The Gurgan-Deniz field is located in the shallow part of the Caspian Sea, west of the Absheron archipelago, south of Pirallahiy Island. The depth of the sea in this area reaches 0.5-2 m, in some areas up to 8 m. The field is tectonically complex with a decussate structure. It is 10 km long and 3.6 km wide.
The Gurgan-Deniz field is a part of the tectonic south-eastern descent of the southern fold of the Pirallahi Island field and is separated from it by saddles. Although the first exploration work in the field began in 1932, the structure was not studied precisely because the results of the work carried out until 1934 were not clear. In 1937, more than 80 exploration wells were drilled here and initial information about the structure of the field was studied. The oil reserves of the field were calculated for the first time in 1942. In 2019, 136.6 km2 3D seismic exploration was carried out to clarify the geological structure, study the collector properties of the layers and predict the distribution area of hydrocarbons in the Gurgan-Deniz area. As a result of the analysis of 3D seismic data, the geological structure of the Gurgan-Deniz has been clarified (length - 17 km) and the fact that the Pirallahi structure of the uplift is a far southeastern periclinal has been confirmed once again.
The Gurgan-Deniz field was developed after obtaining industrial-significant oil from well number 7 in 1947 and produced10 tons of oil per day. Following the initial extraction of industrial-significant oil, intensive exploration for oil reservoirs in the productive layers of the horizon was conducted, resulting in positive outcomes. This, in turn, had a great impact on the drilling of new wells at a high rate, putting them into operation with high production and, as a result, increasing the annual oil production. So, if in 1947, 2 thousand tons of oil were produced by the exploitation of 1 well, in 1949, 177 thousand tons of oil were produced from 7 wells and in 1950, 493 thousand tons of oil were produced from 37 wells. In 1952, production at the field reached its highest level - 923.1 thousand tons.
The field oil is high-resin and low-paraffin and consists of high-octane petrol, ligroin and kerosene, and no sulfur. It has dry gas - the content of methane in the associated gas reaches 92%. During the operation of the Gurgan-Deniz field, more than 7.3 million tons of oil and about 600 million m3 of gas were extracted there. Although the field was suspended in 1987 due to severe hydraulic failures, a new foundation was laid in 2002 to drill six new wells. Well No. 211 drilled from the new foundation was put into operation with a daily production of 25 tons of oil, and well No. 207 with a daily production of 40 tons of oil. As of the 1st of January 2024, a total of 180 wells have been drilled in the field, of which 2 are observation, 4 conservation, 174 liquidation stocks.
Due to the failure of hydraulic structures, the operation of the field was completely stopped with the conservation of 4 wells drilled from the new foundation No. 210 in April 2018. Geologists consider it expedient to recalculate the field’s reserves in the future and, if necessary, drill new wells.
The drilling of an exploration well for the lower horizons of the Gala formation is planned with the aim of studying the oil and gas content of the lower part of the productive layer in the field. The lithological composition of the section called Pulcuglu will be clarified through the analysis of cutting samples taken during the drilling of the well and the oil and gas potential of the lower areas will be studied.
The drilling of an exploration well for the upper subsurface beneath the Qala Formation is planned with the aim of studying the oil and gas content of the lower part of the productive layer in the field.
The field is on the balance sheet of SOCAR’s Azneft PU’s Absheronneft OGPD.