The Elsa Field
Top Maiolica reservoir depth structure showing range in oil water contact.
The B.R268.RG Permit containing Elsa is located on and at the northern margin of the Jurassic-Miocene Apulian Carbonate Platform. Several commercial discoveries of oil are in close proximity including the Rospo Mare and Ombrina Mare fields on the platform, and the Miglianico field on the platform margin. While the Elsa discovery is analogous to the neighbouring Miglianico Field, numerous additional prospects and leads have been identified both on the platform and at the platform margin in the adjacent acreage.
The Elsa field is located off the eastern coast of Italy, approximately 7 km offshore in around 35m water. The field was discovered by AGIP in 1992 with well Elsa-1, which encountered an oil column of approximately 65m in the Lower Cretaceous Maiolica Formation at a depth of around 4,500m. The reservoir is a dolomitised bioclastic carbonate formed on the basin floor on the northern margin of the Apulian Platform by re-sedimentation of carbonates shed off the platform through gravity sliding and slumping during the late Jurassic/early Cretaceous. Due to casing restrictions, a sub-optimal open hole drill stem test was attempted with both water and oil zones exposed to the wellbore. Oil samples, contaminated with water, recovered from the test string had a reported oil gravity of 15° API. Uncertainty remains over the oil gravity, especially in light of yellow-gold fluorescence reported while drilling through the reservoir, and close proximity to the Ombrina Mare and Miglianico fields, which lie at depths of around 2,900m and 4,800m respectively, but which have API gravities of 18° and 34° respectively. Both Orca and Petroceltic believe that the Elsa field will be commercial at 15° API oil, however several indications give rise to the expectation that the crude gravity may be higher than the 15° API.
Elsa-1 Summary CPI log
The B.R268.RG Permit containing Elsa is located on and at the northern margin of the Jurassic-Miocene Apulian Carbonate Platform. Several commercial discoveries of oil are in close proximity The Elsa-2 appraisal well has the primary objective of confirming the commercial production potential of the reservoir when completed with a 1,000m horizontal drain. Positive results from Elsa-2 will be followed by a 3D seismic survey over the field.
The full field mid case STOIIP potential of Elsa is 410 MMbbl. Recoverable reserves are in the region of 100 MMbbl, depending on oil gravity and viscosity, with a potential development via 8 horizontal wells with 1,000m drain length and pressure support maintained by injection of produced water and gas. Production would be to an FPSO and export via a shuttle tanker.
Central Apennines Exploration
The farm-in agreement with Petroceltic includes equity in eleven offshore exploration permits both on the Apulian Platform and just north of the platform margin. A number of prospects and leads have been identified ranging in age from Jurassic, Cretaceous and Tertiary and having primarily oil and some gas potential. The total prospect inventory including Elsa has a reserve potential of 443 MMbbl. A further programme of seismic acquisition is planned to evaluate more fully the potential of these exploration permits.