This paper discusses technological learning in the oil sector in Venezuela, with the help of a case study of ORIMULSION®, which heralded a very important techno logical breakthrough for the evolution of the nationalised oil industry in this country, being at the same time a challenge and an opportunity. The technological R&D policy for heavy and extra-heavy oils and bitumens of the Orinoco Oil Belt created the conditions for the domestic system of innovation in the oil industry to realise a catching up process, taking advantage of the available opportunities: the geological wealth offered by the national subsoil, a small but growing scientific and technical community of practitioners having direct access to operational activities of the newly nationalised industry, and an institutional learning procees based on an original technological trajectory both in INTEVEP, the oil industry's technological research centre, and in the domestic operating firms. The paper traces the complexity of the learning process at different times and in a number of dimensions, with an emphasis on the mechanisms through which the researchers, technicians and managers acquired and/or improved their know-how: