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To surpass the main challenges established by deep water, high gas-oil flowratios, flow assurance and constant increases in produced water, Petrobras is developing, within PROCAP Technology Program - Future Vision, several projects in the subsea processing area, such as: Compact Oil-Water and Gas-Liquid Separation Systems, Multiphase Pump with High Differential Pressure and Gas Compression System. The main applications of these projects are in fields with high fraction of gas and water, in fields/discoveries located far away from Production Units and to increase the reservoir recovery factor. Furthermore, the application of these technologies may have great benefits, such as: production anticipation, reduction of process system footprint on the Production Unit, decrease in CAPEX/OPEX and especially an increase of the topside oil processing capacity. This paper aims to present an overview of those technologies being developed in PROCAP - Future Vision. Also, this article shows the main motivations of these developments, the main benefits of using each technology, the technological challenges and gaps, typical application scenarios and results of the evaluations performed so far. Major petroleum companies are searching for new technical solutions that fulfill their needs of reducing both CAPEX and OPEX while increasing oil and gas production. The development of new subsea processing technologies, as stated above, will enable, and in some cases reinforce, the use of these technologies for deepwater and/or subsea to shore scenarios. Introduction Subsea processing is a key enabler for challenging field developments, and their benefits increase with water depth, flowrates and step-out. Regarding subsea separation, these advantages are maximized when employing subsea compact separation technologies. Also, subsea processing brings HSE benefits related to reduction of waste disposal to sea, an environmental contribution of subsea oil-water separation systems, and the possibility of using smaller platforms - or none at all - due to the use of processing equipment on the seabed instead of topside, reducing operational risks. In terms of compact separation technology development, Petrobras has been conducting several R&D initiatives for the last ten years. Firstly, these R&D initiatives were developed for topside and onshore applications, but always keeping on mind the subsea employment. In order to evaluate these technologies several tests have been performed. More recently, the Marlim SSAO 3-Phase Subsea Separation System is a very significative example of compact subsea technology employment, for a single producer well application. Multiphase boosting is always considered as a good alternative to develop oilfields, mainly for remote areas. Petrobras invested a lot on the development of twin screw and helicoaxial concepts for multiphase pumps, targeting applications with required differential pressures up to 60 bar. Recently, analysis has indicated that High Differential Pressure Subsea Boosting (up to 150 bar) is economically and technically attractive to various Petrobras scenarios and, because of that, many R&D efforts are being done to develop such technology.

This paper initially discusses the tendency to wider the conceptual envelop of subsea systems in oil production installations. From the conventional boosting systems to more complex gas/oil/water separation equipment and even polishing devices for coarsely separated fluid stream, there is nowadays a tendency to increase the complexity of subsea production systems far beyond manifolds and other maneuver stations. In sequence the pros and cons of subsea processing as an alternative to conventional topside primary processing are also discussed. Restrictions of the subsea environment and the consequent requirement for unconventional solutions and equipments comparing to topside traditional separation equipment are also mentioned. The limitations of the expression "subsea processing" are emphasized and both advantages and technological gaps of new "building blocks" for processing plant for topside and subsea application are discussed. Besides, operational aspects are also addressed so as to emphasize the new challenges subsea systems pose to operation crew: some important paradigm changes should be captured by operators when changing from a topside plant to a subsea system. The problems arising from having a new subsea system connected to an old production unit in a brown field are also discussed. The drive for the qualification of new conceptions and new equipment is approached not only for subsea use but also for the new generation of topside production facilities. The paper tries to bring some conclusions on the means to allow further development -filling up the gaps -and qualification of the new "compact" or "in-line" building blocks for subsea processing plants. However, it must be emphasized that the focus of this work is on processing technology not on equipment or marinization technologies. Thus, subsea engineering (hardware) qualification is beyond the scop of this work.

There are still few subsea water removal systems, but looking at deeper offshore scenario the conventional topside water removal and treatment configuration is not acceptable, either from the economic or technical point of view. Increasing water cuts penalizes field revenue outcome along its productive life. The paper will demonstrate on several business cases that the best way to reduce these penalties is to get rid of water as soon as possible with subsea solutions. We start discussing the economics of a subsea primary separation station. In this focus, some examples based on hypothetical production curves show the gains in terms of increased total volume of recoverable oil that can be obtained with the approach of using a subsea water removal system, compared to conventional topside produced water management system. Some sensitivity on the influence of the parameter hypothetical values used in the analysis is also presented and they show that this trend is indisputable. It can also be concluded that these advantages increase with increasing water depth. The main conclusion of the paper is that the traditional all topside water management system, although being one business case for a field development, it is not the best configuration and it leads to lower net present value (NPV) for the whole project, since some oil is left behind due to increasing water cuts, and subsea water removal improves NPV of the project. Then it is discussed the question on why, being this the case, not much Operators consider this alternative configuration for production development. On this focus, the paper also discusses the main concerns regarding a subsea processing installation, from the point of view of operation, maintenance and reliability – justifiable concerns that have to be addressed by subsea system suppliers. Finally, it is presented the optimized concept of configuration for subsea water removal, treatment and re-injection system, whose first version was already object of an OTC presentation in 2015 (OTC-25934-MS), and since then it has been further developed and optimized through Joint Industry Projects with Operators. It is shown that this system is conceptually designed in order to increase robustness regarding a wide diversity of field conditions and production issues, requiring low maintenance. This analysis is made comparing SpoolSep concept with the alternative solutions already installed worldwide. No direct discussion on the losses implied by adopting a conservative "all topside approach" for green field development project (or even a revamp for a brown field) is easily found on literature. This paper addresses these losses and highlights the benefits of taking subsea water removal into account when studying a production development project either during green fields development planning or brown fields revamping planning. Of course, these benefits should be balanced against any sound concerns on subsea processing. Subsea Equipment and System Suppliers, on the other hand, have to focus on simplicity and robustness, aiming to offer to the Operators cost effective subsea processing solutions.

This paper presents the selected concept, the main challenges of the adopted scenario and in consequence the requirements for a development of an extensive Technological Qualification Program performed on the components and on the whole sub-sea water separation and re-injection pilot system for Marlim field -known as SSAO Marlim Project. Due to being a pioneer project, even considering the previous Troll and Tordis sub-sea separation and re-injection systems, it was necessary to perform a very extensive and broad Technological Qualification Program (TQP). Two main characteristics of the SSAO project are responsible for the mentioned pioneer character of the project. Initially, in opposition to the mentioned existing systems, separated water has to be re-injected in the production reservoir formation, due to non available disposal reservoir in production field area. Thus, required water quality, relating to oil and sediment content after separation, was very strict in order to avoid loss of injectivity. Furthermore, due to the deep water depth of the installation site (870 m) and due to the fact that the SSAO is a pilot for future deep water installations, conventional gravity separators -as used in the mentioned projects -would not be feasible and new technologies, not yet used elsewhere, have to be adopted.