Lower-right map’s location is roughly indicated by the blue dashed box in the upper map.
Total cumulative gas (Mmcf) and water (bbl) production. Gives sense of scale of the resource and the water disposal issue.
Peak gas (mcf/month)and water (bbl/month) production. Peak production is typically within the first few years of a well’s life. Robinson’s Bend and parts of Cedar Cove have high water production and variable gas production. Blue Creek, Deerlick Creek, and White Oak Creek fields have lower water production and generally good gas production.
Typical decline curve
Typical decline curve
Yearly water production – Illustrates the general pattern of lower water production in a well/area over time. Note, Brookwood field is mostly wells in and immediately around the mines where extensive de-watering had already occurred.
Processed produced water discharge points. Almost all discharge into the Black Warrior River or one of its tributaries.
TDS map, metals trend with TDS.
Produced Water | Session IV - Nick Tew
Characteristics of Coalbed
Methane Produced Water in
Alabama State Geologist/Oil and Gas Board Supervisor
Geological Survey of Alabama
State Oil and Gas Board of Alabama
Fossil Fuel Produced Water Workshop
June 24-25, 2013
Alabama’s Fossil Fuel Energy Endowment
Black Warrior Basin Coal Measures
Coastal Plain Lignite (low-rank coal)
SW Alabama Oil and Condensate
Black Warrior Basin Oil
Oil Sands of North Alabama
Oil Shale of North Alabama
Black Warrior Basin
Coalbed Methane of Black Warrior Basin
Paleozoic Gas Shales of North Alabama
Coalbed Methane in Alabama
• Degasification experiments for mine safety began in the
• Commercial production began in 1980.
• Currently close to 5,000 active wells in 20 fields.
• Annual gas production between 105 and 121 Bcf for the last
• More than 2.1 Tcf cumulative gas production.
• More than 1.7 billion barrels of water produced.
Cumulative Gas Production
Cumulative Water Production from
Cumulative Gas and Water
Development and Production
• Drilling and hydraulic fracturing currently uses “city” water
• Usually trucked to location
• Additional water during production is not needed
• CBM production is pressure driven and usually requires
dewatering of coals to lower hydrostatic pressure for gas
• Water production is generally high early in a well’s life and
• Gas production generally peaks in the first few years, after
peak water, then decreases.
• High water production can limit how often and how much a
well can be pumped, limiting gas production.
• As new areas of production come on line, water production
is relatively high.
• As an area reaches maturity, the water production will slow
and level off.
• Some areas, with high recharge rates, will continue to
produce significant water volumes over the life of the well.
• In and around mining, where water levels have been drawn
down prior to drilling, wells produce little to no water.
Water Treatment and Disposal
• In-stream disposal is the dominant practice in the Black
• Prior to disposal, water is treated to remove
silt, clay, iron, and manganese compounds.
• Underground injection can augment in-stream disposal in
areas of highly saline water; however, currently all produced
water is disposed of in-stream.
• Potential beneficial uses exist for produced water with less
than 3,000 mg/L TDS.
• In the southwestern CBM fields, water is more saline and
limits the ability to pump wells.
Mostly sodium-chloride, some areas are dominated by sodium bicarbonate
Generally low in sulfate, magnesium, and calcium.
Almost all wells exceed secondary drinking water standards for TDS (500
mg/L), but the average well is in a USDW (<10,000 mg/L).
Average levels of barium, cadmium, fluoride, lead, and thallium
exceeds the drinking water MCL; average levels of zinc and
manganese exceed the secondary drinking water regulations.
CBM Produced Water in Alabama
Potential Beneficial Uses:
Aquaculture and irrigation water, in particular shrimp farming
Water for drilling and hydraulic fracturing
Alternative water treatment:
Reverse osmosis systems
Artificial wetlands (Clemson-Chevron research)
Alternative to in-stream disposal:
SWD wells, however, no consistent high capacity zones
GSA CBM Produced Water Project funded by the U.S.
Dept. of Energy, Office of Fossil Energy, NETL, DOE
Award Number DE-FE0000888.
GSA Research Team: Marcella McIntyre-
Redden, Steve Mann, Jack Pashin (now at OK
State), David Kopaska-Merkel, Ashley Williams, and