[en] The literature tries to apprehend the weakness of the economic growth of oil culminates by the assumption of ousted growth factors. In the Dutch Disease models the non-oil exporting sector would be ousted whereas in the analyses in terms of economic policies it would be the efficient economic policies. We consider the phenomenon through the growth theories, the oil income being regarded as an additional exogenous income for the economy. In this manner the growth dynamic of oil countries, even the most unfavourable, can be modelled without utilizing any concept of economic inefficiency. The last part of our work is devoted to the Saudi economy. After having developed a macro-econometric model, and using scenarios of oil prices, we lead a forecasted analysis of this economy. (author)