Publications

Oil remains the world's major source of energy, accounting for almost 40% of primary energy demand. Coal and gas account for some 26% and 21% respectively. The occurrence of hydrocarbons is widespread and reserves of oil have been discovered in some 90 countries. However, these reserves are unevenly distributed with just four Middle Eastern countries possessing more than half the estimated 1005 billion barrels of the world's total proven reserves. These reserves now correspond to approximately 45 years of supply at current production levels, compared to 30 years in 1973. This increase has resulted, in part, from recent technological breakthroughs in the understanding of reservoir complexity and behaviour, a more integrated approach to the management of hydrocarbon assets in existing fields and, since the mid-1980s, a greater emphasis on energy conservation. Thus, today, more than three-quarters of the annual additions to the world's total reserves of oil are procured by optimising the recovery from producing fields, whilst the discovery of new oil from exploration accounts for the remainder. Since the major field discoveries of the 1960s and early 1970s, no major petroleum province - such as the North Sea or Alaska - has been found. Despite intensive worldwide exploration efforts in the last decade, most petroleum basins are approaching or have reached maturity. Exploration rewards in terms of added value to the business have been lower than expected. Undoubtedly there will still be exploration successes in these basins, but discoveries are likely to be increasingly smaller and located in more complex settings. Equally, greenfield exploration may also be successful, although, in many cases profitable development will have to rely on innovative engineering. The challenge for the oil industry in the 1990s is, therefore, to identrfy strategies for maximising the potential value of the discovered reserves, whilst optimising future investments in both exploration and exploitation activities. Hence, increasingly, the explorer, the petroleum engineer and the production engineer must evaluate together the options for exploration drilling to ensure that in case of success, the discovery has the potential of being developed economically. This review paper outlines some of the key technologies that Shell companies employ to tackle upstream challenges. Furthermore, it discusses how a multidisciplinary approach, coupled with technical innovation, will allow a better evaluation of future projects.