Sulfonated Polystyrene Nanoparticles as Oleic Acid Diethanolamide Surfactant Nanocarriers for Enhanced Oil Recovery Processes.

Shalimar P C Caplan,Elizabeth R Lachter,Agatha D S Franscisco,Regina S V Nascimento,Thaís B G Silva

doi:10.3390/polym11091513

Shalimar P C Caplan, Elizabeth R Lachter + Show 3 more

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https://doi.org/10.3390/polym11091513

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Journal: Polymers	Publication Date: Sep 17, 2019
Citations: 11	License type: CC BY 4.0

Affiliation: Universidade Federal do Rio de Janeiro

Abstract

The aim of this study is the evaluation of partially sulfonated polystyrene nanoparticles (SPSNP) efficiency as nanocarriers for a non-ionic surfactant, oleic acid diethanolamide (OADA), in the reduction of the surfactant losses and the increase of oil recovery. The synthesized oleic acid diethanolamide was characterized by FTIR, 1H NMR, 13C NMR, surface tension (γ = 36.6 mN·m−1, CMC = 3.13 × 10−4 M) and interfacial tension of mineral oil/OADA aqueous solutions (IFTeq = 0.07 mN·m−1). The nanoparticles (SPSNP) were obtained by emulsion polymerization of styrene, DVB and sodium 4-styrenesulfonate (St-S) in the presence of OADA aqueous solution and were characterized by FTIR and PCS. The results show that the presence of ionic groups in the polymer structure promoted a better nanoparticles suspensions′ stability, smaller particles production and more pronounced IFT reduction. The SPSNP obtained with an OADA concentration twenty times its CMC and 0.012 mol % of St-S presented a particle size around 66 nm and can act as efficient nanocarriers decreasing the water/oil interfacial tension to low values (0.07 mN·m−1) along the time, when in contact with the oil. Transport and oil recovery tests of the nanocarriers systems in an unconsolidated sand porous medium test show that the SPSNP do inhibit surfactant adsorption onto sand particles surface and induced an increase of oil recovery of up to about 13% relative to the water flooding oil recovery, probably due to a synergistic effect between the nanoparticles and surfactant action at the water/oil interface.

Highlights

Enhanced oil recovery (EOR) techniques have been employed to decrease the water to oil ratio in the exploiting of mature fields in order to increase the economic viability of those operations
Nanocarriers based on polystyrene containing sulfonate groups and the surfactant oleic acid diethanolamide (OADA) were developed
Experimental investigations were performed to evaluate the influence of some polymerization reaction parameters, such as crosslinking agent, stabilizer and sulfonated comonomer amounts, on the main properties related to EOR application

Summary

Introduction

Enhanced oil recovery (EOR) techniques have been employed to decrease the water to oil ratio in the exploiting of mature fields in order to increase the economic viability of those operations. It is expected that an EOR process will reduce the amount of residual oil not recovered by primary and secondary recovery, which can correspond to 35–50% of the original oil in place [1,2]. Several types of EOR processes have been employed, and surfactant injections are among the most successful ones. It reduces the water/oil interfacial tension and lowers the capillary pressure, increasing the aqueous medium capacity to remove residual oil from the reservoirs’ pores. To achieve a desirable oil recovery, it may be necessary to inject larger amounts of surfactant, but its high prices turn this process economically unfeasible [3,4]

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