Natural Gas drilling using shallow wells is not new to West Virginia, but deep well drilling is.
Deep well drilling requires a larger drilling site up to five acres and a much longer drilling time, potentially weeks of drilling continuously for 24 hours, seven days a week.
These sites require access roads and evaporation ponds where water contaminated with fracing fluids and muds are held once the shale is fractured and gas is released. Drilling in the Marcellus shale differs from conventional natural gas production in many ways. Those differences mean that deep well drilling can have potential demands on our water supply.
The technology to drill deep wells is relatively new and so new information is available daily as to the longer term effects on future land use near drilling sites.
Western Pennsylvania is just ahead of West Virginia in deep well extraction.
According to the Pittsburgh Post-Gazette article by Matthew Spolar, Monday, June 16, "Whereas experts say a traditional gas well may require 40,000 to 80,000 gallons of water pumped into an impoundment to increase pressure on the gas, a single Marcellus well takes from 1 to 6 million gallons of water to drill properly. This worries those who oversee the state's aquifers. Additionally, state agencies fear that contaminated water could seep back into nearby streams. On May 30, these concerns caused the DEP to order the partial shutdown of two exploratory shale drilling operations in Lycoming County."
The Marcellus shale lies in the subsurface beneath much of West Virginia, western Pennsylvania, and parts of New York. Shale is a common geological term to describe what was once layers of clay or mud, but with time and pressure, were compressed into a seam of sedimentary rock. Pockets of natural gas under extremely high pressure are trapped within this shale. Gas companies are hopeful that new methods of drilling and extraction will make it economically feasible to recover the gas from the Marcellus shale.
And, here in Pocahontas County, land agents are putting land under contract to prepare for future exploration and potential drilling.
Just how deep is this deposit?
While the depth of the shale varies, the majority of the Marcellus lies approximately one mile below the surface. In some places, the shale is more than 9,000 feet deep. The well is drilled through the surface and the freshwater aquifer, through the brine and saltwater table, beyond layers of rock strata, finally reaching the shale containing the pressurized natural gas.
But drilling deep is only part of the story.
The shale must also be fractured, usually using water and other chemicals, so the gas can be released and brought to the surface. Hydraulic fracturing involves pumping high-pressure fluid into the formation causing low grade seismic activity to fracture the shale. Then horizontal drilling allows access to several fracture points along the shale.
Beyond the technical requirements of this type of drilling, there are sizable resource demands. Hydraulic fracturing, or fracking, requires a lot of water. Although it is difficult to determine just how much water each well will need, one can look to examples of fracturing and horizontal drilling in other regions of the country for a rough estimate of the water requirements.
A similar scenario using hydraulic fracturing is occurring in Texas, specifically with the Barnett shale deposit. Oil and gas companies, most notably Halliburton, have used advanced fracking techniques with great success. Based on numbers from the Railroad Commission of Texas, one producing well in the Barnett shale region can use anywhere from 1.2 million gallons to 3.5 million gallons of water.
One company, Devon Energy, has reported water usage of approximately 3 million gallons of water for one of their horizontal wells. In many cases, wells must be fracked several times to increase the production of gas. Additionally, this level of fracturing produces large quantities of used hydraulic fluids and wastewater which can be stored on site or transported off site, depending on individual lease.
Simply put, horizontal drilling requires an enormous amount of water, and if done improperly, hydraulic fracturing may further contaminate groundwater sources.
According to a study presented at the 2005 People's Oil and Gas Summit and conducted by the Subra Company, contaminants from natural gas drilling include various volatile organic compounds (VOCs), including benzene, a known carcinogen.
Also present are heavy metals such as arsenic, selenium, lead and mercury, and NORM, or Naturally Occurring Radioactive Material. Exploration of the Marcellus shale potentially could expose groundwater and soil to NORMs, including radium. An extensive list of contaminants can be found at www.ogap.org.
Further complicating the risk to local water supplies is the lack of federal oversight. In 2005, the Energy Policy Act exempted oil and gas companies, and specifically hydraulic fracturing, from certain requirements of the Safe Drinking Water Act.