Silica Nanofluids in an Oilfield Polymer Polyacrylamide: Interfacial Properties, Wettability Alteration, and Applications for Chemical Enhanced Oil Recovery

Abstract

Oil production from matured crude oil reservoirs is still associated with low recovery factors. Chemical enhanced oil recovery (EOR) is one of the techniques which can significantly improve the recovery factor of the trapped oil. This is mainly achieved by lowering the interfacial tension (IFT) of the crude oil−brine/aqueous chemical and increasing the viscosity of the injected fluid. Nanofluids have demonstrated potential in this respect, and we thus examined how such nanofluids behave when formulated with standard oilfield polymers, with a particular focus on their EOR efficiency. In this work, silica (SiO 2 ) nanofluids with (NSP) or without (NP) surfactant (sodium dodecyl sulfate) added and with varying nanoparticle concentration were formulated with polyacrylamide (PAM) and characterized by DLS and ζ-potential measurements. These nanofluids were then tested in EOR core-flood experiments. Various studies involving the stability and viscosity of nanofluids, interfacial tension of the nanofluidcrude oil system, their effect on wettability alteration, and efficiency for EOR studies as a function of temperature have been reported. The efficiency of the nanofluid systems for IFT reduction and EOR has also been compared with the conventional polymer (P) and surfactant−polymer (SP) flood schemes. The SiO 2 nanofluids significantly increased oil recoveries, particularly at higher temperatures, mainly due to IFT reduction, fluid viscosity increase, and wettability alteration (from intermediate-wet to strongly water-wet). We conclude that SiO 2 nanofluids can potentially be attractive EOR chemicals, particularly for wettability alteration operations and high temperature applications.

Effect of SiO2 on the foamability, thermal stability and interfacial tension of a novel nano-fluid hybrid surfactant

“…In comparing with the SiO2-PAM blend, PAM had significant stabilization effect at a concentration of 0.05 %. Similar observation of the particle stabilization with PAM was reported in the work of Sharma et al (2016), where the authors found that, SiO2 blend containing surfactant and PAM induced additional flocculation of particles, which resulted to rapid particles sedimentation. Thus, PAM in our study could only improve the viscosity of SiO2-IBS, but not its stability.…”

“…Despite high oil recovery achieved in FAWAG, obtaining stable foams in high temperature oil reservoirs are difficult and consequently affect their overall performance (Kapetas et al, 2016). However, silica nanofluid (SiO2), which is a recently employed technology, has been found to show a remarkable improve on the rheology, stability and interfacial properties of surfactants (Esmaeeli Azadgoleh et al, 2014;Sharma et al, 2016). The effects of SiO2 on stabilizing foams in different type of surfactants have been reported (Xue et al, 2016;Sun et al, 2015).…”

Effect of Silica Nanoparticles on Fluid/Rock Interactions during Low Salinity Water Flooding of Chalk Reservoirs

“…The efficiency of wettability change by silica NPs was shown to be enhanced at higher temperatures [20]. Apart from wettability change, silica NPs have also been shown to reduce oil-water interfacial tension thereby improving the mobility of oil phase [27][28][29] and stabilize oil in water emulsions [30][31][32][33] for EOR application. Monfared, et al [34] studied the adsorption of silica NPs on calcite surfaces.…”

Strategy for Synthesizing Novel Acetamidines as CO2-Triggered Switchable Surfactants via Acetimidates

“…Surfactants, whose amphiphilic structures enable the stabilization of emulsions with two immiscible phases, are widely applied in many processes such as cleaning [1], viscous oil transportation [2], and enhancing oil recovery [3]. Excellent stabilization is required in these processes, usually followed by a subsequent emulsion-destabilization step to effectively recover the two immiscible phases.…”