Due to the ever-increasing energy demand, the study of gas production from marine methane hydrate attracts intensive interest around the world. Vertical wells were adopted in most of the previous production tests, although horizontal well might be with significant advantage over vertical well in production performance. To evaluate the gas production performance from a high irreducible water saturated hydrate reservoir with free gas underlain using horizontal well, a multilayered hydrate reservoir model is established, of which all the sediment layers are with high saturation of irreducible water and a free gas layer occurs beneath the hydrate zone. Gas production performances on single horizontal well and two paralleled horizontal wells are investigated. The simulation results obtained show that gas production with horizontal well can yield a high gas production rate, especially at the early stage of production with the contribution of free gas. A horizontal well located at the bottom of the hydrate layer is recommended, because it can not only extract free gas in gas production but also induce more dissociation of hydrate. When two paralleled horizontal well-configuration is applied, the middle and bottom well pattern can generate a synergistic effect that accelerates hydrate dissociation and reduces water production. The sensitivity analyses of free gas saturation and irreducible water saturation show that either of the two factors can result in a high gas-to-water ratio.

由于能源需求不断增加，海洋甲烷水合物产气研究引起了全世界的广泛关注。尽管水平井在生产性能上可能比垂直井具有显着优势，但在之前的大部分生产测试中都采用了直井。为评价水平井下含游离气的高束缚水饱和水合物储层的产气动态，建立多层水合物储层模型，其中所有沉积层均具有高束缚水饱和度，下方存在游离气层。水合物区。考察了单口水平井和两口平行水平井的产气动态。模拟结果表明，水平井采气具有较高的产气率，尤其是在生产初期，有游离气的贡献。建议在水合物层底部设置水平井，因为它不仅可以提取天然气生产中的游离气，还可以引起更多的水合物离解。当采用两个平行水平井配置时，中底井网可以产生协同效应，加速水合物分解并减少产水。游离气饱和度和束缚水饱和度的敏感性分析表明，这两个因素中的任何一个都会导致高气水比。建议在水合物层底部设置水平井，因为它不仅可以提取天然气生产中的游离气，还可以引起更多的水合物离解。当采用两个平行水平井配置时，中底井网可以产生协同效应，加速水合物分解并减少产水。游离气饱和度和束缚水饱和度的敏感性分析表明，这两个因素中的任何一个都会导致高气水比。建议在水合物层底部设置水平井，因为它不仅可以提取天然气生产中的游离气，还可以引起更多的水合物离解。当采用两个平行水平井配置时，中底井网可以产生协同效应，加速水合物分解并减少产水。游离气饱和度和束缚水饱和度的敏感性分析表明，这两个因素中的任何一个都会导致高气水比。中底井网可产生协同效应，加速水合物分解，减少产水量。游离气饱和度和束缚水饱和度的敏感性分析表明，这两个因素中的任何一个都会导致高气水比。中底井网可产生协同效应，加速水合物分解，减少产水量。游离气饱和度和束缚水饱和度的敏感性分析表明，这两个因素中的任何一个都会导致高气水比。