Multifunctional poly(citric acid)-based ionic liquid polymer composite for scale control and emulsion stabilization: structural and interfacial mechanistic evaluation

Mineral scale formation and emulsion instability are major challenges in high-salinity oilfield systems, leading to operational inefficiencies and reduced oil recovery. In this study, a partially bio-based ionic liquid polymer, poly(2-hydroxypropane-1,2,3-tricarboxylic acid)-based ionic liquid polymer (HPTA-ILP), was synthesized from citric acid and evaluated as a multifunctional additive for simultaneous scale inhibition and emulsion stabilization. The polymer was characterized using FTIR, XRD, and ¹H NMR, confirming the formation of an amorphous, ionically functionalized polymer network. Dynamic scale loop tests under high-pressure and high-temperature conditions (190 °F, 1500 psi) demonstrated effective inhibition of calcium-based scale formation, with a minimum inhibitor concentration (MIC) of 200 ppm. At this concentration, the polymer achieved an emulsion stability index (ESI) of 85% and improved oil recovery efficiency to 87%. The inhibition mechanism involves calcium ion complexation, adsorption on crystal growth sites, and interfacial stabilization through electrostatic and steric effects. These results highlight the potential of HPTA-ILP as a multifunctional additive for improving flow assurance and enhanced oil recovery performance in high-salinity environments.