Studies On Shutoff Agent Applied To Loose Gritstone Reservoir With Big Aperture Of High Temperature And High Salt

According to the special stratum with big aperture which formed by long term waterflood infusion in oil-field water exploitation, general plugging agent exists ungracious plugging effect and the applied limitedness in high temperature and high salt reservoir.Based on the disadvantage clogging performance of crylic acid homopolymer and crylic acid-acrylamide copolymer,this dissertation has designed the molecule structure of target plugging agent through adding temperature-resistance and antisalt functional anion monomer and cation monomer — sodium allylsulfonate , 2-acrylamide-2-methylpropane solfonic acid, dimethyl-diallyl-ammonium chloride and environment friendly organic crosslinking agent.Adopting the aqueous solution free radicals copolymerization method, five series plugging agents formula are optimized by orthogonal experimental design.Compared antitemperature and antisalt capability of the five serieses product,AADM quatercopolymer as the end target product is selected. It's formation is AADM11:monomer total concentration35%, initiator agent concentration 0.5%,crosslinking agent concentration 0.55 ‰ ,monomer proportion 10:2.0:2.0.The synthesized product can tolerance high temperaturet to amount to 150℃ at least, swell to 13g.g-l multiple above after absorbing the brine(10% NaCl+10%CaCl₂).And the product has excellent performance of tenacity and even keep-water.Core flooding simulation experiment and performance evaluation have been done at home. The results showed that the AADM plugging agent was selective to predominate aperture, water shutoff ration was over 98% after 48 hours aging time under 120 ℃ ,break — pressure gradient was above 12MPa/m,and had good drinking capability and oil solubility, which basically meeted with requirements of chemical water plugging in high temperature and high salt reservoir in oilfield. Parallel filled sand pipe water shutoff tests showed that the recovery had different improvement in dealed cores of high and low penetrate rate . Under same injection-recovery system,the profile control was improved in absorbing water capability of two different level penetrate rate core.