The synthesis of various nanoscale materials, such as nanoparticles, nanowires of Au, Pt, Ni Co, Fe, Ag etc., by electrodeposition techniques have been demonstrated in this article. Both potentiostatic and galvanostatic methods were employed to carry out the electrodeposition process under different potential ranges, time durations, and current densities. The electrochemical behavior of the deposited nanoparticles on various substrates was investigated by cyclic voltammetric and chronoamperometric techniques. The synthesis of mono-dispersed gold (Au) nanoparticles on indium tin oxide (ITO) coated glass, preparation of Au nanorods on nanoporous anodic alumina oxide (AAO), formation of Au nanoclusters on polypyrrole-modified glassy carbon electrode and one-step electrodeposition of nickel nanoparticle chains embedded in TiO 2 etc. have been highlighted in this article. The potential applications of synthesized nanoparticles such as the role of maghemite (Fe 2 O 3 ) in arsenic remediation, higher electrocatalytic activity of Ag nanoclusters for the reduction of benzyl chloride, and the role of C 60 nanoparticle-doped carbon film in fabrication processes are also presented in this article.

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The Mancos shale core sample investigated in the present research has been extracted from the late Cretaceous (upper cretaceous) geologic formation of USA. Shale gas is usually obtained by horizontal drilling which induces fractures to increase the flow ability of hydrocarbons. Therefore, it is important to understand the mechanical properties, heterogeneity, and their complexities associated with elastic properties of shale. An experimental study was conducted to examine the morphological characteristics of the Mancos shale core sample both pre- and post-treatment with cryogenic liquid nitrogen (LN2) for various immersion times, namely, 30, 60, and 90 min. The atomic force microscopy technique is used to understand the surface roughness, irregularities in core samples, and for more accuracy. Scanning electron microscopy (SEM) results were employed to visualize the formation of cracks caused by cryogenic liquid nitrogen. Results from SEM showed an increase in the fracture size from 2 to 25 μm with an increase in the aging time up to 90 min under the atmosphere of cryogenic LN2. Nano-indentation measurements revealed that the nano-indentation moduli of the Mancos samples subjected to applied forces of 50 and 200 mN underwent a decrease from 24.6 to 16.8 and 15.6 GPa, respectively, with an increase in cryogenic liquid nitrogen treatment time to 90 min. The permeability of the shale samples after LN2 treatment showed a significant increase, whereas increasing net confining stress from 1000 to 7000 psi for all untreated and treated rock samples exhibited a decrease in permeability, which is attributed to increased compaction between the pore spaces. Moreover, the porosity of the Mancos shale increased from 3.78 to 6.92% for pretreated and treated rock samples.

The energy industry is exploring sustainable chemistry and engineering solutions for exploitation of shale reservoirs. Smectite-rich shale is challenging to drill with traditional water-based drilling fluid (WBDF). The objectives of this study are (i) to investigate acute toxicity of drilling fluids and (ii) to enhance the rheological properties, lubricity, and clay inhibition behavior of WBDF by adding Tween 80 (T80)/ZnO nanoparticles. Acute toxicity results revealed 100% survival rate of white leg shrimp in WBDF waste. At 0.7 g, the optimum concentration of T80ZnO, the plastic viscosity (PV) was improved by 12%; the negative surface charge of nanomaterial might have improved repulsion forces/stability and enhanced viscosity in the drilling fluids. Yield point (YP) was improved by 71%, moreover 10 min gel strength (GS) and 10 s GS were significantly increased by 32 and 54%, respectively. The metal oxide nanosolids induced heat transfer characteristics and ensured gelling and yield strength properties. Lubricity was slightly increased by 7%; the ZnO nanorods between the two sliding contact surfaces (i.e., assuming drill pipe and casing) improved lubricity. Filtrate loss (FL) volume was considerably minimized to 17 and 30% at API and high-pressure, high-temperature (HPHT) conditions, respectively; this observation could be explained by pores plugging in the filter paper. Heated clay swelling inhibition was optimized after addition of 0.6 g of T80ZnO nanoparticles to WBDF. The clay inhibition was enhanced by 9 and 17% when compared to conventional WBDF and fresh water, respectively; this progress might have attributed to the corresponding: (i) pores plugging in the clay and (ii) interparticle pores bridging between existing drilling additives and nanomaterial. The above findings identify that this drilling fluid could attain sustainable environmental and operational success while drilling into montmorillonite/smectite rich-clay and shale rock.

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