BP is set to begin the second phase of development at its sprawling Khazzan gas field in Oman to produce a total of 1.5bn cubic feet per day (cfpd) of gas.
The Ghazeer project is set to come onstream in 2021 following the start-up of phase one of the Khazzan project in September 2017.
The phase one development is made up of about 200 wells and recently reached its design capacity of 1bn cfpd of gas. Ghazeer will add a further 0.5bn cubic feet to daily gas volumes as BP drills another 100 wells.
The Oman Oil Company Exploration & Production holds a 40 per cent interest in the $16bn (£11.3bn) project, which was BP's biggest unconventional gas project outside the US last year.
BP used the fracking know-how it picked up extracting shale gas in the US to unlock the Khazzan field's tight gas reserves, which require both vertical and horizontal wells to be drilled.
Yousuf Al Ojaili, the president of BP Oman, said: “Following the successful startup of Khazzan, we are pleased to announce the sanction of Ghazeer, BP’s first project FID [final investment decision] of 2018.
"Through the transfer of industry-leading skills and technology from BP’s global portfolio, we look forward to futher developing this gas field that is expected to support Oman’s energy needs for many decades to come," Al Ojaili said.
Both phases of the project are expected to deliver total production of 10.5 trillion cubic feet of gas and around 350m barrels of condensate through to 2043, when the agreement with the government of the Sultanate of Oman ends.
Shares in the company were down 1.5 per cent at 490.9p at the time of writing.