A New Era Begins
An Extended Well Test in Tupi has begun and the Santos Basin Pre-Salt Cluster is already producing on an experimental basis.
May 1 enters the history of Petrobras , of Brazil, and of the global oil scenario. On this day, the Tupi Extended Well Test began and the first oil was extracted from the pre-salt province in the Santos Basin. The production was directed to the FPSO* BW Cidade de São Vicente in the presence of the Brazilian minister of Mines and Energy, Edison Lobão; the president of Petrobras, José Sergio Gabrielli de Azevedo; the company’s board of directors; and Petrobras partners in the exploratory block, representatives of the British Gas Group (BG), which holds a 25% stake in Tupi, and Galp Energia, with a 10% interest.
That afternoon, a sample of the oil was presented to the president of Brazil, Luiz Inácio Lula da Silva, in a ceremony in Rio de Janeiro. As usually happens in the passing of the Olympic torch throughout the world, a miniature barrel containing the oil extracted from Tupi was carried by ex-employees of Petrobras and delivered successively into the hands of Brazilian civil organization leaders and celebrities in music, soccer, and cinema until final delivery to the head of state.
The first oil was extracted from the pre-salt province in the Santos Basin
The oil extracted was prospected at approximately 300 km from the coast, at more than 5,000m below sea level, or, more precisely, below a water depth of 2,140m and another 3,000m below the sea bed, going through a layer of salt 2,000m thick. This extraction marked the beginning of the development of the largest oil deposit discovered by Petrobras in Brazil. After all, the preliminary estimated volume of recoverable oil equivalent in Tupi is five to eight billion barrels. The oil is light, 28°API, and quite valuable on the international market.
“The Tupi Extended Well Test in progress consists of the sequential production from wells RJS-646 and RJS-660, the latter still to be drilled in 2009. The purpose is the evaluation of the production from carbonate reservoirs, still without parameters in world history. The performance of fluids in the reservoir and damage to the wells and to the submarine flow lines, among other items, will also be evaluated in order to optimize the pilot project and the definitive systems foreseen for Tupi. This evaluation will make possible a better understanding of the distribution and geometry of the wells, of the type of completion work necessary and of the most appropriate materials for the wells, production lines and risers, as well as of the development of the best systems for the interconnection of the risers with the FPSO. The production obtained will be sent to the FPSO BW Cidade de São Vicente, a unit with a processing capacity of up to 30,000 barrels of oil per day and a storage capacity of 350,000 barrels of oil. The test is expected to last 15 months and is part of the phase of the collection of geographical and production data,” explains Alberto Sampaio de Almeida, assistant to the executive manager of the Petrobras Exploration and Production in the Pre-Salt area.
Still in the information-gathering phase, the Tupi pilot project will begin between October and December of 2010. It will be subdivided into two phases, with an installed production capacity of 100,000 bpd and 5,000,000 m³/d of gas. At this time, the FPSO BW Cidade de São Vicente will be replaced by the FPSO Cidade de Angra dos Reis, currently in a Chinese shipyard, for the adaptation and installation of process plant modules.
In the first phase of the pilot project, the FPSO Cidade de Angra dos Reis will be interconnected with five or six producing wells, two water injectors, and a gas and CO2 injector. A gas pipeline of 216 km will transport the gas produced to the Mexilhão platform, from where it will be taken to the Monteiro Lobato Gas Treatment Unit, in Caraguatatuba, in the state of São Paulo.
In this first phase of the pilot project, which will last until 2012, tests will be carried out in practice on innumerable items, mechanisms, and procedures, for the purpose of anticipating information about production, recovery, and oil flow mechanisms, and the integrity of materials, among other topics. Therefore, it will be possible to gain a better understanding of the scenario and to reduce the risks in future production systems.
