What's shaking up the state?
Kingsley Burns, The Oklahoma Daily
Memories of November’s 5.6-magnitude earthquake are still fresh, and people are still searching for a culprit.
Various news sources such as PeakOil.com, the Miller-McCune magazine and The Telegraph in the United Kingdom have suggested hydraulic fracturing could be the cause of a sudden surge in earthquake numbers in the last two years.
Hydraulic fracturing has sparked debates as to whether it is a safe practice, but most critics cite the possible contamination of the water basin, rather than recent speculation that it causes earthquake activity.
Hydraulic fracturing, or “fracking,” is a gas-extraction method that requires shooting water and chemicals into sand into shale deposits to free trapped methane.
Fracking allows oil and natural gas to move more freely from the rock pores where they are trapped to a producing well, which can bring them to the surface, according to the Interstate Oil and Gas Compact Commission.
Experts say the process doesn’t pack nearly the punch of even a moderate earthquake.
The typical energy released in tremors triggered by fracking “is the equivalent to a gallon of milk falling off the kitchen counter,” said Stanford University geophysicist Mark Zoback.
Since 2001, Oklahoma typically has about 50 earthquakes a year, according to data from Leonard Geophysical Observatory in the Oklahoma Geological Survey.
In 2010, however, 1,047 quakes shook the state, and from Jan. 1 to Nov. 29, a total of 1,140 quakes occurred.
The use of fluid and material creates and restores small fractures in a formation in order to stimulate production from new and existing oil and gas wells.
Oklahoma isn’t new to hydraulic fracturing.
On March 17, 1949, Halliburton conducted the first commercial fracturing treatment in Duncan, but recently the number of fracturing sites in Oklahoma has increased. There are 290 active wells in Oklahoma at the moment, and a significant number of them were built after 2010, according to the Chemical Disclosure Registry.
But despite reports that fracking is not the cause of Oklahoma’s earthquakes, the recent increase in the practice has caused worldwide concern.
In June, the Sénat of France passed a law to prohibit hydraulic, making France the first country in the world to ban such activity.
In the United Kingdom, an independent report written by Dr. C.J. de Pater and Dr. S. Baich in November confirmed that fracking can cause small-scale earthquakes.
They made reference to Cuadrilla Resources, a British drilling firm which is suspected to have caused two earthquakes in May in Blackpool, England.
AT A GLANCE
What is hydrofracking?
A hydraulic fracturing operation often involves the injection of more than a million gallons of water, chemicals and sand at high pressure down a well so methane trapped in rock can be minded.
First, a vertical well is dug. Sometimes, the vertical well might be all that is needed, but in many cases, the well is turned horizontal once it enters the shale layer of the ground. This allows more surface area to be exposed, giving the gas more places to seep into the well.
Once the well is drilled, mini explosives are set off in the shale to create preliminary fractures. The liquid mixture is then pumped into the well at a high pressure in order to expand the fractures to allow natural gas or oil to flow up.
How it happens
1 Water acquisition.
Large volumes of water are transported for the fracturing process.
2 Chemical mixing. Equipment mixes water, chemicals and sand at the well site.
3 Well injection. The hydraulic fracturing fluid is pumped into the well at high injection rates.
4 Flowback and produced water. Recovered water (called flowback and produced water) is stored on-site in open pits or storage tanks.
5 Wastewater treatment and waste disposal. The wastewater is then transported for treatment and/or disposal.
Source: Environmental Protection Agency
The Associated Press contributed to this report.
Editor’s note: This is the first in a two-part series exploring hydraulic fracturing and the rise in earthquakes in Oklahoma. Thursday’s story will look at the amount of fracking that takes place locally and examine what impact it has on the state.