Petroleum Geochemistry

Hunt (1979) defines petroleum geochemistry as "the application of chemical principles to the origin, migration, accumulation and alteration of petroleum, and the use of this knowledge in exploration and recovery of oil, gas and related bitumens." At GERG, petroleum geochemistry research is focused in two primary technical areas:

• Offshore Coring Studies - research related to oil and gas seeps in the Gulf of Mexico and other offshore basins globally
• Regional Studies - basinal studies of oil and source rock occurrences with the objective of better understanding petroleum systems

Additional research topics include thematic studies of oils and source rock hydrocarbon geochemistry and geochemical studies of seafloor hydrates. Because petroleum geochemistry is integral to the search for oil and gas, much of GERG's research is sponsored by the energy industry.

Offshore Coring Studies

The basic justification for the use of oil and gas seeps in offshore petroleum prospecting is that hydrocarbons from deep sedimentary sequences can migrate, either directly from source beds or from reservoirs, to the seafloor.

Analysis of near-surface sediments in a generative basin should therefore be capable of detecting the surface expression of the underlying hydrocarbons.

Geochemical analysis of seafloor sediments is a proven approach to surface detection of thermogenic hydrocarbons. Sediment cores retrieved using a ship-based piston core device are analyzed in the laboratory to detect hydrocarbons derived from seeping oil and gas. With proper core placement, "live oil", shown in the slabbed core, can be recovered. "Live oil" is a weathered equivalent of a reservoir sample that can be used to evaluate hydrocarbon origin and thermal history. It's like getting a sample of the oil in the reservoir without drilling the well!

With support from the petroleum industry, GERG has been studying submarine seepage in sedimentary basins throughout the world for over fifteen years. In addition to contributing to a fundamental understanding of fluid flow in the subsurface, the results of these studies have been used by industry to help reduce the risk of offshore hydrocarbon exploration.