Hydraulic Fracturing in Virginia and the Marcellus Shale Formation
Hydraulic fracturing ("fracing") has received considerable public attention due to exploration and drilling activity in the Marcellus shale. This vast deposit spans parts of New York, Pennsylvania, Ohio, West Virginia, Maryland and small portions of Virginia along the western border of the northern Shenandoah Valley. The following information summarizes fracing as it is used and regulated in Virginia and the specifics of Virginia's portion of the Marcellus shale.
What is “fracing?”
Much of Virginia's natural gas resources are not found in “conventional” subsurface reservoirs or large pools but are trapped in shale, coal or other rock formations. To access these gas reserves, the coal, rock or shale formations must be stimulated or “fraced.” Fracing, which dates back to the 1940s, uses pressurized fluids and/or gases to stimulate or fracture rock or shale formations to release the natural gas. Sand pumped in with the fluids helps to keep the fractures open. The type, composition and volume of fluids used depend largely on regional geologic structure, formation pressure and the specific geologic formation and target for a well. Virginia's geology is different than that of other states where the Marcellus shale exists. The U.S. Geological Survey (USGS) has indicated a Marcellus play for Virginia is on the outer periphery of the major structural body of the shale. As a result, the concerns regarding conditions in other states are less likely to exist in the Commonwealth.
The evolution of fracing and horizontal drilling technology has led directly to a proliferation of wells drilled in the Marcellus shale. The Energy Information Administration estimates that by 2035, 24% of total natural gas production will come from shale formations such as Marcellus. The bulk of Marcellus drilling activity has occurred in Pennsylvania and West Virginia. One gas company is expressing interest in drilling one exploratory Marcellus well in Rockingham County, VA and leasing is taking place in Rockingham and other counties. Hydraulic fracturing techniques that have been used for many years to stimulate wells in Virginia would be used in the development of Marcellus gas wells in Virginia’s Shenandoah Valley.
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Has fracing been used in Virginia?
Fracing has been utilized in approximately 1,800 wells producing from shale, sandstone and limestone formations drilled in Southwest Virginia since the early to mid-1950’s. More than 5,600 coalbed methane wells are producing from coal seams that have been naturally fractured after mining or have been fraced using water or foam. The fluids used in the fracing process in Virginia are mostly nitrogen-based with water, most commonly called a “foam” frac. A pressurized nitrogen-based foam is used to fracture certain formations of gas deposits. Due to the structure of geologic formations in Virginia, large volumes of water are not used in fracing because it may hinder or block the flow of gas within the formation.
Water-based fracing fluids would most likely be used in the Virginia Marcellus formation, but at less volume than reported in neighboring states due to the thinner, less extensive formation characteristics. In both nitrogen-based and water-based fracing, the trace ingredients in the fluids are typically used as friction reducers, gelling agents and antibacterials. The trace ingredients are mostly neutralized in the subsurface, and fracing operations do not result in concentrated volumes of chemical waste. The primary constituents of concern in fluids returned to the surface from fracing are chlorides and other salts that can lead to high conductivity. Additives remain a very diluted constituent in the returned waters.
DMME requirements include the development of a stimulation plan. This plan addresses the specifics of how the well will be stimulated, including fracing fluids to be used, additives, and other factors.
Most wells in Virginia are drilled using air instead of water. If water is used it must meet or exceed regional water quality standards. No modern drilling activities for gas or coalbed methane include the use of diesel fuel.
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How Does Virginia’s Geology Differ From Other Marcellus States?
Virginia's Marcellus geology differs from the geology of the states where significant Marcellus gas resources are being developed. Because Virginia’s portion of the shale formation is not as deep, thick and should have less formation pressure than in Pennsylvania, West Virginia, and New York, less water will be necessary to fracture the rock. Additionally, the lateral portion of a horizontal well in these states may reach distances of 7,000 to 8,000 feet. The shale structure in Virginia is projected to allow laterals of only 3,500 to 5,000 feet. A typical water-based frac job in the Marcellus field is reported to require from to three to six million gallons of water. Frac jobs in Virginia can typically require from 50,000 to 300,000 gallons for a vertical well. Horizontal wells using nitrogen-based fluids require even fewer gallons of water. It is not uncommon for Virginia wells to be fraced with less than 35,000 gallons of water.
While the amount of water required for fracing in Virginia will be less than required in Pennsylvania and other Marcellus states, it is not clear how much water will be required for water-based horizontal well fracs in Virginia until test wells are developed. With a thinner rock formation, less formation pressure and shorter laterals, water amounts could be half of what is utilized in other Marcellus states.
DMME will closely monitor stimulation methods and volumes of water that are used for well development should the Marcellus play in Virginia prove viable. DMME will work with the Virginia Department of Environmental Quality (DEQ) to ensure that water withdrawals and disposal of produced fluids do not harm surface or ground waters and, depending on the volume of water used, whether any additional groundwater and surface withdrawal permits are required.
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What are DMME's Requirements to Protect Water Quality and the Environment ?
DMME's regulatory framework serves to allow for safe and environmentally responsible production of Virginia's natural gas resources. DMME gas and oil permitting rules require the operator complete site-specific assessments of the surface and underground conditions to be affected by drilling, to ensure that operations will not cause off-site disturbances or pollution to surface or groundwater.
