RESUMO
The objective of this study is to evaluate the role of nanoparticles with different chemical structures in completion fluids (CF) in providing a positive dual effect for well stimulation and clay swelling damage inhibition. Six types of commercial (C) or synthesized (S) nanoparticles have been incorporated into a commercial completion fluid. Doses varied between 100 and 500 mg·L-1. CF-nanoparticles were evaluated by fluid-fluid, fluid-nanoparticle, and fluid-rock interactions. The adsorption isotherms show different degrees of affinity, which impacts on the reduction of the interfacial tension between the CF and the reservoir fluids. Fluid-fluid interactions based on interfacial tension (IFT) measurements suggest that positively charged nanoparticles exhibit high IFT reductions. Based on contact angle measurements, fluid-rock interactions suggest that ZnO-S, SiO2-C, SiO2-S, and ZrO2 can adequately promote water-wet rock surfaces compared with other nanomaterials. According to the capillary number, ZnO-S and MgO-S have a higher capacity to reduce both interfacial and surface restrictions for crude oil production, suggesting that completion fluid with nanoparticles (NanoCF) can function as a stimulation agent. The clay swelling inhibition test in the presence of ZnO-S-CTAB and MgO-S-CTAB nanoparticles showed a 28.6% decrease in plastic viscosity (PV), indicating a reduction in clay swelling. The results indicate that a high-clay environment can meet the completion fluid's requirements. They also indicate that the degree of clay swelling inhibition of the nanoparticles depends on their chemical nature and dosage. Finally, displacement tests revealed that CF with nanoparticles increased the oil linear displacement efficiency.
RESUMO
A promising alternative to improve the ultra-gas-wet alteration process by the addition of nanoparticles was developed. This study is focused on studying the functionalization process of nanoparticles of γ-alumina (γ-Al2O3) and magnesia (MgO) using a commercial fluorocarbon surfactant (SYLNYL-FSJ), from an experimental and theoretical approach. Different fluorocarbon surfactant concentrations were used in the functionalization process of the nanoparticles, and the materials obtained were characterized by Fourier-transform infrared spectroscopy (FTIR) and dynamic light scattering (DLS). The experimental setup of the interaction between the surfactant and nanoparticles was reproduced by molecular simulations in order to obtain physical insights into the adsorption process. Experimental results show a suitable functionalization for both nanoparticles with the fluorocarbon surfactant. The γ-Al2O3 nanoparticles showed better behavior based on the obtained nonfrictional conditions, which lead the water and n-decane droplets to slide on the rock surface coated with the functionalized nanoparticles. The experimental contact angles on the functionalized γ-Al2O3 nanoparticles were reproduced by molecular dynamics simulations. From the interaction energies' evaluation, it was also determined that alumina nanoparticles could reduce the adhesive energy to 0.01 kcal mol-1, regarding magnesia nanoparticles. Also, a significant difference was obtained for the surfactant-liquid interactions between the two nanoparticles evaluated, with changes of 17% for surfactant-water interactions and 28% for the surfactant-n-decane. The obtained results explain the pronounced increase for the contact angles of n-decane on the functionalized γ-Al2O3 nanoparticles.