CONTROLLING FACTORS OF CARBAZOLE RATIOS: GENERATION, MIGRATION AND EXPULSION BEHAVIOUR
M. Stockhausen, L. Di Paolo, S. Castellani, R. Galimberti, U. Berner, M. Erdmann, R. Elias, F. Gelin, J.H. Pedersen, R. Di Primio and L. Schwark
Event name: 29th International Meeting on Organic Geochemistry
Session: Posters - NSO in Petroleum
Publication date: 02 September 2019
Info: Extended abstract, PDF ( 351.93Kb )
Carbazole ratios were established as simple-to-use evaluation tools for secondary migration distances. However, the impact of generation, primary migration and expulsion onto these migration proxies has not yet been finally clarified. Knowledge of the compositional changes upon generation and primary migration is crucial to assess the applicability of carbazole ratios as secondary migration proxies. We here present a new approach for investigating carbazole ratios, using the Expulsinator-device: This apparatus performs semi-open hydrous pyrolysis of an intact source rock under near-natural lithostatic and hydrostatic pressure regimes, reproducing natural generation, primary migration and expulsion of oil and gas. Results indicate that both primary migration and generation affects carbazole ratios: Up to a maturity of ~ 0.8 % Ro migration effects are in control of carbazole proxies. Subsequently, during the main generation phase, generation effects become the dominant factors. Furthermore, differences between so called “bad expellers” and “good expellers” become evident: Carbazole ratios of the former tend to show opposing trends compared to the latter.