BEIJING -- China is estimated to have 80 billion tonnes of oil equivalent combustible ice, the Ministry of Land and Resources said Friday.

Li Jinfa, deputy director of the China Geological Survey under the ministry, made the statement at a press conference on China's first success in mining combustible ice at sea.

China announced its success on May 18 in collecting samples of combustible ice in the South China Sea after nearly two decades of research and exploration, a major breakthrough that may lead to a global energy revolution.

Combustible ice usually exists in seabed or tundra areas, which have the strong pressure and low temperature necessary for its stability. It is flammable like solid ethanol.

One cubic meter of combustible ice, a natural gas hydrate, is equal to 164 cubic meters of regular natural gas. International scientific circles have predicted that the natural gas hydrate is the best replacement for oil and natural gas.

"So far, trial mining of combustible ice in the Shenhu sea, about 320 kilometers southeast of Zhuhai city in Guangdong, has made smooth progress with an average of 8,350 cubic meters of gas with high purity extracted each day," Li said.

He said China would accelerate the exploration of potential combustible ice reserves, launch trial mining of different types of combustible ice,and continue to strengthen marine science and technology innovation.

In addition, China will make environment protection a top priority during the trial mining and strive to achieve green exploration and exploitation, he said.

Natural gas hydrate is an efficient, abundant and clean energy and is also strategically important for future global energy development, the Communist Party of China Central Committee and the State Council said in a congratulatory letter last month.

The success marks a historic breakthrough after nearly two decades of continuous efforts and independent innovations by China in theory, technology, engineering and equipment for natural gas hydrate exploration and exploitation, according to the letter.

It is a great technological breakthrough in accessing the deep sea, deep-sea exploration and exploitation, said the letter.