The portion of Gunashli field which is not in the scope of ACG project, lies in 120 metres (390 ft) depth of water and developed by State Oil Company of Azerbaijan Republic (SOCAR) while the deepwater section developed by BP within ACG project is at 175 to 300 metres (574 to 984 ft) The field was explored in 1958–63. The first offshore platform was installed by 1976. Production in this section started in 1982. It consisted of 4 steel jackets for drilling of 10 wells. As per 1980 data, the platform produced 320 tonnes of oil per day.

As of 1995, Gunashli was producing 120,000 barrels per day (19,000 m3/d) of oil. Because of steadily falling rate of production (9%), SOCAR hired Kvaerner to provide project management to rehabilitate Gunashli. In March 2008, a high-flow-rate well No. 244 was put into operation through the platform No. 13. It produces 140 tons of oil and 23,000 cubic metres (810,000 cu ft) of natural gas per day. The well was drilled by SOCAR subsidiary Azeri Drilling Company Ltd. The well No. 247 was drilled by Bayil Limani Offshore Exploration Drilling Unit through platform. It produces 100 tonnes per day

Eastern deep-water section

The deep water section of Gunashli (also called DWG) field has been included for development within the ACG project’s Phase III. First oil from DWG was produced on 20 April 2008 from one of 10 pre-drilled wells. DWG now produces nearly 320,000 barrels per day (51,000 m3/d) of the total 1 million barrels per day (160×103 m3/d) from ACG fields complex. ACG’s DWG complex is located in the eastern side of the Gunashli field and includes two bridge-linked platforms:

• a 48-slot drilling, utilities and quarters (DUQ) platform.
• a process, gas compression, water injection and utilities (PCWU) platform<

Oil produced at DWG is transported through a 30-inch (760 mm) oil pipeline tie-ins and single 28-inch (710 mm) gas pipeline tie-in into pre-installed pipeline junctions from Azeri field leading to Sangachal Terminal.The DWG has 9 operating wells. It has been producing 16,800 tonnes of oil and 6.4 million cubic metres (230 million cubic feet) of natural gas per day

Gunashli Oilfield activities are exploration, preparation, exploitation of onshore and offshore oil and gas fields, transportation, processing, refining and sale of oil, gas, condensate and other related products. Gunashli Oilfield exploration activities cover the prospective offshore fields in the Azerbaijani sector of the Caspian Sea. The current largest fields being explored are Shafag-Asiman, which is explored with BP, and Absheron natural gas fields which is being explored together with BP and TotalEnergies respectively.

In 2010, Gunashli Oilfield and BP signed a new production sharing agreement regarding Shafag-Asiman. In 2014, Gunashli Oilfield and BP signed a joint exploration and development over the Shallow Water Absheron Peninsula. Gunashli Oilfield has explored the Umid and Bulla Deniz gas fields. In 2017, Gunashli Oilfield and a consortium led by BP signed a letter of intent for future development of the Azer-Chirag-Gunashli field. They signed a $6 billion contract regarding the Azeri Central East (ACE) platform on the Azeri-Chirag-Gunashli field.