Copyrlghl 199S OFFSHORE TECHNOLOGY CONFERENCE Thos papar was FePared for presen fat ton al the Offshore Technology C0nferenc9 held In Hw5tcfI T.xas 69 May 19S6 Thts paper was sd!ecfec for prnsentatm" by I he OTC Program C.anmdttw folkn9 renew of Warm'dt!cm cc$ha$cud m an ?&tract subm!ffed by the author(s) CWten!s of the Pqe$ a. preserded, have not ben rewewd by Ihe OfWwro TechIw42Qy and are subjecf to c.xmclon by the abthor(s) The material, as presented, CLWS cat nncasssnfy reffecl any PO$IIIX! of me Off$hcfe Technokgy Cotiererce or fis affKRIs Perrmsswn 10 COPYm remr!cfed m an abstract of nof mcfe than 302 words 111.stratbcmsmay not be copma The abstrad shdd ccdam umspkxous adwwwledgmenl 01 where and by whom the paw was pwsen!ed AbstractThis paper describes the impact that the use of a subsea boosting sys[em will have on the development of a deepwater field . The analysis covers the technology demands and constraints encountered on screening studies executed for the fields of Marlim, Albacora and Barracuda, as well as an overview of the economic benefits encountered. The paper will focus on the technological demands and constrains identified as well as some considerations about possible alternatives . The demands and constrains identified in the study will provide the industry with some more input to guide the development of the subsea boosting technology, as well as a better understanding of how to apply this new tool on the development of deepwater prospects. The results of the screening study are showing that the subsea boosting systems are a valuable tool to reduce the costs of deepwater developments, provide that the industry could meet the technology demands that are indicated on the study. The cost cutting possibilities through an integration between the "conventional" subsea hardware and the subsea boosting systems and the combination of boosting systems are promising alternatives The subsea boosting systems are a new tool that have -although still under development -recently been added to the tool box of the subsea engineers. [derr[ifying the way to get the most out of it, that is, how to use to the full extent this new technology could help the industry to make the deep water developments profitable. The encouraging economic results found, as well as the demands and constraints raised on the paper will be of use for those trying to apply these technologies in various areas of the world.
Since the first subsea well started producing in Campos Basin, this province has turned into a big laboratory where innovations and different concepts have been tested, ranging from one-atmosphere chambers to diverless guidelineless deepwater subsea trees and manifolds. The need to produce successive discoveries in increasing deepwaters imposed the challenge that sparked the continuous technology development in the past 25 years. The subsea trees evolution in the world is very much associated with the developments tested in this province. It starts with the dry subsea trees in wellhead-cellars in Garoupa field, passing through the shallow waters diver operated trees, the development of the lay-away technique and, furthermore, development of the diverless vertical connection system and the guidelineless deepwater subsea trees. The strategic effort on standardization of subsea tree interfaces provided operational flexibility and increased rationalization to deal with wellheads, trees, tools and completion risers of different manufacturers for hundreds of wells. Evolution of subsea manifold architecture and modularization concept has been present along the development of several fields as Garoupa, Bonito, Linguado, Albacora, Marlim and Roncador. The same for subsea controls, including direct hydraulic and electro-hydraulic multiplexed systems. Subsea flowlines, umbilicals and risers were also developed for a variety of conditions of water depth, production facility (semi-submersible, FPSO, monobuoy), fluid characteristics and thermal insulation requirements. These developments included an extensive use of flexible tubes, steel pipelines and the pioneer Steel Catenary Riser connected to a semi-submersible production unit in deepwater. Adding new components to the toolbox of subsea engineers, boosting systems have also been developed, as the first in the world subsea completion with an Electric Submersible Pump (ESP) in Carapeba Field and the Marimbá Subsea Separation System. Supported by the operational experience acquired throughout the years and motivated by the challenge to develop the ultra deepwater discoveries, other technological developments are being conducted by Petrobras. This paper presents the evolution of subsea equipment so far, the development efforts being carried out and the next steps to meet the future demands. Introduction Campos Basin initial production development was based in the widely use of Early Production Systems (EPS), from Enchova field at 120 m water depth (WD) up till now in Roncador field at almost 2,000 m WD. The use of EPS confirmed to be a reliable and cost effective solution being extended for the definitive offshore fields developments. This concept implementation required an intensive use of subsea trees, manifolds and flexible pipes for static and dynamic applications, leading Petrobras to focus in the subsea hardware technology development to overcome the big challenges of producing in shallow, deep and ultra deep waters, as highlighted bellow: The use of drilling equipment for the first Petrobras EPS in 1977, with a test tree (EZ tree) suspended by a drilling rig inside the Blow-Out Preventer (BOP) stack to produce the well 3-ENO-1-RJS at 120 m WD.
