摘要
向水合物储层注入盐类溶液是水合物常规开采技术之一,所以必须掌握储层压力条件下盐类溶液中水合物分解条件及其影响因素.本文研究了NaCl、MgCl2、CaCl2氯盐溶液中甲烷水合物分解条件,结果表明NaCl(2.0、1.0、0.5mo·lL-1)、MgCl2(1.0、0.5mo·lL-1)和CaCl2(1.0、0.5mo·lL-1)溶液中甲烷水合物的分解温度比纯水中分别降低了(4.8、2.4、1.0K(NaCl))、(5.3、1.5K(MgCl2))和(4.3、1.8K(CaCl2)).以vanderWaals和Platteeuw热力学模型为基础,结合电解质溶液中水的活度方程(Pitzer-Mayorga方程),给出了氯盐溶液中水合物分解条件热力学模型,进而比较了模型计算值与实验值,结果显示两者非常吻合.分析表明,氯盐溶液中离子静电作用产生的水分子溶剂化效应和盐析效应降低了水的活度而导致水合物分解温度降低.
A method that can be used for gas hydrate exploitation is the injection of a brine solution into hydrate reservoir, therefore, the hydrate dissociation conditions and the influencing factors in brine solution should be investigated under reservoir pressure. In this paper, methane hydrate dissociation conditions in NaCl, MgCl2, and CaCI2 solutions were investigated. The results show that the dissociation temperature depressions are （4.8, 2.4, 1.0 K （NaCI））, （5.3, 1.5 K （MgCI2））, （4.3, 1.8 K （CaCI2）） in NaCI （2.0, 1.0, 0.5 mol. L-l）, MgCI2 （1.0, 0.5 tool. L-I）, and CaCI2 （1.0, 0.5 mol. L-1） solutions, respectively, relative to those in pure water. The experimental values were in good agreement with the calculated values based on the van der Waals and Platteeuw thermodynamic model and the Pitzer-Mayorga equation for the water activity of electrolyte solution. In chloride salt solution the water molecule solvent effect and the salting-out effect that is caused by an electrostatic field decreases the water activity resulting in a depression of the hydrate dissociation temperature.
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
2011年第12期2773-2778,共6页
Acta Physico-Chimica Sinica
基金
国土资源部公益性行业科研专项经费(201111026-3)
国家重点基础研究发展规划(973)(2009CB219503)
山东省自然科学基金(ZR2009FQ017)资助项目~~
关键词
甲烷水合物
氯盐溶液
分解条件
盐析效应
水的活度
Methane hydrate
Chloride salt solution
Dissociation condition
Salting-out effect
Water activity
