Synthesized graphene oxide and fumed aerosil 380 dispersion stability and characterization with partially hydrolyzed polyacrylamide

Experimental insights into the stability of graphene oxide nanosheet and polymer hybrid coupled by ANOVA statistical analysis

The synergistic potential of using graphene oxide (GO) nanosheets and hydrolyzed polyacrylamide (HPAM) as GO enhanced polymer hybrid (GOeP) for enhancing oil recovery (EOR) purposes has drawn attention. However, the hybridization method and stability of GOeP have not been comprehensively studied. To cover this gap, the current study evaluates the stability of GOeP under different conditions, including temperatures such as 60 and 80 °C, high and low salinities, and the presence of Mg2+ ions (6430 and 643 ppm). Hence, GO nanosheets were synthesized and characterized through XRD, Raman, FTIR, and DLS techniques. The performance of five preparation methods was assessed to determine their ability to produce stable hybrids. Zeta potential and sedimentation methods, coupled with the ANOVA statistical technique, were used for measuring and interpreting stability for 21 days. Results revealed that the stability of GOeP in the presence of brine is influenced by hydrolyzation duration, the composition of the water used in polymer hydrolyzation, the form of additives (being powdery or in aqueous solution), and the dispersion quality, including whether the GO solution was prediluted. The results revealed that the positive impact of higher temperatures on the long-term stability of GOeP is approximately seven times less significant than the reduction in stability caused by salinity. Under elevated salinity conditions, a higher Mg2+ concentration led to an 80% decrease in long-term stability, whereas the temperature impact was negligible. These findings highlight the potential of GOeP for EOR applications, offering insights into optimizing stability under challenging reservoir conditions.

Effect of Temperature and Alkali Solution to Activate Diethyl Carbonate for Improving Rheological Properties of Modified Hydroxyethyl Methyl Cellulose

The applications of cellulose ethers in the petroleum industry represent various limitations in maintaining their rheological properties with an increase in both concentration and temperature. This paper proposed a new method to improve the rheological properties of hydroxyethyl methyl cellulose (HEMC) by incorporating diethyl carbonate (DEC) as a transesterification agent and alkali base solutions. Fourier transform infrared (FTIR) analysis confirmed the grafting of both composites onto the HEMC surface. The addition of sodium hydroxide (NaOH) improved the stability of the polymeric solution as observed from ζ-potential measurement. Shear viscosity and frequency sweep experiments were conducted at concentrations of 0.25-1 wt % at ambient and elevated temperatures ranging from 80-110 °C using a rheometer. In the results, the increase in viscosity at specific times and temperatures indicated the activation of DEC through the saponification reactions with alkali solutions. All polymeric solutions exhibited shear-thinning behavior and were fitted well by the Cross model. NaOH-based modified solution exhibited low shear viscosity compared to the DEC-HEMC solution at ambient temperature. However, at 110 °C, its viscosity exceeded that of the DEC-HEMC solution due to the activation of DEC. In frequency sweep analysis, the loss modulus (G″) was greater than the storage modulus (G') at lower frequencies and vice versa at higher frequencies. This signifies the viscoelastic behavior of modified solutions at 0.50 wt % and higher concentrations. The flow point (G' = G″) shifted to a low frequency, indicating the increasing dominance of elastic behavior with the rising temperature. At 110 °C, the NaOH-based modified solution exhibited both viscous and elastic behavior, confirming the solution's thermal stability and flowability. In conclusion, modified HEMC solution was found to be effective in controlling viscosity under ambient conditions, enhancing solubility, and improving thermal stability. This modified composite could play a significant role in optimizing viscoelastic properties and fluid performance under challenging wellbore conditions.

Utilization of synthesized silane-based silica Janus nanoparticles to improve foam stability applicable in oil production: static study

This study investigated the effect of silane-based silica (SiO2) Janus nanoparticles (JNPs) on stabilizing the foam generated by different types of gases. Two types of SiO2 JNPs were synthesized through surface modification using HMDS and APTS silane compounds. Static analyses were conducted to examine the impact of different concentrations of the synthesized nanoparticles in various atmospheres (air, CO2, and CH4) on surface tension, foamability, and foam stability. The results indicated that the synthesized SiO2 JNPs and bare SiO2 nanoparticles exhibited nearly the same ability to reduce surface tension at ambient temperature and pressure. Both of these nanoparticles reduced the surface tension from 71 to 58-59 mN m-1 at 15,000 ppm and 25 °C. While bare SiO2 nanoparticles exhibited no foamability, the synthesis of SiO2 JNPs significantly enhanced their ability to generate and stabilize gas foam. The foamability of HMDS-SiO2 JNPs started at a higher concentration than APTS-SiO2 JNPs (6000 ppm compared to 4000 ppm, respectively). The type of gas atmosphere played a crucial role in the efficiency of the synthesized JNPs. In a CH4 medium, the foamability of synthesized JNPs was superior to that in air and CO2. At a concentration of 1500 ppm in a CH4 medium, HMDS-SiO2 and APTS-SiO2 JNPs could stabilize the generated foam for 36 and 12 min, respectively. Due to the very low dissolution of CO2 gas in water at ambient pressure, the potential of synthesized JNPs decreased in this medium. Finally, it was found that HMDS-SiO2 JNPs exhibited better foamability and foam stability in all gas mediums compared to APTS-SiO2 JNPs for use in oil reservoirs. Also, the optimal performance of these JNPs was observed at a concentration of 15,000 ppm in a methane gas medium.

Modification of Cellulose Ether with Organic Carbonate for Enhanced Thermal and Rheological Properties: Characterization and Analysis

Reduction in viscosity at higher temperatures is the main limitation of utilizing cellulose ethers in high thermal reservoir conditions for petroleum industry applications. In this study, cellulose ether (hydroxyethyl methyl cellulose (HEMC)) is modified using organic carbonates, i.e., propylene carbonate (PC) and diethyl carbonate (DEC), to overcome the limitation of reduced viscosity at high temperatures. The polymer composites were characterized through various analytical techniques, including Fourier-transform infrared (FTIR), H-NMR, X-ray diffraction (XRD), scanning electron microscope (SEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), ζ-potential measurement, molecular weight determination, and rheology measurements. The experimental results of structural and morphological characterization confirm the modification and formation of a new organic carbonate-based cellulose ether. The thermal analysis revealed that the modified composites have greater stability, as the modified samples demonstrated higher vaporization and decomposition temperatures. ζ-potential measurement indicates higher stability of DEC- and PC-modified composites. The relative viscometry measurement revealed that the modification increased the molecular weight of PC- and DEC-containing polymers, up to 93,000 and 99,000 g/moL, respectively. Moreover, the modified composites exhibited higher levels of stability, shear strength and thermal resistance as confirmed by viscosity measurement through rheology determination. The observed increase in viscosity is likely due to the enhanced inter- and intramolecular interaction and higher molecular weight of modified composites. The organic carbonate performed as a transesterification agent that improves the overall properties of cellulose ether (HEMC) at elevated temperatures as concluded from this study. The modification approach in this study will open the doors to new applications and will be beneficial for substantial development in the petroleum industry.