China, the world’s biggest oil buyer, is on the verge of opening a domestic market to trade futures contracts. It’s been planning one for years, only to encounter delays. The Shanghai International Energy Exchange, a unit of Shanghai Futures Exchange, will be known by the acronym INE and will allow Chinese buyers to lock in oil prices and pay in local currency. Also, foreign traders will be allowed to invest -- a first for China’s commodities markets -- because the exchange is registered in Shanghai’s free trade zone. There are implications for the U.S. dollar’s well-established role as the global currency of the oil market.