OXYGENIC KEROGENIZATION OF ASPHALTENES FROM THE DEAD SEA BASIN (ISRAEL)

A kerogen-like material was generated during a laboratory heating experiment with asphaltenes in the presence of O₂. The asphaltenes had been extracted from a floating block of Dead Sea asphalt, and heated at 100 - 200 C for 1–12 days. This oxygenic kerogenization reaction follows first-order kinetics. The half-life (t_1/2) of the asphaltenes (i.e. the time in which 50% of the asphaltenes had been converted to artificial kerogen) varied from 2,300 days at OC, to 2 days at 100 C. Similar results were obtained with asphaltenes which had been extracted from a number of bitumen-bearing rocks in the Dead Sea area (from the Amiaz, Ein Boqeq, Nebi Mussa and Ef'e boreholes), and also from sandstones from the Heimar and IPRG boreholes which were impregnated with heavy or asphaltic crudes.
These and other results suggest that low-temperature (≤100C) oxygenic kerogenization of Dead Sea asphaltenes (with or without the mediation of meteoric waters) may be a pathway for the formation of kerogen. Asphaltenes extracted from other bituminous rocks — the La Luna limestone (U. Cretaceous, Venezuela); the Serpiano marl (M. Triassic, Switzerland); the Messel shale (Tertiary, Germany); and the Aleksinac shale (Tertiary, Yugoslavia) — underwent laboratory kerogenization in a similar fashion to the Dead Sea materials. This suggests that oxygenic kerogenization may be widespread in porous and fractured, bitumen-bearing rocks.