CNOOC said an underwater natural gas pipeline connected to the Zhuhai terminal near China's southern coast was restored recently after suffering damage from "external forces" in December 2011.
CNOOC said "severe weather conditions" at the source of the rupture complicated repair and restoration operations. The company said the pipeline underwent "intensive repairs" in January and was now back in service.
"The restoration team achieved zero failure rates through using innovative construction methods and strengthening quality control and lately completed the restoration work successfully," the company said Thursday.
CNOOC did not indicate the volume designated for the pipeline or its length.
China is looking to secure more natural gas resources to feed demands from a growing economy. It is among the largest importers of liquefied natural gas in the world and is expected to account for the largest share in the demand for global energy resources.
China is examining the prospects of exploiting shale natural gas deposits though those reserves are considered costly to exploit.