This study suggests a polymer nanocomposite gel system that can effectively be used as water shutoff material for high temperature reservoirs. Based on nanotechnology, a novel cost effective and ecofriendly polymer gel formulation is presented. This newly developed material extends the temperature limitations for high temperature reservoirs.
In particular, this paper reports an innovative graphene-based zirconium oxide nanocomposite as a crosslinker for water shutoff utilizing polyacrylamide polymer and its derivatives. Thermogravimetric analysis (TGA) and X-ray diffraction (XRD) were utilized to characterize the fabricated gel samples. The microstructure of the polymer nanocomposite gel was analyzed using scanning electron microscopy (SEM). The new developed formulation of the nanocomposite gel fluid was evaluated by rheometer tests at different ranges of pH (temperature up to 330°F) to study the gelation behavior and performance of the system for water shutoff application. Furthermore, the newly developed fluid system was injected into core samples to evaluate the ability of the gel to resist extrusion and determine the strength of the treatment under reservoir conditions. The polymer nanocomposite gel showed surprising mechanical properties with extraordinary thermal properties at elevated temperature. The TGA result revealed a remarkable shift of three main decomposition regimes at high temperatures, which confirms the enhancement of thermal stability of the synthesized nanocomposites polymer gel. The XRD pattern of the polymer gel had peaks that confirm the existence of the graphene and zirconium oxide in the system. The SEM images showed that this new class of polymer gel has a homogeneously distributed 3D network microstructure. The small size of the gel grid pores made the network structure thermally stable and firmly locked water within the gel even under high temperatures. The addition of sodium carbonate could also elongate the gelation time from ~70min. to 104 min at high temprature (330°F). The core flooding results showed a significant drop in water production for the sandstone matrix core that had higher permeability before the treatment.
The developed nanocomposites polymer gel with enhanced mechanical and thermal stability can significantly reduce excess water production within high temperature reservoirs at lower costs than the currently available polymer gels.