Red Sea/Gulf of Aden Source Rock Geochemical Evaluation

DUCREUX, C., G. MATHURIN, and M. LATREILLE,* BEICIP, Rueil-Malmaison, France

The potential of hydrocarbon generation in the Red Sea and Gulf of Aden was studied by geochemical analyses of 2271 samples from 23 wells drilled in 6 countries within the area.

Selection of candidate source beds was primarily a function of the sedimentary column penetrated by drilling (i.e., whereas sub-Tertiary sediments are accessible in Somalia and Yemen in the Gulf of Aden, sampling below the thick Neogene evaporitic sequence in the Red Sea could not be achieved due to a general lack of penetration to such levels).

Organic matter content and type, maturity levels, petroleum potential of the rock analyzed, and its capacity to have generated liquid or gaseous hydrocarbons are the basic results provided by the analyses.

Geochemical well correlations within and between subbasins are presented using the two most representative parameters: total organic carbon (TOC) and Petroleum Potential (PP = S1 + S2), expressed in kilograms of hydrocarbons per ton of rock.

In general, results obtained in the two rift basins, with sampling mostly in Neogene sediments in the Red Sea and in sub-Tertiary and Tertiary sediments in the Gulf of Aden, indicate the presence of favorable sources preferentially in this sub-Tertiary succession.

It is stressed that geochemical analysis results are from wells whose locations are generally on structural highs and, therefore, are not representative (especially in terms of maturation) of conditions in adjacent depressions, particularly where the difference in structural level is great.

Sound simulation modeling makes possible the reconstruction regional thermal and burial history and, thus, identification of maturation kitchens.

AAPG Search and Discovery Article #91007© 1991 AAPG International Conference, London, England, September 29-October 2, 1991 (2009)