THE EVOLUTION OF THE DEAD SEA FLOATING ASPHALT BLOCKS: SIMULATIONS BY PYROLYSIS
Article first published online: 18 DEC 2007
Journal of Petroleum Geology
Volume 2, Issue 4, pages 439–447, April 1980
How to Cite
Bein, A. and Amit, O. (1980), THE EVOLUTION OF THE DEAD SEA FLOATING ASPHALT BLOCKS: SIMULATIONS BY PYROLYSIS. Journal of Petroleum Geology, 2: 439–447. doi: 10.1111/j.1747-5457.1980.tb00971.x
- Issue published online: 18 DEC 2007
- Article first published online: 18 DEC 2007
The asphalts found as floating blocks on the Dead Sea and deep-seated in wells differ from all other asphalts of the area, mostly by their more abundand and much better preserved n-alkance. Since biodegradation was found to be the main alteration process through which crude oil was alterd into aphalts, such well-preserved n-alkanes are unexpected. A hypothesis of secondary generation of theise alkanes was tested bny pyrolysis simulations of asphalt at 300d̀C during periods ranging up to 60 days. The abundance and distrubution pattern of the n-alkanes in the simulated asphalts after 14 days of heating resembles that of the floating asphalt blocks and that found at a depth of 3,500 m. In addiation to saturated hydrocarbons, aromatics and gases were also formed at the expense of resins and asphaltenes. The H/C ratio was balanced by the formation of pyrobitumen and by a gradual decrease of the H/C ratio in the residual resins and asphaltenes. The gas formed contained about 60 to 80% methane with an isotopic composition of-41 to 42%%. The hydrocarbon content of the simulated asphalt (gas and liquids) increased from about 15% at the stariting material to about 60% after 60 days of heating.
The recognition that asphalts in the Dead Sea basin are secondarily subjected to alteration upon burial might be of economic importance. Asphalts buried to a depth at which maturation conditions are close to that reached in the pyrolysis simulation at 300d̀C after about 60 days may be counted on as source material for hydrocarbons.