Energy conglomerate Royal Dutch Shell Plc is committing to a "substantial investment" in exploring for conventional and unconventional gas in China to quench the growing thirst for clean energy in the world's second-largest economy.

The company will continue its exploration of shale gas in the Sichuan Basin, where it landed the first contract with State-owned oil giant China National Petroleum Corp, Huibert Vigeveno, executive chairman of Shell in China, said on Tuesday.

"We are now in the exploration phase by drilling various wells and testing underground pressure in these areas. Some parts of the projects have moved into the appraisal stage, and it will take time before we determine our next step," he told China Daily in Shanghai.