The UAE’s Zakum Development Company (Zadco) has extended the deadline for commercial bids on the second major package on early production facilities at its Upper Zakum offshore oil field.

The estimated $4bn EPC2 contract covers the construction of processing trains, pipelines and other facilities on artificial islands being built at the Upper Zakum field off the coast of Abu Dhabi.

Technical engineering, procurement and construction (EPC) proposals were submitted by several contractors in early May, with the deadline for commercial bids initial set for late June. Zadco has now asked the companies involved to submit commercial bids by mid-September.

Companies submitted technical bids for the scheme in early May, including South Korea’s Hyundai Heavy Industries, US-based McDermott, the UK’s Petrofac, Italy’s Saipem and Singapore’s Swiber Holdings, along with a joint bid of Abu Dhabi-based National Petroleum Construction Company (NPCC) and France’s Technip.

The contract is set to be the biggest EPC deal awarded in the UAE’s oil and gas sector this year.

In July, Zadco awarded the $800m EPC1 first Upper Zakum package – covering the offshore section of the development – to a consortium of NPCC and Technip.

Zadco is a joint venture of state-owned Abu Dhabi National Oil Company (Adnoc), US oil major ExxonMobil and Japan Oil Development Company.