The Irma field is situated in Nevada County, Arkansas. At present sixty-five wells produce 2,600 barrels daily from the Nacatoch sand at about 1,200 feet. Irma is a fault field although no deep production has yet been found. The faulting and doming are clearly shown on the surface. The average throw of the fault is about 400 feet. The closure along the fault is about 50 feet. The accumulation of the oil here is due to faulting and the closing of the monoclinal structure against the fault.
Figures & Tables
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 30 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. Fields include: McKittrick, California; Fairport, Kansas; Urania, Louisiana; Artesia, New Mexico; Burbank, Oklahoma; Cabin Creek, West Virginia; and Luling, Texas.