Thermal Stability of Acrylamide-Based Polymers at High Temperature andHigh Salinity

摘要

During polymer floods or surfactant-polymer floods,polymer molecules reside inside petroleum reservoirsfor years.This extended period gives sufficient time for the polymers to react with the in-situ environment(high temperature,oxygen-free,high salinity)which could lead to polymer degradation and viscosity loss.In this study,a systematic glove box operating procedure was developed to reduce oxygen concentration(in polymer solutions)to less than 15 ppb.Viscosity was monitored to investigate the thermal stabilityof one commercially available partially hydrolyzed polymer(HPAM)and three ATBS-based polymers athigh salinity(36,000 ppm to 54,000 ppm)and high temperature(116 °C)conditions through a long period.Acrylamide-acrylate(AM-AA)copolymer Flopaam~TM 3330s and ATBS-AA copolymer ZLPAM @50525were selected as the potential candidates for alkali-surfactant-polymer(ASP)floods.Ammonia and sodiumcarbonate were adopted as the alkali.High ATBS content copolymer SAV 10 and SAV 10xv were testedfor surfactant-polymer(SP)floods at high temperature and high salinity environment.The viscosities ofZLPAM and Flopaam increased first due to hydrolysis,then slowly decreased.The pH of those polymersdropped approximately by one unit.SAV 10 and SAV 10xv showed no noticeable viscosity or pH changes.ZLPAM and Flopaam can be used at high temperature in the absence of divalent ions,whereas SAV 10 andSAV 10xv can be used in the presence of divalent ions.