The Experimental Research On Drilling Fluids System Used In The Gas Hydrate Bearing Formations

Natural gas hydrate is ice-like crystal compound formed by water and natural gas molecules under certain temperature and pressure. Since methane is the chief constituent of natural gas, it is also called methane hydrate. The natural gas hydrate exists mainly beneath the ocean floor or permafrost regions on continental shelves.With the rapid development of economy, China consumes more and more energy resource, the major constituent of which is coal. This will lead to severe pollution. We should make efforts to develop new type of alternative energy resources to keep sustaining development of energy. Natural gas hydrate is considered to be the potential new energy resource in the 21^st century. The energy contains in methane provided by natural gas hydrate is twice as much as all other fossil fuels. According to previous exploration data, it is estimated that the amount of natural gas hydrate in South China Sea may add up to 70 billion ton. So the natural gas hydrate has significant strategic importance on solving the crisis of energy resource shortage, and ensuring the security of national energy strategy.Natural gas hydrate formed within the pipeline could cause the blockage of the production equipment and the pipeline of oil and gas, thus do harm to the drilling operation. Furthermore, the decomposition caused by the change of the condition that gas hydrate exists stable may results in geological hazard. Because methane is a gas of very strong greenhouse effect, the methane released by the decomposition of natural gas hydrate may play a great role on global climate change. At present, the natural gas hydrate has drawn more and more attention around the world. Recently the ICGH 5 (the fifth international conference on gas hydrates) held in Norway, the topic of which includes: (1) kinetics and transport phenomena; (2) structure and physical properties; (3) exploration, resources and environment; (4) industrial applications: current and future technology and (5) thermodynamics aspects.In the 21^st century , the exploration of natural gas hydrate has become the focus of global competition. To some extent the exploration is a reflection of national power and potential of sustainable development. The properties and the specialties of its strata decide that there will be more complicated problems while drilling in the gas hydrate strata than in conventional oil gas...