Porosity enhancement from chert dissolution beneath Neocomian unconformity: Ivishak Formation, North Slope, Alaska

Journal Article · Sun May 01 04:00:00 EDT 1988 · AAPG (Am. Assoc. Pet. Geol.) Bull.; (United States)

OSTI ID:6126188

Shanmugam, G; Higgins, J B

Secondary porosity caused by chert dissolution is common in the hydrocarbon-producing fluvial facies of the Ivishak Formation (Triassic), North Slope, Alaska. Petrographic observations suggest that macroporosity caused by chert dissolution tends to increase toward the Neocomian unconformity. In the Prudhoe Bay field, a lateral increase in core porosity (from 15% at about 30 km from the unconformity to 30% near the unconformity) and in permeability (from 50 md at about 30 km from the unconformity to 800 md near the unconformity) is evident toward the unconformity. This increase occurs within the fluvial facies (zone 4) of nearly uniform grain size and framework composition (chert litharenite). Major chert dissolution probably took place during the Neocomian uplift when the Ivishak Formation was exposed to acidic meteoric waters in the near-surface environment. 16 figures, 3 tables.

• Research Organization: Mobil Research and Development Corp., Dallas, TX (USA)
• OSTI ID: 6126188
• Journal Information: AAPG (Am. Assoc. Pet. Geol.) Bull.; (United States), Journal Name: AAPG (Am. Assoc. Pet. Geol.) Bull.; (United States) Vol. 72:5; ISSN AABUD
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
& Exploration
ALASKA
ALASKAN NORTH SLOPE
ALLUVIAL DEPOSITS
DIAGENESIS
FEDERAL REGION X
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC FORMATIONS
MESOZOIC ERA
MINERAL RESOURCES
NORTH AMERICA
PERMEABILITY
PETROLEUM DEPOSITS
POROSITY
RESERVOIR ROCK
RESOURCES
TRIASSIC PERIOD
USA