Since the beginning of the Santos basin pre-salt commercial production, in December 2010, more than 1 billion barrels of high quality oil have been extracted from these ultra-deep water carbonate reservoirs. To enable and accelerate production, Petrobras and its partners applied advanced and innovative technologies in various areas of engineering. This paper focuses on the reservoir strategies conceived during the design phase of the Lula and Sapinhoá development projects and their application in these fields. The authors highlight practices and processes whose extensive use, in this type of scenario, were not standard. Among these, the dynamic characterization of the reservoirs by the use of long-term tests coupled with remote monitoring of pressure; water and gas production control by alternating injected fluids; intensive use of intelligent completion; convertible wells to accelerate production growth (ramp-up); CO2 injection from the start of production; rock-fluid interaction tests; optimization of well stimulation and many others. Knowledge acquired during the first seven years of commercial production and the actions implemented to manage the reservoirs reflect on the production plateau extension and the final length of their expected productive life. The collection and analysis of static and dynamic data proved to be valuable to reduce uncertainties and support further development decisions. Integrated effort contributed to risk mitigation, production maintenance and increased forecasted final recovery. The results obtained emphasize the importance of an effective reservoir management approach to maximize production and recovery. Concepts adopted are clarified through practical examples showing the advantages and gains from their implementation. The final message is that safe and viable operation of ultra-deep offshore fields benefits from additional investments in acquiring specific reservoir data. Their integrated analysis using advanced and up-to-date techniques is considered essential to maintain and improve asset values.

The purpose of this paper is to present a general overview of the Buzios field development plan, projects’ features, and main achievements so far. The development plan adopted a strategy to pursue the balance between acceleration and cash flow optimization, to maximize the return on the huge investment on the block acquisition, and the risk management related to developing several Greenfield Projects simultaneously. To reduce reservoir uncertainties, a comprehensive data acquisition plan was crafted and implemented considering: (a) seismic acquisition, (b) drilling, logging and testing several exploratory and appraisal wells, (c) massive rock and fluid data sampling along the reservoirs, (d) execution of one Extended Well Test and three Early Production Systems. Additionally, the basic design of wells, subsea systems and Floating Production Storage and Offloading ("FPSO") provided flexibility to cover remaining uncertainties yet present in the Transfer of Rights ("ToR") scope, which allows up to 3,150 billion barrels of oil equivalent ("boe") to be produced. This led to technological challenges that needed to be addressed during project planning. We believe that the innovative solutions applied enhanced currently available technologies and delivered an important legacy to the offshore oil and gas industry. Finally, the results obtained so far, with the ramp-up of Buzios projects 1, 2, 3, and 4 provide evidence of the successful adopted strategy and reinforce the decision of deployment of a fifth FPSO under the scope of the ToR contract. The strong results of the asset led to the acquisition of 90% of the Transfer of Rights Surplus ("ToR+"), together with CNOOC Petroleum Brasil Ltda. (5%) and CNODC Brasil Petróleo e Gás Ltda. (5%), which now paves the way for a second wave of development, including the deployment of up to seven additional FPSOs.

One of the main activities of a reservoir engineer is to manage the production and injection of fluids in a reservoir. By managing the production and injection it is possible to react to the breakthrough of the injected fluids and control the rate at which BSW and GOR increase in the production wells. In wells completed in more than one target zone the reservoir management can be done by restraining or just closing the interval through which the injected fluids are inflowing. However to identify the interval through which the water or gas is produced in this kind of well is not an easy task, being the track of the paths through which the injected fluids flow in the reservoir (as well as in the neighborhood of the well) the main challenge of the reservoir management. In this paper a set of data of different wells of a Santos Basin Pre-salt reservoir is presented. Intelligent completions with more than one target zone are installed in these wells and the temperature data of each zone are analyzed. Simplified analytical models are employed to describe the various regime flows observed in these wells, thus providing some insights in order to characterize the flow. Temperature data of production and injection wells are analyzed in different scenarios were the gas and/or water saturation modifies near the wells. The main hypothesis adopted in this work is that the change in temperature behavior is associated to the modification of the saturation of the different fluids in the reservoir. This paper aims at estimating the length of the modified saturation region near the injection well by assuming that the thermal diffusion is predominant. By doing so the problem is described by the energy balance equation and the boundary and initial conditions depends on the condition of the well (if it is operating or closed). This methodology is further extended to analyze the change of fluids saturation near production wells in order to provide some insight about the breakthrough of injected fluids. By comparing the theoretical response of the methodology presented in this paper to that observed in the wells it is possible to make some conclusions about (i) the injection profile in wells where the isolation between the zones in the well's neighborhood was lost during the stimulation of the formation and (ii) about the distribution of the injected fluid in the reservoir near the wells, whose isolation between zones was not lost during the stimulation.