About This Item

Share This Item

The AAPG/Datapages Combined Publications Database

AAPG Bulletin


Volume: 68 (1984)

Issue: 9. (September)

First Page: 1087

Last Page: 1100

Title: Origin of Reservoir Fractures in Little Knife Field, North Dakota

Author(s): W. Narr (2), Robert C. Burruss (3)

Article Type: Meeting abstract


Thin, vertical, planar fractures observed in the Mission Canyon Formation, at the Little Knife field, are naturally occurring and appear to be extension fractures. The predominant east-west trend of the fractures, measured in oriented core from six wells, parallels the contemporary maximum horizontal compressive stress in the Williston basin. The fractures occur only in carbonate units, but within the carbonates their occurrence is not lithology dependent. Fracture density measured in cores of the reservoir carbonates averages 1 ft (.3 m) of fracture per 2.3 ft (.7 m) of core.

The formation and mineralization of reservoir fractures were the most recent diagenetic events in the Mission Canyon Formation at Little Knife. Study of aqueous and hydrocarbon fluid inclusions associated with the fractures reveals: (1) fractures formed after the strata were buried to at least their present depth of 9,800 ft (2,987 m), which indicates their age is post-Mesozoic; (2) the pore-fluid pressure gradient was normal hydrostatic immediately after, if not during, fracture system development; (3) formation-water salinity has remained fairly constant since fracture initiation; (4) migration of hydrocarbons into the reservoir probably preceded fracture genesis; and (5) methane concentration may have decreased since fracture initiation.

Pay-Per-View Purchase Options

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

Protected Document: $10
Internal 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].