Do you know how many gallons of water are injected into disposal
wells each day? I’ll give you a hint, the number is in the billions. In the
United States, over 2 billion gallons of brine (water saturated with salt) are
injected into Class II disposal wells every
day. This water is the flowback fluid from hydraulic fracturing, the
water that returns to the surface. Keep reading to learn the basics.
What is a Class II Well?
The EPA has well classifications based on the fluids to be
injected, and Class II wells are for fluids associated with natural gas and oil
production. There are three types of Class II wells: enhanced recovery wells,
hydrocarbon storage wells, and disposal wells. There are approximately
144,000 Class II wells in operation within the United States. The EPA states
that as much as 20% of all Class II wells are disposal wells.
What is a Disposal Well?
What, exactly, is a disposal well? Disposal wells are used
to inject fluid into an underground well that is not producing oil and gas. Historically,
underground injection has been the primary disposal method used by the natural
gas and oil industry for their produced water. These wells allow the companies
to return the water produced during fracking to deep underground porous rock
formations. Fluids include water, wastewater, brine (salt water), and water
mixed with chemicals. Companies began the widespread use of injection of produced
water generated during oil production into disposal wells in the 1930’s (EPA page). Discharging flowback fluids into disposal wells requires a
National Pollutant Discharge Elimination System Permit (NPDES) under the Clean Water Act.
What are the Other Options?
Aside from disposal wells, other disposal options include:
recycling for re-use in additional fracking jobs (which conserves water), treatment
and discharge to surface waters, and storage in open air pits. One estimate by the EPA is that the water usage for hydraulic fracturing is 70
to 140 billion gallons annually, which is equivalent to the amount of water
used in one to two cities of 2.5 million people. With such large water usage, recycling the water for re-use
would be a great option over injecting it into disposal wells.
Oil Skimmers are a great first step in recycling and re-using the flowback fluid by removing any oils and greases. Visit our website to learn more about tube Oil Skimmers. The Model 6V or the Model 5H can help remove waste oil from the surface of water or other liquids.
