Development of Hydrophobically Associating Polymer Based Colloidal Dispersion Gel for EOR

The conditions of colloidal dispersion gel,CDG,formed from a hydrophobically associating polymer,AP-P4,of M=1.0×106,HD=25%,and cationization degree=0.25% and an aluminum citrate preparate in a simulation formation brine of TSD=44.8 g/L at 60℃ are investigated on the basis of gel viscosity determinations at 60℃ and following parameters are obtained: polymer concentration 100—300 mg/L,polymer to crosslinker ratio 20—150 and its optimal value 100,gelation time 2—7 days;intermolecular crosslinking takes place at polymer concentration ≥400 mg/L.In artificial sandstone cores of Ka 0.2—1.0 μm2,the resistance factor,RF,and the residual resistance factor,RRF,creacted by AP-P4's CDG of polymer concentration 300 mg/L are of 59.01—23.89 and 43.28—15.86 and by HPAM's CDG——of 41.67—18.63 and 30.58—9.03,respectively;for cores of Kw 0.20—0.23 μm2,the maximal plugging rate of AP-P4's and HPAM's CDGs is of 94% and 78%,respectively.On two sets of parallel lower and higher permeability cores with permeability variation factor 12.72 and 4.65 after water flood completed,injecting 0.5 PV of AP-P4's CDG leads to an enhancement in oil recovery of 16.0% and 13.8%,respectively.In profiling/flooding capability the hydrophobically associating polymer CGD of higher salinity is superior to corresponding HPAM's CDG.