Formulation of an Encapsulated Surfactant System, ESS, via β-CD Host-Guest Interactions to Inhibit Surfactant Adsorption onto Solid Surfaces

In this work, the issue of surfactant adsorption (SA) onto solid surfaces was attempted through surfactant encapsulation via host-guest interactions using β-CD. Formulations of a nonencapsulated surfactant system (Non-ESS) and an encapsulated surfactant system (ESS) were obtained through phase behavior analysis. Rheology shows that the ESS and Non-ESS display low viscosities, shear-thinning flow behavior, and structural stability. The ESS and Non-ESS were applied as surfactant flooding for enhanced oil recovery via coreflooding displacement tests to evaluate their performances in displacing and recovering residual oil. Static and dynamic SA tests of the ESS and Non-ESS were conducted. The experimental results demonstrate the effective propagation of both systems through the sand-packs. At the same flooding conditions, the ESS produced 63% higher incremental oil recovery than the Non-ESS, which confirms a reduced SA and effective surfactant release from the β-CD in the presence of oil. The static SA tests indicate that the ESS reduced SA by 82.42%, 60.59%, and 6.73% onto sand, kaolin, and shale respectively, relative to the Non-ESS. Likewise, the dynamic SA tests demonstrate that the ESS reduced SA onto sand-kaolin surfaces by 43.3% relative to the Non-ESS. Consequently, the ESS shows potential for applications where SA onto solid surfaces is a critical issue.