Petroleum System Modelling
Petroleum System Modelling implies the temporal reconstruction of basin history and specifically refers to the procedure of establishing the sequential record of changes in controls and products which have occurred during the long geologic history of a basin, and which define its oil and gas prospectivity.
Petroleum Systems Modelling is a numerical tool to integrate all the geological elements and processes that are fundamental to the evaluation of a petroleum system.
The relative importance of the variables involved in the puzzle differs on a case by case basis, especially with respect to petroleum generation and migration modelling.
In vertically charged petroleum systems like the Sonda de Campeche (Mexico), migration is predominantly vertical and occurs via faults, charging Tertiary reservoirs with Tithonian petroleum. Source rock facies dictates initial sulphur content, source rock maturity dictates gas-oil ratio and reservoir temperature and pressure define the number of phases present. In foreland basins, long distance lateral migration takes place, and the displacement of oil by gas occurs widely.
In the North Sea, fractionations into gaseous and liquid accumulations e.g. the Viking Graben, the maturity-dependence of fluid properties e.g. the Central Graben, and potential co-sourcing from gas-prone and oil-prone facies e.g. Haltenbanken, Are (L. Jurassic) and Spekk (U. Jurassic), respectively, have all been documented. All these effects have to be deconvoluted, requiring an understanding of the underlying physical, chemical and biological processes involved.