The Chilov Island field is located south-east of the Absheron archipelago of the Caspian Sea, 62 km from Baku City, 20 km from Pirallahy Island, in south-eastern direction. The field is connected with the 7 km long - 5 km wide Chilov Island, which is second among the islands of Absheron archipelago and extends from north-east to south-west as a narrow strip. The depth of sea is about 10 m near the island, 5-25 m in the structure’s territory. Tectonically, the Chilov structure belongs to the Khaly-Oil Rocks anticlinal strip. In 2019, 126 km2 3D seismic exploration was carried out in Chilov Island for the purpose of specifying the geological structure, studying the collector properties of the layers and predicting the distribution area of hydrocarbons.
Chilov Island, formerly known as Shahilan, was not previously used as a permanent settlement due to the lack of drinking water and the unproductiveness of the soil. Chilov has historically been called Chilov-Shahilan. Of the former names, Persians called the island Ronis and Russians - Jiloy. Don Cossack Stepan Razin settled on the island for some time and organised bandit raids on coastal areas. Many islands in the Caspian Sea were renamed in the 17th century after the arrival of the Russians. For this reason, the name of Chilov Island was changed from Shahilan to Jiloy. The meaning of the name “Shahilan” is “shah” from the Persian as “branch”, “straight long branch”, and “lan” means “cape”, “narrow path”, “long narrow land”. It means a long narrow path from the water to the island, because according to historical sources, it was once possible to walk to Chilov Island by sea. At present, it is possible to see underwater rocks while flying by helicopter. Experienced fishermen could walk to the island through these rocks. The depth of the water could be up to 1 m. The other name of the island - “Ronis” means “Rah nist” in Persian - “there is no way”. This name appeared when the Persians wanted to enter the island.
Geophysical research, geological planning, structural mapping and exploration drilling have been carried out in the Chilov Island area and its part covering the sea since 1932. The oil and gas content of the field was determined by well No. 3 drilled in 1947. Development of the Chilov Island field began in 1951. In 1947-1966, 52 exploration wells were drilled in the field. The highest production on the field in 1974 was 171,000 tons from 40 wells.
As of the 1st of January 2024, 134 wells have been drilled in the Chilov Island field and 47 of them are still in exploitation. Since the beginning of the development up to date, 5.555 million tons of oil and 700 million m3 of gas have been produced there. Daily oil output of the field is 155 tons.
At present, the field is in the final fourth stage of its development. It is planned to drill an appraisal well in the southeastern part of the field to determine the oil and gas content.
The Chilov Island field is operated by the 28 May OGPD of SOCAR’s Azneft PU.