Courtesy Kirk Johnson
By Tom Au and Barbara Benson
What is the Marcellus Shale?
The Marcellus Shale is a rock formation 5000 to 9000 feet below the earth’s surface, which has the potential of holding large gas reserves. The Marcellus Shale is similar to the Barnett Shale formation in Texas where gas production has reached 1 trillion cubic feet per year (out of a total US production of 30 trillion cubic feet from all sources). The Marcellus Shale is a very large formation that underlies parts of NY, PA, OH and WV, and which may hold a total of 16 to 50 trillion feet of recoverable gas.
How does one drill for gas so deep?
Recent advances in deep well drilling, horizontal drilling and hydraulic fracturing have
made gas extraction from deep wells practical and economical for gas companies.
Hydraulic fracturing, or hydrofracturing, is a technique that creates long fractures in rock
and coal to release gas from the shale formation to wells to be collected. In order to
create these fractures, a mixture of water, “proppants” particles (sand or ceramic beads)
and chemicals is pumped into the rock at high pressures. The pressure causes the rock to
fracture and the proppants hold open the fracture to allow the gas to flow.
Hydrofracturing requires a large quantity of water. Typical projects use 1 to 3 million
gallons of water and .5 million pounds of sand. Large projects may require up to 5
million gallons of water. The water must be pumped into the well from surface sources
or from underground aquifers or brought in by tank trucks.
Hydrofracturing also pumps process fluid called “flow-back” to be reused or disposed of.
Fracking and treatment fluids do not come back all at one time. At first, the flowback is
primarily treatment/fracking fluids, but this is diluted by brine water. Flowback of
fracking fluids and water can continue over a period of years. The fluid is often
contaminated with chloride or other chemicals. A large percentage (20-40%) of the
injected fluid remains underground.
Pennsylvania currently has several wastewater treatment plants which treat brine water
produced by the oil and gas industry. However, these brine treatment facilities are not
currently equipped to effectively deal with quantity of flow-back water produced by the
Marcellus gas extraction process. DEP is allowing some municipal sewage plants to
accept limited quantities gas industry wastewater at its plant. However, the brine water is
not treated at these plants, only diluted.
Who owns the rights to drill?
In Pennsylvania, land is often separated into surface and mineral estates. The surface
landowner may not own the mineral rights below ground. Often a title search must be
conducted to determine who owns the mineral rights beneath the surface of land. An
exploration company often will negotiate a gas lease with a mineral rights owner or group
of owners to explore on their land. The lease agreement may cover access to property,
compensation for damages to the surface, and royalty payments to the mineral rights
owner.
What DEP permits are necessary?
A well driller must obtain several permits and approvals from DEP and other agencies before drilling:
• Well Drilling Permit and Addendum – The operator must obtain a drilling permit,
pursuant to the Oil and Gas Act, as well as an application addendum outlining a
water management plan for that operation, pursuant to Title 25 PA Code 78.11-
33.
• Earth Disturbance Permit (ESCGP-1) -- The operator must obtain a permit for
implementation of erosion and sedimentation controls, including stormwater
management, if the site disturbance area is more than 5 acres. A plan for erosion
and sedimentation control is required if the site is less than 5 acres.
• Preparedness, Prevention and Contingency (PPC) Plan -- The operator must have
an approved spill prevention plan.
• Water Withdrawal Permits – DEP has required water withdrawal permits for all
withdrawals of surface or ground water. For projects located in the Delaware
River basin and Susquehanna River basin, the river basin commissions (DRBC
and SRBC) have required separate water allocation permits for large withdrawals
of surface or groundwater.
• Obstruction and Encroachment Permit – An operator must obtain a permit from
DEP for construction, excavation, or operation in a wetland, stream, or body of
water under Title 25 PA Code Chapter 105. . A similar requirement is also
required under the Oil and Gas Act.
• Water Quality Management Permit – An operator must obtain this permit if a
centralized impoundment will hold fluids other than fresh water (such as drilling
or fracking fluids). The siting, construction, use and closure of temporary pits are
regulated under Title 25 PA Code 78.54-58. Permits are only required if the pit is
part of a treatment facility. However, permanent impoundments to hold drilling or
fracking fluids are rare.
• Stormwater – An operator is required to meet DEP stormwater requirements,
which are part of the Earth Disturbance Permit.
What is the Sierra Club’s position on gas drilling?
The Sierra Club views natural gas as a transitional fuel as the US transitions to a clean
energy economy. However, the Sierra Club is concerned about the environmental effects
of drilling. Deep well drilling on such a large scale is a relatively new to Pennsylvania;
the environmental effects have not been fully evaluated. The media recently has reported
several environmental problems associated with Marcellus Shale gas drilling, including
the de-watering from headwater streams, contamination of drinking water wells, the lack
of treatment of brine water, and deteriorating water quality in major rivers. We seek
measures to ensure that drilling be done in a manner that does not damage our natural resources.
What are potential environmental problems?
• Well drilling and fracturing consume large quantities of water that will not be replaced since large quantities of drilling water will remain underground.
• Drinking water supplies (surface waters and underground aquifers) and fisheries and streams can be damaged by intentional or accidental discharges of contaminated water from the well head site.
• Drilling and fracturing can affect water quality in water wells and aquifers in the area.
• The gas drilling industry has not yet developed advanced technology for brine
treatment or disposal that does not harm the water quality of streams.
• Operations of diesel generators and trucks can affect local air quality.
• Land clearing for the well sites, haul roads, and gas pipelines can affect
environmentally sensitive lands, can disrupt wildlife, and can introduce invasive
species.
More information about drilling in the Marcellus Shale is being released every day. We
will continue to update the Pennsylvania Sierra Club website to reflect this new
information. For more information on gas drilling in the Marcellus shale, go to the oil and gas accountability website. (This website is not affiliated with the Sierra Club)
Tom Au and Barbara Benson serve as co-chairs of the Chapter's water committee.
Published March 3, 2009