About This Item

Share This Item

The AAPG/Datapages Combined Publications Database

CSPG Bulletin

Abstract


Bulletin of Canadian Petroleum Geology
Vol. 38 (1990), No. 1. (March), Pages 178-179

C.S.P.G. 1990 Convention, "Basin Perspectives"

The Claresholm Gas Field - A Significant Gas Pool in the Deep Portion of the Southern Alberta Basin [Abstract]

Rosenstein, E.S.1

ABSTRACT

Recent drilling in the Claresholm area has demonstrated the existence of a significant gas pool centred in Townships 12 and 13, Range 27 W4M. The principal reservoir is the sandstone of the Glauconite Member of the Lower Cretaceous Blairmore Formation, which occurs at depths ranging from 2000 to 2500 m subsurface in the field area. The reservoir sandstone is a relatively thin, well-sorted, fining-upward quartzarenite, which attains a maximum thickness of 7 m, and is

End_Page 178------------------------

distributed as an extensive blanket sand with an overall north-south lineation. The unit displays a high degree of consistency over a geographically large area and is believed to record the regressive advance of an ancient tidal flat. Reservoir-quality sands have been preserved in the lower part of the unit, which likely was deposited by a system of rapidly-migrating tidal channels. Most of the original porosity has been occluded by syntaxial quartz overgrowths, such that the maximum preserved porosity rarely exceeds 14 per cent. Associated permeabilities are moderate, commonly approaching or exceeding 50 millidarcies.

Although the presence of hydrocarbons was detected in earlier boreholes, the commercial significance of the pool was not demonstrated until MLC and its partner DeKalb completed the drilling of nine wells during the past three years. The limits of the pool have yet to be accurately defined, but appear to be controlled by a regional updip shaleout, and a downdip loss of permeability resulting from excessive induration. Discontinuities within the pool have been observed where younger channels, infilled with relatively impermeable material, locally cut the blanket sandstone. The reservoir appears to be ubiquitously gas-saturated and no true downdip water has yet been encountered.

A gas field covering at least 64 km2 (25 sq. miles) is indicated by the present well control, from which an estimated 1.8 billion cubic metres (60 BCF) of sweet gas may be recovered.

End_of_Record - Last_Page 179-------

ACKNOWLEDGMENTS AND ASSOCIATED FOOTNOTES

1MLC Oil and Gas Ltd., Calgary T2P 3W2

Copyright © 2003 by The Society of Canadian Petroleum Geologists. All Rights Reserved.