Integrated Geological Basin Analysis as a Method of Hydrocarbon Exploration on Continental Shelves

ABSTRACT The scientific technique of hydrocarbon exploration in understudied areas which is presented in this paper relies on integrated geoscience studies of sedimentary basins, with the purpose of arriving at a fact-based model of basin evolution which fits all the available constraints. Such a model mayor may not be quantitative. The Integrated Geological Basin Analysis, in our understanding, involves a combined interpretation of various types of geological and geophysical data. This contrasts with the currently fashionable model-basedtechniques of basin analysis, which frequently rely on advance assumptions of basin type and of many parameters of basin evolution. In our scheme, continentalmargin basins are classified on the basis of the nature of geodynamic processes responsible for their formation, and the determination of basin type is made in the end, not in the beginning, of the analysis. Examples are provided, demonstrating the applicability of our methodology to frontier exploration on the East and West Coast of Canada and in the Beaufort Sea. The Integrated Geological Basin Analysis is recommended to the oil industry and university programs. INTRODUCTION During the last several decades, the oil industry made a number of legendary discoveries in North America and internationally. However, the same oil field cannot be discovered twice, and now onecommonly hears the complaint that "all the easy oil has been found". The chances of making large discoveries with conventional exploration techniques have decreased. On the other hand, advances in exploration methodology and technology allow us to look for oil in ways previously unimaginable and to locate reserves previously unknown. Our growing understanding of geology and our expanding data base make it possible toundertake integrated geoscience studies ofevolution of sedimentary basins, and the attention of researchers and explorationists is drawn increasingly in that direction. THE INTEGRATED APPROACH The Integrated Geological Basin Analysis (IGBA) is based on a combined application of various geoscience disciplines: stratigraphy, sedimentology, paleontology, paleogeography, structural geology, tectonics, geophysics, geochemistry etc., to the study of a sedimentary basin. The objective is generally to gain a better understanding of the evolution of a basin and to use this knowledge for the evaluation of natural resources contained within it, thus prioritizing areas of interest and reducing the exploration risk. Our understanding of the IGBA differs from that of some of the previous workers. For example, Potter and Pettijohn (1977) and Kleinspehn and Paola (1988) appear to have underestimated the role of applied geophysics in sedimentary-basin analysis. Where geophysical techniques are considered (e.g., Berkhout, 1989), they are often limited to reflection-seismic methods only. Green (1985), on the other hand, included economicevaluation of prospects into basin analysis. Although economics are clearly indispensable for the success of oil exploration, we prefer to restrict the definition of the IGBA to natural-science disciplines. Economic reviews should be undertaken at a later stageof exploration, when the regional scientific research has been largely completed and a general petroleum-potential evaluation is available.