高压条件下CO_2滤失性测量装置设计及应用

Design and Application of Measuring System for CO_2 Filtration Performance under High Pressure

设计了CO_2滤失性测量装置,模拟高压条件下液态或超临界CO_2在裂缝中的流动以及CO_2通过裂缝壁面的滤失过程。滤失性测量装置包括气体加压与循环系统、动态滤失岩心夹持器、滤液采集与计量系统、温度控制系统。采用滤液采集高压容器、回压阀,通过计量水的体积代替计量高压CO_2的体积,实现了高压条件下CO_2滤失体积的计量,并计算得到滤失系数。结果表明,随着时间的增加,高压条件下CO_2的滤失速度逐渐增加并达到稳定状态;同时,随着温度的增加,CO_2滤失速度增加,滤失系数增大,测量结果可为CO_2干法压裂设计提供基础参数。

A measuring system was designed to test CO2 filtration performance under high pressure.The system can simulate the processes of flowing in fracture and filtration through fracture surface in CO2 fracturing,it includes gas compression and circulation system,core holder of dynamic filtration,filtrate gathering and measuring system,temperature control system.The filtrate is measured by means of water volume metering instead of high-pressure CO2 volume metering with filtrate gathering vessel and check valve.The filtration factor is calculated by the relationship curve of filtrate volume and time.The result shows,with time increase,the filtration rate increases at its initial stage,and then reaches a stable situation.And with temperature increase,the filtration rate and filtration factor increase.The results can provide basic parameter for CO2 fracturing.