ABSTRACT
This chapter focuses on hydraulic fracturing in the context of enhanced hydrocarbon recovery, and its implications on groundwater resources. The extraction of shale gas from formations with lower permeabilities compared to other rock formations has became economical with the emergence of relatively newer technologies such as hydraulic fracturing and precision drilling of wells. The extraction of shale gas using hydraulic fracturing has increased estimates of natural gas resources enormously in many countries, with an overall worldwide increase from 18 to 118 trillion cubic meters. Hydraulic fracturing artificially enhances fractures or cleans out non-water-producing veins that are clogged, thereby providing a clear transport pathway for groundwater flow into the well. The amounts of chemicals added to injection fluids define the maximum possible mass and concentrations of chemical additives that can be released to contaminate groundwater or otherwise impact the environment. Well stimulation and associated activities may result in the release of contaminants into the environment, including surface and groundwater resources.
