The Prinos Oil Field is the main structure in the Prinos-Kavala basin, located offshore in the Gulf of Kavala. It covers an area of 4 km2, about 8 km north-west of the island of Thassos and 18 km south of the mainland of North Greece, in a water depth of 31 meters.
Following the wells already drilled in the context of the ongoing drilling programme and the interpretation of the 3D seismic data acquired in the summer of 2015, Prinos 2P reserves have been independently audited at 20,8 mbbls (2P), while the 2C contingent resources associated with a notional extension of water injection are 16,6 mln bbls.
Since the summer of 2015, “Energean Force”, Energean’ s own drilling rig, has been executing a 7-well drilling programme in the field, as a part of a new 200-million-dollar investment. After the completion of the drilling of four wells (PA-35A, PA-40, PA-36 and PA-41), production rates exceeded 4,500 bopd of medium grade sour oil plus associated gas within 2016.
Currently, thirteen wells are producing and four are injecting sea water. Prinos’oil production averaged 3,177 bbls daily in 2016, that is a 151% increase compared to 2015 production.
The Prinos field is formed by a low relief faulted anticline, with oil trapped in the Prinos Group reservoir of Miocene Age at a depth of between 2490 and 2770 m TVDSS. The reservoir produces under-saturated sour crude oil with an API gravity of between 27 and 30 degrees.
Prinos contains up to 60% hydrogen sulphide gas. The onshore ‘Sigma’ plant complexity is driven by facilities to remove this toxic gas and convert it to Sulphur. Sulphur is sold to a local fertilizer plant. Excess gas is sold to
the same company.
The Prinos basin was explored in the 1970’s and the Prinos field was discovered in 1974, through the drilling of Prinos-1, the first exploration well drilled in the area. It was developed in the late 1970’s and brought into production in 1981.
The initial development of the field, following the drilling of the delineation wells which confirmed the extent of the Prinos reservoir, took place from 1979 until 1981. Facilities were installed offshore and onshore to allow 30,000 bopd to be produced along with associated gas. Two drilling jackets were installed above the Prinos field, bridge linked to an unmanned offshore processing platform. These offshore facilities were linked by pipeline to shore where a complex gas and oil processing plant was constructed along with oil storage tanks (500,000 bbl capacity) and offshore loading terminal.
Crude oil production commenced in early 1981, at initial rates of 8,000 to 10,000 bopd. Production peaked at more than 27,000 bopd in 1985, however it has steadily declined since then.
Prinos 2P reserves were initially estimated at 60 million oil bbls, but the field has already produced almost 110 million bbls since 1981.