【英文摘要】When drilling through gas hydrate bearing formations, the energy supplied by virtue of the drilling process may lead to a destabilization of the hydrates surrounding the well bore. Therefore, as the number of oil and gas fields being development in deepwater and onshore arctic environments increases, greater emphasis should be placed on quantifying the risks, gas hydrates pose to drilling operations. Dissociation of gas hydrates will affect the globe climate and environment of ocean. So the drilling fluid can control the dissociation of gas hydrate while drilling.On the basis of researching cooperatively with German experts, we used the experimental system of simulating drilling in the gas hydrate formation testing the rates of formation and dissociation of gas hydrates in the laboratory. The results showed that the effect of drilling fluids is playing an importance role in methane hydrates drilling,the author selected the drilling fluids system which is favorable for wellbore stable and well security, and established an experimental foundation of design theory of drilling fluids system when drilling in the gas hydrate strata. which can inhibit the formation dissociation at higher temperature and pressure.We have obtained a series of fruits by performing this project. We won One Hubei Province third prize of scientific and technological progress. One national patent for invention is on publishing. 15 pieces of papers were published openly in academic periodicals (2 of which were embodied by Engineering Index) and 5 papers were presented in international conferences. On the research of this project, one person 1 get doctors degree and are bringing up 2 postdoctoral, 1 doctors and 3 masters now.The research findings of this project can offer basic theories and references for the designing and performing of drilling control, well production equipments, and whole technology system for drilling and recovery, near-situ sampling devices, etc., and moreover, they build the basis for deeper studying correlatively in future.