The Marcellus Gas resource The Marcellus shale is a huge resource, and as such it commands our attention. Consider: •
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Each acre of the Marcellus contains about $30,000 dollars worth of producible gas. This is why companies can offer leases of a few thousand dollars per acre. A well taping 80 acres will yield the energy equivalent of 3 million gallons of gasoline. The Marcellus gas resource is the same size as the oil and gas resource of the North Sea. The ultimately producible resource is expected to be 500 trillion cubic feet which is equivalent to 83 billion barrels of oil. The North Sea reserve is 98 billion barrels of oil equivalent. The economic impact of North Sea oil on the economies of Norway and England provides some measure of the potential impact of the Marcellus gas resource on our area. The Marcellus could sustain current US gas consumption (23 tcf/yr) for 21 years. Gas supplies about 1/3rd of the total US energy, oil ~1/3rd, and coal 1/3rd. Produced over 50 years the Marcellus is the energy equivalent of 324 large (1 gigawatt) nuclear power stations operating over the same period. The US currently has 104 nuclear power stations, many smaller than 1 GW. The Marcellus could reduce our oil imports by $170 billion per year for 50 years. The yearly energy harvest would be the equivalent of 1.7 billion barrels of oil each year. If this were used to replace oil in our heavy vehicle (trucks) fleet, at $100 per barrel, the savings would be $170 billion per year. The calculations and reference on the attached sheet show how these numbers were obtained. In those calculations I assumed a lower recoverable resource (363 TCF rather than 500 TCF). L. M. Cathles Department of Earth and Atmospheric Sciences April 22, 2010 The Marcellus Shale •
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Based on [2] I take the total producible gas resource of the Marcellus = 363 TCF At a probability of >90%, 50% and <10% Engelder [1] estimates 262­489­876 TCF 363 TCF = 16 years of supply at current US consumption rate of 23 TCF/yr [2] The area underlain by productive Marcellus is ~246,000 km2 [4, slide 37], so ~ 1475 scf can be produced, on average, from each square meter (plan) of the Marcellus shale = 363x1012/246x109. The contained gas is about 10 times greater. Only about 10% is assumed to be recoverable. Price of gas is about $5 per thousand cubic feet At $5 per thousand scf ($5/kscf) the value of gas beneath one acre is $30,000: ($5/kscf )(1.475 kscf/m2) (4047 m2/acre)= $30,000. A well tapping 80 acres would produce 0.5 billion cubic ft* of gas with a sales value of $2.4 million and an energy equivalent to 3million gallons of petrol ( 80 acres) (4047 m2/acre) (1475 scf/m2) = 4.77x108 scf (4.77x108 scf)($5/kscf)/(1000scf/kscf)=$2.38x106 6000 scf of gas is equivalent to 1 bbl of oil; 1 bbl oil = 42 gallons with energy ~ 42 gal petrol (4.77x108 scf)(1/6000 scf/bbl)(42 gal petrol/bbl) = 3.3x106 gal petrol If produced over 30 years, the surface power density of Marcellus gas is ~1.6 W/m2 1 barrel of oil has an energy content of 6.12x109 joule. (1475 scf/m2)(1/6000 scf/bbl)(6.12x109 joules/bbl)= 1.5x109 joules/m2 If produced over 30 years the power density = (1.5x109 joules/m2)(1/30 yrs)(1/3.15x107 s/yr)=1.6 J/s/m2 = 1.6 W/m2 Wind generation power density = 2 W/m2 [3] If produced over 30 years and used for transportation, we would not need to import 2 billion bbls/yr and thus would save about $200 billion/yr in import costs (363x1012 scf)(1/30 yrs)(1/6000 scf/bbl) =2x109 bbl/yr At $100/bbl, this is $200 billion savings per year If produced over 30 yrs, the Marcellus energy production is equivalent to 400, 1 GW nuclear power plants operating over the same 30 years (2x109 bbl/y)(6.19x109 J/bbl)/(3.15x107 sec/y)=4x1011 W = 400 GW References: [1] Engelder, T., 2009, Marcellus, 2008: Report card on the breakout year for gas production in the Appalachian Basin: Fort Worth Basin Oil and Gas Magazine, August 2009, p. 19‐22. [2] Soeder, D. J., and Kappel, W. M., 2009, Water resources and natural gas production from the Marcellus Shale, USGS Fact Sheet 2009‐3032. [3] MacKay, D. J. C., 2009, Sustainable Energy‐ without hot air, www.withouthotair.com p. 177. [4] John Harper, Chief, Geological Division, Pennsylvania Geological Survey.
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* This is a low estimate. [2] suggests 2.5 bcf/80‐acre well, [1] suggests 3.75 bcf/80‐acre well