The Zohr play in the Cyprus EEZ: geological observations from Miocene reef outcrops and offshore seismic

Abstract

Summary The interpretation of offshore 2D seismic lines has here been integrated with onshore drone-based digital photogrammetry and fieldwork to shed new lights on the stratigraphic and reservoir properties of Eastern Mediterranean Miocene carbonate units. A near-top Miocene carbonate platform seismic reflector has been mapped regionally in and around the Eratosthenes seamount. These shallow-water carbonate units are buried under Messinian evaporites in structurally lower positions; however, such seal layer is missing on the central Eratosthenes high. Pliocene-Quaternary pelagic carbonate layers record a recent history of fast subsidence and platform drowning. Miocene shallow-water carbonates have so far proven poor reservoir units offshore, unlike the world-class Cretaceous reefal reservoir rocks of the Zohr and Calypso discoveries. The preliminary reservoir properties of an isolated Miocene reef outcropping in Cyprus have here been described. Hand-samples generally show low permeability and low-medium porosity; however dense open fracture networks have been mapped. Within the carbonate build-up, several depositional facies were discriminated, each with different reservoir and fracture parameters. These observations suggest that Miocene reefs could serve as a commercial reservoir, although well placement should be optimized by targeting the best intra-platform facies belts through the integration of 3D seismic geomorphology and more detailed reservoir outcrop analogue studies.