Changes

===General characteristics of the Greater Green River basin BCGS===

===General characteristics of the Greater Green River basin BCGS===

* Area: 19,700 mi² (51,000 km²)

* Area: 19,700 mi² (51,000 km²)

* Source rocks: Upper Cretaceous and lower Tertiary coal beds and carbonaceous shales in the Fort Union, Lance, Almond, and Rock Springs formations. Organic matter is largely gas-prone type III kerogen<ref name=Law_1984 /> with additional contribution from thermally cracked oils sourced from sapropelic coal beds.<ref name=Garciagonzalesetal_1993a /><ref name=Garciagonzalesetal_1993b /><ref name=Macgowanetal_1993 /><ref name=Surdametal_1997>Surdam, R. C., Z. S. Jiao, and H. P. Heasler, 1997, [http://archives.datapages.com/data/specpubs/mem67/ch12/ch12.htm Anomalously pressured gas compartments in Cretaceous rocks of the Laramide basins of Wyoming: A new class of hydrocarbon accumulation], ''in'' R. C. Surdam, ed., Seals, traps, and the petroleum system: AAPG Memoir 67, p. 199-222.</ref>

* Source rocks: Upper Cretaceous and lower Tertiary coal beds and carbonaceous shales in the Fort Union, Lance, Almond, and Rock Springs formations. Organic matter is largely gas-prone type III [[kerogen]]<ref name=Law_1984 /> with additional contribution from thermally cracked oils sourced from sapropelic coal beds.<ref name=Garciagonzalesetal_1993a /><ref name=Garciagonzalesetal_1993b /><ref name=Macgowanetal_1993 /><ref name=Surdametal_1997>Surdam, R. C., Z. S. Jiao, and H. P. Heasler, 1997, [http://archives.datapages.com/data/specpubs/mem67/ch12/ch12.htm Anomalously pressured gas compartments in Cretaceous rocks of the Laramide basins of Wyoming: A new class of hydrocarbon accumulation], ''in'' R. C. Surdam, ed., Seals, traps, and the petroleum system: AAPG Memoir 67, p. 199-222.</ref>

* Generation-expulsion-migration: late Eocene-late Oligocene (40-25 Ma)

* Generation-expulsion-migration: late Eocene-late Oligocene (40-25 Ma)

* Reservoir rocks: Cretaceous to lower Tertiary sandstones. Multiple, stacked reservoirs occur in rock intervals as thick as 14,000 ft (4267 m) ([[:file:BasinCenteredGasFig6.jpg|Figure 3]]). Individual reservoirs range in thickness from 15 to 125 ft (4.6-38 m). Gas reservoirs are saturated and contain water at irreducible levels. The gas-bearing interval does not commonly contain interbedded, water-bearing reservoirs.

* Reservoir rocks: Cretaceous to lower Tertiary sandstones. Multiple, stacked reservoirs occur in rock intervals as thick as 14,000 ft (4267 m) ([[:file:BasinCenteredGasFig6.jpg|Figure 3]]). Individual reservoirs range in thickness from 15 to 125 ft (4.6-38 m). Gas reservoirs are saturated and contain water at irreducible levels. The gas-bearing interval does not commonly contain interbedded, water-bearing reservoirs.