Study On The Percolation Properties And EOR Characteristics Of High Temperature-tolerant And High Salinity-resistant Polymer

Aiming at understanding the EOR of Shengli type ? reservoirs(high-temperature and high-salinity)and solving the problem that no obvious effect have been produced with injection of HPAM in Shengli type ? reservoirs(high watercut with highly permeable layers),this paper investigates the percolation properties and EOR abilities of an associative polymer APP5,and compares it with two conventional polymers HPAM1 and HPAM2.Tests on viscosity show that the critical association concentration of AP-P5 is 1300mg/L under high temperature(85?)and high salinity(33000mg/L),above this concentration,the apparent viscosity of AP-P5 solution increases sharply,and is significantly higher than that of HPAM,indicating that associative polymers are temperature-tolerant and salinity-resistant.Shearing tests show that AP-P5 has the lowest viscosity retention rate after shearing though its viscosity remains higher than HPAM,and exhibits to some extent the ability to restore its viscosity.Percolation experiments indicate that the injection pressure,flow resistance and dynamic retention rate of AP-P5 is high,and it has good mobility control ability,it can cause profile inversion at a higher injection volume,whereas HPAM cannot effectively sweep into the low permeable layers under heterogeneous conditions.Flooding tests under homogeneous conditions show that the superiority of AP-P5 decreases with the increase of permeability.APP5 has a better EOR ability when the permeability is 6?m2,but it falls between HPAM1 and HPAM2 at 3?m2,AP-P5 has no superiority as the permeability further decreases to 1?m2.Flooding tests under heterogeneous conditions show that HPAM cannot effectively sweep into less permeable layers,thus has lower EOR effects.Although compared with HPAM,AP-P5 can better exploit oil from low permeable layers,there remains large quantities of oil within those layers,therefore it is recommended that measures be taken to plug the highly permeable layers.