“During this period, the performance of the secondary oil recovery methods, such as water injection, gas injection, or water and gas alternatively into the reservoir, will be monitored. The pressure throughout the reservoir, both vertical and horizontal, will be observed. Different well geometries, that is, vertical, inclined, and horizontal, for example, will be tried. Different forms of well stimulation, such as the injection of acid to dissolve carbonates and enable the well to produce better, will be implemented, to verify the results. The oil flow through submarine pipelines at low temperatures will be observed, so as to monitor the possible deposit of paraffin and the formation of hydrates. The frequency which will be necessary to launch PIGs** through the annular lines, making them return through the production lines, in a looping operation, so as to clean them, will be evaluated. The integrity of the production and injection risers will also be tested throughout the period,” explains the manager of Conception and Alignment of Projects for the Exploration and Production in the Pre-Salt area, Antonio Carlos Capeleiro Pinto.
Special care will also be taken to prevent the liberation of CO2 coming from the producing reservoir into the atmosphere, since this gas contributes to the formation of the greenhouse effect and global warming. “We will monitor the operation of the CO2 capture and sequestration plant installed on the platform, reinjecting the CO2 to increase the recovery of the reservoir and we will avert corrosion using special steel alloys in the lining of the well production columns, in subsea production equipment, and in components of the processing plant installed on the platform,” clarifies Capeleiro Pinto.
Tupi will enter the final development phase in 2017
In the second phase of the pilot project, which will run from 2012 on, the FPSO will already be operating with the definitive system. At that time, between 2012 and 2017, in Phase 1A of the development of the Santos Basin Pre-Salt Cluster, if the current forecasts are confirmed, another 10 Pre-Salt Cluster production units will be installed: two pilot units and eight definitive system units. The production units should be constructed in Brazil with some being assigned to Tupi. Consolidated technologies or technologies in the process of consolidation will be used in their projects. As there will be uncertainties at this point, the production systems will be planned so as to guarantee flexibility in the various drainage solutions of the reservoirs.
The preliminary project of Tupi’s future production systems contemplates the interconnection of 20 wells, on average, divided between producers and injectors, in each production unit. “The injection wells will be capable of receiving water and gas alternatively, and one or two of them may be dedicated to CO2 injection. The idea is to start the development with a smaller number of wells and, as production declines, interconnect more wells until the forecasted total is reached. The oil will be transported by shuttle tankers and later offloaded to deliver the partner companies’ oil share,” says Pinto.
The final phase of the Tupi development, which is part of Phase 1B of the total development of the Santos Basin Pre-Salt Cluster and which will be initiated in 2017, foresees the intensive application of new technologies and the possibility of unconventional solutions. Among these are the use of dry completion units, multiphase seabed pumping, centralized gas and/or water processing systems, the injection of water alternating with CO2 injection in determined locations to increase the final recovery of oil, and the adoption of shipped liquefied natural gas***. Once the current estimates are confirmed, the production in the Santos Basin Pre-Salt Cluster should total 1,000,000 bpd by around 2017.
At present, the production arising from the Tupi Extended Well Test is limited to 14,000 barrels per day because the maximum production flow of gas negotiated with the National Oil Agency (Agência Nacional do Petróleo, Gas e Biocombustíveis - ANP) consists of 500,000 m³/day. The oil produced is transferred to terminals on the mainland by means of shuttle tankers.
Judging by the estimated recoverable volume of oil equivalent from Tupi, which will be further complemented by eighboring deposits in the Santos Basin Pre-Salt Cluster, and by the challenges overcome to initiate production in this environment, such as the drilling of wells through a thick layer of salt, the production of oil at depths in excess of 5,000m, and the great distance from the coastline, among others, it is no exaggeration to say that a new era has begun. It is an era of challenges, some of which are being faced now and others which will arise throughout the work in the Pre-Salt Province. Victories are being achieved thanks to the talent and perseverance of the Petrobras workforce and the support of all Brazilians. After all, the Brazilian government participates in the company and the Petrobras achievements are of and for all Brazilians.