Simulation And Application Of Micro - Elastic Properties Of Natural Gas Hydrate

Gas hydrates, ice-like compounds which can be directly ignited, typically form at ambient temperatures and moderate pressures and are mainly located in outer continental margin sediment and in polar regions commonly associated with permafrost. That carbonic clean energy are highly efficient,1m3of whichcan release approximately164mJ of methane gas. The total carbon of methane from gas hydrates within3000kilometers deep in sea are more than twice the total amount of traditional fossil fuels like coal, oil and gas, which demonstrates it is a rare strategic energy.For natural exploration and development of gas hydrate resources, drilling is the most direct and main technical means, and successful drilling natural gas hydrate is the key to the whole resource development. Therefore, the change of the mechanical properties of gas hydrates should be discussed and researched.Firstly, this paper discussed some basic properties and structural stability, including basicphysicalproperties, formation physical characteristics, chemical properties, molecular microstructures and crystal structures. And by setting the simulation, investigation on the response of hydrates molecular structures with the action of embedded molecularas well as electric field are finished based on first principles density functional theory.Secondly, van der Waals forces are the intermolecular interactions of gas hydrate which result in the weak interaction of molecule crystals. This article, therefore, utilizes several molecular crystal systems’(urea, ice and graphite) to calculate the optimum strains in order to find the right way to work out molecular crystals’elasticity according to CASTEP and analyzes the regularity of micro elastic properties along with pressure changes, so that the calculated elastic modulus of gas hydrate provide fundamental basis for pressure control in the process of drilling. Thirdly, the conditions of gas hydrate formation and accumulation mechanism are explored, and the reservoir and distribution characteristics are discussed. In the end, drilling progress, drilling parameters and drilling difficulties are introduced,the managed pressure drilling is reasonably raised according to the micro-mechanical properties and macro-forming conditionsmentioned before.and the stability control under complex conditions is analyzed.Combined with researches above, this paper can provide a clearer understanding of the basic properties, structures, formation and accumulation of gas hydrates. Not only the structural stability, performance of the applied electric field, pressure effection on elasticities of gas hydrate are obtained, but also the controlling of wellbore pressure is proposed, which provides theoretical guidance and help for high-efficientlyexploitgas hydrate.