利用超临界CO_2解除地层石蜡堵塞实验研究

Experimental study on removing formation paraffin deposits using super-critical carbon dioxide

采用室内模拟实验装置研究超临界CO_2解除地层石蜡堵塞的可行性,并分析超临界CO_2解堵石蜡的作用机制及驱替参数对解堵效果的影响规律。结果表明:超临界态CO_2对石蜡具有溶胀和冲刷双重作用,其解堵效果远好于气态和液态CO_2;随着驱替时间延长,解堵效果逐渐变好,超过一定时间后,岩心渗透率不再增加;解堵效果随着温度和驱替速度的增大而变好;随着压力的升高,解堵效果先增强后减弱,存在一个最佳解堵压力。

The feasibility of removing formation paraffin deposits by super-critical carbon dioxide was studied through indoor simulation test apparatus. The mechanism of super-critical carbon dioxide removing paraffin deposits and the influence of flooding parameters were analyzed. Experimental results show that the plug removing performance of super-critical carbon dioxide is much better than gaseous and liquid carbon dioxide due to the combined effects of swelling and flooding of super-critical carbon dioxide on the paraffin. The plug removal effect becomes better with the displacement time increase. And the permeability of cores would not increase after several hours. The plug removing effect becomes better as the temperature and flow rate increases. As the flooding pressure rises, the plug removing effect increases firstly then decreases and there is an opti- mum pressure for removing paraffin plugging by super-critical carbon dioxide.