China announced a discovery of 427 million metric tons of oil reserve in the Sanmenxia Basin, setting an example for the oil and gas exploration of small and medium-sized basins nationwide, China Geological Survey said on Wednesday.

In 2024, the CGS identified the Sanmenxia Basin as a key breakthrough area for small and medium-sized basins and conducted exploration. This resulted in a major discovery, achieving a maximum daily industrial oil output of 15.83 cubic meters, marking the first significant oil and gas breakthrough in the region, according to the CGS.

Following this success, the CGS, together with Henan government and relevant enterprises, continued to drill two additional wells, which produced maximum daily industrial oil flows of 15.5 and 92.52 cubic meters, respectively, confirming the basin's promising oil and gas exploration prospects and bolstering confidence in future exploration, the CGS said.

Located in the western part of Henan province and the northwestern part of the Southern North China Basin, the Sanmenxia Basin is a typical small and medium-sized basin, covering an area of 4,550 square kilometers.

China now has 356 small and medium-sized basins, but as of 2020, resource evaluations had been conducted for only 89 of these basins, the CGS said.

The breakthroughs in the Sanmenxia Basin indicate significant resource potential in the remaining 267 unevaluated basins, which may boost future reserves and enhance China's oil and gas security, the CGS added.