Abstract:
Objective In view of the practical engineering problems of the limited plugging capacity of conventional profile control agent for low permeability reservoirs with fractures and the poor effect of adjusting the water injection profile, nano-polymer microsphere PADC-1 using acrylamide (AM), 2-acrylamido-2-methylpropane sulfonic acid (AMPS) and dimethyl diallyl ammonium chloride (DMDAAC) as monomers is used as profile control agent to improve the recovery of low permeability reservoirs.
Methods The applicability of polymer microsphere in profile control and flooding were tested by microscope, laser particle size analyzer, high temperature rheometer and core flow displacement experimental device. The applicability of polymer microsphere in profile control and flooding of high temperature, high salinity and low permeability reservoirs was discussed.
Results The experimental results show that PADC-1 has good dispersion and viscoelasticity for the properties of good sphericity, narrow particle size distribution, average particle size of 85.8 nm. PADC-1 swells rapidly after absorbing water, and the swelling ratio increases with the increase of temperature. PADC-1 has a temperature tolerance of more than 120 ℃ and a salt tolerance of 1.8×105 mg/L, the average oil recovery of cores with different permeability increases by 13.46%.
Conclusions Nano-polymer microsphere PADC-1 can effectively improve the diversion rate of different permeability formations by water absorption and expansion, thereby improving the recovery efficiency of low permeability reservoirs.
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