Several international engineering firms are preparing to submit bids on a study for a major offshore gas development in Abu Dhabi, according to sources close to the bidding process.

Abu Dhabi National Oil Company (Adnoc) is planning to develop sour gas reservoirs at the Hail and Ghasha fields in what would be one of the largest ever upstream projects in the UAE.

Companies have been set a deadline of 28 August to submit front-end engineering and design (feed) bids, pushed back from a cut-off date earlier in the month. Prequalified bidders are thought to include:

The Hail and Ghasha scheme is planned to install 1 billion cubic feet a day (cf/d) of additional gas capacity from sour gas reservoirs at the offshore fields.

US-based Occidental Petroleum (Oxy), which has a 40 per cent stake in the completed onshore Shah gas development, was awarded a $500m contract by Adnoc in February 2015 to carry out a technical evaluation at the Hail and Ghasha fields.

Oxy has cooperated with Adnoc on activities including 3D seismic surveys, the drilling of appraisal wells and conducting engineering studies necessary for the fields’ development. It was expected to take two years to carry out the technical evaluation of the two fields.

In March, Austria’s OMV revealed it had entered into a four-year agreement with Oxy and Adnoc to evaluate several undeveloped fields in the North West Offshore area of Abu Dhabi, including the Hail and Ghasha areas. However, it is unclear if this is connected to the sour gas development.