Integration of surfactants and time release nutrients with pneumatic fracturing process

The objective of this laboratory study was the development of two novel improvements to the pneumatic fracturing process which would extend its present application. The first involved use of surfactant during pneumatic injection, and the second was subsurface injection of time-release dry nutrient pellets for enhancement of in situ biodegradation. Bench scale tests demonstrated that pneumatic fracturing can be successfully performed with air containing a surfactant solution (foam fracturing). The results showed that foam fracturing followed by increased the rate of surrogate contaminant removal from 8% to 10% compared with regular pneumatic fracturing. These increases were attributed to enlarged fracture networks and increased airflow. Commercially available anionic surfactants, which are biodegradable, were used for the process. Recommendations for field scale applications were also developed. It was also shown that injection of time release nutrient pellets into subsoil during pneumatic fracturing is feasible. Bench scale equipment for this process was developed and tested. Mechanical damage of the nutrient pellets during pneumatic injection was evaluated by different methods, and it was determined that serious damage was sustained above 75 psi. These results suggest pellets with higher mechanical strength characteristics are necessary for successful field integration with pneumatic fracturing process