Highly Robust Nanogels from Thermal-Responsive Nanoparticles with Controlled Swelling for Engineering Deployments

Abstract

Regular nanogels have been demonstrated their inefficiency for subterranean oil recovery due to their intrinsic drawbacks of fast swelling within minutes, thermal instability, and salinity vulnerability. Prior deployment of swelling delayed nanogels mainly depended on the reservoirs at a relatively higher temperature. To address the issues encountered during engineering deployment, hereinwe devised an integrative approach to in situ form swelling delayed robust nanogels by introducing radically active monomers with thermally sensitive moieties. The nanoparticles with hydrophobic cores in brine in response to thermal input in situ generated well-dispersed hydrophilic nanogels, which showed a pronounced delayed swelling of a week compared to traditional nanogels showing swelling kinetics within minutes. Furthermore, the formation of swelling-delayed nanogels could occur at ambient temperature. This behavior was radically different from that of temperaturecontrolled labile cross-linkers containing nanogels, requiring temperatures greater than 50 °C for volume increase thanks to ester hydrolysis. In addition, the in-situ formed nanogels displayed long-term thermal stability and salinity tolerance under hostile media at temperatures up to 130 °C. The release of an acidic proton under aqueous conditions has been demonstrated to control the microenvironment for various scenarios. The nanotechnology of converting hydrophobic nanoparticles to hydrophilic nanogels could be applied in a wide range of practical applications such as plugging materials and foaming stabilizers for in-depth conformance control during water and CO 2 flooding.

High-Performance Nanogel-in-Oils as Emulsion Evolution Controller for Displacement Enhancement in Porous Media

“…Polymeric gel particles, with sizes ranging from millimeters to nanometers, are regarded as promising agents due to their stability, tunability, and deformability. − Microgel particles at the millimeter and micrometer scale have been developed as effective additives to block high-permeability zones and divert the invading fluid into low-permeability layers. , The plugging effect can be achieved by single-particle blockage or multiparticle bridging depending on particle sizes. − The size-matching rule has been extensively discussed in previous studies, whereas the optimal ratio between the particle diameter and the characteristic pore size remained controversial. ,− In recent years, nanogel particles at the nanometer scale have drawn great attention owing to their better injectivity and potential interfacial effects. Many studies focused on the trade-off between injectivity and plugging efficiency. − The advances in synthesis methodology provided nanogels with intriguing properties, such as delayed swelling behaviors and enhanced mechanical strength. The adsorption of nanogel particles at the solid surface and liquid–liquid interface and their impact on fluid properties have also been investigated. − However, the important role of adjusting the suspension composition and colloidal state in manipulating particle behaviors seemed to be overlooked.…”