--> ABSTRACT: The Messinian Salinity Crisis: Impact on Prospectivity in the E. Mediterranean, by Fraser, Alistair; Guderjahn, Chuck G.; Allen, H.; Al-Balushi, Abdulaziz; #90135 (2011)

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The Messinian Salinity Crisis: Impact on Prospectivity in the E. Mediterranean

Fraser, Alistair 1; Guderjahn, Chuck G.2; Allen, H. 1; Al-Balushi, Abdulaziz 1
(1)Dept of Earth Science and Engineering, Imperial College, London, United Kingdom. (2) BP Exploration, London, United Kingdom.

The offshore Eastern Mediterranean is currently attracting considerable industry interest, following recent significant discoveries in the pre-Messinian of both the Nile Delta in Egypt and the offshore Sirt Basin, Libya. In support of this activity, a substatial industry 2D and 3D dataset has been acquired covering the region from the offshore Levant westwards across the Nile Delta and into offshore Libya. Although acquired to target deeper exploration prospects the data is shedding important new light on the structural and stratigraphic complexity of the shallower Messinian interval.

There are two aspects to the impact of the Messianin on pre-Messinian prospectivity in the Eastern Mediterranean. Firstly, the Messinian evaporite layer has a visible impact on the quality of pre-Messinain seismic imaging particularly below a high amplitude and highly rugose dolomite and anhydrite layer interpretred as sabkha deposits. Historically, the issue has had been approached from a geophysical perspective with ever more sophisticated multi-azimuth seismic acquisition and processing techniques being applied to the problem. However, a better understsnding the lateral facies variations and structural response to the sudden fall in Miocene sea-level during the Messinian will provide a geological framework within which to design geophysical solutions and should provide the key to designing ‘smart’ seismic programs with corresponding cost savings and potentially improved imaging.

Secondly, we discuss the impact of the Messinian salinity crisis on the petroleum systems in the region. Removing (and replacing) in excess of 1000m of water and sediments will have changed (geologically instantaneously) the petroleum phase and seal capacity of existing traps. Is significant post-Messinian burial (such as under the Pliocene Nile Delta) going to be key to successful exploration in the region?

 

AAPG Search and Discovery Article #90135©2011 AAPG International Conference and Exhibition, Milan, Italy, 23-26 October 2011.