Abstract The Edison oil field, 12 miles southeast of Bakersfield, Kern County, California, was discovered in 1934. Oil is produced from several sands, the lower of which have been grouped together and designated as the “Lower Duff” zone. The lower sands are oil reservoirs of the stratigraphic trap type.

Abstract The Kern Front oil field was discovered by the Standard Oil Company of California in 1915. There are now 3,165 proved productive acres of which 80 per cent are developed. Total production to January 1, 1941, is 45,500,000 barrels of oil ranging in gravity from 12° to 17°. Production is obtained from non-marine sand zones which are interbedded with siltstone, claystpne, and gravel, also of continental origin. In the northern end of the field oil is obtained from discontinuous sands in the lower part of the Etchegoin marine member. It is believed that the oil accumulation of the Kern Front oil field results from a thinning of section accompanied by a loss in porosity and permeability at the north end of the field, combined with a fault seal on the east side.

Abstract The Greasewood oil field is located in Sees. 13 and 24, T. 6 N., R. 61 W., at the eastern boundary of Weld County, Colorado. The early geology of the area by the Hayden Survey was concerned with the stratigraphy in relation to other areas of the Great Plains. The writer was engaged by the Greeley Chamber of Commerce to make a reconnaissance of the oil possibilities of the county in 1923, which study resulted in the discovery of the Greasewood anticline. Later work under the direction of R. D. George resulted in the drilling of a test well, which discovered oil in the Greasewood sandstone on October 10, 1930. Surface rocks of the area belong to the Laramie and Fox Hills (Cretaceous) formations, and oil is produced from the lower part of the Cretaceous series at depths of 6,639-6,683 feet. The producing area is very small and the reservoir rocks are very erratic. Only three wells out of nine drilled in the immediate area were commercial producers. One well is still producing 15-30 barrels of oil per day, flowing naturally. Accumulation of oil in the Greasewood sandstone is due to a combination of stratigraphic and structural factors.

ABSTRACT The Bush City oil field is in the shallow district of eastern Kansas. The oil is in a sand body 13 miles long and about 1/4 mile wide 30–40 feet below the top of the Cherokee shale of the Pennsylvanian system. The sand is believed to be a channel filling. The field is not related to any particular type of surface structure but is folded in several minor anticlines and synclines. The largest wells were on the anticlinal parts of the trend. The recovery has been 1,500–2,500 barrels per acre. The accumulated production of the field since the discovery in 1923 has been about 4 million barrels from 800 wells on 1,900 acres.

Abstract The Chanute oil pool in Neosho County, southeastern Kansas, was first exploited by the City of Chanute for gas between 1895 and 1898. Oil wells were drilled in 1899 and produced until 1908 when they were abandoned. The field was redrilled in 1913 for oil and again redrilled in 1937 to 1941 for water-flooding operations. The oil-bearing sand is a shoestring sand body in the Cherokee shale. It is locally called Bar ties ville, although it is probably somewhat younger than the Bartlesville sand of the type locality. The sand lies at a depth of about 725 feet and its maximum thickness is about 50 feet. The sand body was cored and subjected to laboratory examination prior to the initiation of water-flooding operations. Nearly all new wells were drilled for the water-flooding project. Water is obtained from the Neosho River, chemically treated, and injected into input wells at a pressure of 700 pounds. The spacing between wells in lines parallel with the longer axis of the sand body is greater than in lines across the sand body because it has been found that the water travels faster lengthwise the sand body than across it. The total oil produced per acre by water flooding has been about 2,300 barrels in 3 years on one lease and 3,500 barrels in 2 years on another lease.

Abstract The Hugoton gas field, located near the southwestern corner of Kansas and an adjoining part of Oklahoma, was discovered in 1927 and became a gas reserve of major importance in 1930. The proved gas-producing area now covers parts of eight counties. The gas occurs throughout a thickness of 250 feet of dolomite and limestone beds belonging to the lower (Big Blue) series of the Permian system. The porosity of these rocks is believed to be due primarily to the chemical action of ground waters and, perhaps to some extent, to sub-aerial weathering. The structure of the field is that of a generally eastward-dipping homocline, the inclination of the beds increasing with depth. Gas accumulation is controlled by lateral variation in the character of the sediments forming the reservoir rocks. Study of drill cuttings and of insoluble residues shows that these sediments are predominantly of organic origin throughout the greater part of the field, but grade to increasing percentages of fine clastic materials toward its western edge. This pinching-out of gas-bearing beds is thought to have resulted from fluctuating conditions of deposition along the margin of the Permian sea. The rock pressure of the field is subnormal and the average open-flow volume of wells is comparatively small. No oil has been found with the gas. A few of the deeper field wells have reached water depths below those at which the gas occurs. At the end of 1939, the Hugoton field had 300 gas wells (there are no dry holes) with a reported open-flow volume (in Kansas) of 2,712 million cubic feet. Metered withdrawals of gas at that time totaled 211 billion cubic feet.

