US-based McDermott and South Korea’s Hyundai Heavy Industries (HHI) have emerged as frontrunners to win two major offshore oil contracts in Abu Dhabi, according to sources close to the bidding process.

Abu Dhabi Marine Operating Company (ADMA-OPCO) is assessing engineering, procurement and construction (EPC) bids on the phase-two development of its Nasr oil field.

McDermott submitted the lowest bid of about $850m on package one of the project on 4 May, with the second and third lowest proposals lodged by local group National Petroleum Construction Company (NPCC) and HHI respectively.

UK-based Petrofac and Italy’s Saipem also submitted commercial bids for package one, which covers the construction of seven wellhead platforms, pipelines, modifications to the Integrated Gas Development (IGD)-Habshan platform (HAP) and associated facilities.

For the larger package two, the lowest bid was submitted by a consortium of HHI and US-based KBR on 6 May, according to sources. Package two covers the construction of three processing platforms and associated facilities and is estimated to be valued in the region of $1.5bn.

HHI/KBR is one of the five consortiums vying for the contract. Lead bidders in the other consortiums were South Korean groups Daewoo Shipbuilding & Marine Engineering (DSME), Hyundai Engineering & Construction and Samsung Heavy Industries, and Abu Dhabi’s NPCC.

Both contract awards are expected to be officially announced in the coming months.

The full-field development is the second phase of the expansions of the Nasr field. Phase one, covering the early production facilities, is currently under execution after the EPC deal was awarded to Indian contractor Larsen & Toubro in 2011.

The scheme forms part of Adma-Opco’s plan to add 400,000 barrels a day (b/d) of production capacity by 2020 from several offshore field developments including Nasr, Satah al-Razboot (Sarb) and Umm al-Lulu. The main EPC packages on the Sarb and Umm al-Lulu projects were awarded in 2013.

Adma-Opco is majority-owned by state-run Abu Dhabi National Oil Company (ADNOC), with minority stakes held by the UK’s BP, France’s Total and Japan Oil Development Company (Jodco).