Offshore Production Units for Pre-Salt Projects

摘要

Petrobras and partners have been developing Brazilian Santos Basin Pre-Salt ultra-deepwater areasrnthrough the use of Floating Production Storage and Offloading Units (FPSOs), equipped with topsidernfacilities designed to receive produced fluids and process them to generate end streams to export andrninjection.rnThe large hydrocarbon volumes in Santos Basin Pre-Salt areas, which have been successivelyrnconfirmed by the results of exploratory and productions wells, have encouraged Petrobras and partners tornchoose an aggressive development strategy over a more conventional one. Based on this decision, FPSOsrnwere chosen, mainly due to crude oil storage capability thus not requiring the construction of long-lengthrnoil pipelines, and also because of other characteristics that allow a short term completion with economicrnadvantages. Therefore, the topside process plant conceptual design had to deal with uncertainties in thernreservoir fluid compositions and production profiles. This means a wide range of CO2 and H2S contents,rnoil API gravity, flow rates and arriving fluid pressures and temperatures, in order to guarantee an adequaternnominal capacity and turndown, and also the proper performance within the established design cases.rnThe main purpose of the topside facilities is to gather and treat the produced fluids to be sent ashore.rnThe treated oil is routed to cargo tanks, the produced water is treated and discharged overboard, an dthernbulk treated gas stream is exported through a gas pipeline network, which allows to send the stream tornthree different gas processing sites onshore. The separated CO2-rich stream is injected back to thernreservoir.rnBesides the production units specially designed for Santos Basin Pre-Salt features, some Pre-Saltrnreservoirs from Campos Basin have been also being produced, by connecting new wells to existingrnproduction units. The main approaches regarding these units and its production in Campos Basin Pre-Saltrnare also part of the scope of this paper.rnAs a result of these different strategies and due to the daily efforts to overcome the forementionedrnchallenges, more than six hundred thousand barrels per day of crude oil, as a monthly average, have beenrnproduced in Brazilian Pre-Salt areas, after only eight years since the early developments of the area.