Santos Basin Pre-Salt Cluster, Deepwater Southeast Brazil, is a unique scenario due to the heterogeneous nature of its microbial carbonate reservoir, underlain by 2,000 m salt layer and distant 300 km from the coast. Other characteristics for development are the variable CO2 content and compositional grading with depth of the reservoir fluids, flow assurance issues and special demands concerning subsea engineering, well construction and processing plant.
Recognizing reservoir and development uncertainties, Petrobras and its partners have opted for a staged development, based on intensive information gathering, extended well tests (EWTs), multi well production pilots and definitive systems prioritizing the standardization of well projects and production systems. This strategy aimed both accelerated cash flow and dynamic characterization of the reservoir behaviour, subsea gathering system and the processing of fluids in production units. Long term recovery was not forgotten as flexibility was planned for different recovery mechanism as water, gas and water alternating gas (WAG) injection.
This paper presents an overview of the main drivers and concepts which served as basis for the development of the prolific pre-salt fields. Pre-salt mega-projects management was early identified as especially challenging: it should assure that the main uncertainties were known and mitigated at project sanction, as well pursuing strategies for CAPEX reduction, on-time long lead items delivery and local content accomplishment, among others. Integration of disciplines and the flexibility were paramount to achieve these goals.
The first results are on stream: after only eight years from discovery, production in the Santos Pre-Salt Cluster reached, in February, 2014, 240,000 bopd. This production comes from ten producers; water and gas injection are also being performed. Considering the whole pre-salt reservoirs offshore Brazil, production is over 400,000 bopd. The lessons learned are being considered to optimize the next generation of production systems. Three FPSOs are operating in the Santos Pre-Salt, two additional FPSOs will be installed in 2014, and 8 more until 2016. An oil flow rate of more than 1 million bopd, operated by Petrobras, is expected for 2017.
Many papers have been written describing the pre-salt discoveries made in ultra-deep water offshore Brazil in recent years - exploration activities started in 2002 encompassing an area of approximately 11,600 km2 (Figure 1) (for more details on the exploratory activities in pre-salt area see the paper by Carminatti M. et al). In this paper the main focus is the main drivers associated to the production development projects planning and execution. But, before doing so, it is important to briefly review some of peculiarities of these huge discoveries.