French industrial gases group Air Liquide has signed a long-term agreement to supply Saudi Aramco with nitrogen, Reuters has reported. According to the 20-year deal, Air Liquide is to supply at least five million standard cubic feet per day of nitrogen to support sea water injection in Aramco's oilfields, the two firms said during a signing ceremony. Air Liquide would also build an interface inside sea water injection facilities as well as an air separation plant in Qurayyah, south of Alkhobar. Construction work would take 18 months to be completed.