Toward Smarter Oilfield Chemicals for EOR/IOR

Abstract

Summary The advances in nanotechnology are receiving much attention to transform the oilfield chemicals into smarter, greener and sustainable chemicals. This work describes the synthesis of novel nanofluid via encapsulating superparamagnetic iron oxide nanoparticles (SPIONs) in nanosurfactant (NS), using an inexpensive, scalable, and straightforward method. This nanofluid (NF) is designed to enhance or improve the oil recovery at lower concentrations at reduced cost and, comparing to the conventional chemical flooding. Superparamagnetic iron oxide nanoparticles (SPIONs, 5 and 10 nm in toluene, (5 mg/mL) were obtained from commercial supplier. Different amount of SPIONs was encapsulated into NSs to establish maximum encapsulation concentration. For that, first, 5 and 10 nm SPIONs in toluene were mixed in different ratios with as received Petronate HL/L (61 wt% active) and further formulated into the high-salinity and high-temperature stable NFs. Stability of the formulations in the presence of high salinity was verified through incubation at 100 °C for an extended period. Equilibrated interfacial tension (IFT) measurements were performed using spinning drop tensiometer. The SPIONs encapsulated nanofluid exhibited remarkable colloidal stability at 100 °C and high-salinity of 56,000 ppm of total dissolved solids for over a year. We conducted an equilibrated IFT measurement between different types of crude oil and SPIONs encapsulated nanofluid with corresponding control measurements. Significant reduction in IFT (0.001-0.005 mN/m) was observed for the nanofluid with the encapsulated 5 nm SPIONs when compared to the first generation of NS (0.02 mN/m). The cryo transmission electron microscopy (cryo-TEM) images confirmed the SPIONs encapsulation within the nanosurfactant vesicles. The lower IFT owes to the great synergy between SPIONs and the NS to reduce the IFT by more than two orders of magnitude comparing to NS alone. This work demonstrates the synthesis of economic, efficient and environmentally friendly nanofluid to allow further improve oil mobilization beyond the waterflooding. A novel SPIONs encapsulated nanofluid was synthesized using an inexpensive, scalable, and simple synthesis method. The new nanofluids exhibited colloidal stability under reservoir conditions for a year. The synergy between NS and SPIONs resulted in lower IFT values compared to the use of SPIONs and NS alone. These findings open the horizon to encapsulate a wide range of nanoparticles to generate a library of multifunctional nanofluids to support several upstream applications.