| Summary: | 碩士 === 國立成功大學 === 資源工程學系 === 106 === Gas hydrates are solid components in which gas molecules are trapped by water molecules. Gas hydrates are found in the geological environments with high-pressure and low-temperature conditions, and therefore large amounts of hydrate resources exist in the permafrost region and deep ocean sediments. Most geological explorations that have been conducted have noted that there are hydrate resources lying under the ocean sediments in the offshore area of southwestern Taiwan. Most of the prospective geological sites are considered to be Class-3 hydrate deposits. According to the trial gas production tests from other hydrate reservoirs, formation sanding is a critical issue during gas production from hydrates. Therefore, the purpose of this study is to construct a simulation model to simulate the formation sanding phenomenon that occurs during hydrate depressurization by using the CMG STARS simulator. In this study, the sand production module was controlled by the sand production reaction and the mobility of the components. The results of the depressurization model with the inclusion of the sand production module showed that the production behavior was slightly influenced by the formation sanding. As for the results of the sensitivity analysis, lowering the depressurization rate allowed for the mitigation of the formation sanding. The portion of producible sand reflects the degree of the formation that can withstand the shear effect, such that a smaller amount of producible sand indicates that the formation can better withstand the shear effects and produce less sand.
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