Abstract

The largest accumulations of heavy oil and bitumen under development in the world are located in Venezuela and Canada1. So far, Canada and Venezuela have developed technologies that make it technically and economically feasible to develop these accumulations.The successful thermal methods as steam injection, combustion in-situ and its variations applied in the onshore heavy oil projects have severe limitations to be applied in offshore deep waters. The technological and logistic aspects of the offshore environment make these methods unsuitable if considering the current technologies.

Nowadays, cold production is the only method that could be applied for offshore fields located in deep waters. Even if this technology is applied, it should have some limitations. Unlike the cold production in operation today in Venezuela and Canada, where sand is produced with oil, offshore sand production would be prohibitive due to the high costs of processing or transporting the sand to shore.

The crude production in Brazil is increasing and more and more heavy oil has been produced. In addition, large resources of heavy oil have been discovered during the last 6 years and are under evaluation. In this scenario, the development of technologies that improve the economics of such discoveries is critical for the country to reach and maintain the so aspired self-sufficiency in petroleum.

This paper will summarize the planned path to overcome the challenges related to the exploration, development, production and marketing of the offshore heavy oil in Brazil.

History

The onshore oil production in Brazil started in 1939 with the discovery of the Lobato field in the State of Bahia. The onshore exploration and production phase extended as far as the end of the sixties. Starting the offshore phase, some discoveries were made in the Potiguar and Sergipe-Alagoas basins, in an offshore shallow water environment, in northeast of Brazil, and are still on production today. The discovery of the Garoupa field, in the early 70's, in the Campos basin, which turned out to show the most promising offshore basin, marked the beginning of the discovery and the oil production development phase in shallow waters which lasted until the beginning of the eighties. In 1988, with the installation of the RJS-376D well, at a 492m water depth, PETROBRAS broke the 400m limit, thus entering the deepwater development phase.

As from 1990, discoveries started to be made in water depths deeper than 1000 m, leading to the beginning of the ultra-deep water development phase. The fields discovered in this phase will be in production by 2010. Simultaneously to the increase in the water depth, a variation in the density of the oil discovered can also be observed, from an initial 20 to 26 API range, for shallow waters, to a 15 to 20 API range, for deeper waters.

The plot below shows the Campos Basin production as a function of water depth.

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