“Zohr” Giant Biogenic Gas Field Discovery and its Importance for Cyprus Block 11

 

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The discovery of the giant reserve of biogenic natural gas, Zohr, constitutes a game changer for the Eastern Mediterranean. For this discovery, the Italian company ENI used its experience from the development of a similar reservoir, Perla of Venezuela, which was formed in a similar manner, ie, in paleo lagoons.
ENI stated that, this is the first discovery made within the Mediterranean based on the above mentioned model, which takes into account collateral invigoration- during the Miocene period- of karst limestone reserves from adjacent mother rocks with biogenic gas, which was created in conditions of extremely salty environment, within lagoons.

Scientists strongly believe that, these regions should receive utmost attention, because there are reasonable possibilities that Cyprus strategic natural gas stocks, are trapped within giant reserves of karst limestone.
The Cypriot psammite natural gas reserve Aphrodite, with an area of 100 square kilometers (km2), has recoverable reserves of ~ 120 Billion cubic metres of N / G, whereas, the Zohr reserve, with also an area of 100 km2, obtains recoverable reserves, most probably 5 times greater.
This observation indicates the importance of identifying natural gas target reserves with karst limestone reservoirs, as opposed to the classic up to recently discovered natural gas deposits in psammite reserves.

Mr. Solon Kassinis and Elias Konofagos presented during the International Conference MARE FORUM in Athens the expected targets of new giant karstified limestone fields of Zohr in the EEZ of Cyprus as well in the EEZ of Greece.
The first and most significant fact seems to be today the new Cypriot target of the Zohr type field which is located entirely within the Cypriot EEZ and has been recently mapped by the French company “TOTAL” .

This target is considered today scientifically mature for drilling, the characteristics of this field being described briefly as follows:

• The Cypriot Zohr is located within the offshore block 11.
• The base of the Cypriot target of type Zohr seems to be in a distance of just 5 kilometers from the base of the Egyptian field Zohr.
• The Egyptian field Zohr is almost filled with natural gas.
• The possibility of a new type Zohr field to be discovered in the entire height of its structure (around 660 meters, pay zone) something exceptionally rare even on a global scale. This leads to the conclusion that the organic substance which the exceptionally saline paleolagoons of the Mediterranean created huge quantities of pure natural gas which satisfactorily fed the paleohigh reservoirs of karstified limestone of the Miocene period.

• The probability of a new field of type Zohr to be discovered in Cyprus-full of natural gas- by the company TOTAL in the offshore block 11, should exceed 70%.
• As known the existence of watertight sheets of evaporites of the Messinian which exist in the peaks of the structures ensures completely their tightness of seal this way ensuring high pressure supplies of natural gas to the drilling productions. This property leads almost always to much lower development cost of the fields. Especially today that we are in a period of low oil and gas prices, this factor is quite significant.
• The expected probable reserves of the Cypriot Zohr are estimated in our opinion today, to be at least 15 Trillion cubic feet of natural gas (triple that of Aphrodite’s) while the respective possible reserves could reach 28 Trillion cubic feet.
• The above probable reserves could contribute drastically to the development of pipelines transferring natural gas from Cyprus towards the European Union via Greece but also to the substantial resolution of the Cypriot problem.

Conclusion:

As the hydrocarbon system for Zohr comprises a biogenic gas source from the enclosing Oligocene and Miocene shales, and a top seal from ubiquitous thick Messinian halite, there is a high probability that the Zohr play is very repeatable on a very large scale both in Egypt and Cyprus. The opportunity exists to discover sufficient gas, in these very large resource potential features, to rewrite the play book for the development of the gas industry in the Eastern Mediterranean.
Authors: E. Conophagos, N. Lygeros, A. Foscolos