Magnetically Labelled Hybrid Nanosurfactant MLHNS for Upstream Oil and Gas Operations

Nanoencapsulation and targeted chemical delivery techniques have transformed many fields such as pharmaceutical drug delivery for medical treatment and diagnosis, and can similarly transform several upstream oil and gas operations. This paper describes the dual nanoencapsulation of superparamagnetic iron oxide nanoparticles (SPOINs) and petroleum sulfonate surfactants to produce hybrid nanosurfactant (MLHNS) in high-salinity water (56,000 ppm) using an inexpensive, scalable, and straightforward synthesis protocol. This novel magnetically labelled nanofluid (NF) is designed to: 1) enhance the residual oil mobilization via altering the rocks wettability and reducing the interfacial tension, and 2) enable in-situ monitoring of injected fluids when combined with EM surveys. NFs encapsulating a petroleum sulfonate surfactant and three different concentrations of 5-nm SPOINs were prepared using a two-step nanoencapsulation method. Both colloidal and chemical stability of the prepared formulations were tested at 90 °C for over a year. Results showed that all the formulations exhibited remarkable long-term colloidal and chemical stability under these close-to-reservoir conditions. Transition electron microscopy (TEM) images confirmed the encapsulation of SPIONs. The SPOINs-NFs have successfully reduced the interfacial tension (IFT) between crude oil and water by more than three orders of magnitude (from ~ 25 mN/m down to ~ 0.01 mN/m). These IFT and stability results demonstrate a strong synergy between SPIONs and the petroleum sulfonate surfactant. It is worth mentioning that this novel encapsulation platform enables the encapsulation of a wide range of nanoparticles (NPs) to generate a library of multi-function NFs to support several upstream applications.