BEIJING - Royal Dutch Shell is aiming to spend $1 billion a year over the next five years on shale gas in China if exploration works under way prove a success, Chief Executive Peter Voser told Reuters on Sunday.

Shell is drilling 17 wells in China, including those for tight gas and shale gas, in regions such as Sichuan, China's most prolific gas province.

Inspired by the massive success of unconventional gas - coalseam methane, tight gas and shale gas - in the United States, China has over the past year embarked on an exploration campaign for shale gas, part of Beijing's goal to boost use of cleaner-burning fuel and cut coal.