Reservoir management in offshore fields is a challenging task, particularly for mature fields because of a typical excessive production of water and/or gas. Due to several constraints on facilities capacity, assisted reservoir management process can deliver solutions to operate properly offshore fields, seeking for increasing oil production with better assessment of water and gas production and injection. Optimal Reservoir Management (ORM) can be applied aiming to maximize reservoir performance and to deliver well controls applicable to field operations. In this work, we implemented an assisted optimization procedure to maximize overall oil production for a field offshore Brazil in Campos Basin. We applied our ORM technique in an important field offshore Brazil, where cumulative oil production is maximized by optimally controlling water rates through injecting wells. Injection rates can vary in time, honoring operational requirements of smoothness. Geomechanical limits on injection pressures are considered to avoid loss of rock integrity and platform constraints on overall production and injection are imposed all times. Our approach deals with reservoir uncertainties described within a large set of calibrated simulation models to decide on optimal injection rates, taking into account possible risks. The model-based ORM under uncertainty that we developed has shown gains in total oil production over 20 years of operation up to 7.2% with respect to the base strategy currently applied. On average, results show an increase around 4% in oil production, with concomitant reduction in total water production and in the overall water injection. A pilot test in the actual field has been implemented to verify the consistency between modeling and reality (data observation), in order to guarantee that the gains forecasted by our study are feasible. We have chosen an area in the field to proceed an optimal injection control pilot, aiming to check the quality of the uncertain models in comparison with the observed data in practice. The pilot area has been selected based on aspects related with geological description, connectivity expected in the reservoir and operational constraints. The results of 8 months of pilot show clear coherence between models and reality within the uncertainty range expected to the reservoir of interest. To the best of our knowledge, it is the first time that an offshore field is actually operated based on a set of controls obtained by an assisted optimal reservoir management procedure, although it was performed still in a pilot scale. Results suggest robust benefits under reservoir uncertainties consideration and large-scale application shall take place soon, but it is out of the scope of this work. The pilot provided more confidence on field applications, leading to broader perspective for full-field implementations.
This paper describes recent efforts into continually increasing the recovery factors in the Campos Basin reservoirs, which translate in significant investments foreseen for the next years to increase the production and recovery of the Basin. Some strategic efforts comprise measurement and critical analysis of current recovery factor, evaluation of recovery potential per reservoir and the creation of initiatives focused on the main technical requisites that would allow higher recoveries. Campos Basin complexity, along with the maturity of the existing infrastructure, brings new challenges to the continuity of production. Among those challenges are the capacity to process large amounts of produced water and the demand for revitalization of production facilities, including topside, subsea and new wells. Despite excellent results achieved in pre-salt reservoirs in Santos Basin in the recent years, Campos Basin remains an important province for Brazil's oil production. Still responding for 40% of the current production of oil in Brazil, the basin presents a promising future in the next decades. Revitalization projects, development of recent pre-salt discoveries and concession contract extensions are among the ongoing efforts towards Campos Basin renewal. Along with operations and complementary projects, a strategic program called RF Ambition was set up in 2019, aiming to: deepen the diagnosis of the recovery factor per reservoir;establish recovery targets and ambitions for each reservoir;identify initiatives to boost recovery;provide the technical support to deploy the projects with potential to allow achieving the targets and ambitions in Brazilian fields. An accurate diagnosis of the basin's recovery factor relies on a careful and thorough detailing of its reservoirs. Campos Basin has hundreds of production zones with different lithologies, in place volumes, types of fluids, geological complexities and water depth. Data analysis, evaluation and comparison to analytical estimates and international benchmarks can minimize the risk of reaching superficial or even incorrect conclusions. The remaining potential of the reservoirs, approached by the identification of opportunities, translates into mid- and long-term supplementary projects to exploit undeveloped zones and optimize the recovery of the reservoirs, thus increasing overall recovery of the fields in Campos Basin. The aggregated contribution of these new opportunities integrates an ambitious target of recovery factor for the basin. There are significant opportunities to increase Campos Basin's recovery factor and, to achieve the forecasted targets, technical and economic challenges must be overcome with the contributions of all agents involved in the upstream chain.
SummaryReservoir management in offshore fields is a challenging task, particularly for mature fields because of a typical excessive production of water and/or gas. Because of several constraints on facilities capacity, an assisted reservoir management process can deliver solutions to optimally operate offshore fields, seeking to increase oil production with better assessment of water and gas production and injection. Optimal reservoir management (ORM) can be applied aiming at maximizing reservoir performance and to deliver well controls applicable to field operations. In this work, we implemented an assisted optimization procedure to maximize overall oil production for a field offshore Brazil in Campos Basin.We applied our ORM technique in an important field offshore Brazil, where cumulative oil production is maximized by optimally controlling water rates through injection wells. Injection rates can vary with time, honoring operational requirements of smoothness. Geomechanical limits on injection pressures are considered to avoid loss of rock integrity, and platform constraints on overall production and injection are imposed at all times. Our approach deals with reservoir uncertainties described within a large set of calibrated simulation models to decide on optimal injection rates, taking into account possible risks.The model-based ORM under uncertainty that we developed showed gains in total oil production over 20 years of operation up to 7.2% with respect to the base strategy currently applied. On average, results show an increase of near 4% in oil production, with concomitant reduction in total water production and in overall water injection.To guarantee that the gains forecast by our study are feasible, a pilot test in the actual field has been implemented to verify the consistency between modeling and reality (data observation). We have chosen an area in the field to proceed with the optimal injection control pilot, aiming to check the quality of the uncertain models in comparison to the observed data in practice. The pilot area has been selected on the basis of aspects related to geological description, connectivity expected in the reservoir, and operational constraints. The results of 8 months of the pilot show clear coherence between models and reality that is well within the uncertainty range accepted at the reservoir of interest.To the best of our knowledge, it is the first time that an offshore field is actually operated on the basis of a set of controls obtained through an assisted ORM procedure, although it was performed at a pilot scale. Results suggest robust benefits under reservoir-uncertainties consideration, and large-scale application will take place soon, but that is outside the scope of this work. The pilot provided more confidence in field applications, leading to a broader perspective for full-field implementations.
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