Australia-based Roc Oil has made what it describes as a major breakthrough in exploration at Block 03/33 in the Pearl River Mouth basin of the South China Sea, leading to a significant hydrocarbon find and the first commercial discovery in this part of the sea.

Roc said its latest Chinese wildcat encountered 50 metres of vertical pay when drilled to the Paleogene target horizon in early September.

The well that was drilled by semi-submersible drilling rig Nanhai 6 flowed more than 1000 barrels per day of oil during drill stem testing earlier this month.