A History of Organic Geochemistry

Abstract

Organic geochemistry is the fruit of questions about the origin of petroleum, and for the time being, its development has been closely linked to that of petroleum exploration. It only became an autonomous science shortly after 1960. The years 1965-1985 were extremely productive: during this period, the mechanisms of the formation of oil and natural gas fields were clarified, and many biomarkers, testimony of the organic origin of oil, were identified. The knowledge of kerogens, the raw material for the formation of oil, also made decisive progress, and tools to aid petroleum exploration were created, such as oil-source-rock correlation methods, Rock-Eval, and mathematical models simulating the formation and migration of oil. A rapprochement took place at the same time with coal science and an extension of organic geochemistry to various fields such as organic sedimentology, the microbiology of sediments and the formation of orebodies. The current period is characterized by the growing application of the knowledge gained to fields other than petroleum exploration, and its integration with all geological disciplines. This integration has, among other factors, taken place through its contribution to the development of "basin simulators", which mathematically simulate the evolution of the sedimentary basins over time and the resulting formation of oil and natural gas fields. In the coming years, organic geochemistry will continue to play an important role in the exploration and production of oil, and of fossil fuels in general, but its long term future probably lies in the study of interactions of the products of man’s activity, in particular organic pollutants and greenhouse gases, with the geosphere, in relation with the search for sustainable development and the understanding of mechanisms of climatic changes. The development of modern organic geochemistry owes a great deal to the professional research institutions and particularly to two of them, Institut français du pétrole (IFP) in France and Kernforschungsanlage (KFA) in Germany: credit is certainly due to the creators and the early leaders of the organic geochemistry departments of these two institutions, B. Tissot and D. Welte.