The Campos basin is a sedimentary basin located in offshore Brazil, between the north coast of Rio de Janeiro State and the south coast of Espírito Santo State, encompassing many oilfields. Most of the reservoirs in the basin are high-permeability sandstones containing low API gravity oil but are without strong water drives. Long horizontal producer wells are the best economic option for field development but require water injection to maintain reservoir pressure. Horizontal sections generally range from 1000 to 2000m, which demands gravel pack as a sand control method. Gravel packing such long wells is a challenge and requires thoughtful engineering to optimize pumping techniques and technology. Presented here are best practices to overcome several challenges faced in this field to achieve overall success. The challenge for extended-reach gravel packing is that the long horizontal section develops high friction during the alpha and beta wave propagation. Increasing the pumping pressure to overcome this friction increases the risk of fracturing the formation, consequently reducing the equivalent circulation rate downhole impairing the proppant transportation. In contrast, a reduced pump rate during alpha wave propagation can lead to a premature screenout due to the increase in dune height of over 85%. To overcome these issues and place gravel packs in these wells, careful engineering and simulation, lightweight proppants, friction reducers, and thorough job planning were used to successfully perform gravel packs in more than 40 horizontal wells completed in the Campos basin from 2011 up to 2017. The experience of pumping the longest gravel pack jobs in offshore Brazil (horizontal length more than 2,000m) offer insights into best practices for gravel packs in extended-reach horizontal wells: Design considerations, specific well challenges faced, technologies deployed, and operational planning requirements. Specifically, highlighting the benefits of using lightweight proppants and optimized fluid systems to minimize screen out risks and maximize pack efficiency.

Pre and post salt carbonate reservoirs are becoming the main source of hydrocarbon production in Brazil. One of the reasons behind this success is the development of many fields located on pre salt areas along the Brazilian shore. Production optimization is vital for sustainability, which requires efficient methods and technology to stimulate these reservoirs. The main cost-effective approach used in Brazil to improve the production in carbonate reservoir areas is matrix acidizing. Stimulation fluids are pumped into the formation below the fracture pressure to create wormholes that can bypass near wellbore damage and increase the drainage radius along the wellbore. This study offers an insight of the most common methods and technology used to perform matrix acidizing on offshore carbonate reservoirs in Brazil. The main aspects of the study are fluids selection, pumping strategies, completion design and pressure behavior analysis. Before 2012, most of the offshore stimulation operations in Brazil were performed on sandstone reservoirs. With the advent of pre salt development this scenario changes drastically leading to a high volume of matrix acidizing on carbonate reservoirs in both post and pre salt zones. The main challenges to designing and executing matrix acidizing on carbonate reservoirs in Brazil are the long reservoir intervals combined with high permeability contrasts, high formation temperature and the need of large fluid capacity to accommodate the required treatment designs. Additionally, super duplex stainless steel metallurgies must be considered for corrosion inhibition protection. To overcome these challenges: first, a proper fluid diversion technique must be employed to distribute the treatment fluid across all targeted zones; next, a proper fluid selection must be made to avoid carbonate face dissolution; and finally, corrosion protection is required for the well bore completion components from the corrosion rates increased by the high temperatures downhole. The lessons learned and best practices captured over the past decade on more than 250 offshore carbonate matrix acidizing operations has led to much success in the post and pre salt zones of Brazil.

The Campos basin is a sedimentary basin located in offshore Brazil, between the north coast of Rio de Janeiro State and the south coast of Espírito Santo State. Most of the reservoirs on the post-salt layers are high permeability sandstones (2,000 mD up to 6,000 mD), containing low API gravity oil. In addition to the high permeability, these sandstones are unconsolidated, which demands a sand control method to make oil and gas production feasible. In the original field development, conventional gravel packs were used as a sand control method, but post job analysis indicated high skins after the treatment, even using the best completion and placement techniques. This study offers an insight of the best practices and lessons learned from the design and pumping of more than 130 packs over more than two decades in offshore Brazil (water depths from 33 up to ~1800m). The main aspects discussed include frac pack design considerations, typical procedures, fracturing equipment overview, pressure management strategies and the need for a high quality fluid system and proppant. Frac pack completions were introduced in the end of the 90's and became a usual completion method for the Campos basin. Post job analysis indicates that this type of treatment provided better results than the convention gravel pack including lower skins after treatment. Due to the challenging reservoir characteristics, the strategy for frac pack design was to create a highly conductivity fracture, aiming to reduce the skin as much as possible, by using aggressive Tip Screen Out (TSO) designs. The TSO provides a short but wide and very conductive fracture, which is essential for high permeability wells. This technique bypasses the near wellbore damage caused by the previous drilling and completion practices such as drilling fluids, perforating debris and completion fluids invasion. This method can improve the effectiveness of the production, enhancing the oil recovery.

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