天然气水合物热分解引起多场响应的特征时间分析

THE CHARACTERISTIC TIMES OF MULTI-FIELD DURING GAS HYDRATE THERMAL INDUCED DISSOCIATION IN STRATUM

  • 摘要: 天然气水合物是我国的战略能源,而要实现商业化开采,必须首先回答如何避免引发地质灾害与环境问题。开采过程涉及传热、水合物相变、渗流、地层软化与应力重分布的多场响应,进而可能引起地层破坏,甚至大尺度塌陷、滑坡、甲烷喷发泄漏等灾害。本文针对天然气水合物热分解引起多场响应的问题,通过量纲分析得到传热、水合物相变、渗流、地层应力重分布的特征时间,进一步比较分析发现,它们的时间尺度之间相差2个数量级以上,从而提出解耦分析方法,该方法已在系列模型实验设计与理论分析中得到应用。

     

    Abstract: Gas hydrate is a new kind of strategic energy resource. The potential geological hazards and environmental damages due to the commercial production should be predicted and taken effective precautions. The production practice of gas hydrate will lead to evolution of multi-physical processes, i.e. the heat conduction, gas hydrate dissociation and phase transformation around the well, accompanied by multiphase seepage, softening and deformation of the stratum. Soil failures such as large-scale settlement, marine slide and gas outburst could occur because the build-up of excess pore pressure after the dissociation-induced release of gas and water in the porous media. The characteristic time of each physical process is reached in this paper, and it is found that the times differ in two orders of magnitude, hence, the decoupling method is used effectively in the previous investigation.

     

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