--> ABSTRACT: Reassesment of Southern Red Sea Hydrocarbon Potential Through Crustal Stretching Redundancy, by John D. Pigott, Eshetu S. Gebretsadik, Ahmed O. Alahdal, and Girma L. Tefera; #90906(2001)

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John D. Pigott1, Eshetu S Gebretsadik1, Ahmed O Alahdal1, Girma L Tefera2

(1) University of Oklahoma, Norman, OK
(2) GeoQuest, Houston, TX

ABSTRACT: Reassesment of Southern Red Sea Hydrocarbon Potential Through Crustal Stretching Redundancy

Anecdotal, qualitative evidence has implied that the Red Sea is too hot at present for liquid hydrocarbons. In order to quantitatively assess the effect of spatially and temporally varying tectonics upon Southern Red Sea source rock maturities for the evaluation of exploration petroleum play concepts, a crustal stretching redundancy (CSR) technique is employed to quantify two-dimensional (2D) estimates of lithospheric attenuation. CSR provides increased accuracy over individual beta determination techniques, specifies both vertical and horizontal slice approximations to a 2D areal determination, and by virtue of borehole and/or sequence control, are stratigraphically constrained. The three techniques employed are one-dimensional borehole Airy tectonic subsidence analyses, 2D reflection seismic derived cross-section structural balancing, and 2D horizontal plate kinematic slices. The tectonic subsidence analyses of the offshore Yemen Meethag 1 borehole reveal four stretching episodes and associated betas: pre-18 Ma / 1.22; 18-14Ma / 1.195; 11-5 Ma / 1.21; post 5 Ma / 1.24. Seismic stratigraphic analyses of offshore Eritrean multichannel reflection seismic profiles show spatially distinct stretching zones with times and maximum attenuation betas of: 25.2 Ma / 1.03; 14.2 Ma / 1.12; 5.2 Ma / 1.35; 0 Ma/¥. The square root of plate kinematic 2D beta estimates are for 25-20 Ma / 1.11; 15-10 Ma / 1.07; 10 - 5 Ma / 1.11; 5 - 0 Ma / 1.36. These data demonstrate that rifting in the Southern Red Sea is episodic and argue against a singular, simple rifting model. Through the incorporation of the CSR technique, in a regional paradigm of high temperatures, thermally depressed anomalous areas in offshore Eritrea and Yemen are especially illuminated which imply the existence of source rocks at present within the oil window.

AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado