The 55,000-km(2) Orinoco oil belt in southern Venezuela contains accumulations of heavy and extra-heavy hydrocarbons. The first well was drilled in 1935, but because of the low gravity, high viscosity, and metals content of the oil, the multinational companies lost interest in the area. From 1978 to 1983, an intensive exploration and evaluation program resulted in a detailed evaluation of the regional geological model, reservoir characteristics, and crude physicochemical properties. Facility requirements for oil transportation and processing also were analyzed.