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.

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An adaptative multimeshing algorithm is introduced to simulate hydraulic fracture propagation considering temperature evolution in a petroleum reservoir. The methodology enables an implicit solution by which fracture damage is solved semi-explicitly and sequentially, in a pseudo time evolutionary procedure. In the poroelastic medium, the interaction between rock deformation and fluid flow is strongly coupled and solved implicitly in a non-linear Newton solver while the heat flow problem is weakly coupled. This strategy is justified by the quite different time scales of each phenomena. The proposed remeshing procedure uses different meshes for the poroelastic and heat flow problems and has the advantage of dynamically matching the frature path and the critical zones in the domain, where high temperature, pressure or stress gradients are present. This approach allows the designer to fine tune meshing parameters ensuring proper representation of the physical phenomena in the analysis. The numerical approach uses finite elements to discretize both the poroelastic and the heat flow problems while it uses lower-dimensional cohesive interface elements dynamically fitted to the damaged and the fractured interfaces. The results presented herein address performance and accuracy issues, stress parameter setup in fracture propagation and thermal front evolution models. It was found that working with multiple meshes in numerical simulation runs is advantageous because it enables dealing with more complex scenarios while balancing accuracy and computational cost. The analysis of the proposed methodology also evaluated the scalability, showing promising capacity to scale up for the analysis of huge complex models.

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