TOTAL’s drilling at marine block 11 proved that – economically – the choice of Onisiforos West-1 was a drilling geographically placed in a misguided situation.
Even though it has proved that there is a Zohr type reserve there, but with a minimum of natural gas plenitude.
Onisiforos’ certified reserves are more likely to be around 350 billion cubic feet or approximately 10 billion cubic meters.
However, 10 billion cubic meters represent a reserve which is 10 times larger than the largest natural gas reserve which has been discovered so far in Greece, the South Kavala reserve in Thassos, which locally fueled the region with natural gas for 20 years.
The Cypriot sea depths require today discoveries of reserves with stocks exceeding the 6 trillion cubic feet, or 170 billion cubic meters so that they may be considered economically exploitable in their own right.
In order however, for reserves of that magnitude to be discovered, it will be necessary for target reserves to be located, which paleogeographically were promptly covered by waterproof layers of Messinian salts prior to natural gas escapes from the target structures of interest.
We are aware that in the case of the Zohr reserve paleogeographically, this limestone structure was covered with Messinian salts at the point of time that it was almost full of natural gas.
Quite the contrary, at Onisiforos there were indications of biogenic natural gas escapes, as well as water inflow.
In previous publications of ours, we had refered to Solon Kassini’s suggestions made two decades ago, ie, to primarily investigate the target reserve which is only 8 kilometers away from the Zohr reserve and within the Cypriot EEZ, and for the research to be expanded afterwards
Instead in this case, a location is chosen 40km away, with the excuse of a more efficient supply of the Onisiforos structure with biogenic natural gas, given that there were all around this structure underlying parent rocks present.
As it turned out that factor was not the most important factor of success.
What now is considered the most important factor of success however, is when and whether a target structure was covered early enough by a sufficient thickness of waterproof rocks, ie, Messinian salts, at the time when it obtained the maximum biogenic natural gas plenitude, through an existing neighbouring paleo-lagoon.
This dimension will in the future constitute the most important factor of success in regards to the probable Cypriot drillings in limestone reef targets.
We strongly believe that the research efforts of the oil companies within the Cypriot EEZ ought to concentrate on that, but in the wider context as well, all the scientific sectors involved with the issue of the location and discovery of reef limestone reserves of some economic interest within the Eastern Mediterranean, should be focused on this.