页岩气压裂返排液浓缩结晶实验研究

Experimental Study on Concentrated Crystallization of Shale Gas Fracturing Flow Back Fluid

对四川长宁页岩气田压裂返排液进行水样分析,其具有含盐量高、成分复杂的特点。探究利用机械蒸汽再压缩技术处理压裂返排液,通过蒸发结晶分离水和盐。实验研究了两种压裂返排液的浓缩结晶特性:返排液介稳区宽度和过饱和度对浓缩结晶的影响。实验结果表明:返排液介稳区随温度升高而减小,但结晶速率随温度升高而增大。温度从60℃增加到80℃,结晶平均粒径增长了56%左右;返排液结晶的主要成分为氯化钠。

Water quality analysis of shale gas field fractured flow-back fluids in Changning of Sichuan showed that it had the characteristics of high salt content and complicated composition.The mechanical vapor recompression technology was explored to deal with fracturing flow-back fluid,then water and salts were separated by evaporation crystallization.The concentration and crystallization properties of two kinds of fracturing flow-back liquids were studied,including the meta-stable zone width and the influence of supersaturation on the concentration and crystallization.The experimental results showed that the meta-stable zone decreased with the increase of temperature,while the crystallization rate increased.The average particle size increased by about 56%,when the temperature from 60℃to 80℃.Besides,the main component of flow-back fluids crystallization was sodium chloride.