The Mitsue field, in north-central Alberta, produces large quantities of oil and minor gas from the Middle Devonian Gilwood Sandstone Member of the Watt Mountain Formation. This sandstone is generally clean, well sorted, fine to medium grained, and quartzose. The average oil column at the field is 4 m, and porosity averages 15-20 percent.
In retrospect, it seems surprising that for more than a decade explorationists condemned the Gilwood as being either “tight” or water bearing. The Gilwood is an excellent example of the type of widespread sandstone units common in sedimentary basins throughout the world. Many such units have not been explored fully and undoubtedly contain petroleum reservoirs awaiting discovery.
Figures & Tables
With three previous volumes published by AAPG on structure of American oil fields, this publication takes 17 of these oil fields and describes them in detail. The reservoirs described in these 17 papers range in age from Devonian to Pleistocene; their litholgies are standstone, limestone, or dolomite; and the trapping mechanisms are structural or stratigraphic or a combination of the two. The North American oil fields described are distributed from Alaska and the McKenzie Delta area of Canada on the northwest, to the Gulf of Mexico and Southern Floriday on the southeast. This publication also includes an index to those North American oil and gas fields which have been described in previous AAPG publications.