剪切与吸附对弱凝胶深部调驱作用的影响

Effects of shear and absorption on in-depth profile control and oil displacement of weak gels

分别用玻璃微珠、石英砂、露头砂制作填砂模型,研究了弱凝胶体系的动态性能变化以及剪切与吸附对其深部调驱作用的影响。研究结果表明,动态条件下弱凝胶体系在3种介质中均可发生交联反应,其封堵能力、有效作用距离、深部调驱作用在玻璃模型、石英模型、露头模型中依次降低,水驱后弱凝胶均呈颗粒状。剪切作用可破坏弱凝胶三维结构及聚合物分子链,延长动态成胶时间,降低弱凝胶的封堵强度及其深部调驱作用;吸附作用可富集交联剂,加快交联速度,缩短动态成胶时间,降低弱凝胶本身强度、可运移性及其深部调驱作用。

Three sand-packed models were prepared with fine glass beads, quartz sand and outcropping sand respectively. The dynamic characteristics of weak gels as well as the influence of shear and absorption of porous media on the in-depth profile control and oil displacement of the weak gel generated from the cross-linked polymer were investigated. The results indicate that under the dynamic condition, cross-linking reaction happens in three sand-packed models, and the shut off capacity, effective range and in-depth profile control and oil displacement of the weak gel decrease successively in glass beadpacked model, quartz sand-packed model and outcropping sand-packed model, while the weak gel in these three cases be- comes small gel particles after water flooding. The three-dimensional structure of the weak gel and molecule chain of polymer are broken by shear action which can prolong the dynamic gelation time and decrease the shut off intensity and effect of indepth profile control and oil displacement of weak gels. The cross-linking reaction rate of the weak gel is accelerated, the dynamic gelation time is cut down and the intensity, mobility and effect of in-depth profile control and oil displacement of weak gels are weakened because of the enrichment of cross-linking agent caused by adsorptive action.