Preparation and migration study of multi-walled carbon nanotube hybrid polymer gel particles: EOR implication

Abstract

Multi-walled carbon nanotube hybrid polymer gel particles (MWCNTs-HPGP) were synthesized using the free radical polymerization approach to reduce water cut at first. The microstructure, particle size distribution, swelling characteristics, strength, and rheology of MWCNTs-HPGP were then studied. Subsequently, the migration and plugging properties of MWCNTs-HPGP were assessed at the core scale. The morphology of MWCNTs-HPGP was irregular with interpenetration networks, and MWCNTs-HPGP could expand by 48.2–94 times in brine with varying salinities (0 ∼ 20 × 104 mg/L NaCl), according to experimental results. After 60 d of age, MWCNTs-HPGP retained 95.2% of strength. Furthermore, the MWCNTs-HPGP dispersion solution’s shearing thinning feature and good viscoelasticity supplied it with favorable injectivity and deep migrating capacity. In addition, when the matching coefficient (β, the ratio of MWCNTs-HPGP median particle size to the average pore diameter) was 1.06 and the flooding rate was 0.5 mL/min, MWCNTs-HPGP could efficiently plug large pores with a plugging efficiency ranging from 82.7% to 98.5%. All the experimental results demonstrated that MWCNTs-HPGP could be a potential candidate for deep profile control and displacement in high temperature and high salinity reservoirs.