By Sigrún Stanton
Part of the Spotlight Series
The forthcoming 2019 Israeli international bid round includes offshore acreage for 19 licence blocks in the Eastern Mediterranean. After disappointing bidding last year, with just six licences granted, Israel hopes to entice investment with more favorable conditions and more comprehensive geological studies. By illuminating the regional geological context of the new licence blocks using the Neftex® Insights portfolio, light is shed onto the potential plays of the region. The Levantine Basin also represents a useful analogue for studying adjacent basins such as the Herodotus Basin.
The Levantine Basin holds numerous exploration opportunities divided in four main play fairways:
- Latest Oligocene–Miocene turbidite sandstones
- Pliocene turbidite sandstones
- Jurassic and Cretaceous shallow-marine and reworked carbonates
- Early Cretaceous clastic basin floor fans
The Late Oligocene–Miocene clastic fairway contains the greatest reserves of biogenic gas (>42 Tcf) and represents the most commercially successful play in the Levantine Basin. During the Oligocene–Miocene, the paleo-Nile fed sandstones from the active Red Sea rift shoulders through slope channels in the Nile Delta before depositing them as basin-floor fans in the Levantine Basin. Early Miocene sandstone reservoirs are characteristically thick, with porosities of 20% and permeabilities of 500mD preserved at Tamar. A comprehensive assessment of reservoir, source and seal are discussed in detail in our Exploration Insights magazine, a Neftex® Insights publication.
The Pliocene clastic fairway, proven in the south of the basin at Mari-B and Gaza Marine, comprise deep-marine turbidite sandstones charged during the Pliocene–Pleistocene by biogenic gas. Since this occurred after the Messinian lowstand, structures in this play are likely to be filled to spill. Additional potential in down-dip equivalents to the north should be investigated; however, during the Pliocene, Nile-derived sands were diverted north- and north-westwards, away from the Levantine Basin (Petroleum Potential of the Herodotus Basin: Applying Regional Analogues to Predict Plays and Reduce Potential Risk).
Since the discovery of Zohr in 2015, the identification of carbonate plays has encouraged exploration throughout the region. In the Levantine Basin, Jurassic shallow-marine carbonates are proven in both onshore fields (e.g. Ashod, Helez) and along the paleo-shelf margin in the present-day offshore (e.g. Yam Yafo, Yam-2). Potential for Cretaceous carbonates are also identified along the paleo-shelf edge in the onshore basin, a feature likely inherited from detached Tethyan structural highs (discussed in a previous article published in our Exploration Insight magazine). Research shows that reservoirs are likely to be too deeply buried to be in communication with Cenozoic biogenic gas systems, as they are at Zohr, relying instead on an unproven thermogenic source rock.
A final fairway is characterized by Early Cretaceous turbidites and basin floor fan sandstones. Reservoir quality slope channel sandstones are proven in the Yam West-1 and Yam-2 wells in the southern Levantine Basin and in the Mango Field in the adjacent eastern Nile Delta. Further down-dip, these sandstones could extend into the deep offshore, being trapped behind Tethyan structural highs. Again, this play relies on high-risk unproven thermogenic source rocks.
A range of proven and unproven clastic and carbonate plays offer potential exploration opportunities in the area of the 19 new licence blocks offshore Israel. Using the Neftex Insights portfolio, you can find out more about the risks associated with these plays, placing them in their regional context.
For more information contact us today.
This article first appeared in the February issue (no. 16) of the Smart & Connected E&P™, an iEnergy® newsletter.