针对裂缝性低渗油藏堵水困难且堵剂注入性差、封堵强度弱等问题,以丙烯酰胺(AM)、2-丙烯酰胺-2-甲基丙磺酸(AMPS)和N-(3-二甲氨基丙基)甲基丙烯酰胺(DMAPMA)为原料制备P-AAD共聚物,并以酚醛树脂作为交联剂制得新型选择性堵水剂。利用红外光谱、核磁共振和扫描电镜进行表征,并对堵水剂的抗剪切性能、注入性能、油水选择性及耐冲刷性能进行评价。结果表明,在不同剪切力作用下,黏度保持率均在80%以上,具有良好的抗剪切性能;在裂缝开度为19 μm时,注入压力适中,对微裂缝依然有良好的注入性;油相封堵率为11%~21%,水相封堵率为82%~91%,说明堵水剂具有堵水不堵油的特性;在注入水冲刷后,水相渗透率降低幅度极小,说明堵水剂在裂缝壁面形成强吸附和强滞留,具有良好的耐冲刷性能。

In order to solve the problems of difficult water plugging,poor injectivity and weak plugging strength when water-plugging agent is applied in fractured low-permeability reservoir,a novel selective water-plugging agent is prepared by using phenolic resin as cross-linking agent to process P-AAD copolymer that is made from acrylamide,2-acrylamido-2-methylpropanesulfonic acid and N-(3-dimethylaminopropyl) methacrylamide.The water-plugging agent is characterized by means of infrared spectroscopy,nuclear magnetic resonance and scanning electron microscopy,and its anti-shearing property,injection property,oil-water selectivity and erosion resistance are also evaluated.The results show that the viscosity retention rate always exceeds 80% under different shear forces,showing a good shear resistance.This water-plugging agent needs a moderate injection pressure when the crack opening degree is 19 μm,and it shows a good injectivity to micro fractures.It exhibits a plugging rate of 11%-21% for oil phase,and 82%-91% for water phase,indicating that it has the characteristics of water plugging without oil plugging.After being washed by injected water,the permeability of water phase decreases slightly,indicating that it forms strong adsorption and strong retention on the fracture wall,showing a good erosion resistance.