shale gas field is located in Chongqing's Qijiang District and Xishui County of southwest China's Guizhou Province, according to Ma Yongsheng, chairman of Sinopec.

The latest discovery indicated a great prospect of deep shale gas for exploration and development, and is expected to further contribute to China's energy security, said Ma.

However, given the great depth and complex crustal stress, it is difficult to explore and develop the shale in the area, Ma said.

Shale gas is mainly methane and is considered a clean new energy resource.