刘乐乐, 李彦龙, 张旭辉, 等. 2021. 降压开采导致天然气水合物系统状态演化模拟实验[J].工程地质学报, 29(6): 1916-1925. doi: 10.13544/j.cnki.jeg.2021-0695.
    引用本文: 刘乐乐, 李彦龙, 张旭辉, 等. 2021. 降压开采导致天然气水合物系统状态演化模拟实验[J].工程地质学报, 29(6): 1916-1925. doi: 10.13544/j.cnki.jeg.2021-0695.
    Liu Lele, Li Yanlong, Zhang Xuhui, et al. 2021.Experimental study on gas hyirale system stale evolving dluring deyessuration[J]. Jourmal of Engineering Geology, 29(6): 1916-1925. doi: 10.13544/j.cnki.jeg.2021-0695.
    Citation: Liu Lele, Li Yanlong, Zhang Xuhui, et al. 2021.Experimental study on gas hyirale system stale evolving dluring deyessuration[J]. Jourmal of Engineering Geology, 29(6): 1916-1925. doi: 10.13544/j.cnki.jeg.2021-0695.

    降压开采导致天然气水合物系统状态演化模拟实验

    EXPERIMENTAL STUDY ON GAS HYDRATE SYSTEM STATE EVOLVING DURING DEPRESSURIZATION

    • 摘要: 天然气水合物是一种重要的潜在替代能源,降压法是现阶段水合物开采的首选方法。水合物降压开采涉及传热、多相渗流、分解相变和储层变形等多个相互影响的物理效应,深入理解其在降压开采过程中的演化规律,对于促进水合物开采效率、实现商业化开发具有重要的指导意义。本文基于一维实验模拟系统,开展了水合物降压开采储层多物理场演化模拟实验,在非均匀温度条件下采用过量气法合成水合物,分析了水合物非均匀性分布特征,探讨了降压过程中样品孔隙压力和温度的演化规律,对比了产气过程与传热演化过程的对应关系。结果表明:水合物合成后温度分布呈两侧高中间低的抛物线形状,水合物分布具有中间多而两侧无的非均匀性特征,且温度回升具有由两侧向中间发展的特点;降压分解产气过程与传热演化过程具有良好的对应性,稳态产气阶段由传热效应控制。控制降压模式、以对流换热替代热传导等方式有益于提升水合物开采产气效率。

       

      Abstract: Natural gas hydrate has been treated as a potential energy resource for decades. Depressurization is currently the most promising method for hydrate production. However, its efficiency is far from the commercial need. Hydrate production involves heat transfer, multi-phase seepage, phase transition, and reservoir deformation. A thorough understanding of how multiple physical processes evolve during depressurization is of great significance for efficiency enhancement of hydrate production. An experiment was carried out to simulate depressurization induced evolution of the multiple physical processes. Methane hydrate was formed by using the gas excess method under a heterogeneous temperature condition. Evolutions of pore pressures and temperatures were analyzed. A comparison between gas production process and heat transfer process was discussed. Main conclusions are drawn as follow: temperature distribution is parabola-like after hydrate formation, which has higher temperatures in two sides of the sample. In addition, hydrate distribution is inhomogeneous. Pore pressures decrease completely from the outlet to the inlet, and temperatures increase from the two sides into the middle part. The gas production process related to the heat transfer process well, and the stable stage for gas production is controlled by the heat transfer process. It is a feasible way to replace heat conduction by heat convection or choose a slow depressurization strategy to enhance production efficiency for the commercial need.

       

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