There have been no documented instances of surface water or groundwater degradation from fracing in Virginia.
Surface and groundwater protection is achieved largely through casing and fluid management requirements that must be met when drilling and stimulating a well. As shown at right, multiple layers of steel pipe and concrete extend through groundwater zones to provide protection and prevent the intrusion of water into a gas flow stream.
ABOVE: Cross-section of multiple steel casings with cement between them.
Cemented casing is required at least 300 feet below the surface or 50 feet beneath the deepest known groundwater horizon, whichever is deeper. Typically, fracing occurs in formations that are at least 500 feet (for coalbed methane wells), and often thousands of feet (for conventional gas wells) below fresh water zones. These requirements are to ensure protection of groundwater from fracing fluids and its trace ingredients.
Graphic from ProPublica.org
DMME regulations also protect water quality once fracing fluids return to the surface.
Typically, only about 15-30% of injected fracing fluids return to the surface. Once returned to the surface, the fracing fluids must be stored in lined pits until ready for permanent disposal. All gas well sites are “closed loop" systems. No off-site disturbances or discharges are allowed. Fracing fluids are disposed in an off-site permitted facility such as a Class II EPA waste disposal well or are land applied after meeting regulatory requirements.
DMME regulations also govern on-site road and gathering pipeline construction and operation. Construction must meet all erosion and sediment control, storm water, and reclamation requirements, and all these activities are covered under performance bonds.
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Can Fracing in the Marcellus Shale be Conducted Safely in Virginia?
Virginia’s regulatory programs are put in place so that gas and oil development, including development of the Marcellus shale, can be conducted in a safe and environmentally responsible fashion. The fracing process is currently being used to a great extent in Southwest Virginia and is projected to continue as development continues in the Devonian and Marcellus shale formations. There have been no known water quality issues in Virginia directly associated with hydraulic fracturing.
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|Gas Well Development & Hydraulic Fracturing
Who has primary regulatory authority over natural gas and oil wells in Virginia?
DMME is the regulatory authority for statewide gas and oil permitting and operations. Interstate pipelines and gas storage fields are under the jurisdiction of the State Corporation Commission.
Do DMME inspectors have Marcellus Shale drilling experience?
Virginia inspectors have experience with more than 1,800 active conventional vertical and horizontal gas wells in other formations, including Devonian-age shales similar to the Marcellus.
How often are the gas wells inspected by DMME?
DMME uses a risk-based inspection process in Virginia. This means inspectors are present during the most critical stages of well development – site construction, drilling, fracing, and reclamation. Once the well is producing, there is a substantially reduced risk of problems. DMME continues to inspect the site through the life of the well. Also, at this point, gas company well tenders, on average, are visiting conventional well sites once per week and coalbed methane wells two to three times per week to check production meters and well site conditions. Virginia law requires that companies immediately notify DMME of any on site or off site problems related to the well, pipeline or facility.
Has Virginia received any permit applications for a well in the Marcellus Shale?
To date, one application for an exploratory well in Rockingham County has been received from Carrizo Marcellus, LLC, a Texas company. The County is studying the potential impacts of exploratory drilling, and the company has set aside the application indefinitely.
Does DMME consult any other governmental agencies (national, state, or local) during the permit application review process?
During the permit review process, research is conducted concerning the proposed well site, including contacts with the U.S. Forest Service and/or the Virginia Department of Forestry. The applicant is required to contact agencies that require additional site permitting, including the Virginia Marine Resources Commission, Virginia Department of Transportation and others. The number of agencies contacted by DMME and the applicant will vary on a site by site basis.
Concerns have been raised about the chemicals used in the hydro-fracturing process in deep shale deposits, like the Marcellus. Do drilling companies have to identify the chemicals they are using?
Although companies were not required to identify all chemicals being used, a new website was recently established by the Ground Water Protection Council and the Interstate Oil and Gas Compact Commission (IOGCC) for that purpose. Funded by the U.S. Department of Energy, this landmark, web-based national registry discloses the chemical additives used in the hydraulic fracturing process on a well-by-well basis, starting with wells drilled in 2011. Visit the website at www.fracfocus.org.
Is there a risk of radioactivity in the solids and water produced during the drilling and hydro-fracturing process?
Naturally Occurring Radioactive Materials (NORM) from rock formations and minerals are a common phenomenon. While this potential risk is known to be present in all drilling, it is believed to be an extremely low risk due to the geology in Virginia.
How are waters produced back during drilling and fracing handled?
- Virginia regulations provide for ground application of fluids if lab tests, conducted by an independent lab, show the fluids meet water quality standards. If the produced fluids do not meet quality standards, the operator is required to transport fluids to an approved Class II EPA waste disposal well or other properly permitted facility.
- Regulations require an independent lab test of any water well or spring within 500 feet of a proposed well bore before drilling begins.
- Water used during the drilling process is required to meet state water quality standards by-region. This could be water drawn from a stream or river or well. Public Service Authority water may also be used, if preferable and available.
- The well casing/cementing program for each well is designed to protect ground water resources and coal seams below the surface. Virginia's casing program is a multi-casing and cementing program with the cement circulated to surface. This prevents contamination of groundwater, protects the coal resources, and isolates the gas production.
- The Virginia Gas and Oil Act and Regulations do not allow off-site impacts or discharges to surface waters.
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