Petroleumssystemet

Petroleumssystemet, or the petroleum system, is a geological concept that describes the processes and components involved in the formation, accumulation, and preservation of petroleum (oil and natural gas) in the Earth's crust. It encompasses the entire sequence of events from the generation of organic matter to its migration and entrapment in reservoir rocks.

The petroleum system typically includes several key components: source rocks, reservoir rocks, and seal rocks. Source rocks are organic-rich sedimentary formations where petroleum is generated through the thermal breakdown of organic matter, primarily through processes like diagenesis and catagenesis. The generated petroleum then migrates through porous and permeable rocks, known as reservoir rocks, where it can accumulate and form commercial oil and gas fields.

Seal rocks, which are typically impermeable formations like shales or evaporites, play a crucial role in preventing the migrated petroleum from escaping the reservoir rocks. These rocks act as a cap, trapping the petroleum beneath them and allowing it to accumulate over geological time.

The petroleum system is influenced by various factors, including the type and quality of organic matter, the thermal history of the basin, and the structural and stratigraphic framework of the sedimentary basin. Understanding the petroleum system is essential for exploring and developing hydrocarbon resources, as it helps in identifying potential source rocks, reservoir rocks, and seal rocks, as well as predicting the distribution and quality of petroleum accumulations.