In order to introduce low toxicity mineral oil base drilling fluids in Brazil, we carried out a series with a low aromatic content basic oil for lubricants, produced by PETROBRAS: the Lubrax Industrial OB-9 (Lubind OB-9). This oil, as well as its mixture with aviation kerosene to reduce viscosity, was found adequate for use in drilling fluids together with other national products developed by companies that supply additives for drilling fluids in Brazil. We present the results of laboratory tests with systems of four different manufacturers, one of which was chosen for initial field tests. These tests, which were carried out at the Miranga and Bu River Fields, in the Drilling District of Bahia, produced satisfactory results. We anticipate the use of these fluids in other areas where the company operates. (author) 2 refs., 3 tabs.
Ponte, Ielton Frederico da 
- PETROBRAS, Rio de Janeiro (Brazil). Centro de Pesquisas. Div. de Explotacao