Abstract The Nikkei pool, located in McPherson and Harvey counties, Kansas, had produced on October 1, 1940, 7,135,147 barrels of oil from 55 wells. This represents an average recovery of 129,730 barrels per well. The pool is now producing about 400 barrels of oil per day. Nearly all of the oil has been produced from the Hunton limestone, a reservoir that is unique since the accumulation has been the result of a stratigraphic trap in a Hunton limestone outlier that has been arched and faulted.

Abstract The Wherry pool is producing from a stratigraphic trap. The pool is situated on the homoclinal southeastern flank of the Central Kansas uplift. The geologic history of the Wherry pool is closely related to that of the uplift. The oil is produced from a chert zone in the Sooy conglomerate at the base of the Pennsylvanian system. The pool covers approximately 5,700 acres. Per-acre ultimate recovery for the pool is expected to be low.

Abstract The Zenith pool is in southeastern Stafford County, Kansas. Oil is produced from the Misener, Maquoketa dolomite, and Viola. Since the three producing formations lie in contact, one with another, and the oil and water from each producing formation are strikingly similar to those in the other formations, it is thought that both oil and water are from a common source of supply. The Zenith pool is considered an excellent example of a stratigraphic type oil field. It is pointed out that the limited amount of structure that can be shown is not sufficient to account for the oil accumulation at Zenith. The limited distribution of the Misener sand and limestone and Maquoketa dolomite; truncation of the producing formations at the north end of the pool; the presence of an effective impermeable seal above all producing formations; and lateral changes of effective porosity and permeability in the Viola are thought to be the principal causes of oil accumulation in the Zenith pool. The Zenith pool was discovered in September, 1937, and has produced more than 3,500,000 barrels of oil to the end of 1940. Five wells have tested the possibilities of Arbuckle production without finding any showings of oil or gas below the Viola. Four of the Arbuckle tests were drilled within the producing area of the Zenith pool.

Abstract The Big Sinking field is located high on the eastern side of the Cincinnati anticline and only 20 miles or so east of the outcrop of the Chattanooga shale and the Devonian limestone. The Silurian Lockport and Cayugan dolomites thin westward from about 600 feet in Magoffin County to extinction before the outcrop is reached, and the Devonian Hamilton limestone which is present at the outcrop thins eastward, is gone in the main part of the Big Sinking field, and if present at all west of Magoffin County is represented only by thin outliers. About 60 feet of strata are present between the Chattanooga shale and the green Silurian shales on the western edge of the field, perhaps a third of it being Hamilton and the rest Lockport, while 80-100 feet of strata occupy this position in the main part of the field, all of which is Lockport. Pre-Hamilton movements in the Cincinnati arch, with consequent stripping and leaching of the Silurian dolomites together with post-Hamilton erosion, were responsible for the creation of reservoir beds. This was not a case of oil accumulating on the side of a structure, but rather of the structure being responsible for the initial porosity and permeability of the formations lying unconformably below the Chattanooga shale. Silurian, and in some places even Ordovician, beds occupying this unconformable position have produced in various places around the Jessamine dome of the Cincinnati arch. The wells are long-lived and respond readily to repressuring with air and gas, although acidization, perhaps due to the dolomitic character of the reservoir rock, has been less successful.

Abstract The University field, East Baton Rouge Parish, Louisiana, is a deep domal type structure with minor faulting. Production from the field is obtained from Miocene sands. The main and most important oil-producing sand is the 6,400-foot sand. Other producing sands are the 4,300-foot gas sand, the 6,700-foot oil sand, and the 7,100-foot gas sand Aside from these four producing sands, there are three potentially productive sands: the 4,100-foot and 6,200-foot sands in which oil has been cored, and the 6,900-foot sand containing gas As yet, no attempt has been made to produce from the latter sands. This field is of particular interest because of the presence of a greater number of stratigraphic traps (oil and gas reservoirs) than are known in any other field of the Gulf Coast except from piercement-type domes. Accumulation in the 4,300-foot sand, which is among the producing sands, and in the 4,100-foot sand and the 6,200-foot sand of the potentially productive sands, is controlled by stratigraphic factors which created traps. Individual contour maps on these three sands delineate their respective lines of pinch-out and, with the assistance of cross sections of the sands in the field, provide an accurate picture of the stratigraphic traps which they form. An hypothesized explanation is given, based on the assumption of erratic contemporaneous deposition of sediments from different sources in the same area.

