Heavy oil represents a significant portion of the remaining oil reserves and there are strong economic incentives within industry to develop technologies to profitably produce these oil reserves. The success of Early Production System phase (EPS) and Definitive System (DS) solutions for Atlanta Field development certainly presents a promising way forward to achieve a safe production of extra-heavy oil in deep waters.

As the Operator, Enauta made the farm-in of Atlanta Field in 2011. Atlanta is a heavy oil field with 14°API grade with viscosity equivalent of an oil with 12°API, a shallow reservoir around 800 meters below sea bed with low temperature of 40°C and water deep around 1,550 m. Heavy oils are often characterized by their high viscosities, stable emulsion formation tendency and low reservoir energy. These combined characteristics makes production, transportation and processing operations very challenging. Likewise, the Atlanta crude imposes enormous challenges for the characterization of the reservoir, drilling and completion, flow assurance from the wells to FPSO, topsides process ing (phase separation, heat and power generation methods) and cargo storage as well as offloading from the FPSO to tankers.

This paper describes EPS implementation and DS development to overcome these project challenges with the use of the best available technical solutions and approaches to keep production safe and profitable, focused on the specifics strategies to overcome flow assurance challenges, techniques employed for the fluid viscosity management and emulsion breaking, techniques to enhance phase separation, heat and power generation methods and fuel alternatives to optimize OPEX and various design features to reduce atmospheric emissions.

Production aspects will also be described from the solution adopted for the oil processing and offloading for the EPS FPSO as well as the DS "flex-FPSO" concept to enable oil production using alternative fuels, bearing in mind CAPEX/OPEX optimization, operational flexibility, robustness and ever tightening environmental regulations.

To ensure safe operations, different contingency plans have been implemented, like this innovative solution: a software developed and tested offshore to reliably predict the drift (SW-Drift) of the drilling ship for both forecast and real-time metocean data, to accurately determine the conditions under which a support vessel shall be aware in advance to avoid collision of the drilling ship caused by a possible blackout event.

The Atlanta Field development presents a successful real case to the Oil Industry to be considered in similar difficult oil and project conditions.

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