Nanostructured Particles for Controlled Polymer Release in Enhanced Oil Recovery

Abstract

With the decline in oil discoveries over recent decades, it is believed that enhanced oil recovery (EOR) technologies will play a key role to meet energy demand in the coming years. Polymer flooding is used commonly worldwide as an EOR process. In this work, we propose the synthesis of protected polyacrylamide (PAM) nanoparticles (PPNs) with a hydrophobic polystyrene (PSt) shell by one‐pot two‐step inverse emulsion polymerization, in which the PSt shell was created by surface polymerization. The shell protects the active PAM chains from premature degradation caused by the harsh environment in the reservoirs, controls the release of the chains as rheological modifiers, and additionally, it provides the chains with prolonged stability. The time‐dependent release of the PPNs promotes the effectiveness of the PPNs as viscosity modifiers, as the maximum viscosity enhancement is achieved at longer residence times in the reservoirs. This can be up to 30 days, and the released polymer maintained its activity. Under conditions of high salinity (total dissolved solids=178 082 mg L−1), temperatures up to 90 °C, and shear rates up to 1000 s−1, PPNs have shown superior properties, such as elastic modulus, shear rate behavior, viscosity loss, and sand adsorption over PAM, whereas the areal sweep efficiency of PPNs is similar to that of PAM and higher than that of conventional water flooding. All of this makes PPNs promising candidates for polymer‐enhanced oil recovery.

Optimizing synthesis and application of an enhanced oil recovery agent: stability assessment of the optimized nanostructured PNIPAM/PS core–shell polymer using a developed DLVO-based model

“…The most popular water-soluble polymers for EOR -including synthetic (e.g. partially hydrolyzed polyacrylamide (HPAM), HPAM copolymers with other acrylic monomers such as N-vinyl pyrrolidone [4,5] , copolymers based on polyether's [6] , Hydrogels [7] , and Hyperbranched polymers [8] ) and natural or biobased polymers (e.g. Xanthan, Guar gum, and Arabic gum [9] ) -are not usually applicable for carbonate oil reservoirs [10] .…”

Graphene Oxide Nanosheets for Oil Recovery

“…Energy plays a key role in the sustainability and development of human life, so it seems necessary to shift toward the use of nonrenewable energies. , Currently, oil reserves are among the main nonrenewable energies in the world, about half of which are in the preferentially oil-wet carbonate reservoirs, and their production requires the application of enhanced oil recovery (EOR) methods. − It is, hence, essential to deploy a suitable EOR method that can enhance oil recovery by altering the reservoirs’ wettability from oil-wet toward neutral-wet or even water-wet. , To do so, nanoflooding, which has attracted the attention of many researchers, can have an important role. − In nanoflooding, a series of smart fluids, which are prepared by dispersing particles in the range of 1–100 nm in the base phase, are flooded into oil-wet samples under different scenarios. The particles, called nanoparticles, are mainly metal or metal oxide. − Nanoparticles, because of their small size and high specific area, are able to pass through the micron-sized throats of the reservoirs’ rock and alter the wettability .…”

“…Energy plays a key role in the sustainability and development of human life, so it seems necessary to shift toward the use of nonrenewable energies. 1,2 Currently, oil reserves are among the main nonrenewable energies in the world, about half of which are in the preferentially oil-wet carbonate reservoirs, and their production requires the application of enhanced oil recovery (EOR) methods. 3−5 It is, hence, essential to deploy a suitable EOR method that can enhance oil recovery by altering the reservoirs' wettability from oil-wet toward neutral-wet or even water-wet.…”

Investigation of inverse emulsion assisted controlled release of polyacrylamides for enhanced oil recovery

“…[25][26][27] Core-shell-protected nanostructures and polyelectrolyte complex nanoparticles are effective methods to encapsulate AM for controlled release. [28][29][30][31][32] Inverse emulsion polymerization of an aqueous acrylamide solution and copolymerized polystyrene nanolayer coating as a hydrophobic protective shell have also been reported as a controlled polymer release system, [33][34][35][36] however complex synthetic processes and high cost limits their scale up in oil elds.…”