井筒挤注用防垢剂制备及室内性能评价研究

Preparation and Indoor Performance Evaluation of Anti-scaling Agent for Wellbore Squeeze

采用顺丁烯二酸酐(MA)、丙烯酸甲酯(MMA)和3-烯丙氧基-2-羟基-1-丙磺酸钠(HPA)为单体,通过自由基聚合法合成了一种新型的防垢剂PAWG。通过单因素实验优化了聚合反应条件,得到了最佳反应参数:单体质量比为1:1:0.8,反应温度为80℃,反应时间为3h,引发剂用量为单体总质量的6%,引发剂滴加时间为50min。在此条件下,PAWG的阻垢率达到93.64%。红外光谱表征表明,PAWG分子链上含有羧基、酯基和磺酸基等活性基团,能够与Ca^(2+)形成稳定的螯合物,从而有效抑制水垢的生成。防垢性能实验表明:PAWG单剂和HPND+PAWG复配防垢剂为30mg·L^(-1)时,其静态阻垢率超过90%;HPND+PAWG复配防垢剂注入水驱替天然岩心,驱替PV数增大时,岩心渗透率保留率微降,当100PV时,低渗岩心渗透率保留率超过90%,说明防垢剂能有效抑制沉淀和结垢,保护储层。

The maleic anhydride(MA),methyl acrylate(MMA)and sodium 3-allyloxy-2-hydroxy-1-propanesulfonate(HPA)are used as monomers to synthesize a new type of anti-scaling agent PAWG.The polymerization reaction conditions are optimized through single factor experiments,and the best reaction parameters are obtained as follows:the mass ratio of monomers is l:l:0.8,the reaction temperature is 80℃,the reaction time is 3 h,the amount of initiator is 6%of the total mass of monomers and the initiator dropping time is 50 min.Under these conditions,the scale inhibition rate of PAWG reaches 93.64%.The infrared spectrum characterization shows that the molecular chain of PAWG contains active groups such as carboxyl,ester groups and sulfonic acid groups,which can form stable chelates with Ca^(2+),thereby effectively inhibits the formation of scale.The anti-scaling performance experiments show that when PAWG single agent and HPND+PAWG compound anti-scaling agent are 30 mg·L^(-1),the static anti-scaling rate reaches more than 90%o;the HPND+PAWG compound anti-scaling agent is injected into water to displace natural rock core,when the displacement PV number increases,the permeability retention rate of rock core decreases slightly.When the PV number is 100,the permeability retention rate of core with low permeability exceeds 90%,indicating that the anti-scaling agent can effectively inhibit precipitation and scaling and pro tect the reservoir.