Laboratory study on the potential EOR use of HPAM/VES hybrid in high-temperature and high-salinity oil reservoirs

Polymer flooding represents one of the most efficient processes to enhance oil recovery,and partially hydrolyzed polyacrylamide (hpam) is a widely used oil-displacement agent,but its poor thermal stability,salt tolerance,and mechanical degradation impeded its use in high-temperature and high-salinity oil reservoirs. in this work,a novel viscoelastic surfactant,erucyl dimethyl amidobetaine (edab),with improved thermal stability and salinity tolerance,was complexed with hpam to overcome the deficiencies of hpam. the hpam/edab hybrid samples were studied in comparison with hpam and edab in synthetic brine regarding their rheological behaviors and core flooding experiments under simulated high-temperature and high-salinity oil reservoir conditions (t: 85°c; total dissolved solids: 32,868 mg/l; [ca2+] + [mg 2+]: 873 mg/l). it was found that the hpam/edab hybrids exhibited much better heat- and salinity-tolerance and long-term thermal stability than hpam. core flooding tests showed that the oil recovery factors of hpam/edab hybrids are between those of hpam and edab. these results are attributed to the synergistic effect between hpam and edab in the hybrid. © 2013 dingwei zhu et al.