This paper identifies the international market niches of Brazil's heavy acid oils. It analyzes the perspectives for making wider use of heavy acid oils, assessing their importance for certain oil-producing regions Such as Brazil, Venezuela, West Africa, the North Sea and China. Within this context, the oil produced in the Marlim Field offshore Brazil is of specific interest, spurred by the development of its commercial brand name for placement on international markets and backed by ample production volumes. This analysis indicates keener international competition among acid oils produced in Brazil, the North Sea and the West Coast of Africa, through to 2010. However, over the long term, refinery conversion capacity is the key factor for channeling larger volumes of heavy acid oils to the international market. In this case, the future of acid oil producers will depend on investments in refineries close to oil product consumption centers. For Brazil, this means investments in modifying its refineries and setting up partnerships in the downstream segment for consumer centers absorbing all products of high added value, such as the USA and even Southeast Asia and Western Europe. (c) 2004 Elsevier Ltd. All rights reserved.