PETROLEUM GEOCHEMICAL STUDY

Petroleum geochemistry is the fruit of questions about the origin of hydrocarbons, and for the time being, its development has been closely linked to that of petroleum exploration. It is a young science, most of it having been acquired in less than 40 years. However, petroleum geochemistry nowadays plays an important role in the exploration and production of oil, and of fossil fuels in general.

The single most significant contribution of petroleum geochemistry to exploration efficiency is that it can be used to show genetic relationships among crude oils and source rocks. Geochemistry also increases petroleum exploration and production efficiency by accounting for many of the variables that control the volumes of petroleum available for entrapment (charge), including source-rock quality and richness, thermal maturity, and the timing of generation-migration-accumulation relative to trap formation. Geochemistry is most powerful when used with other disciplines, such as seismic sequence stratigraphy and reservoir characterization. Including geochemistry in prospect appraisal remarkably improves exploration efficiency. The research works show that forecasting efficiency based only on structural and reservoir data (e.g. geophysics) approximately doubles when geochemical charge and retention parameters are included in prospect evaluation. Costly exploration failures, such as the Mukluk OCS Y-0334 No. 1 well in Alaska (∼$140 million in 1983 dollars) are painful reminders that large structures indicated by seismic data may lack oil and gas due to geochemical charge factors.