China’s onshore supermajor PetroChina has made a potentially massive shale oil discovery at the Gulong prospect in the area of the mature Daqing oilfield in northern China’s Songliao basin, with reserves said to be exceeding 1 billion tonnes.

In an area covering 1413 square kilometres, PetroChina said it had detected 1.268 billion tonnes of oil in place (9.3 billion barrels), describing the Gulong find as fitting the bill for replenishing production at Daqing.