borges, Glauco Sousa, and Roberto Dias, Petrobras Summary The paper details a modeling project to understand the uplift associated with a multicomponent towed streamer acquisition and processing workflow in the Espirito Santo basin offshore Brazil. A complex model was built representing many of the common geological features in the Espirito Santo basin including allochthonous salt bodies, post-salt anticlinal generated fractures, volcanic intrusions, and shallow meandering channels. Synthetic seismic data was generated for a number of geometries, both single and multicomponent, including a very densely sampled control measurement. The synthetic measurements were reconstructed/interpolated to a 12.5-m crossline surface receiver sampling interval. The various datasets were compared both pre- and post-migration. The results suggest that the multicomponent measurement in conjunction with multicomponent reconstruction better samples the complex waveforms. Introduction Multicomponent towed-streamer seismic systems have recently become available for hydrocarbon exploration projects. A multicomponent towed streamer measures the pressure field and the vertical and crossline particle acceleration fields. The particle acceleration measurements allow for derivation of the pressure gradient in the vertical and crossline directions, which accommodate true 3D receiver deghosting and reconstruction to spatial frequencies well beyond those predicted by nyquist theory (Robertson 2008). As with any new technology, the industry has to go through the process of understanding where the technology will provide the most uplift and which geological and geophysical challenges it will best address. This paper summarizes a project in which the multi- component towed streamer technology was evaluated using computer simulations rather than in-field experiments. A model was built which was representative of the geophysical challenges in the Espirito Santo basin, and this model was used to generate multicomponent synthetic seismic data as well as conventional single-component synthetic seismic data. The datasets were processed through to final image after maximizing the spatial bandwidth of the data to provide a number of different comparisons. Earth model building Accurate 3D velocity and density models are required to generate seismic synthetic data. An area on the continental rise of the Espirito Santo basin was selected to build these models. The Espirito Santo basin is characterized by thick autochthonous salt and shallower allochthonous salt bodies with complex shapes which can be attached or separated from the original salt. The shallow section is characterized by faulting associated with the salt deformation which could form hydrocarbon migration routes. Additionally, the water bottom can be complex with wide canyons. The velocity model was derived from a dense 3D velocity field available in the area of interest. The deeper portion of the 3D density model was built from well log data extrapolated along interpreted horizons. An updated version of Gardner’s relation was derived to convert the velocity model to density, which was then used to populate the shallow sediment layers of the density model. The overall model size was around 19 x 11 x 5 km (Figure 1). The model incorporated a complex allochthonous salt body of constant velocity and density. This structure appears on the North East corner of Figure 1. A 60-m thick, 2000-m long and 3000-m wide surface was introduced into the Figure 1: Earth model showing main geological structures and density sections. Page 3287 SEG Denver 2014 Annual Meeting © 2014 SEG T