The Norman Wells oil field is located on Mackenzie River in the Northwest Territories of Canada, about 90 miles south of the Arctic Circle. Although the first well was drilled in 1920, the distance of the field from markets and lack of transport facilities prevented full development until 1942, when war conditions brushed aside economic considerations. The oil reservoir is a reef limestone in shales of Upper Devonian age. The structure is monoclinal and the strata dip about 5º SW. Closure on the updip side is caused by pinching-out of the reef. The top of the reservoir reef limestone is encountered in the wells at depths from 1,050 to 1,950 feet, depending on their position on the structure. The field has 60 productive wells and these outline an area of 4,010 acres that will probably be productive. Estimated recoverable oil reserves are 36,250000 barrels from a drainable area of 2,600 acres. The other 1,410 acres of potentially productive territory are covered by the river and are not considered drainable at present.
The wells produce by natural flow, and under rigid control the field produced at the rate of more than 4,300 barrels per day in October, 1944. The original reservoir pressure was 695 pounds per square inch at 1,000 feet subsea, which is abnormally high for wells having an elevation of approximately 300 feet. The oil has a gravity of 39°-41°. On January 1, 1946, the field had produced 2,050,528 barrels.
Figures & Tables
Structure of Typical American Oil Fields: A Symposium of the Relation of Oil Accumulation to Structure
Modern petroleum geology in the United States had its beginning in the first decade of the 20th Century when the U.S. Geological Survey began mapping the structure of the rocks in and near old fields in order to discover the various types of structural conditions under which oil and gas are trapped. Structural geology has evolved as a branch of the broader science far more rapidly than have methods of mapping the attitude of rocks at the surface. This volume, published in the late 1920s, was designed to afford authoritative and modern descriptions of the structure of typical oil fields in the United States. Each of the 39 fields contained here is described by an author who is intimately familiar with the available data. The relationship of structure at the surface and at depth for different terranes is clearly set forth wherever the strata are not parallel. The volume concludes with a summary paper on the role of geologic structure in the accumulation of petroleum. Fields include: Florence, Colorado; Stephens, Arkansas; Kevin-Sunburst, Montana; Bradford Pennsylvania; and Salt Creek, Wyoming.