Nisku

Nisku Formation Study, Southeastern Alberta


Summary:
Location: T1-17, R1-17W4
Strata: Nisku
Year of Study: 1990


Introduction

A multidisciplinary (geology, hydrodynamics, geophysics, satellite imagery) examination of the Devonian section in southern Alberta (Twp 1-17, Ranges 1-17W4M) has determined the primary controls on known Nisku production, and outlined new prospective areas. The primary controls on Nisku production are salt collapse at the Beaverhill Lake level, the lateral extent of the Beaverhill Lake salt basin, and the timing of salt removal.

Study of all of the deep wells reveals that localized pre-Nisku salt dissolution in the Beaverhill Lake Group created local Leduc thicks. Subsequent dissolution of the surrounding Beaverhill Lake salt resulted in the creation of Nisku highs. This dissolution sequence has resulted in the preferential preservation of Wabamun salts within Nisku lows proximal to Nisku production. Furthermore, there is a strong relation between the locations of Nisku production and Mesozoic structural movements in the Grand Forks/Hays/Enchant area.

The eastern flank of the Beaverhill Lake salt basin displays salt remnants up to 25 metres thick. These salts generally thin to 1-6 metres to the north in the Suffield area. The northwestern extent of this salt basin is unknown. However, evidence from three wells which penetrate the Nisku Formation suggest that it extends at least to the Badger area in Township 16, Range 18W4M, and possibly as far as Township 20, Range 20W4M. A possible western continuity of the Beaverhill Lake salt remnants is located in the vicinity of the Bow River between Townships 14 and 19. Salt remnants may also help localize petroleum within Jurassic and Lower Cretaceous reservoirs (e.g. Grand Forks, Hays). East of the Bow River relatively little structural relief is encountered.

Total dissolved solids (TDS) content within the Beaverhill Lake, in combination with the distribution of Nisku potentiometric lows, can be used as a guide to pinpoint the southern extent of salt remnants. High TDS and a potentiometric low characterize the Grand Forks area. An untested area with similar attributes is found north of Pakowki Lake.

Seismic data indicate that possible Beaverhill Lake salt remnants associated with high relief Nisku structures are encountered north of Pakowki Lake which may indicate a possible northeastern flank to the Beaverhill Lake salt basin in the Pakowki Lake - Manyberries area. The presence of Nisku oil shows here suggests that a more detailed seismic evaluation is warranted.

For more information contact:

Leslie Sears
Petrel Robertson Consulting Ltd.
500, 736- 8th Avenue S.W.
Calgary, Alberta
T2P 1H4

Phone: (403) 218-1618
Fax: (403) 262-9135
lsears@petrelrob.com
Copyright © 2014 Petrel Robertson Consulting Ltd.