A “supergiant” field with a resource potential of up to 850 billion cubic meters of gas in place (5.5 billion barrels of oil equivalent), covering approximately 100 square kilometers. This is the category that Zohr belongs to: the deposit discovered by Eni off the coast of Egypt announced on August 30. “A historic discovery that will be able to transform the energy scenario of an entire country, which has welcomed us for over 60 years” according to Claudio Descalzi.
Zohr represents the largest gas discovery ever made in Egypt and in the Mediterranean Sea and could become one of the biggest gas finds in the world. The well Zohr 9, through which the deposit was found, is located at 1,450 meters of water depth, in the Shorouk block.
As described by Marco Alfieri on eniday.com, “the story of Zohr began in mid-2012, when Egas, the Egyptian state agency for research in the offshore Nile Delta, announced a competitive bid, or “ round bid”, to use the technical term, in the Mediterranean offshore, offering 15 blocks to oil companies to be evaluated .”
At the announcement of the tender, Ieoc, which historically has been the driver of Eni’s exploration activities in Egypt, performed a preliminary screening with available data on all 15 blocks (for experts on the subject it was technically speaking regional gravimetric and magnetometric data and old seismic lines) with information on the Levantine basin where Texans and Israelis had been finding interesting things. At that point it was decided upon to buy the governmental “data package “ of 10 of the 15 blocks, in order to extend the technical evaluation.
At the end of the monitoring period the team brought 3 of the 15 blocks to the technical and economic assessment stage; and of these only block 9 (Shorouk) ended up on the desks of Eni’s senior management. Why Shorouk? Initially, the goal was to search in Egyptian waters for the geological model tested by the recent giant gas discoveries (Leviathan, Tamar and Aphrodite) made by the Delek-Noble Energy consortium in offshore Israel and Cyprus. Eni explorers looked for similar structures with the same “play concept”, on the assumption that the oil system discovered in the Eastern Mediterranean might also extend to Egypt.
What emerged is an area in block 9 where there appeared to be a “high regional” situation: not the classic theme in Miocene sands like Leviathan, Tamar and Aphrodite or the Nile Delta, but a huge bio-structure. A “reef”, as geologists would call it, writes Alfieri. “But a very, very big reef. To have an idea of just how big, you have to think of a large massif in the Dolomites, such as the Sella-Pordoi , but buried under 3 thousand metres of sediment and 1,500 metres of water.”
In the new geological model the “lead”, i.e. the potential object of exploration, is actually described as a biostructure allegedly of the Miocene age (about 10 million years ago) that has grown on another preexisting plain of the Cretaceous period. The interesting thing is that the bio-structure is covered with evaporite rock (rock salt) of Rosetta formation (the equivalent of the chalky-sulphurous Apennines and Sicily), notoriously good for sealing the reservoir. Moreover, we know from the fields discovered in Cypriot and Israeli waters, that the oil system of migration of biogenic gas should be active in the area. Block 9 has all three of the basic conditions for a potential accumulation: a reservoir, a cap that seals, the source rock.
Alfieri continued: “But time is running out and it will not be easy to get the green light for the project from the top floor. What’s more, the Shorouk area was held by another operator (a big major) for ten years, during which 9 wells were drilled without commercial results. How is it possible that they didn’t see the the “big potato”? The explanation of Eni’s explorers is that they were looking for a different geological game, a classic of the Nile Delta (Miocene sands), not the sea-mount carbonate variety that seems to be the case with the “big potato”, and currently the only one of its kind.”
In San Donato the explanation was deemed convincing and in February 2013 the IEOC sent an offer to the Egyptian government. During the summer Eni informally learned that it had won the bid, even though the official signing came only in January 2014 when 100% of Block 9 was assigned to the IEOC. As expected competition was limited; the majors had held their positions without exposing themselves, waiting for better times.
On 25 June, the huge Saipem 10000 was located in Block 9 and work on the well physically started on 3 July. Then the first confirmations started to arrive: the well is mineralised natural gas and carbonate reservoir rocks are of excellent quality. They recommence drilling the “big potato”. The numbers started to become big, very big, and this is how they became aware of the Zohr discovery.