SEOUL — South Korea's GS Energy said it had agreed to buy a stake worth 743 billion Korean won ($676 million) in a new 40-year onshore oil concession in Abu Dhabi, the latest move by import-dependent Asian countries to secure upstream assets. GS Energy would join Japan's Inpex Corp and France's Total in developing the UAE's (UAE) biggest oilfields after a deal with Western oil majors that dates back to the 1970s expired in January. The 3 percent stake in the Abu Dhabi Company for Onshore Oil Operations (Adco) concession would provide South Korea with its biggest oil asset of 800 million barrels, GS Energy said in a statement. GS Energy, owned by GS Holdings Corp, has a 50 per cent stake in South Korea's second-largest crude oil refiner, GS Caltex Corp, with US oil major Chevron Corp holding the other half. The Adco purchase would "greatly contribute to stable energy supplies" in South Korea, GS Caltex said in a statement. — Reuters