Geologic aspects of tight gas reservoirs in the Rocky Mountain region

Journal Article · Mon Jul 01 04:00:00 EDT 1985 · J. Pet. Technol.; (United States)

DOI:https://doi.org/10.2118/11647-PA· OSTI ID:5131402

Spencer, C W

The Rocky Mountain region contains major gas resources in tight (low-permeability) reservoirs of Cretaceous and Tertiary age. These reservoirs usually have an in-situ permeability to gas of 0.1 md or less and can be classified into four general geologic and engineering categories: marginal marine blanket, lenticular, chalk, and marine blanket shallow. Microscopic study of pore/permeability relationships indicates the existence of two varieties of tight reservoirs. One variety is tight because of the fine grain size of the rock. The second variety is tight because the rock is relatively tightly cemented and the pores are poorly connected by small pore throats and capillaries. Other characteristics of tight gas reservoirs are: discrete gas/water contacts are absent in lenticular and marginal marine blanket reservoirs; most of the gas occurs in stratigraphic traps; well log analysis is difficult in tight reservoirs; many Rocky Mountain tight gas basins are either overpressured or underpressured; and formation damage may occur when wells are drilled and completed.

• Research Organization: U.S. Geological Survey
• OSTI ID: 5131402
• Journal Information: J. Pet. Technol.; (United States), Journal Name: J. Pet. Technol.; (United States) Vol. 37:8; ISSN JPTJA
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020300* -- Petroleum-- Drilling & Production
CENOZOIC ERA
CRETACEOUS PERIOD
ENGINEERING
FEDERAL REGION VIII
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGY
MESOZOIC ERA
MINERAL RESOURCES
NATURAL GAS DEPOSITS
NATURAL GAS FIELDS
NORTH AMERICA
PERMEABILITY
POROSITY
RESERVOIR ENGINEERING
RESERVOIR ROCK
RESOURCES
ROCKS
SANDSTONES
SEDIMENTARY ROCKS
TERTIARY PERIOD
USA