The applicability of weak gels of two different polymers and crosslinkers is studied as permeability profile modifying/flooding agents at standard reservoir conditions of Shengli (temperature 70°C and TSD of formation water 7277 mg/L). It is shown that HPAM (hydrolyzed polyacrylamide)/AI citrate/artificial formation water (AFW) systems (M = 1.7 × 107 for HPAM) gelate very quickly and the gel viscosity is not stable and maintains for < 48 hr; hydrophobically associating polymer NAPs/Al citrate/AFW systems form gels with improved stability at rather high polymer concentration (> 1200 mg/L); NAPs/Cr3+ (from an organic acid salt)/AFW systems containing 600-800 mg/L of polymer form gels of viscosity 300-500 mPa/sec in 1-3 days which keeps stable in > 45 days (the experimental time duration limit); by introducing 50-250 mg/L of a selected organic acid as gelation retarder into system of 700 mg/L of NAPs + 500 mg/L of Cr3+ crosslinker + AFW, the gelation time of the system is delayed from 1-3 to 5-15 days and more. This delayed gelling NAPs/Cr3+ fluid can meet the requirements to permeability profile modifying/flooding fluid in field used where the amount of the fluid to be injected is large.
Preparation of heat resistant and salts tolerant hydrophobically associating polymer weak gel as permeability profile modificator/oil displacing agent. Available from: https://www.researchgate.net/publication/296738291_Preparation_of_heat_resistant_and_salts_tolerant_hydrophobically_associating_polymer_weak_gel_as_permeability_profile_modificatoroil_displacing_agent [accessed Sep 30 2018].