Abstract The Michigan Stray sand, from which most of Michigan's gas is produced, consists of sand bars formed on offshore shoals in a shallow Mississippian sea. The shoals that caught the bars are on pre-Mississippian anticlinal trends, the sea-floor topography having been determined partly by structure and partly by erosion during a previous period of emergence. Contour maps of the sand bodies are strikingly similar to those of present-day offshore bars. In a field where the pre-depositional sea-floor topography has been worked out, the sand bars were accurately modelled to the shoals that caused them, and the sand piled up behind a small subsea hill or island and built up on the top of a subsea ridge, and a smaller bar formed on a lower shoal across a narrow channel, through which passed enough current to keep the channel almost, but not quite, free from sand. Isopach and isopore maps show that the cleanest sand was deposited in the thickest parts of the main bar, with muddier sand on the lagoonward side. In another field, successive bars were built across a wide shoal area, each bar inshore from its predecessor, and the channels between them were partially filled to form the whole into a continuous sand body. The sand bodies are of some magnitude and are important gas reservoirs. The largest so far explored is about 9 miles long and 3 wide, and originally held about 50 billion cubic feet of gas. Twenty-three of these shoestring gas fields have been found, with a total original gas content approximating 150 billion cubic feet. None of the shoestring reservoirs of Kansas and Oklahoma show's more clearly its origin as an offshore bar.

ABSTRACT Development of the Border-Red Coulee district in Toole County, Montana, and Alberta, Canada, in 1930-1931, marked the fourth discovery of a commercial oil field on the Sweetgrass arch. The proved area in Montana is about 500 acres, and in Alberta about 100 acres. The course of the International Boundary through the north end of the productive area presents an exceptional situation for an oil field. Various regulations of both countries have prohibited drilling in a strip about 525 feet wide. Directional drilling has not been attempted. On January 1, 1940, the total production of the field was 1,078,694 barrels of 31.50 A.P.L gravity oil with intermediate base. Approximately three-fourths of this came from 21 wells in Montana; and the remainder from 7 wells in Alberta. Reserves are estimated to be about 200,000 barrels. Structurally, the field is on a small, plunging anticlinal nose, which may be the north extension of the axis of Kevin-Sunburst dome. A buried hill on the eroded surface of the Madison limestone appears to have localized its development. Differential compaction occurred over this feature and exerted some influence upon the position and form of the reservoir sands. Deformation took place sometime during the middle or later stages of the Eocene epoch. Oil is produced from the Vanalta and Cosmos sands at the base of the continental Kootenai formation at an average depth of 2,520 feet. These sands are the equivalent of the Cut Bank sand in the Cut Bank district at the south, whose development followed in 1932-1933. First identification of the stratigraphic horizon of this zone was made in the Border-Red Coulee district. Although the sands are lenticular and stratigraphic traps of several different types are present, migration and accumulation have probably taken place through fractures. The field is, therefore, not a simple or unmodified stratigraphic trap. Such conditions are probably uncommon. In addition to a thorough review of the regional stratigraphy, structure, and geologic history, this paper describes in detail the sand conditions and the nature of the petroleum and field waters as a background for suggestions about the manner of migration and accumulation of the oil. Brief accounts of production and technology are also included.

