HONG KONG, Aug 27 - PetroChina Co Ltd, Asia’s top oil and gas producer, posted a 34.5 per cent fall in first-half earnings after refining losses and windfall taxes dented gains from soaring crude prices.

The largest of China’s energy triumvirate, which includes top Asian oil refiner Sinopec Corp and offshore specialist Cnooc Ltd, said its first-half net profit came to 53.62bn yuan (US$7.83bn) versus 81.83bn yuan a year earlier.