does coalbed methane affect coal mining?
Coalbed methane operations can affect coal mining.
Wells drilled ahead of an advancing mine must be removed or barriers must
be left to protect the well in question. Leaving a barrier around the well
would probably affect the well's performance: if the well were in the same
coal that is being mined, the fluid and gas flow necessary for the well to
produce may be destroyed or disrupted and the drainage area of the well may
be restricted. Produced water discharged to the surface upstream from a mine
could create water control and runoff problems not present or anticipated
in the original mine plan. The mine operators may have to re-engineer their
mine designs to handle the additional water and re-work their reclamation
plans to include new wetland areas. From a more positive standpoint, dewatering
and degassing the coal in advance of mining could eliminate or lessen some
pre-mining activities. Coal mining can affect the coalbed methane recovery
by removing the coal and thus, the gas reservoir itself. Coal mining can also
remove some of the water in the coal nearest the mine, thus stimulating more
free gas production as coalbed methane operations approach the active mine
owns the produced water?
The operator of the well, who has obtained a water well
permit with the State of Wyoming's Department of Environmental Quality (DEQ),
is responsible for the water. Each coalbed methane well must be permitted
as both a gas well and a water well. At least three permits are required to
operate a coalbed methane well: an application for permit to drill (APD),
a water permit, and a water discharge permit. (TOP
does the produced water go?
Most water produced from a coalbed methane well is currently
discharged at the surface and runs off into surface drainages, or it flows
into ponds where it can seep back into the soil or evaporate. (TOP
the produced water any good?
The produced coalbed methane water in the Powder River
Coal Field, Wyoming generally meets drinking water standards. It is fresh,
potable, and suitable for stock watering and human needs. In other places
in the basin and in other parts of Wyoming, this may not be the case. Water
quality studies will be needed continuously to identify areas of concern and
ensure that appropriate action and remedies are taken to protect the quality
of the state's waters. (TOP
if the water produced from a coalbed methane well is of poor quality?
State and federal standards for produced water force
producers to maintain proper water quality. For example, if the produced water
is of poor quality, it cannot be discharged into drainages. Options such as
lined impoundments (evaporation ponds), chemical treatment, or re-injection
of the water into other aquifers can be considered in isolated areas of poor
water quality. Monitoring wells are continually being put in place to measure
flows, drawdown, and quality; other studies will be undertaken to determine
areas of water quality concern. (TOP
can use the water and what can it be used for?
Because most of the water is of good quality, it is suitable
for many uses. Ranching and farming uses include livestock watering, field
irrigation, and drinking water. It has been proposed as a separate or supplemental
source for municipal water in some areas and its use in a coal slurry pipeline
is even being considered. Wildlife management groups see the creation of new
wetlands as a plus for many wildlife species; fisheries groups have proposed
reservoirs for fishing and other recreational uses of the waters. Additional
uses proposed for the water include various industrial purposes such as cooling
water for coal-fired power plants, synfuels, and even coal gasification.
if the landowner doesn't want the produced water?
The State of Wyoming encourages the coalbed methane operator
and the surface landowner to cooperate with each other and to explore suitable
ways to handle produced coalbed methane water in a mutually beneficial way.
It may be possible to pipe the water off a property or send it down stream
to those that would like the additional water. (TOP
does coalbed methane production affect the shallow aquifers?
Coalbed methane wells pump water from the coal seam when
the coal is the local aquifer. Water levels can be lowered and gas could flow
from local water wells. This means that some water wells in the coal can be
adversely affected. Water regulatory officials encourage ranchers and other
landowners to register their water wells so that if a water well is damaged,
it can be remedied by the responsible coalbed methane operator. A few studies
have shown that some shallow aquifers are being recharged with water produced
during coalbed methane operations and production. Re-injection of water into
specific shallow aquifers (or into the source coal bed itself) has not yet
been done. Many landowners negotiating with coalbed methane operators are
now signing letters of understanding, which specify what will be done if their
wells are damaged by the coalbed methane activity. Copies of these sorts of
agreements can be obtained through the Wyoming State Engineer's Office, upon
the water produced offset by recharge elsewhere?
Recharge back into subsurface aquifers is constantly
taking place, but it is not known how fast or into what aquifers the recharge
is occurring. However, it may take hundreds of years to fully recharge the
producing coal beds. As deeper coal beds are tapped for methane in multiple
coal zones, it may be possible to re-inject water produced from the deep beds
into the gas-depleted shallow coal beds, thus accelerating the natural recharge
do I contact about coalbed methane?
Oil and Gas Conservation Commission: drilling permits (APDs or Applications
for Permit to Drill) and production permits;
State Engineer's Office: water well drilling and completion permits;
Department of Environmental Quality: water discharge permits;
State Geological Survey: technical assistance and information; and oil and
gas and coalbed methane maps (see De Bruin, 1999 and De Bruin and others,
2000a, 2000b); and
government agencies, including:
Bureau of Land Management (BLM),
Forest Service (FS),
Protection Agency (EPA), and
Geological Survey (USGS).
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Geological Association Guidebook, 1999 Field Conference, Tertiary Geology
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