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This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper OTC 24498, "Subsea Processing and Boosting in Brazil: Status and Future Vision" by F.A. Albuquerque, M.G. Morais, M.L. Euphemio, C. Kuchpil, D.G. Duarte, and R.T. Orlowski, Petrobras, prepared for the 2013 Offshore Technology Conference Brasil, Rio de Janeiro, 29-31 October. The paper has not been peer reviewed.
Subsea processing and boosting can be key enablers and optimization alternatives for challenging field developments whose benefits increase with water depth, flow rates, and stepouts. This paper summary focuses upon reporting new research-and-development (R&D) initiatives related to subsea processing and boosting offshore Brazil.
In the initial exploitation stages of offshore oil and gas fields, the main concern involves the initial investment to construct the production units, drill the wells, and install all equipment necessary for production. Operators usually adopt a conventional solution at this stage, failing to view new technologies as a first alternative. Such technologies are usually considered only when they are vital for a specific field development.
For most fields in the Campos basin offshore Brazil, the main recovery mechanism from the beginning of production is waterflooding. A typical curve of produced fluids starts with the predominance of oil rising to the production plateau until the water breakthrough occurs. At this point, production presents increasing water content in the liquid stream. Therefore, because a massive water injection is necessary to maintain the pressure of the reservoir, after a few years the water cut increases considerably. Additionally, there is a need to overcome the constraints of existing platforms.
There are currently additional motivations for using subsea technology. Revitalization of mature fields can provide opportunities to develop subsea separation technologies for higher flow rates (including higher water cuts) and to develop subsea multiphase pumps for higher differential pressures, among other options. Other possible scenarios include small fields where old floating units can be replaced by subsea systems or fields where subsea boosting or processing systems optimize the production.
For a discussion of past and current proven technologies, concepts, and approaches that have been used as building blocks for new developments in both green and brown fields, please see the complete paper.
Future Vision of Subsea Processing and Boosting: Ongoing R&D Initiatives
There are several new R&D initiatives related to subsea processing and boosting being considered by the operator for application in potential scenarios involving both mature fields and green fields. These initiatives include the following:
Compact Subsea Oil/Water-Separation System. One of the main objectives of a subsea oil/water-separation system is to perform the primary processing of fluids on the seabed, providing produced water with a destination other than the topside facilities at the floating production unit. This is an attractive option for most of the fields in their mature phase of production.
Subsea separation is also interesting from the point of view of primary processing, because the sooner the water is removed from the production stream, the easier it is to treat both water and oil streams. All the shearing on the multiphase production stream to the topside installations that takes place when production is routed to a platform is greatly reduced, making treatment at least potentially easier and more effective. This kind of separation system is used mainly for mature fields, and it can be considered for application in a specific area with an existing infrastructure or for revitalization of a mature field in a remote region. To enable production in these mature-field remote regions, in which oil-flow rates are not high enough to justify a dedicated platform, the adoption of a subsea oil/water-separation system can be a solution.
The Troll pilot, installed in 1999, was the first subsea oil/water-separation system installation. In 2007, the Tordis system, designed for higher flow rates, was installed. In 2012, the Marlim threephase subsea oil/water-separation system, which reinjects water into the same producing reservoir, was installed; it is the world’s first system for deepwater separation of heavy oil and water.
