User:Aciast1/sandbox

Epsilon Field

General Information

Topdown view of Epsilon field in the Prinos basin.

The Epsilon field is an oil producing fielding located in the northern Aegean Sea at the center of the Prinos oil basin with a relatively shallow water depth of 30m. The field was discovered in 2000 and is currently owned and operated by Energean Oil & Gas. It began production in 2010 with an estimated reserve of 30 million barrels with a production rate 2000 barrels per day.

Geology

Prinos Basin

The Prinos basin was formed because of post alpine tectonism that started in the early to mid-Miocene; breaking the Aegean plate in the process. The basin has primarily been shaped by several normal faults, resulting many favorable petroleum traps. The reservoirs are primarily sandstone and siltstone that were created due to the marine and turbiditic environments that took place. Due to the high salinity and rapid sedimentation of the field, this type of environment was able to preserve organic matter and allow hydrocarbon generation throughout the basin.

Well log displaying stratigraphic columns and gamma ray readings for fields in the Prinos Basin.

Despite the closeness of the wells, coring samples suggest differences in the source rocks and maturity of the hyrdorcarbons throughout the basin. In the Epsilon and Prinos fields, hydrocarbons are immature, generated from marine organic production and migrate into the sedimentary zones. While similar, the hydrocarbons found in Prinos North fields are even more immature and were generated from an argillaceous source rock. The primary reason for this variance in hydrocarbon maturity is due to the Epsilon and Prinos fields being generated in a deeper stratagrapic horizon, allowing for higher thermal maturation.

Stratigraphy

3-D Seismic data collection of Epsilon lasted from 1993-1997 near the northern slope of the Prinos basin, where a potential hydrocarbon field was likely to exist. The seismic data showed evidence of several anticlines with down-thrown faults. These geophysical results were confirmed following the first well being drilled in 2001.

Cross section displaying series of Epsilon field.

The stratigraphy model of the basin is divided up into three series: Pre-Evaporitic, Evaporitic, and Post-Evaporitic. The Paleozoic basement is made up of metamorphic rocks such as gneiss, quartz and dolomite. The Pre-Evaporitic series begins with conglomerates from the basement, immature sandstone, thick coal seams, and a deposition of gray claystone that is petroliferous with sandstone intercalations. The Evaporitic series found in the Epsilon field is composed of 7-8 layers of salt with a total thickness of 800m. The Post-Evaporitic series is clastic and marine, with a large presence Pliocene foraminifera and algae.       

Production and Development

Despite confirmation of hydrocarbons in 2001 and few drilling problems, the well was suspended due to unfavorable permeability. Drilling continued in 2002 and was sidetracked improve performance.

The first completed well was drilled in January of 2010 to a depth of 5500m. The average initial pressure for the producing zone were 6000 psi. The oil produced from Epsilon is immature and aromatic with 36.5° API and high levels of hydrogen sulfide and carbon dioxide. Initial estimates put the total reserves at 40 billion barrels of oil, but has since been curtailed to 30 billion barrels. At a production rate of 2000 barrels per day, the well is expected to produce until 2024.