China, however, may need Russian gas to meet its latest targets for natural-gas consumption, which are pegged at 420 billion cubic meters a year by 2020, up from 170 billion cubic meters in 2013.Although the country has pinned hopes on ramping up domestic production of unconventional shale and coal-bed methane gas, large-scale output may still be at least a decade away. China wants to double the share of the cleaner-burning fuel in its energy mix to 10% by 2020 amid heightened worry over pollution.