China Petroleum and Chemical Corp, or Sinopec, has announced the discovery of a proven geological reserve totaling 235.69 billion cubic meters at the Ziyang Dongfeng shale gas field in the Sichuan Basin, marking the birth of China's first ultra-deep shale gas field of this scale.

The breakthrough pushes the country's shale gas exploration past the 4,500-meter depth mark, realizing a strategic leap from "deep" to "ultra-deep" extraction, the State-owned energy giant said.

Certified by the Ministry of Natural Resources, the gas reservoir is buried between 4,500 and 5,200 meters underground. Formed over 540 million years ago, it is the world's oldest commercially discovered shale layer.

Extracting gas from such depths is widely recognized as a world-class engineering challenge due to complex geological mechanics, extreme high-temperatures and high-pressure conditions.

After more than a decade of dedicated research, Sinopec has successfully established a replicable technological path to overcome these hurdles. The company stated that the discovery will significantly expand China's strategic energy reserve growth and play a crucial role in safeguarding national energy security.

Since the discovery of the Fuling field in 2012, China has become the third country in the world to achieve commercial shale gas development, following the United States and Canada. As the Ziyang Dongfeng field enters the ultra-deep era, the nation's shale gas industry is accelerating its high-quality push deep underground.