Abstract The Cut Bank oil and gas field is in Glacier County, Montana, 50 miles east of Glacier National Park, and extends to within 3 miles of the Canadian border. It is 31 miles long and up to 10 miles wide. The field is on the west flank of the Sweetgrass arch. The structure is monoclinal and the regional dip is about 75 feet per mile slightly south of west. The trend of the producing area is parallel with the regional strike. It is still in an active stage of development and as of July 1, 1940, 506 oil wells, 78 gas wells, and 86 dry holes had been drilled, proving 40,000 acres for oil and 55,000 acres for gas production. Average daily oil production was about 11,000 barrels, which also represented the potential for the field, and daily gas withdrawal about 21 million cubic feet. Total oil production to July, 1940, was 18,645,500 barrels and total gas withdrawal 62,890 million cubic feet. Average well depth in the oil area is 2,950 feet. The discovery well, completed in 1926, sought a west extension of the Kevin-Sunburst field when it found a stray sand containing commercial amounts of gas above the objective horizon. Another well found oil lower structurally in the same sandstone in 1929, but active development of the oil field did not take place until 1932. The stray sand was first named the Darling, later renamed the Cut Bank, and is the main reservoir of oil and gas. The Upper Cretaceous Two Medicine, Eagle sandstone, and Colorado shale formations; the Lower Cretaceous Kootenai (lower Blairmore) formation; and the Upper Jurassic Ellis formation are penetrated. The Kootenai lies unconformably on the Ellis. The three producing zones lie in the lower 200 feet (lower third) of the Kootenai and are: the Moulton sand zone at the top, the Sunburst sand zone in the middle, and the Cut Bank sand at the base. The lower Cut Bank or principal producing sand rests unconformably on the Ellis shale. The Kootenai is a continental formation and the source of its sediments and that of the producing sands is believed to have been from the west and northwest from the erosion of a Jurassic landmass occupying the approximate position of the Purcell and Selkirk ranges in southern British Columbia and adjacent parts of Montana and Idaho, 160-300 miles from Cut Bank.

Abstract Oil production began in southeastern Ohio during the year 1861. Since that time central and southeastern Ohio have produced about 215 million barrels of oil. Most students of central and eastern Ohio regard all producing sands there as lenticular, for, although the Cow Run, Big Injun, and Berea are similar in outcrop to the subsurface producing formations, their variations in thickness and their rapidly changing physical properties suggest lenticularity.

ABSTRACT The Davenport field, discovered in 1925, has produced 11,338,000 barrels of oil to January 1, 1941. Future production will be very small. Average per-acre yield to January I, 1941, is 5,585 barrels. The production is mainly from the Prue sand of Pennsylvanian age. A small amount of oil and gas was obtained from the Cleveland sand, also of Pennsylvanian age. The surface beds show a minor structural terrace. The occurrence of oil in the Prue sand is an accumulation in a sand lens.

Abstract The Dora oil pool is in the south-central part of T. 7 N., R. 6 E., and the north-central part of T. 6 N., R. 6 E., in the so-called “Greater Seminole area.” It is one of the more prolific Pennsylvanian sand pools developed in this region in recent years. The discovery of the pool resulted after several dry holes, a few of which had oil showings in some of the shallow sands, had been drilled on the edges and at locations surrounding the pool. D. B. Malernee's West No. i,in the SE. J, SE. J, NW. i of Sec. 33, T. 7 N., R. 6 E., the discovery well of the Dora pool, was completed on October 2, 1935. This well had an initial production of 117 barrels of oil per day from the “Dora” sand encountered at a depth of 2,934-2,959 feet. The pool was developed rapidly in 1937 and 1938. The Dora pool represents a stratigraphic type of oil pool; it is somewhat similar to the Olympic and Burbank pools of Oklahoma, and to some of the shoestring pools of Kansas, all of which are oil pools in thick sand lenses. The producing sand, known as the Dora sand, formed as an offshore bar or beach deposit. It has a lenticular shape, and is slightly convex upward. Structural movements, together with differential settling of the sediments overlying the Dora sand, have produced a slight doming or nosing and structural flattening of the strata overlying the pool. There is evidence of faulting, local uplift, and truncation of early Pennsylvanian beds at the extreme southeast end of the structure.

Abstract East Tuskegee is one of the smaller pools of Creek County, Oklahoma. The main producing formations are the Misener and the “Wilcox” sands, now of about equal importance since several wells originally completed in the Misener sand have been deepened to the "Wilcox." Initial productions from both sands have been small, resulting in slow development of the pool. Misener wells are approximately 3,250 feet deep and the “Wilcox” wells about 3,400 feet deep. A few wells produce from the Dutcher sand. The upper 3,000 feet of section drilled is Pennsylvanian in age. The remaining section is Mississippian and Ordovician (on the assumption that the Chattanooga shale and Misener sand are Mississippian in age). The structure of the pool is a small northwest-southeast-trending anticline with a small domal apex at either end. Production is limited to these small domes. Misener production is limited to the flanks of the domes, but the “Wilcox” production is limited to the apex of the “highs.”