Natural gas hydrate is one of the most important potential energy sources

at the same time which is the triggering factor of global climate change and geologic hazards. The phase equilibrium of hydrates bearing sediments (HBS) is a basic issue for resources evaluation

exploitation and effection on environments. There is larger differece on association and dissociation of gas hydrate in pure water and sediments. By summarizing the research information both indoor and outdoor and based on the inverstigation needs of geotachnic engineering in the exploration and utilization of natural gas hydrates

the state of art on the effection of HBS formation mode

character of sediments

salinity of pore water and components of gases on the phase equilibrium of HBS

some techniques and methods for making samples

determination of composition content and the theoretical model is presented. Results show that formation mode

property of sediments

salinity of pore water and component of gases effect on phase equilibrium remarkably. There is poor precision in quantitative analysis or expensive costs in the numerous advanced methods and equips used in experiments and tests about HBS. The micro-theoretic models of phase equilibrium of HBS could model the phase equilibrium very well; however

complexity in expression and acquire hardly is the limitation of its application about geotechnical engineering problem in the exploitation of hydrate.