"The petroleum drilling and exploration operation of Zhongjiannan Project was smoothly completed on schedule on July 15th with the oil and gas shows found," the company said in a statement.
CNPC dispatched a drilling rig to an offshore area claimed by both the Chinese and Vietnamese governments.
Both sides met last month in Hanoi to discuss the situation, though each side blamed the other for the lingering tensions. Vietnam says its vessels in the region were harassed by Chinese patrol ships, though Beijing said Vietnam was painting itself as the victim in the dispute.
CNPC said it's been conducting seismic surveys in the region to get a better understanding of the reserve potential there since 2004.
"In accordance with the work procedures of deep-sea petroleum exploration and development, a comprehensive assessment of hydrocarbon horizons is to be implemented based on the geological and analytical data collected through the drilling and exploration operation," the company said. "Next phase arrangements are subject to the aforesaid comprehensive assessment."
For the sake of regional peace, Vietnamese Foreign Ministry spokesman Le Hai Binh called on China to avoid sending any rigs back to the contested waters.