This paper describes the challenges faced on the deployment of intelligent well completion (IWC) systems in some of the wells built in Buzios field, mostly related to heavy fluid losses that occurred during the well construction. It also presents the solutions used to overcome them. This kind of event affects not only drilling and casing cementing operations, but may also prevent a safe and efficient installation of the completion system as initially designed. The IWC design typically used in Brazilian pre-salt areas comprises cased hole wells. Perforation operations must be performed before installing the integral completion system, as it does not include a separation between upper and lower completion. Therefore, the reservoir remains communicated to the wellbore during the whole completion installation process, frequently requiring prior fluid loss control as to allow safe deployment. Rock characteristics found in this field make it difficult to effectively control losses in some of the wells, requiring the use of different well construction practices that led to the development of some new well designs. The well engineering team developed a new well concept, where a separated lower completion system is installed in open hole, delivering temporary reservoir isolation. This new well architecture not only delivers reduced drilling and completion duration and costs, but also provides the IWC features in wells with major fluid losses. This is possible by the use of multiple managed pressure drilling (MPD) techniques when required, which were considered since the initial design phase. Safe and effective construction of some wells in pre-salt fields was considered not feasible before the adoption of MPD solutions, both for drilling and completions. Other important aspects considered on the new well design are the large thickness and high productivity of Buzios field reservoirs, as well as the need of some flexibility to deal with uncertainties. Finally, the new completion project was also designed to improve performance and safety on future challenging heavy workover interventions. The well construction area has gradually obtained improved performance in Buzios field with the adoption of the new practices and well design presented in this paper. The new solutions developed for Buzios field have set a new drilling and completion philosophy for pre-salt wells, setting the grounds for future projects. The improved performance is essential to keep these deepwater projects competitive, especially in challenging oil price scenarios. One of the groundbreaking solutions used is the possibility of installing the lower completion using managed pressure drilling techniques.

Pre-salt heterogeneous carbonate reservoirs typically present long net pays, high production/injection rates and some flow assurance risks. This paper presents general information, results and lessons learned regarding the installation of Intelligent Well Completion (IWC) in Santos Basin Pre-Salt Cluster (SBPSC) wells. It also presents some important improvements to be introduced in the future IWC systems specification and qualification based on the lessons learnt in these projects, setting some new challenges to the industry. The benefits expected with the use of IWC are achieved at the expense of challenging well engineering, since well completion design becomes more complex and well construction risks increase. Detailed and integrated planning is essential for the success of the operations, starting at the earliest phases of the well design and continued through detailed execution plans. The use of standardized practices and procedures has led to significant increases on installation performance. On the other hand, an open mind and a constant search for improvements allowed new solutions and procedures to be developed throughout the years. Regarding the system integration, a flexible and standardized control architecture was developed to allow combining different IWC providers and subsea vendors, which proved to be a successful approach. The most important improvement in IWC installation was the anticipation of the acid stimulation, nowadays performed before the vertical Wet Christmas Tree (WCT) installation. In order to achieve this goal some crucial improvements were gradually implemented in the stimulation practices, such as, an initial injectivity increase solution and some new acid diversion solutions, which allowed eliminating the use of coiled tubing and, as a consequence, the need of a subsea test tree. The well design team conducted an integrated risk assessment to properly evaluate the new practices and establish some actions to reduce the risks. Intense communication between production zones was observed during the acid job in some of the initial wells, ruining the gains of the IWC. After a comprehensive analysis, some possible causes were identified and with the new stimulation practices this issue was eliminated. Over the years, with the introduction of several improvements, some of them presented in this paper, the well completion duration was reduced to less than 50% of the one observed in the initial wells. This major performance increase has been essential to keep this deepwater projects feasible, especially in the oil scenario seen in recent years. Some of the new practices and lessons learned in this 100 wells equipped with IWC has set groundbreaking practices for Brazilian pre-salt fields development and may stand as a reference for the industry in similar deepwater projects. Additional requirements for future systems are expected to improve even further the performance in this scenario.

The ambitious plan to develop and produce the prolific Pre-Salt reservoirs in the Brazilian Santos Basin was kicked off by the discovery of the gigantic Lula Field in 2006 (previously known as "Tupi"). For Petrobras, the first decade of this century was therefore marked by the significant challenges imposed by these complex carbonate reservoirs, requiring the accelerated introduction of new technologies and innovative approaches to well construction. This article describes the history of well construction in the offshore Brazilian Pre Salt area. It summarizes the evolution in well design that resulted from the implementation of innumerable "lessons learned" that were acquired since drilling of the first wildcat well in the Pre-Salt Cluster. The commulative experience of more than 100 wells drilled and 29 wells completed (to date), has resulted in a progressive reductions of time and CAPEX required for the construction of the development wells in the Santos Basin.

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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.