Screening key parameters affecting stability of graphene oxide and hydrolyzed polyacrylamide hybrid: Relevant for EOR application

Graphene oxide-enhanced hydrolyzed polyacrylamide (GOeH) hybrids present a promising advancement for enhanced oil recovery (EOR), addressing a knowledge gap in understanding the stability of these materials under different conditions. The current study investigates how key parameters, including polymer concentration (1000 and 1500 ppm), graphene oxide (GO) concentration (100 and 300 ppm), salinity (seawater and 0.1 seawater), and the presence or absence of divalent ions (Mg²⁺), affect the stability of GOeH hybrids at high temperatures (80 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mo>°C</mml:mo></mml:mrow> </mml:math> ). A 2^K-full factorial experimental design and analysis of variance (ANOVA) were employed to quantify these effects. GO was synthesized and characterized using common methods, including XRD, FTIR, Raman, and DLS analysis. Zeta potential was used to assess stability over 21 days, while the sedimentation method measured instability. ANOVA results reveal that, within the studied range, neither polymer concentration nor the presence or absence of Mg²⁺ significantly impacts stability. However, both factors seem to contribute positively to long-term stability. Notably, GO concentration has a significant positive effect on stability, with a percent contribution of 38.24 %, suggesting that higher GO concentrations enhance the stability of the GOeH hybrid. Conversely, salinity has a statistically significant negative impact on stability, potentially due to the salt-in effect. Additionally, the interaction between polymer concentration and Mg²⁺ shows a borderline significant effect, indicating that excessive cross-linking at higher polymer concentrations could reduce stability. These findings offer valuable insights into optimizing EOR strategies, aiding in developing more effective approaches to utilizing GOeH hybrids for different conditions.