Kinematic reconstitution and tectono-sedimentation associated to salt domes in deepwater of Santos Basin, Brazil

Abstract

This article presents new methods for structural restoration and kinematic evolution of salt domes during the opening stages and growth of a passive margin in the Santos Basin. The traditional method or restoration of salt bodies uses softwares and a 3D database. Using 2D seismic data and adapting/impro-ving methods published in the oil industry literature, we developed a method based on the observation of the stratal geometric patterns of sedimentary pa-ckages associated to the salt bodies such as tabular forms (straight parallel reflectors, pre or post-tectonic sedimentary sequences), or dish/bowl forms (with very distinct depocenters and thinned margins with fanning of dips, syntectonic/halokinetic sedimentary sequences), and on the determination/mapping of growth axes and thinning axes in halokinetic strata. Horizontal and vertical reconstitutions of the salt flow (inflation, deflation and horizontal flow) were deduced based on isochron (isopach maps in time) and axes maps and flattened seismic sections at the time of deposition of each associated sedimentary sequence. The resulting maps and reconstitutions presented an amazing correlation with the current patterns mapped in the study area. The interpreted tectonic phases of halokinetic evolution, deduced from the produced maps and reconstitutions, showed a good agreement with the regional events that affected the Santos Basin and adjoining basement. Based on those results, we believe that the application of this method provides an important contribution for the oil exploration industry, considering that it presents outstanding results based on 2D seismic data. It allows an understanding of the structural and kinematic evolution of the salt bodies and of the halokinetic sequences associated, with im-portant implications on the modeling of petroleum sys-tems, thus, reducing the risk of exploration prospects.