Abstract: Artificial water curtain is the key technology of unlined underground oil and gas storage cavern. China’s first large-scale groundwater-sealed cavern with a total capacity of 3 million m³ and 9 chambers of 20m×20m×(484-717)m was built. Hence China’s “national strategic underground storage of petroleum” was materialized. In the present paper, the principle of artificial water curtain, the key technologies of specific implementation, and the water seal effect are presented. Theoretical analysis and actual practice show that it’s feasible to build crude oil storage cavern in granitic gneiss with average annual precipitation of 736mm. Technologies of constructing the first large underground oil storage cavern is of guiding importance for subsequent caverns.

Key words: groundwater-sealed, large-scale cavern, artificial water curtain, key technology, water seal effect