Owned by PetroChina, the country's largest oil producer, the 4,000-km long pipeline was constructed with help from international oil firms including Royal Dutch/Shell, Gazprom, and ExxonMobil. However, as the country's gas consumption is now expected to reach 100-120bn cum/yr by 2010, with the figure likely to double by 2020, further pipeline gas-transportation capacity is urgently needed.