About This Item

Share This Item

The AAPG/Datapages Combined Publications Database

AAPG Bulletin


Volume: 72 (1988)

Issue: 5. (May)

First Page: 523

Last Page: 535

Title: Porosity Enhancement from Chert Dissolution Beneath Neocomian Unconformity: Ivishak Formation, North Slope, Alaska

Author(s): G. Shanmugam (2), J. B. Higgins (3)


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.

Pay-Per-View Purchase Options

The article is available through a document delivery service. Explain these Purchase Options.

Watermarked PDF Document: $14
Open PDF Document: $24

AAPG Member?

Please login with your Member username and password.

Members of AAPG receive access to the full AAPG Bulletin Archives as part of their membership. For more information, contact the AAPG Membership Department at [email protected].