Since the first subsea well started producing in Brazil, Campos Basin has turned out into a big laboratory where innovations and different concepts ranging from one-atmosphere chambers to diverless guidelineless wet Christmas trees have been tested. Supported by the operational experience acquired throughout the years, motivated by the large number of subsea wells to be drilled and completed in the new fields and pressed by the need of some rationalization to deal with rigs, tools, risers, wellheads, trees and spare parts for more than two hundred wells, PETROBAS started its own efforts on standardization of subsea equipment. To achieve the desired interchangeability with equipments manufactured in different occasions and even by different suppliers, it is necessary to define not only functional and performance requirements, normally found on API Specs, but also some crucial geometry and dimensions, mostly of interfaces. This paper describes the experience with some standardization made in the past, the programme being carried out in the present, the equipments and interfaces being standardized and how far PETROBAS is going into equipment definition. INTRODUCTION After hundreds of wells drilled in Brazilian waters, more than 170 wet x-mas trees installed in water depths from 70 to 781 meters, 10 floating production systems and 14 fixed platforms installed, and a considerable mileage of flowlines and umbilicals laid, the experience obtained with these offshore operations performed in Campos Basin has made it possible to evaluate the pros and cons of standardization of subsea equipment. The simple conclusion was that standardization really brings considerable benefits. The resulting operational flexibility associated to the use of proven equipment and procedures saves rig time and can reduce production loss during workovers. Savings can also be detected from the reduction of the number of spare parts and tools, but the savings in values related to the operations exceed considerably those ones connected to equipment acquisition and store. So the great benefit is the operational flexibility. On the other hand, non-standardized equipment serves as an open door to continuous modifications of equipment design, which is welcome when the equipment is not satisfying customer's requirements. But once the equipment is properly tested and proven, unnecessary proliferation of slightly differing designs need to be avoided. FIRST STEPS ON STANDARDIZATION The first significant interface adopted as a standard by PETROBAS in the early 1980's, was the subsea wellhead external profile and the sealing area for VX/Ax rings. At that time, the various rigs contracted to drill in Brazilian waters had BOPS provided with H4 connectors of different sizes: 21.1/4", 18.3/4", 16.3/4" and 13.5/8", leading to the use of different wellhead systems and x-mas trees connectors. PETROBR&3 then defined the 18.3/4" H4 profile as the standard external profile for all high pressure housings, and the BOPS were equipped with appropriate connectors. More recently, this definition had to be divided in accordance to the drilling system type:
Ccwwht 19%3 Whore Technology Confereme This PVW was pmpsred fci presenhbon at me Clfshom Technology Contwencn held In Hcinton Texas, 6.9 May lSM Th8s papu was sel.hd for pmwntabnn by me OTC Prcgnm Commmles follwhg rwww & i.fwmabon ccmtimed m s. abstraci w bm Itt@d by du a.lhor(s) Contents al the papu al prawnted, haw twt tun mbmwd by fhe O#shore Tcchnokgv and sw subJ.ct to cwe-do. bv the atiof (s] Tho mated qe prase.ted, does nti nwescanly feffect any !s+sbon of tha Offshore Tectvwlogy Con femnc8 or !ts offwm Permm8!on to copy IS mstwt.d te an alntrati of not more than X4 wds II Iustratlons may not be copied The abstract shod d conta n .wn8Puu0us aeknow+edirment d wfwr. and by -h papu was presented Abstract Subsea equipments can be considered nowadays a mature option for offshorefield developments. In Brazil, since the first oil in Campos Basin, different concepts ranging from oneatmosphere chambers to deepwater guidelineless x-mas trees, have been tested, contributing for this development.The experience acquired during these years makes it possible to combine the proven systems to the new technologies being developed, for the design of subsea manifolds The main target is more etllciency and cost reduction. When choosing a manifold concept. a usual rule is applicable: the simpler the better.The maturity, cotildence and reliability obtained, allow the usage of resident hydraulically actuated valves, simpli~ing considerably the manifold arrangement. Other contributions come from: the reduction of piping bend radius allowed by the new pigs; the increased reliability of subsea instrumentation and chokes, allowing elimination of the gas-lift-test flowline, and the development of the direct vertical connection, that turns subsea tie-ins very fast and easy operations. Combining all that with the new technology of multiphase meter (to eliminate the test flowline and even the test separator on the platform), we can achieve a cost effective solution.This paper describes the possibilities of simplifying the subsea manifolds and presents a comparison of different designs. The usage of mature technology combined with the new developments, can help the industry to make deep waler developments profitable, worldwide.
Aiming the rationalization of subsea operations to turn the production of oil and gas more economical and reliable, standardization of subsea equipment interfaces is a tool that can play a very important role. Continuing References, nomenclature and figures at end of paper.importance of a frank information flow through the involved companies and how a simple manufacturing philosophy, with the use of construction jigs, has proved to work satisfactorily.
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