A Sinopec pilot area has realized total commercial gas output of 73 million cubic meters, marking major progress for China in shale gas development, an official statement said Thursday. The average output per well stood at 150,000 cubic meters per day in Sinopec's pilot zone in the Fuling District of southwest China's Chongqing Municipality, the National Energy Administration said in a statement. Shale gas is natural gas that is found trapped within shale formations. As a clean and efficient energy source, it has become an increasingly important source of energy throughout the world. "We should fully understand the significance of shale gas development in ensuring China's energy security and optimizing energy structure, and intensify efforts in promoting shale gas development," the statement said. The country should build more pilot zones for shale gas development, intensify technological research and domestic equipment production, and offer more government support for the sector, it said. According to a shale gas plan for 2011-2015, China aims to produce 6.5 billion cubic meters of shale gas annually by 2015.