Atlanta Field: Producing Heavy and Viscous Oil in Ultradeepwater

Abstract

Summary Atlanta Field is a post-salt heavy-oil field located 185 km off the city of Rio de Janeiro, in Santos Basin, Brazil, at a water depth of approximately 1550 m. Atlanta, however, is not just another ultradeepwater heavy-oil field. Several additional challenges had to be overcome for its development, such as low reservoir overburden (800m), highly unconsolidated sandstone reservoir (36% porosity and 5,000 md permeability), heavy and viscous crude flow assurance (14 °API and 228 cp at initial reservoir conditions), high-naphthenic-acidity oil [total acid number (TAN) 10mg KOH/g], high-power artificial-lift pumping-systemrequirement (1,600 hp), and complex-topside crude facilities. The development of Atlanta Field was phased in two stages: an early production system (EPS), which is expected to last from four to five years and comprises three horizontal production wells; and a definitive production system (DPS), which will add nine wells to complete the development plan with 12 horizontal producers. The first two EPS wells were successfully constructed and tested during 2013 and 2014, proving the feasibility of surpassing the great challenges imposed by the field’s unique environment and enabling the beginning of the production phase of the field. The first oil occurred in May 2018 with these two wells producing to the floating production, storage, and offloading unit (FPSO) Petrojarl I. The third and last producer of the EPS was constructed in 2019 and began operation in June of the same year. More than five million barrels of oil were already produced to date. Marsili et al. (2015) described in detail the exploration and development phases of Atlanta Field, focusing on their challenges, the overcoming process, and solutions adopted. This current work intends to present an updated review of the paper, providing the most recent information related to the project with a subsequent focus on the production phase findings and results. Among others, the initial prediction and expectations will be compared with actual field performance. For all milestones achieved, the Atlanta project is considered a great success so far and a benchmark for the industry in this harsh and adverse environment.