Atlanta Field: Lessons Learned with Tracers and Other Reservoir Management Technics

Abstract Atlanta Field is a post-salt heavy oilfield located 185 km from the city of Rio de Janeiro, in Santos Basin, Brazil, in a water depth of approximately 1,550 m. Several challenges had to be overcome for its development, such as low reservoir overburden, highly unconsolidated sandstone reservoir, heavy and viscous crude flow assurance, and aquifer performance. To cope with these challenges, Atlanta Field development was phased in two stages: (i) an Early Production System (EPS) and after it (ii) a Full Field Development (FFD). The EPS was projected to de-risk reservoir uncertainties such as: well productivity, inflow performance along the horizontal section of the well and aquifer support. Understanding these unknowns was essential to define drainage strategy and FFD design. To improve economic results, long Open Hole Horizontal Gravel Pack wells were required and following completion of the first two wells, it was decided to use AICD (Autonomous Inflow Control Device) in the screens. To evaluate oil inflow distribution and water entrance along the horizontal section of the wells, and AICD effectiveness, tracers for oil and water were installed in different positions along the wells’ screens. The tracer production data, associated with the EPS dynamic data, such as PDG pressure (including build-ups), water cut progress, and GOR behavior, enhanced the understanding of the aquifer drive performance, water production progress, and well productivity index behavior. This comprehensive analysis has significantly contributed to define Atlanta's Full Field Project. This paper presents the lessons learned of the Atlanta EPS, emphasizing the application of oil and water tracers as part of the development strategy used in Atlanta Field to mitigate reservoir-related risks and to optimize the development of a heavy oil deep water field with a large underlying aquifer. Also, the updated field development plan is described, highlighting the first results of FFD production for Atlanta FPSO, providing the most recent information related to the project with a subsequent focus on the production phase findings and results. The Atlanta's Early Production System project is considered a great success that un-risked and improved the Full Field Development of Atlanta Field.