If oil and gas drilling is happening near you, you most likely have questions about the impact it could have on land and water resources. FracFocus was designed to help you find what you need to know to be well-informed – specifically, in the area of hydraulic fracturing chemical use and disclosure.
To understand what hydraulic fracturing is, it helps to first understand what it is not. Fracturing is not a drilling process. It is a technology employed after a hole is drilled. It uses materials, carried by fluid at high pressure, to create or expand small fractures in a formation. These fractures facilitate the flow of natural gas or oil, allowing significantly greater amounts of the resource to be recovered.
The formations that contain oil and gas are located hundreds or thousands of feet below the surface. Thanks to horizontal drilling technology , these resources can be reached as far as several thousand feet away from the vertical well bore.
Hydraulic Fracturing Fluids
Because hydraulic fracturing typically uses large volumes of fluids, with some chemical additives, which are pumped under high pressure, operators have a great responsibility to assure that hydraulic fracturing fluids do not impact land or water resources during the fracturing process. Regulations, enforced by the states, provide operators with a set of requirements designed to prevent land and water contamination from hydraulic fracturing.
Fluid is managed in three ways:
- In ground impoundments, called pits, are used to hold flowback fluids. These are typically lined with compacted clay or synthetic materials to prevent seepage.
- Tanks are used as aboveground containment systems.
- As an alternative to pits, closed-loop fluid-handling systems are used to store fluids within a series of pipes and tanks throughout the entire fluid storage process.
After the fracturing process is complete, flowback fluids – liquids that return to the surface – are most often disposed of as waste. The most common disposal method is underground injection through wells, constructed of protective casing and cement, which carry the fluids into porous geologic formations. In areas unsuited for safe isolation, the fluids may sometimes be treated and discharged or transported to a location where formations which can hold the fluids are available.
You may see an injection well referred to as belonging to one of six classes (I-VI). The EPA uses these classifications to categorize wells according to their function, construction and operating features, which in turn ensures appropriate technical requirements, are met. Wells that inject oil and gas produced fluids are called Class II wells.