Shale Gas: H.-M. Schulz SS 2013
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13th - 14th of June 2013
Shale Gas
Hans-Martin Schulz
TheKeyFactorforProduction:MineralogybestBarnettShaleproductioncomesfrom
zoneswith45%quartzandonly27%claybrittlenesscontrolsfrac stimulation
Shale Gas: H.-M. Schulz SS 2013
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! Shale gas is self-contained HC system !
Total Organic Carbon (wt%)- Heterogeneities -
0 4 8 12 16
80
60
40
20
Dep
th (m
)
TOC (%)
0 2 4 6 8 10 12TOC (Wt%)
0
50
100
150 compare,Barnett Shale
Courtesy Brian Horsfield (2011)
Mesozoic black shale:different coloursIndicate different wells
Shale Gas: H.-M. Schulz SS 2013
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Methane in gas shales is stored
Fractureporositymatrix porosity
(blue)
asfreegas
on the surface of clay minerals
insorbedstate
on the surface ofthe organic fraction
+dissolvedmetha
ne+
dissolvedmetha
ne
Fracture gasis produced immediatelyAdsorbed gasis released dueto pressure declines
Shale Gas: H.-M. Schulz SS 2013
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Processes in a source rock leading to oil, gas, andcarbon-rich residue (pyrobitumen)
High-maturity shale-gas systems derive high gas contentsfrom the indigenous generation of gas from kerogen, bitumen, and oil cracking.
Jarvie et al. (2007): Unconventional shale-gas systems: The Mississippian Barnett Shale of north-central Texas as one model for thermogenic shale-gas assessment AAPG Bulletin, v. 91, no. 4 (April 2007), pp. 475499
Gas Content vs. TOC in Two Shale Gas Plays Implication:Gas Associated with Organic Matter
Courtesy A. Aplin (2011)
Shale Gas: H.-M. Schulz SS 2013
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Sorbed CH4 Increases with Pressure and Amountof Organic Matter
Increasing TOC
Methane adsorption isotherms, Antrim shale, Michigan BasinCourtesy A. Aplin (2011)
^^
.but CH4 Sorption Decreases with Temperature
Data for Dietz Coal
Bustin and Bustin (2008)
Courtesy A. Aplin (2011)
Shale Gas: H.-M. Schulz SS 2013
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Shale Gas: H.-M. Schulz SS 2013
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Typical sorption isotherm
Bob Cluff (2006)
Shale Gas: H.-M. Schulz SS 2013
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How Much of the Porosity is Associated with Organic Matter?
Passey et al. (2010)
Loucks et al. (2011): Origin and Classification of Pores in Mudstones from Shale-Gas Systems. Search and Discovery Article #40855
Shale Gas: H.-M. Schulz SS 2013
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Loucks et al. (2011): Origin and Classification of Pores in Mudstones from Shale-Gas Systems. Search and Discovery Article #40855
Dark grey:organic matter
Grey: mineral matrix
