Atlanta is a post-salt oil field located offshore Brazil in the Santos Basin, 150 km southeast of Rio de Janeiro. The combination of ultra-deep water (1550m), heavy and viscous oil (14 API), unconsolidated sandstones, low overburden (800m), faulted reservoir rock, etc., composes a unique and challenging scenario for which the remarkable solutions applied have been already detailed (Marsili et al. 2015; Pedroso et al. 2017; Monteiro et al. 2015; Pedroso et al. 2015; Rausis et al. 2015; Pedroso et al. 2015). The Atlanta field project was planned to be developed in two phases: the Early Production System (EPS) with three production wells, and the Definitive Production System (DPS) with up to nine wells. No injection wells have been planned. In 2013 and 2014 the first two wells, here called ATL-2 and ATL-3 (ATL-1 was a pilot well), were successfully drilled, completed, and tested as described in the above references. In May 2018, they started production. After almost one year and 5,000,000 bbl of produced oil, the third EPS well was constructed. The lessons learned in each phase of the well construction - drilling, lower completion, and upper completion - were applied in the third well, repeating the good operational performance. An analysis of this comparative performance is presented. Technology improvements were implemented, such as the use of autonomous inflow control devices (AICD), the use of micro-tortuosity logging to better position the electrical submersible pump (ESP), the use of an annulus diverter valve (ADV) to avoid the pressure drop across the ESP in case of failure, etc. The result was a well constructed ahead the planned time with a Productivity Index (PI) that exceeded expectations.

Sand control is a major issue for offshore unconsolidated sandstone reservoirs, where any workover or production interruption event is associated with high costs. Horizontal well openhole gravel packs proved to be a very reliable strategy to prevent sand production in the prolific offshore Brazil fields. Over 250 operations were successfully performed in different critical scenarios, such as ultra deepwater wells, long horizontals, in the presence of shale interlayers, etc. Pushed by the present fluctuations in oil production revenues and aware of the expressive costs related to gravel pumping operations, PETROBRAS started a broad R&D and field test strategy to reduce operational times and costs. This article details both aspects of the development, as follows: An unique flow loop test program developed as a technical cooperation agreement with HALLIBURTON, including real scale 8.5 in open hole and 12.25 in rat hole sections. Such tests allowed the validation of novel technology, pumping procedures and products including limit flow rates which avoid premature rat hole screen outs, low cost conventional and lightweight propants and high concentration slurry pumping.2. The learning curve of new pumping design strategies, and their associated cost reduction, in different offshore fields including Marlim Sul, Albacora Leste, Marlim Leste, Roncador, Jubarte and Golfinho fields. New strategies contemplate multiple alpha waves, multiple propants and high concentration slurry designs.

The demand for well plug and abandonment (P&A) operations in Brazil has increased significantly during the last 3 years, resulting in a steep learning curve that can lead to development of state-of-the-art methodologies that save time, reduce operational risks, and provide reliable cost-effective solutions. This paper presents a comprehensive analysis of recent well abandonment operations in a mature field in Brazil, which included wells that were depleted or no longer economically viable. A methodology is discussed and highlights the use of a casing collar locator (CCL) to perform depth correlation before setting packers and placing cement plugs, real-time pressure signals to monitor packer setting, and coiled tubing (CT) internal and external pressure management to help ensure that all cement is pumped out of the CT.