Oil Investigations in Illinois in 1914; Area South of the Colmar Oil Field, by William C. Morse and Fred H. Kay. the Coolmar Oil Field--A Restudy, by William C. Morse and Fred H. Kay. the Allendale Oil Field, by John L. Rich. Volume 31 (Paperback)

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1915 edition. Excerpt: ...is not well developed, though it gains sufficient prominence to appear upon the contour map and to affect materially the production of the wells located in its vicinity. Its top is about 25 feet lower than that of the eastern anticline. As already indicated, it marks the western limit of the elevated area. On its western flanks the beds dip steeply to the west. In the southern part of the field there appears to be a minor ridge extending through the W. H. Armstrong farm and northward to include wells No. 7 and No. 8 on the McMillen farm. This elevated area is separated from the Caroline Smith dome by a shallow trough or syncline (see Plate V). Another structural feature which deserves mention is the small terrace in the western part of the SE. J4 sec. 4 upon which are located the four wells Wm. Wolf, H. Jones No. 1, and Elisha Litherland Nos. 1 and 2. This is a relatively inconspicuous feature, yet its effect is very evident in the production records of the wells located upon it. Production Records In Relation To Structure The accompanying map (Plate VI) shows the initial and the present (July 1, 1914) production of each of the wells from which data could be secured. A study of these records in relation to structure yields strong confirmation of the theory that oil tends to accumulate at or near the crests of anticlines or domes or on local flattenings (terraces) in dipping rocks. From the map it is evident that only the wells situated upon the crest or high on the sides of the elevated tract were productive. The most conspicuous features brought out by this map are: (1) the uniformly high initial yield of the wells situated upon the higher parts of the main anticline and of the Caroline Smith dome; (2) the good yields of the four wells...