Investigation on the development of Novel PAM structure as high-performance clay inhibitor in HT/HP conditions by using functional groups

Abstract

Polyacrylamide (PAM) molecular structures are not stable at higher temperatures, limiting their effectiveness in water-based drilling fluid (WBDF) applications. This study focuses on identifying functional groups that can enhance the thermal stability of PAM structure. It presents a comprehensive and comparative analysis of the swelling inhibition capacity of both low and high molecular weight (MW) PAM-based polymers at high temperature and high pressure (HT/HP). The mechanism by which modified PAM interacts with and adsorbs to the clay (Na-MMT) surface is examined, along with an analysis of the surface properties of the clay minerals. Therefore, molecular dynamic (MD) simulation results revealed that the Novel PAM polymers with high MW containing ethyl and benzyl groups demonstrate greater stability and more controlled deformation behavior compared to conventional PAM at HT conditions. Surface modification and hydrophobic effects were observed in the interactions between polymers and Na-MMT. Low MW PAM-based polymers showed larger fluctuations in d-spacing, indicating various or more disruptive interactions. In contrast, the insertion of high MW PAM-based polymer resulted in significantly narrower and lower d-spacing fluctuation ranges. The Novel PAM exhibited superior performance, providing lower d-spacing fluctuations compared to both low MW PAM-based polymers and standard PAM. Across a temperature range from 300 to 600°K, the Novel PAM consistently improved polymer adsorption on the Na-MMT surface compared to standard PAM. Indicating that the modifications effectively reduce the interaction between Na-MMT particles and water molecules while enhancing the interaction between the polymer and Na-MMT, potentially leading to more stable structures in HT/HP environments. The enhanced stability suggests that Novel PAM is more suitable for WBDF applications, as it is less prone to structural changes and can maintain its integrity under harsh conditions. The modifications provide the polymer with better resilience, potentially leading to improved performance in practical applications.