French industrial gases group Air Liquide signed on Saturday a long-term agreement to supply nitrogen to state oil giant Saudi Aramco.

Under the 20-year deal, the French firm will supply at least 5 million standard cubic feet per day of nitrogen to support sea water injection in Aramco's oilfields, officials from Aramco and Air Liquide said during a signing ceremony.

It would also supply liquid nitrogen to Saudi Aramco facilities. Nitrogen removes oxygen from sea water which is injected into the reservoir to maintain the well potential.

The value of the agreement was not disclosed and no details were provided as to which oilfields would be targeted.

Air Liquide would also build an interface inside sea water injection facilities as well as an air separation plant in Qurayyah, south of the eastern city of Khobar.

Construction work would take 18 months to be completed. The company won the deal after a bidding process.

Air Liquide signed a contract with Aramco in September to supply hydrogen to the new 400,000 barrels per day (bpd) refinery in Yanbu, on the Red Sea coast of the world's largest oil exporter Saudi Arabia.-Reuters