Reduce the charge risking applying migration tracers
Hydrocarbon exploration success depends on matching the pre-drill assumptions. Geological and geochemical studies are made to identify, understand and reduce the pre-drill risk of a well. In the Norwegian North Sea, the charge risk became the most important risk, as charge failure accounts for the main reason of being a dry well for post well analysis. Although the Norwegian North Sea is an area where up to ten thousand wells have been drilled and the petroleum system is extensively studied. Based on the charge failure post drill the focus is now on charge and migrations, as the proven source rock quantity and quality are in many cases proven. Current charge risking primarily relies on basin models built on geophysical, geological, geochemical source rock parameters. Geochemical post well analyses are typically done only for oil–oil or oil–source correlations and in many cases not integrated to geophysical and geology evaluations. Migration pathways are often only evaluated with basin modeling software and not verified with geochemical data, even though migration is the key factor to determine whether hydrocarbons reach a reservoir or not. This thesis addresses secondary hydrocarbon migration as the main charge risk by applying molecular migration tracers and uses benzocarbazoles plus methylxanthones as migration tracers to reconstruct migration routes and reservoir filling histories in the Norwegian North Sea. Benzocarbazoles and methylxanthones are polar compounds and undergo systematic geochromatographic fractionation during migration through a pore network. The migration tracers are used as proxies in relation to migration distance and direction. Benzocarbazoles and methylxanthones are direct geochemical measurements of hydrocarbon migration. Geochemical analyses are independent from other data and just based oils or extract samples from drilled wells. The study objective is to demonstrate that molecular migration tracers can significantly improve charge risking, reduce exploration uncertainty, and establish geochemistry as a key element for petroleum system analysis. Integration of migration tracers with geophysics, geology, sedimentology, and petrophysics in a basin model provides a real added value for the understanding of the charge and hence reduce the charge risk significantly.
Migration Tracer, Benzocarbazoles, methylxanthones, Petroleum System, Basin Model, BCR, MXR, Hydrocarbon Migration, Reservoir filling history, Geochemistry, Petroleum Geochemistry, Brage, Johan Sverdrup, Edvard Grieg, migration marker, petroleum filling,, biomarker, geomarker, Solveig field, Haugland High, Norwegian North Sea, Viking Graben, Garlichs
Networked Digital Library of Theses and Dissertations