摘要
弱凝胶运移封堵能力的强弱是决定其能否实现深部调剖的关键因素之一。本文通过多测压点填砂模型中的封堵性能评价实验，研究了弱凝胶（酚醛交联部分水解聚丙烯酰胺体系）对高渗通道的运移封堵特征。结果表明，封堵能力较强体系应以残余阻力系数（Frr）为评价指标，封堵能力较弱体系应以渗透率封堵率（E）为评价指标。动态成胶状态对弱凝胶封堵能力影响较小，为了最大限度的实现深部调剖，凝胶溶液注入后可连续地进行后续注水而无需候凝。弱凝胶能通过自身运移对模型未注胶部位形成良好封堵。注胶深度为4.2 m、注入体积为2.0 PV时，其能在0~8.5 m形成较强封堵（E≥96.3%、Frr=27.0~385.7），在8.5~25.8 m形成部分封堵（3.0%≤E≤76.7%、Frr=1.0~4.3），在25.8~32.0 m则无封堵。与注胶部位相比，弱凝胶对未注胶部位的封堵能力显著降低。多孔介质的剪切作用导致弱凝胶黏度和粒度大幅减小，使其封堵能力随运移距离的增大而显著降低。图8表1参12
Abstract
The plugging capacity of weak gel during its flowing process was one of the most important factors affecting the realization of in-depth profile control. In this paper, a long sand-packed model was used to conduct the evaluation experiments of weak gel plugging capacity, and the migration-plugging property of a class of weak gel (phenolic crosslinking partially hydrolyzed polyacrylamide system) was studied. The results showed that the residual resistance factor (Frr) was the best index for the strong gel evaluation process, while for the weak gel permeability plugging rate (E) was the best choice. Dynamic gelation condition had little effect on the plugging capacity of weak gel. And to achieve the most in-depth profile control, the subsequent water flooding should be conducted continuously after the injection of gel solution rather than waiting for the gelation. By its flowing ability, weak gel could well plug the part without gel injection. When the gel injection depth was 4.2 m and the injection volume was 2.0 PV, the weak gel could strongly plug in 0—8.5 m section (E≥96.3%, Frr=27.0—385.7) and partially plug in 8.5—25.8 m section (3.0%≤E≤76.7%, Frr=1.0—4.3), and there was no plugging in 25.8—32.0 m section. Compared with the gel injection part, the plugging capacity of weak gel in the part without gel injection was much weaker. Shearing effect of porous media made the viscosity and particle size of weak gel decrease significantly, resulting in the obvious drop of its plugging capacity with increasing migration distance.
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