The challenges on the CCGS monitoring in the development of Santos Basin Pre-salt Cluster

Abstract

The Santos Basin Pre-salt reservoirs are located in deepwater offshore Brazil and although the oil has a good quality, their CO2 concentrations are higher than those generally found in other Brazilian fields. PETROBRAS and its partners established that they will not vent the CO2 produced in the Pre-salt layer to the atmosphere so a CO2 injection scenario is a potential alternative to improve the oil recovery. An extensive monitoring program is being considered in order to ensure the Carbon Capture and Geological Storage (CCGS) projects efficiency. However, there are several challenges to be confronted concerning the CO2 monitoring in such adverse conditions as the Pre-salt reservoirs. Among the existing techniques for monitoring offshore storage sites, some of them have already technological maturity and applicability to the Pre-salt environment but other methods must rely on some development or methodology adaptation to the specific features of these fields and they will be initiatives of the PRO- CO2 technological program of PETROBRAS Research Center. This paper addresses the main technological challenges for PETROBRAS and its partners related to the methods applicability for the CO2 storage monitoring in the Santos Basin Pre-salt Cluster and also exposes the strategies found to solve the problems.