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.