The Potential of a Novel Nanofluid in Enhancing Oil Recovery

A surface-active and green flooding agent, modified nanocellulose (NC), which is expected to be an alternative to the current flooding systems for enhancing oil recovery (EOR), was provided in this work. The physical properties of the NC samples including dispersity, rheology, phase behavior, emulsifiability, etc., as a function of mass fraction and charge density, were comprehensively studied to evaluate their EOR potential. The results indicate that this modified nanomaterial could be well dispersed in 1 wt % NaCl brine, forming a series of homogeneous nanofluids at the concentration above 0.4 wt %. Rheological analysis evidenced the viscoelastic properties and pronounced shear-thinning behavior of the nanofluids. Because of the presence of the active groups, the dynamic interfacial tension (Oil/Nanofluid) decreased to an order of 10(-1)mN/m, which accordingly promotes the microscopic recovery efficiency through an emulsification effect. It was also observed that the emulsifiability of the nanofluids was closely related to the charge density. Visual EOR experiments were conducted in a micromodel, from which two mechanisms, (1) sweep volume improvement and (2) emulsification and entrainment, were established for NC nanofluid flooding. As an eco-friendly material, this nanofluid is supposed to be a promising flooding agent in the near future.