天然气水合物注热水开采热前缘移动规律实验研究

摘要

注热水开采是天然气水合物的有效开采方式之一，其中热前缘的移动决定了分解速率的大小，是决定注热水开采效果好坏的重要参数。采用自制的一维天然气水合物开采模拟实验装置，首先在填砂模型中生成水合物，然后对不同条件的水合物进行注热水开采实验，分析热前缘移动规律。结果表明：水合物饱和度越大，热前缘移动速率越小；随着初始温度的增加，热前缘移动速率略有增加；注热水温度越高，注热水速度越大，热前缘移动速率越大。水合物饱和度和注热水速度对热前缘移动速率的影响最大，注热水温度次之，而初始温度对热前缘影响较小。为了提高开采速度，建议在技术可行的情况下适当增加注热水速度，同时适当降低注热水温度，虽然开采速度略有降低，但开采经济可行性会增加。%Injecting hot water is one of the effective ways to dissociate natural gas hydrate (NGH),and the movement of thermal front determines the dissociation rate of hydrate,which is a key parameter for thermal stim-ulation.A one-dimensional experimental system is designed to form NGH with different initial conditions in sand-packed tube,and then hot water with different thermal parameters was injected to analyze the movement of thermal front.Results show that the higher the NGH saturation is,the less the thermal front movement rate is;the thermal front movement rate increases slightly with the initial temperature increasing;the thermal front movement rate is larger with higher hot-water temperature and larger hot-water injection rate.Among the four parameters,i.e.NGH saturation,initial temperature,hot-water temperature and hot-water injection rate,the most sensitive parameters are the NGH saturation and hot-water injection rate,followed by the hot-water temper-ature,and the least sensitive parameter is initial temperature.In order to increase dissociation rate of hydrate,it is reasonable to increase the hot-water injection rate within the technical feasibility.Lowering the hot-water tem-perature can slightly decrease the dissociation rate of hydrate,while the economic feasibility will increase.