PetroChina Co. Ltd. (NYSE: PTR) has conducted its first major internal transfer of mining rights between subsidiaries to allow those with mature fields to look for oil and gas in under-developed regions,  China’s National Petroleum Corp. (CNPC) said on Dec. 8.

A total of 16 E&P blocks have been transferred, including blocks in the basins of Ordos, Sichuan and Qaidam in the central and western parts of the country, CNPC said.

Recipients of transferred blocks include PetroChina units in Daqing, Liaohe, Huabei and Yumen, all of which operate ageing fields, mostly in the country’s east, with rapidly declining hydrocarbon reserves.

The transfer of the exploration rights is part of broader sector reform driven by the government has spearheaded to solve the problem of resource imbalances, CNPC said.