Petroleum Potential of the Herodotus Basin: Application of Regional Analogs to Predict Plays and Reduce Risk

Abstract

Over the last few years, play-opening gas discoveries in the Nile Delta and Levantine Basin have prompted a renewed interest in the Eastern Mediterranean. While recent exploration efforts have focused on these basins, the adjacent deep-water Herodotus Basin remains almost totally unexplored. The Herodotus Basin, located along Egypt’s northern coastline, forms a down-dip extension to the Nile Delta province and likely shares multiple play elements with these prolific basins. The upcoming EGAS bid round is expected to include offshore acreage for six blocks in the East Mediterranean, covering a large frontier zone in the Herodotus Basin. This study evaluates the petroleum potential of the Herodotus Basin, using regional analogues from the Nile Delta and Levantine Basin to assist in play prediction and reduce exploration risk. Two key fairways are considered: (1) the successful Oligo-Miocene clastic fairway of the Nile Delta and Levantine Basin, represented by numerous major discoveries (e.g., Satis and Tamar) and (2) the Early–Middle Cretaceous carbonate fairway, opened up by Zohr in 2015 and subsequently extended by the Calypso discovery in February 2018. The possible extension of these plays into the Herodotus Basin was assessed by conducting a basin-scale risk assessment of the presence, distribution, and effectiveness of individual play elements for each play. Overall, basin screening suggests that the potential for technical success in the Herodotus Basin is high. Maturity modelling for potential biogenic sources indicates that many proven biogenic fields in the Eastern Mediterranean lie close to or beyond the conventional biogenic gas window, with reservoir temperatures as high as 85°C, suggesting effective biogenic gas charge for both play types to depths as great as 4000 m, diminishing charge risk for potential deep targets. However, some key differences between the Herodotus and adjacent basins should be considered. Significant variations in trap geometries for the Oligo–Miocene play suggest fields are likely to be smaller than equivalent fields in nearby basins. For the Cretaceous carbonate play, the absence of rifted highs over oceanic crust across much of the Herodotus Basin has limited the development of potential reservoirs. The lowest risk targets within Zohr-type plays are high relief buildups over detached continental highs that are sealed, and potentially charged, by Oligo–Miocene mudstones.

AAPG Datapages/Search and Discovery Article #90332 © 2018 AAPG International Conference and Exhibition, Cape Town, South Africa, November 4-11, 2018