碱在多孔介质中传输机理

Alkali transfer mechanism in porous media

运用数值模拟的方法对碱在多孔介质中的传输机理进行了研究。研究结果表明,数值解与实验值有良好的一致性;综合吸附作用使得碱运移存在着严重的滞后现象,使得碱在多孔介质中段塞浓度下降,削弱了化学剂的驱油效率,影响其在多孔介质中的波及体积;综合扩散作用不仅使碱迅速的扩散到岩心中更大范围,扩大了波及体积,而且扩散作用使得碱的有效浓度降低,以及在岩心出口过早的排出,使得碱驱替的有效期变短,降低了驱油效率,为了保持段塞浓度,势必要增加段塞尺寸,这就要提高经济成本;段塞尺寸过小可能在岩心中完全形成无效驱替带,因此应该结合实际情况来考虑段塞尺寸。

Using numerical simulation the alkali transfer mechanism in porous media has been studied. The results show that the numerical solution is well consistent with the experimental data; integrated chemical adsorption makes alkali migration lag seriously and causes alkali concentration in porous media slug to decline, which weakens the efficiency of oil displacement and affects swept volume in porous media; integrated diffusion not only does make alkali quickly spread to the rock cores in a greater scope and expand the size of swept volume, but also does make alkali effective concentration decrease as well as be discharged too early at outlet, making valid period of alkali displacement shorter and reducing the efficiency of oil displacement. In order to maintain the slug concentration, the slug is bound to increase in size, which increases economic costs; too small slug size may cause invalid displacing area in cores. Therefore, it should be considered that slug size is based on actual circumstance.