The economics of petroleum refining have undergone substantial changes in the four years since the authors prepared their paper on "Current Economic Trends in Location and Size of Refineries in Europe" for the Fifth World Petroleum Congress, but the trends then traced have continued to determine events. The tendency to shift refineries towards consuming areas has been accentuated and is now noticeable, not only in the main centres of demand, but also in developing countries primarily in Asia and more recently in Africa. This has been dictated by political circumstances but it has been made economically less onerous not only by the rapid rise in demand which has brought more areas within the range of building a local refinery of economic size but also by refineries becoming simpler and thus cheaper and by the cost difference between larger and smaller refineries narrowing somewhat. In the course of these events the tendency for several companies to build at some points joint refineries is still increasing.
Transport elements have remained of paramount importance: bigger and better tankers, more and larger crude oil pipelines have increased the difference between the cost of moving crude oil and products, this also tends towards decentralisation of refineries (a trend only occasionally counteracted by products pipelines).
There are taking place technical developments in the utilisation of petroleum products which are likely to affect future refinery yields. Among other relevant events were the rising importance of the use of light petroleum fractions for chemical purposes, the planning of refineries next to thermal power stations, and the offtake of some fractions for gasification. On the other hand the advent of natural gas in certain areas will progressively diminish the opportunities for using refinery products as sources of thermal energy as such. * Fronkel, Paul H., Great Britain, Consulting Economist, Dr., Vienna University, Petroleum Economics Ltd. ** Newton, Walter L., Great Britain, Consulting Economist, E. A. (Cantab.). Petroleum Economics Ltd.
Quatre années se sont écoulées depuis la préparation par les mêmes auteurs d'un article soumis au Cinquième Congrès Mondial du Pétrole, et intitulé «Tendances économiques affectant le choix de l'emplacement et de la taille des raffineries en Europe-. De nombreux changements ont eu lieu depuis, toutefois les tendances générales décrites précédemment sont restées les mêmes. La construction de raffineries près des centres de consommation s'est accélérée et s'étend maintenant au-delà des grandes zones industrielles jusque dans les pays en cours du développement, principalement en Afrique et en Asie.
Bien entendu des raisons politiques ont souvent été pré- pondérantes. Toutefois deux éléments ont
