Wells used for hydraulic fracturing are more than just holes in the ground. Typically reaching depths a mile or more below the surface, these wells can also extend for more than a mile in several directions horizontally. The process of drilling and producing such a well in a safe and controlled manner is referred to as well integrity. Well integrity engineers are responsible for designing the systems that protect both people and the environment during the drilling process and through the production life of the well.
The steel casing and cement sheaths installed in the well are critical to containing the integrity of the well. Geologic conditions and state regulations, which oversee water location, quality and protection, dictate the number of barriers that are installed. In most cases, two to eight barriers are sealed in place to ensure safe well construction and drinking-water protection.
Well integrity involves a system of tools, monitoring equipment, and well test data to monitor well activity beneath the surface during drilling and production to ensure the well is under control at all times.