Abstract Subsea processing and boosting can be key enablers or optimization alternatives for challenging field developments and their benefits increase with water depth, flowrates and step-out. Petrobras has invested a lot on the development of such technologies, supported, among other pillars, on an aggressive R&D policy through its technological programs like PROCAP, and several subsea processing and boosting systems have successfully operated in Petrobras fields. Considering that, these technologies are being considered for application in potential Petrobras' scenarios including mature and green fields. This paper aims to give an overview of the systems developed and applied in Petrobras prospects during the last twenty years, such as the Vertical Annular Separation and Pumping System (VASPS), Boosting Systems with Electrical Submersible Pumps (Mudline ESP and MOBO), Subsea Multiphase Pumps, Subsea Raw Water Injection and Subsea Oil-Water Separation (SSAO). It also reports the new R&D initiatives related to subsea processing and boosting that are being developed within PROCAP - Future Vision technology program, showing the main motivations of these developments, the main benefits of using each technology, the technological challenges and typical application scenarios. Also, this paper illustrates the analysis and evaluations performed so far, for all of the new developments presented. Introduction Petrobras has developed and applied several technologies during the last 20 years, forming a very useful " toolbox" for subsea processing and boosting applications. After successful implementation of several technology-projects, on subsea boosting and processing, Petrobras and other operators have demonstrated that such technologies are definitely a very important field development tool, as predicted decades ago. In the beginning of the exploitation of oil&gas offshore fields, the main concern is related to the initial investment to construct the production units, to drill the wells and to install all the equipment necessary for the production. During this phase, there is a lack of information regarding the field, mainly about the reservoir behavior. Normally, the reservoir behavior is calibrated during the productive life of the field. Due to this, the operators usually adopt a conventional solution, not considering the use of new technologies as the first alternative. These are considered most when they are vital for a specific field development. For most fields in Campos Basin, Brazil, the main recovery mechanism for reservoirs, since the beginning of the production, is waterflooding. A typical curve of produced fluids starts with the predominance of oil, rising to the production plateau, until the water breakthrough occurs. At this point, the production presents increasing water content in the liquid stream. So, as it is necessary a massive water injection to keep the pressure of the reservoir, after a few years the watercut of the production increases a lot. Additionally to the two aspects described above, there is also a need to overcome the constraints of existing platforms. These motivations led Petrobras to start in the early 90's the development of subsea processing and boosting solutions. Technological Programs were created to support these developments. Several processing and boosting projects were installed since year 2001, when the VASPS was deployed in the Marimba Field (Campos Basin, Brazil). These projects will be described in a brief way in this paper, focusing their main technological aspects.
Albuquerque, Fabio Alves (PETROBRAS) | Vianna, Flavio L V (PETROBRAS) | Alves, Robson Pereira (PETROBRAS) | Kuchpil, Cassio (PETROBRAS) | Morais, Marcos G.G. (PETROBRAS) | Orlowski, Rene Thiago Capelari (PETROBRAS) | Moraes, Carlos Alberto Capela (PETROBRAS) | RIBEIRO, ORLANDO (PETROBRAS)
Abstract 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.
Wu, Xingru (University of Oklahoma) | Babatola, Feyidamilola (Linde Process Plants) | Jiang, Lei (Rhombus Energy Solutions) | Tolbert, Brandon T. (University of Oklahoma) | Liu, Junrong (China University of Petroleum (East China))
Subsea processing is an evolving technology in response to ultradeepwater hydrocarbon development and has the potential to become one of the most attractive methods in the oil industry to economically unlock hydrocarbon resources. The objective of this paper is to examine the features of subsea fluid-processing technologies and capabilities, and compare the advantages and disadvantages of different facility types. The advantage of subsea processing systems is that they allow fluids to be boosted from longer tieback distances. Constraints associated with subsea processing systems include operation efficiency, produced-water and sand-handling capabilities, and the system’s ability to handle hydrates/scale. In this paper, we reviewed the application of subsea systems in 12 deepwater fields and discussed the significance of each. Furthermore, future subsea-technology development and anticipated challenges are outlined in this paper. The significance of this study is to summarize the lessons learned from current available uses so that future decisions regarding the application of these subsea processing technologies can be made appropriately and efficiently.
As oil and gas development projects tackle some of the pumps, separation equipment, and other infrastructure world's most remote locations and extreme environments, is often more expensive, sometimes prohibitively. "One is cost, the other is the reservoir. But surface facilities Subsea technology comprises wellhead and related are a huge expense, and reservoirs sometimes are very production infrastructure placed on the seafloor, rather spread out, making it hard to drill from one surface facility. By minimizing the size and number Subsea wells and infrastructure are tied back by flowlines, of surface facilities, you can save your project a lot risers, and umbilicals to surface producing facilities that of money." On the other hand, building a larger, heavier surface facility to hold the wellheads, space is at a premium on any kind of floating facility, and the need for additional equipment (e.g., separation, waterhandling, and compression facilities) as a project matures is difficult to accommodate by retrofitting late in field life.