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Title: San Juan Basin contains large reserves of nonassociated gas

Journal Article · · Oil Gas J.; (United States)
OSTI ID:6532908

Approximately 23 trillion CF of nonassociated gas occurs in the underpressured, low-permeability reservoirs in the essentially structureless low part of the central San Juan basin in northwestern New Mexico and southwestern Colorado. Characteristics and distribution of natural gas and associated hydrocarbons (oil and condensate) for all producing units indicate an increased level of maturation to the northeast: (1) Pennsylvania production is limited mostly to the Four Corners platform, where oil production changes in a northeasterly direction to isotopically heavy dry gas with H/sub 2/S and CO/sub 2/, (2) hydrocarbon production from the Dakota sandstone displays a northeast change from oil to wet gas and condensate to dry gas, (3) the Tocito sandstone Lentil of Mancos shale is a major producer of oil and associated gas in the basin, (4) the Mesaverde contains large quantities of nonassociated gas generated mainly from nonmarine source rocks, and (5) Pictured Cliffs gases (probably derived from associated coalbeds) are isotopically heavier and chemically drier than gases from the underlying Mesaverde group and produced very little condensate. Significant reserves of nonassociated gas remain in the San Juan basin - the primary targets for future exploration will be the coalbeds in the Fruitland formation, channel sandstones and coalbeds in the Menefee formation, and low-permeability sandstones in all units at the north end of the basin.

Research Organization:
Geological Survey, Washington, DC
OSTI ID:
6532908
Journal Information:
Oil Gas J.; (United States), Vol. 81
Country of Publication:
United States
Language:
English