Preparation and migration study of graphene oxide-grafted polymeric microspheres: EOR implications

Through an inverse emulsion polymerization technique, graphene oxide-grafted polymeric microspheres (RGO-PMSs) with superior suspension properties, thermostability, hydration swelling, elasticity and strength were developed for in-depth profile control and displacement. RGO-PMSs undergo migration and adsorption in large pores; capture by means of single plugging, coincidence plugging and bridging plugging; and elastic deformation-recovery in small pores to increase seepage resistance. When matching coefficient was 2.11, RGO-PMSs particles could not enter the porous media. However, RGO-PMSs particles entered core samples smoothly and perform plugging when the matching coefficient ranged from 0.78-1.44, while RGO-PMSs particles could not effectively block the pores when the matching coefficient was 0.67. An increase in the injection rate improved RGO-PMSs injectivity while weakening plugging efficiency. Additionally, the increase in the RGO-PMSs concentration and strength enhanced the plugging efficiency. Moreover, RGO-PMSs had a favorable anti-outwash property with a retention ratio of 88.7%, maximum additional flow resistance of 7.12 kPa and additional flow resistance of 4.53 kPa during migration. All the results indicated that RGO-PMSs could be an applicable candidate for in-depth profile control and displacement.