Dumas, Guilherme E. S. (Petrobras E&P) | Freire, Ednilson B. (Petrobras E&P) | Johann, Paulo R. S. (Petrobras E&P) | Silva, Luciana S. (Petrobras E&P) | Vieira, Roberto A. B. (Petrobras E&P) | Bruhn, Carlos H. L. (Petrobras E&P) | Pinto, Antonio C. C. (Petrobras E&P)
Over the last 40 years Petrobras has developed several oilfields in the prolific Campos Basin, including giant fields such as Marlim, Roncador and Jubarte, among others. All of these giant fields produce mostly from siliciclastic turbidite reservoirs, ranging in age from Albian to Miocene, which contain medium API gravity oil (mostly 18 – 24°API). Sea water injection is the main method for improving oil recovery. Reservoir management is particularly complex because of the deep to ultra-deep water depth and the use of subsea well completion. Therefore, several methodologies, tools and technologies are required to help reservoir management, such as: (1) data acquisition for reducing reservoir uncertainties, including extended well tests in the development plan design phase; (2) continuous improvement in the reservoir characterization and modeling incorporating dynamic data; (3) 4D seismic for monitoring oil and gas production, allowing the identification of areas with bypassed oil and secondary gas caps; (4) single well and inter-well tracers and production logs, also to help tracking the remaining oil; (5) infill drilling, to replace high water cut wells by wells located in areas with low water saturation; (6) produced water reinjection; (7) remote well treatment to restore water injectivity, as well as to inhibit or remove inorganic scaling in production wells; and (8) active reservoir management aiming the optimization of well production and injection rates, based on the flow simulator and field responses. The results have been so far very good, with the reduction of production losses and the gradual increasing in the ultimate recovery factor. A good example is provided by the Marlim Field, that already reached an oil recovery of 40%, and the actions planned for the field revitalization indicate an ultimate recovery factor of over 50%.