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The AAPG/Datapages Combined Publications Database

AAPG Bulletin


Volume: 64 (1980)

Issue: 8. (August)

First Page: 1286

Last Page: 1286

Title: Absence of Connate Water in Michigan Reefs Attributed to Anhydrite: ABSTRACT

Author(s): Donald L. Katz

Article Type: Meeting abstract


Dehydrated gas stored in depleted reef reservoirs behaves uniquely in that the gas comes out essentially as dry as when injected. This observation leads to the conclusion that the major part of the reservoir does not contain connate water. However, the base of the reservoir, usually of low porosity, is filled with brine.

Reef rocks contain anhydrite. A study of anhydrite occurrence leads to the relation of gypsum to anhydrite. A review is made of the controversial views held as to this relation in the earth. One concludes anhydrite in the earth must react with liquid water to form gypsum. Further, it is believed the anhydrite conversion to gypsum forms the seal to project salt layers.

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Copyright 1997 American Association of Petroleum Geologists