Enhancing cement properties for oil wells using MgO-PAM nanocomposites

Achieving an optimal balance between cement weight, viscosity, strength, and fluid loss is a persistent challenge in well cementing, especially in oil and gas applications. This study investigates the potential of MgO-PAM (polyacrylamide) nanocomposite as an additive to enhance the performance of Class-G cement. This research introduces a novel application of MgO-PAM nanocomposite in cement modification, addressing critical challenges in durability, viscosity control, and permeability reduction for oil and gas well cementing under extreme conditions. The study represents a unique approach by optimizing the synergy between magnesia nanoparticles and polyacrylamide, achieving significant mechanical and structural improvements not previously demonstrated in this combination. In this study, a base cement was formulated with a 50% water-cement ratio (WCR) and 10% pozzolan, and its properties were compared with modified formulations incorporating either 1 wt% polymer (PC) or 1 wt% nanocomposite (NC). The addition of the polymer and nanocomposite improved the cement slurry's viscosity by 12% and 14%, respectively, and reduced fluid loss from 122 to 45 mL and 32 mL. Furthermore, the thickening time (time before reaching the slurry viscosity to 100 cp) was extended from 9 h for the base cement to 13 h for the polymer and 14 h for the nanocomposite. Calorimetric results confirmed that the modified cements showed increased hydration energy in the second peak, indicating improved hydration. After curing, the compressive strength of the polymer-modified cement increased by 17% and 19% at 7 and 28 days, respectively, while the nanocomposite cement exhibited even more pronounced improvements of 32% and 35%. Permeability was significantly reduced, with values reaching 0.5 mD, 0.8 mD, and 0.1 mD for the base, polymer, and nanocomposite cement, respectively. Microscopic analysis (SEM) revealed that the nanocomposite-modified cement exhibited a more uniform microstructure with minimal porosity compared to the polymer-modified cement, which showed particle settling and voids. These findings demonstrate the superior performance of the MgO-PAM nanocomposite in improving cement's mechanical properties, fluid loss control, and long-term durability, providing significant advantages for oil and gas well integrity.