Interpretation, Characterization and Importance of the Internal Salt Cycles for Seismic Processes - a Santos Basin Example

Abstract

Along with the discovery of the Pre-Salt reservoirs in Santos Basin, the necessity to understand and model the large salt bodies in a more realistic way became quite clear, especially for seismic purposes. However, a closer look to what is so-called only by “Salt” reveals an enormous depositional complexity, formed by cycles that are directly related to the basin environmental and geological history. One of the industry major challenges is to model these salt bodies using the available data since the climate mechanisms that regulate salt deposition and preservation are yet to be fully understood. Nowadays, it is known that the balance of the mechanisms that regulate the salt precipitation is very delicate and that little climate changes may alter the way salt minerals precipitate and their preservation. According to analog and experimental data, there is a defined precipitation order, which, in general, behaves like this: carbonates, gypsium or anhydrite, halite, and complex salts (tachyhydrite, carnalite, sylvite). It is possible to say that geological and environmental factors control salt precipitation and preservation together and that the major cycles described in literature are trackable in the studied area and that the incorporation of their properties and geometry on models produces better results. The main contribution of this work is to interpret and characterize the internal salt cycles using seismic data, comparing with the well information and evaluate the incorporation importance of this task for seismic processes.