Difficulties and countermeasures of gas hydrates coring drilling of marine deep water

　In this paper, the nature, formation, stable conditions, distribution, and new trends of investigation both at home and abroad of gas hydrates are briefly introduced. The difficulties in gas hydrates coring drilling are discussed, and the countermeasures are put forward. Furthermore, the ideas of carrying out gas hydrates coring drilling in China are proposed. All these may help the research on related technologies in the country.