The Gunashli field is located in the Azerbaijani sector of the Caspian Sea, 120 km east of Baku and 12 km south-east of Oil Rocks. The Gunashli fold is included in the Chilov-Oil Rocks anticline. The depth of sea in the field’s area varies between 80-300 m. The field is 12.5 km long and 4 km wide.
The Gunashli structure was first identified as a result of seismic surveys conducted in 1958-1963. Exploration well No. 1 was drilled in the area in 1977 and full-scale exploitation of the field began. Well No. 4 drilled in the field in 1979 produced 230 tons of oil per day by the fountain method from a depth of 3,423-3,455 m. As a result of subsequent exploration work, it was determined that the Gunashli field has oil-gas-condensate and gas-condensate. Although the field was opened in 1979, its industrial development began in 1985. Intensive drilling was started in the field in 1983. In that year, drilling was carried out on two stationary platforms (deep water platforms No. 1 and 2), and in the following years, 12 more platforms were built and put into operation. Intensive construction of the platforms took place in 1985-1990. A total of 15 deep seabed foundations have been built in the field. Oil and gas produced in the field is transported via submarine pipelines to the collection and transportation points in the Oil Rocks, and from there to Dubandi Terminal.
The oil extracted from the Gunashli field, which produces more than 60% of Azneft’s production, is also of the highest quality among other fields. The oil produced here is fully compliant with the Azeri Light brand, which is an Azerbaijani brand in world markets in terms of composition and viscosity (fluid flow rate). The difference between the products of the Gunashli and onshore fields is that the first one produces light oil (density 0.85-0.86 g/cm3), but the last - heavy oil (density 0.88-0.90 g/cm3). The oil in the Gunashli field contains a small amount of asphaltene, resin and paraffin. The amount of transparent substances (petrol, kerosene, ligroin, diesel fuel, etc.) is 50%. Dynamic viscosity varies between 14-20 cSt (centistocks). This figure is higher for onshore oil.
Natural causes such as long-term operation of wells in the field, depletion of formation energy and the water drive of reservoirs affect the reduction of oil production in the field. In 1991, the average daily oil production per well was 161 tons, while in 2020 this figure was 51.7 tons. Work is underway to apply artificial methods to intensify production. Since 1986, the injection method has been used to keep the reservoir pressure constant. Since the beginning of water drive until the 1st of January 2023, 48800.3 thousands m3 of water was pumped into the reservoirs, as a result of which about 7.771 million tons of oil was extracted. Following the research of the Oil and Gas Research Project Institute, it is planned to improve and expand water drive in Gunashli, along with other offshore fields.
As of the 1st of January 2024, a total of 371 wells have been drilled in the Gunashli field and 277 of them are exploited now. 205 million tons of oil (including condensate) and more than 131.6 billion m3 of gas have been produced there since the beginning of the development. The highest production rate was observed in 1991. In that year, 6.7 million tons of oil was extracted from 114 operating wells. The highest gas production - 6.6 billion m3 – was in 2008. Currently, the field is in the third phase of the development.
The Gunashli field is operated by the 28 May OGPD of SOCAR’s Azneft PU.