Experimental and Numerical Observations of Hydrate Reformation during Depressurization in a Core-Scale Reactor
Experimental and Numerical Observations of Hydrate Reformation during Depressurization in a Core-Scale Reactor
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DOI：
10.1021/ef1014567
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发表时间：
2011
期刊：
影响因子：
5.3
通讯作者：
Y. Seol;E. Myshakin
中科院分区：
文献类型：
--
作者：
Y. Seol;E. Myshakin
据预测，在含天然气水合物储层的降压产气过程中，天然气水合物会在井筒周围形成。这一过程对产气速度有不利影响，需要时间，有时还需要采取特殊措施来恢复生产井的气流。由于缺乏适用的现场数据，实验室规模的实验仍然是研究水合物重整的宝贵信息来源。在这项工作中，我们报告了实验室实验和互补的数值模拟，以研究水合物重组现象。在有热流通过边界和无热流通过边界的情况下进行减压，可以诱导含水砂土压力容器的产气。利用医用x射线CT扫描仪和压力和温度测量监测水合物分解。对含水试样的CT图像进行处理，得到适合数值模拟的非均质孔隙度和相饱和度的三维数据。在实验中，只有在没有外界热源的情况下才观察到天然气水合物的重整，这与数值模拟结果一致。通过允许岩心两侧产气，数值模拟表明初始水合物分布模式会影响样品内的气体分布和流动。这是不均匀孔隙网络导致含水沉积物水力特性变化的直接结果。«少
Gas hydrate has been predicted to reform around a wellbore during depressurization-based gas production from gas hydrate-bearing reservoirs. This process has an adverse effect on gas production rates and it requires time and sometimes special measures to resume gas flow to producing wells. Due to lack of applicable field data, laboratory scale experiments remain a valuable source of information to study hydrate reformation. In this work, we report laboratory experiments and complementary numerical simulations executed to investigate the hydrate reformation phenomenon. Gas production from a pressure vessel filled with hydrate-bearing sand was induced by depressurization with and without heat flux through the boundaries. Hydrate decomposition was monitored with a medical X-ray CT scanner and pressure and temperature measurements. CT images of the hydrate-bearing sample were processed to provide 3-dimensional data of heterogeneous porosity and phase saturations suitable for numerical simulations. In the experiments, gas hydrate reformation was observed only in the case of no-heat supply from surroundings, a finding consistent with numerical simulation. By allowing gas production on either side of the core, numerical simulations showed that initial hydrate distribution patterns affect gas distribution and flow inside the sample. This is a direct consequence of the heterogeneous pore network resultingmore » in varying hydraulic properties of the hydrate-bearing sediment.« less