Combining seismic facies analysis and well Information to guide new interval velocity models for a Pre-Salt study, Santos Basin, Brazil

Abstract

Since 2006, several extraordinary hydrocarbon discoveries occurred in the pre-salt section of Santos Basin, Brazil. During this period, the good quality of the seismic data exerted a fundamental role to the rather impressive exploratory results obtained. The reservoir characterization process to field development purposes requires a higher precision and resolution of the seismic data, to better image the reservoirs and reduce project uncertainties. With this goal, several efforts are made to improve the seismic acquisition and processing consistency. In this paper, we will show an approach that used the sonic and density logs and cutting samples in order to build a 3D probabilistic facies model to create a velocity model with a stratified salt layer. This better salt modelling can allow several applications, as following: i- perform a more accurate illumination study; ii- do a better uncertainty analysis regarding depth positioning; iii- improve geomechanical modelling, once there are several different salt types and a good positioning of them inside the salt section; and iv- reprocess the seismic data (PSDM, RTM) with a more realistic velocity model.