The concept of heating the near-wellbore zone (NWZ) using activated aluminum alloys offers a novel approach to enhancing oil recovery. This article reviews research on the development of hydrocarbon-based solvent formulations for removing asphaltene–resin–paraffin deposits (ARPD) in the NWZ and restoring well productivity. A comprehensive analysis of ARPD composition enabled the selection of solvent systems tailored to specific deposit types. The efficiency of ARPD removal from the NWZ, downhole equipment, and oil gathering systems in heavy and highly viscous Kazakhstani crude oils was evaluated using hydrocarbon solvent blends (e.g., hexane–toluene, gasoline–o-xylene, o-xylene–hexane–1-hexene) with surfactants (polyoxyethylene sorbitan–maleic anhydride esters), atactic polypropylene (APP), and activated aluminum alloys. The developed formulations accelerated ARPD breakdown and reduced energy consumption. It has been established that the optimal concentration of APP (0.5 wt.%) provides up to 100% cleaning efficiency and increases dissolving capacity by 25–30% compared to traditional binary systems. Cleaning efficiency is driven by a thermochemical reaction between water and the aluminum alloy, 2Al + 6H2O → 2Al(OH)3 + 3H2↑ + 17 kJ, which depends on the alloy’s microstructure, grain boundary condition, and additive distribution. The exothermic effect of the reaction leads to the formation of a hot gas–steam–hydrogen mixture, where atomic hydrogen actively breaks down ARPD and increases the reservoir permeability by 2 to 4.5 times. Results show that a composite formulation of hexane–toluene–alloy–H2O2 (46.5:15:0.25:38.25) reduces the treatment time of ARPD-3 from 60 to 10 min while maintaining high efficiency at the level of 98.3%.
The relevance of this study is determined by the need for new technological solutions to enhance the productivity of wells producing heavy and highly viscous crude oil. The work investigates multicomponent Al–Ga–In–Sn alloys as reactive systems capable of generating heat and hydrogen upon contact with water. The focus is placed on optimizing melting parameters and assessing how alloy composition and structural features affect reactivity. Phase composition was analyzed by X-ray diffraction, microstructure by SEM-EDX, and elemental composition by XRF. The results show that the hydrogen generation rate and heat release depend on melting temperature, holding time, and ratios of activating metals, as well as the physicochemical properties of the formation water, particularly salinity and pH. Reaction enthalpy and conversion efficiency were quantified. The highest hydrogen output and thermal effect were observed for the following compositions—90 wt.% Al, 5 wt.% Ga, 2.5 wt.% In, 2.5 wt.% Sn; and 85 wt.% Al, 5 wt.% Ga, 5 wt.% In, 5 wt.% Sn (825 °C, 30 min). Rapid heat and gas release is attributed to the eutectic structure and micro-galvanic interaction, which eliminate the induction period. These findings demonstrate the potential of such alloys for in situ heating, enhanced oil recovery, and autonomous hydrogen-energy applications.
1 January 2020 in Chemical Bulletin of Kazakh National University
Molybdenum is one of the most important uranium-related metals. In the ores of many deposits, the molybdenum content is comparable to the uranium content. The processing of complex uranium-molybdenum ores is based on the methods of acid and soda autoclave leaching, in which uranium and molybdenum pass into solution. At the present time, the associated extraction of molybdenum by the sorption method has been developed and introduced. In this case, the capacity of ion exchangers with respect to uranium and molybdenum substantially depends on the salt composition of the medium. The aim of this work is to study the sorption of molybdenum from a carbonate leach solution on BD-301G-I anion exchange resin in the presence of the most common anionic impurities in industrial solutions. Studies of the sorption capacity of anion exchange resin with respect to molybdenum were carried out under static conditions with stirring of the solution with the sorbent during eight hours. Sorption of molybdenum was carried out from carbonate solutions with the corresponding given concentrations of impurity components. According to the results of studies, it was found that, according to the strength of the depressing effect, the considered anions arranged in the following row: S2O32- > NO3- > Cl- > SO42- > HCO3- > CO32- > PO43-. The results of this study can be used to further study the sorption of molybdenum from real industrial solutions of carbonate leaching.