Swelling performance of sodium polyacrylate and poly(acrylamide-co-acrylic acid) potassium salt.

The application of superabsorbent polymer hydrogels in the oil and gas industry for reservoir and well management is gaining more traction. In this study, the swelling performance and adsorption kinetics of two commercial superabsorbent polymer hydrogels - poly(acrylamide-co-acrylic acid) potassium salt and sodium polyacrylate - were evaluated, based upon their stimuli response to pH and salinity at varying temperature and reaction time periods. Characterisation and evaluation of the materials were performed using analytical techniques - optical microscopy, scanning electron microscopy, thermal gravimetric analysis and the gravimetric method. Experimental results show that reaction conditions strongly influence the swelling performance of the superabsorbent polymer hydrogels considered in this study. Generally, increasing pH and salinity concentration led to a significant decline in the swelling performance of both superabsorbent polymer hydrogels. An optimal temperature range between 50°C and 75°C was considered appropriate, based on swell tests performed between 25°C to 100°C over 2-, 4- and 6-hour time periods. These findings serve as a guideline for field engineers in the use of superabsorbent polymer hydrogels for a wide range of oilfield applications. The study results provide evidence that the two superabsorbent polymer hydrogels can be used for petroleum fraction-saline water emulsions separation, reservoir zonal isolation, water shutoff and cement plugging applications.