基于磁悬浮天平的超临界CO_2-癸烷溶液密度特性研究

Study of density properties of supercritical CO_2-decane solution using magnetic suspension balance

超临界CO2溶解原油的能力主要取决于超临界流体的密度.基于高精度磁悬浮天平实验系统,利用癸烷模拟原油,系统测量了不同温度(313～353K)和压力(12～18MPa)下,不同CO2质量分数(0、8%、20%、43%、67%)CO2-癸烷溶液的密度,并分析了各参数对CO2-癸烷溶液密度的影响.研究发现在CO2质量分数一定的情况下,CO2-癸烷溶液密度随着压力的增加而增加,随温度的升高而降低.CO2溶解质量分数对溶液的性质有显著影响,CO2的注入量对驱油存在一个有效的区间,可以根据井下温度、压力来决定注入量,从而达到最佳的驱油效果.

The capacity of supercritical carbon dioxide （sc-CO2） to dissolve crude-oil is mainly determined by the density of supercritical fluid. Using decane instead of crude-oil, magnetic suspension balance （MSB） is applied to the measurement of CO2-decane solution density of different CO2 mass fractions （0, 8%, 20%, 43%, 67%） at different temperatures （313-353 K） and pressures （12-18 MPa）. And the effects of the three parameters on CO2-decane solution density are analyzed. The experimental results show that the CO2-decane solution density increases with the pressure increasing and decreases with the temperature increasing at the certain CO2 mass fraction. The CO2 mass fraction plays a decisive role in CO2-decane solution properties. During CO2 flooding processes, CO2 injection rate has a relative effective region. In addition,the optimal region of CO2 injection rate is determined by the reservoir temperature and pressure.