A SHIPBUILDING contract worth 6.5 billion Norwegian kronor (about HK$7.6 billion) for the construction of four liquefied natural gas (LNG) carriers has been awarded to Kvaerner Masa-Yards, the Finnish shipbuilding subsidiary of Norway's industry-leading Kvaerner group. Placed by Abu Dhabi National Oil Co (Adnoc), the order is the largest in Kvaerner's history and has been won against stiff competition from Japanese and other European shipyards. Construction will take place at the Kvaerner Masa-Yards in Turku, Finland, with delivery scheduled between January and June 1997. The contract for the four 135,000 cubic metre LNG carriers brings the total net order backlog for Kvaerner's shipbuilding business area to 20 billion kronor. Intended to ship natural gas from Abu Dhabi - a member of the United Arab Emirates - to Japan, the new ships will replace five vessels currently handling these shipments. Four of the existing carriers were built by Kvaerner's Rosenberg Verft yard in Stavanger in 1973, 1975, 1976 and 1977 respectively. Work on the contract will begin immediately, with steelwork at the Turku yard due to commence in November on a tight schedule to meet completion dates. ''This contract confirms our strong international position as a builder of special ships,'' says Diderik Schnitler, executive vice-president for shipbuilding at Kvaerner.