HONG KONG, March 25 – PetroChina, Asia’s top oil and gas producer, posted a 39 per cent drop in fourth-quarter net profit, hit by asset writedowns amid a sharp drop in crude oil prices.

PetroChina, the world’s second-largest oil company by market value after Exxon Mobil, said October-December net profit fell to 20.9bn yuan ($3bn) from a restated 34.25bn yuan a year earlier.