Subsea-Systems Innovations Improve Heavy-Oil Production in Ultradeep Water

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This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 199003, “Subsea Systems Innovations and the Use of State-of-the-Art Subsea Technologies Help the Flow Assurance of Heavy-Oil Production in Ultradeep Water,” by Carlos Alberto Pedroso, SPE, Geraldo Rosa, SPE, and Priscilla Borges, Enauta Energia, et al., prepared for the 2020 SPE Latin American and Caribbean Petroleum Engineering Conference, Bogota, Colombia, 17–19 March. The paper has not been peer reviewed. Flow assurance in ultradeep water is a major issue for production. The Atlanta field, which produces heavy oil in ultradeep water, is a project combining several challenges: hydrates formation, emulsion tendency, scale formation, foaming, and high viscosities. The complete paper discusses innovations and technologies applied to make Atlanta a successful case of ultradeepwater heavy-oil production. Introduction Discovered in 2001, the Atlanta field is in the presalt exclusion area in the north of the Santos Basin, 185 km southeast of Rio de Janeiro, at a water depth of 1550 m. The postsalt reservoir is contained in the Eocene interval and is characterized by high net-to-gross sands (82–94%) with a high average porosity of 36% and high permeabilities in the range of 4–6 Darcies. These excellent rock properties, however, are offset by the poor quality of the Atlanta crude, which is heavy (14 °API), viscous (228 cp at reservoir conditions), and highly acidic. The development of the field took place in two phases, an early production system (EPS) and a definitive production system (DPS). First oil occurred in May 2018. The EPS is expected to last from 4 to 5 years, producing from three horizontal wells to a floating production, storage, and offloading vessel (FPSO) with a processing capacity of 30,000 BOPD. The DPS will consist of 12 horizontal producers tied to a larger-capacity FPSO.