Assessment of modified chitosan composite in acidic reservoirs through pilot and field-scale simulation studies.

Chemical flooding through biopolymers acquires higher attention, especially in acidic reservoirs. This research focuses on the application of biopolymers in chemical flooding for enhanced oil recovery in acidic reservoirs, with a particular emphasis on modified chitosan. The modification process involved combining chitosan with vinyl/silane monomers via emulsion polymerization, followed by an assessment of its rheological behavior under simulated reservoir conditions, including salinity, temperature, pressure, and medium pH. Laboratory-scale flooding experiments were carried out using both the original and modified chitosan at conditions of 2200 psi, 135,000 ppm salinity, and 196° temperature. The study evaluated the impact of pressure on the rheological properties of both chitosan forms, finding that the modified composite was better suited to acidic environments, showing enhanced resistance to pressure effects with a significant increase in viscosity and an 11% improvement in oil recovery over the 5% achieved with the unmodified chitosan. Advanced modeling and simulation techniques, particularly using the tNavigator Simulator on the Bahariya formations in the Western Desert, were employed to further understand the polymer solution dynamics in reservoir contexts and to predict key petroleum engineering metrics. The simulation results underscored the effectiveness of the chitosan composite in increasing oil recovery rates, with the composite outperforming both its native counterpart and traditional water flooding, achieving a recovery factor of 48%, compared to 39% and 37% for native chitosan and water flooding, thereby demonstrating the potential benefits of chitosan composites in enhancing oil recovery operations.

Investigating the potential antiviral activity drugs against SARS-CoV-2 by molecular docking simulation.

Recently, scary viral pneumonia is known as (COVID-19) has swept the whole world. The new virus strain designated as SARS-CoV-2 belonging to the coronavirus family. Although the current medical research directed towards the development of a novel therapeutic agent, no anti-viral drug approved until now. On the medical scale, the development of an approved drug is a time-consuming process, so research is directed towards screening of ligands and drugs multimodal structure-based-design and then docked to the main viral protease to investigate the active binding sites. The bioinformatic approaches used to evaluate the competence of a comprehensive range of ligands and drugs before their clinical implementation. In this study, a computational approach through molecular docking simulation is conducted for screening the antiviral activity of drugs, natural sources, and inhibitory compounds against the SARS-CoV-2 genome. The main virus protease was collected from a Protein Data Bank (PDB# 6YB7) and docked with a sequence of 19 approved antiviral drugs, 10 natural inhibitory ligands against COVID-19 downloaded from PubChem, in addition to 10 natural sources optimized for Escherichia coli BL21 (DE3) to identify the antiviral activity of these candidates against COVID-19. The docking results were promised and indicated that the reported ligands can firmly bind to the SARS-CoV-2 main protease and leads to inhibition of its infectious impact.

Synthesis of acryloylated starch-g-poly acrylates crosslinked polymer functionalized by emulsified vinyltrimethylsilane derivative as a novel EOR agent for severe polymer flooding strategy.

Starch is a natural polysaccharide with reasonable biodegradable properties, which grafted with vinyl monomers through different initiators to be applied in enhanced oil recovery (EOR) techniques. Several authors stated about starch modification through copolymerization and grafting of different monomers, however, these derivatives have some drawbacks related to bacterial biodegradation, ionic and thermal aging under severe reservoir conditions. The present study reported the preparation of grafted acryloylated starch with acrylamide/acrylic acid monomers and vinyltrimethylsilane through initiation copolymerization with the aid of quaternary ammonium-based surfmer. The chemical analysis generated by various spectroscopic analysis comprising IR, NMR, meanwhile particles distribution estimated through DLS. The embedded silica through a polymer matrix photographed by TEM, SEM and EDX elementary analysis, and the thermal effect determined by thermal gravimetric analysis. The rheological analysis estimated relative to shear degradation, ionic strength, and thermal aging at imitated reservoir environment. Flooding runs performed on linear non-consolidated sandstone model at nearly practical field conditions, where the displaced oil by polymer effect was recorded through the volumetric collector. The flooding tests designate that the synthesized starch-g-copolymer is prospering for chemical flooding applications under severe reservoir conditions, and achieve a recovery factor of 46% Sor.

Synthesis of starch functionalized sulfonic acid co-imidazolium/silica composite for improving oil recovery through chemical flooding technologies.

Polymer flooding in HPHT reservoirs using modified biopolymers and their composites acquire incremental attention nowadays. Some literature reported about limitations of native starch through enhanced oil recovery applications regarding bacterial degradation, thermal and ionic stability under severe reservoir environment. In the present study, functionalization of the starch biopolymer with thiol derivative then oxidation of thiol to sulfonic acid by environmentally friendly oxidants has been prepared and confirmed, after that starch derivative copolymerized with vinyl-containing monomers by free radical/redox emulsion polymerization in presence of silica seeds. Spectroscopic characterization and structure determination carried out by different spectroscopic techniques comprising FTIR, 1H NMR, while particles size measured through DLS and TEM, and thermal analysis determined by TGA analysis. Evaluation of the prepared composite as a novel enhanced oil recovery (EOR) candidate as well as the precursors conducted at simulated reservoir condition, where the oil recovery factor and water cut percentage calculated relevant to injected pore volume. The flooding data indicate that the prepared starch functionalized sulfonic acid co-imidazolium/silica composite is favorable for enhanced oil recovery applications as it can withstand high temperature and salinity conditions and the recovery factor reaches 39% of residual oil saturation.

Synthesis and evaluation of acryloylated starch-g-poly (Acrylamide/Vinylmethacrylate/1-Vinyl-2-pyrrolidone) crosslinked terpolymer functionalized by dimethylphenylvinylsilane derivative as a novel polymer-flooding agent.

Starch is a natural biopolymer that subjected to various chemical modifications through different industrial applications. Molecular structure of starch allow its grafting with different vinyl monomers in the presence of crosslinking agents to synthesize cross-linked hydrogels, which used in enhanced oil recovery (EOR) applications, water shutoff and drag reduction. Application of native starch in the field of petroleum reservoirs as a flooding agent suffer from some limitations concerned with microbial degradation, thermal and salinity resistance under harsh petroleum reservoir conditions. In the current research, we stated the synthesis of acryloylated starch then it's grafting with poly (Acrylamide/Vinylmethacrylate/1-Vinyl-2-pyrrolidone) terpolymer in presence of dimethylphenylvinylsilane through emulsification polymerization. Characterization and structure determination occur by different spectroscopic techniques as stated throughout the manuscript. Rheological and solution properties carried out as a function of shear rate, salinity and temperature at simulated reservoir conditions. Flooding tests carried out through linear-dimensional sandstone model at simulated reservoir conditions, and recovered oil amount calculated on volumetric basis. The obtained results indicate that the prepared starch-g-terpolymer can tolerate to severe flooding conditions of high temperature and salinity, moreover it can increase recovery factor up to 49% of residual oil saturation so considered as a promised EOR candidate.