Natural gas hydrate, also known as combustible ice, is distributed in deep-sea sediments or terrestrial permafrost, and is an ice-like crystalline substance formed by natural gas and water at high pressure and low temperature. After combustion, only a small amount of carbon dioxide and water will be produced. The pollution is much smaller than coal, oil and natural gas, but the energy is ten times higher than coal, oil and natural gas. Moreover, there are huge reserves of combustible ice. It is estimated that the total amount of organic carbon contained in natural gas hydrate is equivalent to twice the total amount of coal, oil and natural gas known in the world, and it is an internationally recognized alternative energy source for oil and natural gas.
In 2004, with the support of Ministry of Science and Technology, Ministry of Land and Resources and China Geological Survey, Jilin University carried out the research and development of onshore gas hydrate drilling and production project. In the case of international technology monopoly and lack of reference materials, Sun Youhong, vice president of Jilin University, independently developed and assembled more than 30 researchers in geology, geological engineering, heat, bionics, chemistry and materials science, and formed the "national team" for combustible ice drilling and production.
After 10 years of technical research, the scientific research team has overcome many technical problems such as construction in high altitude and severe cold areas, and successfully developed the first key technology of hydrate cold drilling and thermal recovery with independent intellectual property rights at home and abroad. Different from the international common drilling principle of "passive pressure-keeping and thermal insulation sampling", the new technology put forward the principle of "active cooling and freezing sampling" for the first time, and invented the enhanced refrigeration method of drilling mud, the rapid freezing sampling method at the bottom of hydrate hole and the high-temperature pulse thermal huff and puff mining technology. The main technical indicators exceed similar foreign technologies.
In Muli Basin, Qinghai Province at an altitude of 4,000 meters, the scientific research team used this technology for the first time to drill a physical sample of terrestrial natural gas hydrate in China, successfully realized the trial production of terrestrial natural gas hydrate, broke the monopoly of foreign hydrate drilling and production technology, and filled the technical gap of terrestrial natural gas hydrate drilling and production in China.