Abstract: The experiments on microscopic displacement of weak gel (WG) flowing in porous media were carried out with the transparent single-layer sand-packing model. The distribution of multiple fluids during WG treatment and post-water flooding processes was investigated. The experimental results of the microscopic displacement indicate that WG flows preferentially through the larger channels occupied previously by injected water in WG injection process. In the post-water flooding process, WG in the larger channels diverts the injected water entering the smaller pores and displacing residual oil to form oil bank in the front of the displacing water. The diverting effect of WG in pores can improve the microscopic swept efficiency and oil recovery. The visco-elastic effect of WG can promote injected water entering in-depth reservoirs.

Key words: weak gel, porous media, enhanced oil recovery, microscopic displacement experiment, sand-packing model, displacement mechanism

摘要： 利用室内微观驱替实验装置,采用透明的单层油砂充填模型研究了弱凝胶驱和后续水驱过程中不同时刻各相流体在多孔介质中的分布。微观驱替实验结果表明,弱凝胶沿原先被水占据的大孔道流动,并且可以通过变形被挤入窄小孔喉,在弱凝胶的前沿存在稳定的水胶界面。在后续注水过程中,存在于大孔道的弱凝胶迫使后续注入水改向进入未被注入水波及的小孔隙,驱替的残余油滴聚集并形成油墙。弱凝胶的流体改向作用是提高微观波及效率和采收率的主要因素;弱凝胶的粘弹作用有利于在油藏深部进行深度调剖。

关键词: 弱凝胶, 多孔介质, 提高采收率, 微观驱替实验, 填砂模型, 驱油机理