One of the most recent discoveries in the Campos basin is the Jubarte oil field off Epirito Santo state in 1000- to 1500-m water depths. Reserves are approximately 95 x 10(6) m(3) of 0.95-g/cm(3) oil. Initial tests in a vertical well indicated that the productivity index (PI) was insufficient for commercial oil production. Later tests on a horizontal well recorded a PI 12 times the PI of the vertical well, indicating that it would be possible to produce Jubarte field heavy oil at commercial rates.