What is a Disposal Injection Well?
Injection wells are vertical pipes drilled into deep layers of rock. Drilling companies use the wells to dispose of wastewater produced as a result of hydraulic fracturing, or “fracking.” The wells utilize the earth’s soil and bedrock to filter and treat the contaminated water, which is then spread across a wide subsection of the surrounding bedrock for final storage.
Disposal injection, a cost-effective technique, is viewed by many energy companies as the best way to dispose water waste.
Other disposal alternatives involve directly discharging treated wastes into receiving waters, or utilizing treated water for irrigation purposes. Both techniques can suffer from prohibitive financial and environmental costs, as well as large electric and maintenance requirements. Recycling of wastewater has not taken off the industry, either, meaning that billions of gallons of wastewater from drilling are being sent underground for disposal in Texas.
Texas is not immune to the disposal well-and-manmade-earthquakes trend. As the nation’s number one oil and gas producer, it’s developed a wastewater disposal system to match. There are more than 50,000 injection wells in Texas, servicing more than 216,000 active drilling wells, according the Railroad Commission.
Do Disposal Wells Cause Earthquakes?
A recent spate of earthquakes in the Midwest – and, more recently, Texas – -has attracted the attention of many geologists who link the abnormal seismic activity to disposal wells located close to the quake epicenters. Quakes in Arkansas, Colorado, Ohio, Oklahoma and Texas have been tied to disposal well activity.
Christopher Joyce, an NPR science correspondent, explains how the use of disposal wells can cause quakes: “The water first used in fracturing rock is retrieved and pumped into these waste wells, which take lots of water. And at more than 9,000 feet deep the water is under high pressure that can build up over months or years. It’s this pressure that can actually create earthquakes.”
Experts attribute the abnormal seismic activity in Oklahoma, where a 5.8-magnitude quake took place on November 5, 2011, to the 181 wells located just miles from the quake’s epicenter. Until two years ago, Oklahoma typically experienced about 50 earthquakes a year, but in 2010, 1,047 quakes shook the state. The explanation, according to the U.S. Army and the U.S. Geological Survey, rests in pressure-breaks from deep-well injections.
Do Earthquakes Linked to Disposal Wells Happen in Texas?
Should Texans think of stocking up on earthquake survival kits? Maybe. Beginning in November of 2013, the towns of Reno and Azle in the Dallas-Fort Worth area saw over 30 earthquakes in the span of a few months. The number of larger quakes recorded in the state has surged tenfold since the drilling boom began in 2007. The link between disposal wells and earthquakes is common knowledge in the scientific community.