Mammut Building Systems from the UAE is the favourite to win the contract after submitting the lowest bid of AED620m ($169m).
Mammut’s bid is more than 10 per cent lower than the second lowest bid of AED683m ($186m) submitted by Gulf Petrochemical Services & Trading from Oman.
Both companies expect to take 15 months to expand the reservoir.
The third-lowest bid of AED700m ($190.7m) was submitted by India’s Nagarjuna Construction Company, which estimated that the job would take 21 months.
Five other local and international companies bid for the contract.
United Engineering Construction (UNEC), a UAE company, built the reservoir’s second and third phases in 2001 (MEED 7:9:01).