China has officially confirmed a massive ultra-deep shale gas field containing more than 235 billion cubic meters of reserves in Ziyang City, southwest China's Sichuan Province, representing a major leap in the country's shale gas exploration from deep to ultra-deep formations.

China's energy giant Sinopec announced on Wednesday that its Ziyang Dongfeng shale gas field has received official certification from the Ministry of Natural Resources. The field holds proven geological reserves of 235.687 billion cubic meters. The discovery extends China's shale gas exploration and development into layers exceeding 4,500 meters, marking the country's first ultra-deep shale gas field of this scale.

The Dongfeng shale gas field lies in the Sichuan Basin. In 2024, exploration of the Ziyang-2 well recorded a daily industrial gas flow of 1.257 million cubic meters, representing a breakthrough in exploration of Cambrian Qiongzhusi Formation – the Earth's oldest commercial shale layer that dates back 540 million years. Following the success, technical teams intensified exploration and evaluation, steadily increasing test production and ultimately discovering a large, contiguous gas field at depths of 4,500 to 5,200 meters.

The field poses extreme engineering challenges due to its thick, hard-to-drill strata and extreme high-temperature, high-pressure underground conditions. Researchers have overcome these difficulties by innovating geological theories and developing a series of core technologies. For the first time, they systematically clarified the accumulation pattern in the Cambrian Qiongzhusi Formation, laying a strategic foundation for future shale gas exploration in China.

Large potential in shale gas exploration

In recent years, advances in oil and gas exploration technologies have positioned shale gas as a critical area for China's sustainable production growth. Rich in resources, China's shale gas formations are geologically complex, making exploration and development challenging.

China's commercial shale gas development began with the discovery of the Fuling shale gas field in 2012, making the country the third nation after the US and Canada to achieve commercial shale gas development. In 2017, Fuling became China's first shale gas field with a production capacity exceeding 10 billion cubic meters. Subsequent discoveries, including the Weirong, Qijiang, Yongchuan and Hongxing fields, expanded China's deep and ultra-deep shale gas reserves. In 2018, Weirong was recognized as China's first deep shale gas field exceeding 100 billion cubic meters, followed by Yongchuan and Hongxing in 2025.

So far, China's proven shale gas reserves have exceeded 4 trillion cubic meters, with annual production surpassing 27 billion cubic meters, accounting for over 8% of the nation's total natural gas output. By 2030, shale gas production is expected to exceed 50 billion cubic meters annually, accounting for about 15% of China's total natural gas supply.