The authors introduce the synthetic process and the evaluation results for surfactant/polymer inorganic nanocomposite specially designed for the enhanced oil recovery (EOR) process in the high temperature and high brine-hardness offshore reservoirs. The SiO 2 nanoparticles (NPs) were introduced to the polymer matrix through the core-shell encapsulation-polymerization. New core-shell NPs were blended with surfactants in different ratios. The monodisperse particles, with the size of 50nm to 100nm identified by transmission electron microscopy (TEM), were investigated on their properties and morphology by IR spectroscopy, and thermal degradation (TGA). The blends of NPs and surfactants in brine were aged in one month in Dragon Southeast reservoir conditions to evaluate on the capacity as EOR agent. The results show that the nanocomposites produced IFT reduction and viscosity enhancement at critical concentration, high thermostability and salt-tolerance. These improved properties of core/shell NPs were suitable for producing high sweep volume and increasing crude oil displacement efficiency. The core flooding experiment was performed at 92 o C on the fractured-granite core model and brine blend of 800 ppm of surfactants and 200 ppm of core-shell NPs was injected in 0.25 PV. After water flooding, the oil saturation was reduced into 30% and by the core-shell NPs injection, the oil was displaced in 6.2% additionally. The obtained results shown the capacity of using the core-shell NPs as a really good EOR agent for HTHP offshore reservoirs.

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Background Nano-particles of metals can be routinely synthesized. The cereal seeds treatment with the particles can improve early growth and crop production. Moreover, the treatment is robust and economical. Methods Metal (Fe0, Cu0, Co0), zinc oxide (ZnO) and chitosan-stabilized silver nano-particles were synthesized and applied to cereal seeds. The germination rate, early plant development and inhibition effects on pathogenic fungi were quantified. Results It was found that all nano-particles had a positive effect on the development of healthy cereal seedlings. In particular, the length of the above-ground part of the seedlings was increased by 8–22%. The highest inhibition effect was observed on Helminthosporium teres with the application of Co0 and chitosan-Ag. Pre-sowing treatment with metal nano-particles reduced the number of infected grains by two times for wheat and 3.6 times for barley. The application also increases the chlorophylls and carotenoids in both uninfected and infected seedlings. Conclusions The results demonstrated a robust application of nano-particles in improving cereal production. Graphical Abstract

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To avoid the instability and degradation of downhole injection fluids, such as polymers and surfactants, for use in high-temperature (HT) offshore reservoirs, nanofluids with particles modified in different ways have been proposed as a capable thermoresistant, highly active solutions which can be used in many offshore oil and gas exploitation works, especially in enhancing oil recovery. This study presented the process of synthesising two nanocomposite materials for nanofluid preparation. First, magnetite nanoparticles (MNPs(A and B)) were prepared by standard coprecipitation and hydrothermal methods. Then, polymer-coated magnetite nanoparticles (PCM(A) and PCM(B)) were synthesised by directly covering magnetite with oleic acid (OA) to get OA-MNPs, and then simultaneously enveloped with copolymers of acrylamide and the N-vinyl pyrrolidone via polymerisation reaction. The obtained PCMs characteristics were analysed by all required analytical tools. In addition, the thermostability of PCM-based nanofluids as downhole injection agents for HT offshore reservoir applications was investigated by bottle test annealing PCM(A)- and PCM(B)- based nanofluids at the White Tiger (WT) Miocene and Oligocene reservoir temperatures. Based on the obtained data, MNPs have an average particle size of 12 nm and 10 nm for MNPs A and B. A dominant phase of magnetite (Fe3O4) and 10.5% and 11% of the mass of PCM belong to their copolymer coating. The good thermostability of nanofluids annealed for 31 days (at 120 °C for PCM(A)- and 134 °C for PCM(B)-based nanofluids) showed a promised orientation for use as an EOR agent in HT offshore reservoirs recommendation.