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目前有关天然气水合物(以下简称水合物)的研究主要集中在物理化学性质考察和开采(分解)方法探索方面。在进行后者的研究过程中,地层渗流过程的物理模拟至关重要,但目前借助于石油开采研究中广泛应用的填砂管等多孔介质对水合物进行动态过程的研究却鲜有报道。为此,利用河砂填砂管在岩心驱替装置上进行了甲烷水合物生成过程的物理模拟,考察了地层温度、甲烷压力及地层模型性质参数等对水合物生成过程的影响。结果表明:(1)利用冰融水作为地层模型的束缚水可显著提升甲烷水合物的生成速率;(2)多孔介质条件下过程驱动力(即实验压力或温度偏离水合物相平衡对应值的程度)对甲烷水合物的生成起着决定性作用;(3)当甲烷压力高于水合物相平衡压力1.4倍以上,或者实验温度低于相平衡温度3℃以下时,甲烷水合物生成诱导期几乎不随温压条件的变化而变化;(4)渗透率、含水饱和度、润湿性等参数对实验中甲烷水合物的生成率不构成明显影响。
At present, the research on natural gas hydrate (hereinafter referred to as hydrate) mainly focuses on the exploration of physical and chemical properties and exploration (decomposition) methods. In the process of the latter study, the physical simulation of formation seepage process is very important. However, little research has been reported on the dynamic process of hydrate by means of porous media such as sand filled pipe which is widely used in petroleum exploration. Therefore, the physical simulation of methane hydrate formation was carried out on the core flooding device by means of river sand filling tube. The effects of formation temperature, methane pressure and formation model parameters on the hydrate formation process were investigated. The results show that: (1) The irreducible water of ice formation can increase the rate of formation of methane hydrate significantly. (2) The process driving force under the condition of porous media (ie, the experimental pressure or temperature deviates from the corresponding value of hydrate phase equilibrium (3) When the methane pressure is higher than 1.4 times higher than the equilibrium pressure of the hydrate, or the experimental temperature is below the phase equilibrium temperature of 3 ° C, the induction period of methane hydrate is almost (4) permeability, water saturation, wettability and other parameters of the experiment methane hydrate formation rate does not constitute a significant impact.