热盐水分解甲烷水合物实验研究

An experimental study on dissociation behavior of methane hydrate under hot brine stimulation

利用一维开采模拟系统,注入NaCl水溶液,进行甲烷水合物分解过程和开采模拟研究。结果表明在NaCl水溶液的作用下,甲烷水合物降温吸热分解。气体产出过程可以分为自由气产出阶段,水合物分解阶段以及水合物分解结束后常规气藏的气体产生阶段,而NaCl的加入可以提高水合物分解阶段的产气速率。在自由气产出期间基本没有水产出,在水合物分解期间,产水速率稍高于注水速率,水合物分解结束后,产水速率等于注水速率。

The dissociation behavior of methane hydrates in a one-dimensional experimental apparatus under the hot brine （NaCl solution） stimulation is studied. The results show that with the injection of NaCl solution methane hydrate dissociation is accompanied with the temperature decreasing and endothermal changes. In addition, the characteristics of the dissociated gas and water from methane hydrates in the porous sediment under the hot brine stimulation are investigated. The experimental result illustrates that the gas production process is generally divided into the following three stages： free gas production, hydrate dissociation and general gas production for reservoir after hydrate dissociation. The dissociation rate of hydrates can be enhanced by NaCl added. In the stage of free gas production there is little water production. In the stage of hydrate dissociation, the rate of water production is slightly higher than that of water injection. In the final stage, the dissociation of hydrate is completed, and the rate of water production equals that of water injection.