Full Open Hole Intelligent Completion: A Game Changer in Brazilian Pre-Salt

Abstract

This paper presents a new intelligent completion solution recently introduced in Brazilian pre-salt fields, such as Búzios and Mero. Since the introduction of open hole wells with intelligent completion in 2019, this kind of design has become the prevalent architecture in pre-salt. However, the current completion design, with the ICVs in the upper completion, limits the number of remotely controlled intervals to a maximum of two. The new solution aims to deliver additional zonal control. As an initial step, Petrobras has organized some close interactions with all major service providers, looking for possible solutions for new well designs that could meet the requirements. The development of these new concepts was followed by a selection process when the most suitable solution was identified. After this step, the engineering team went into the detailing phase, where some technology and experience gaps were identified. A plan was put in place to develop the missing technologies and to gradually introduce the new design in the field to "derisk" the projects and achieve the required readiness. A well configuration with ICVs installed directly in open hole was selected. This allows deploying more than 2 valves in each well, as the concentric flow design is not required. In the other hand, running them in open hole results in some risks and uncertainties that were not applicable in cased hole. Wellbore stability, control lines integrity and zonal isolation are just some of the aspects that were part of the well engineering studies. A new expandable packer assembly with feed through capability was developed for proper and reliable zonal isolation. Other important guidelines for the project were workover readiness and compatibility with severe fluid losses scenarios. For both challenges, downhole disconnection systems are being developed. They will allow the disconnection and reconnection of the control lines in downhole environment. Additional equipment is also under development to allow installing the lower completion in a dual trip approach along with the use of MPD techniques. As part of the introduction of the new solution, three full open hole 3-zones intelligent completion systems were installed in Mero and Búzios field in 2021. Though none of them used the downhole disconnection system, a successful and valuable experience was obtained regarding the intelligent completion deployment in open hole. The comprehensive solutions envisioned for well construction in pre-salt fields include the fast development and intense application of new technologies, resulting in groundbreaking concepts. A significant cost reduction is expected with the new design and was already observed in the 3 pilot wells. At the same time, it also delivers all the required functionalities and incorporates improvements for the well life cycle. The introduction of this innovative concept is a game changer for pre-salt projects.