Lower Cretaceous Sands Research Articles

South Glenrock, A Wyoming Stratigraphic Oil Field

Wyoming, long the stronghold of anticlinal occurrence of petroleum, is now yielding to the stratigraphic trap. South Glenrock, a 1950 discovery on the southwestern margin of the Powder River Basin, has developed a 50-million barrel reservoir in Lower Cretaceous sands of the and Muddy zones, without the benefit of structural closure. The term Dakota for the lower sand fits current usage, but is a sand at a stratigraphic level different from other sands of the Wind River Basin on the west, also called Dakota. oil at South Glenrock is trapped by a westward facies change on a large eastward plunging nose off the prominent anticlinal structure of the Big Muddy oil field. Muddy oil is found in lenticular sands associated with prominent channeling at a point of unconformity, 100 feet above the zone. South Glenrock structurally is integrally related to the Big Muddy anticlinal oil field, but produces from different sands. The sands exhibit depositional evidence of being influenced by an ancestral structural feature which was a pre-Laramide incipient high at the locale of South Glenrock. This was offset from the younger Laramide anticline which afforded structural accumulation at Big Muddy. A close study of older sedimentation in other Wyoming localities probably will point to an earlier structural history of local uplifts. Many of the ancestral structures may be offset from their more robust Laramide progeny.

South Glenrock, A Wyoming Stratigraphic Oil Field: ABSTRACT

Wyoming, long the stronghold of anticlinal occurrence of petroleum, is now yielding to the stratigraphic trap. South Glenrock, a 1950 discovery on the southwestern margin of the Powder River basin, has developed a 50-million-barrel reservoir in Lower Cretaceous sands of the and Muddy zones, without the benefit of structural closure. The term Dakota for the lower sand, fits current usage, but the sand is at a different stratigraphic level from other sands of the Wind River basin on the west, also called Dakota. oil at South Glenrock is trapped by a westward facies change on a large eastward plunging nose off the prominent anticlinal structure of the Big Muddy oil field. Muddy oil is found in lenticular sands associated with prominent channeling at a point of unconformity, 100 feet above the zone. South Glenrock structurally is integrally related to the Big Muddy anticlinal oil field, but produces from different sands. The latter exhibit depositional evidence of being influenced by an ancestral structural feature which was a pre-Laramide incipient high at the locale of South Glenrock. This was offset from the younger Laramide anticline which afforded structural accumulation at Big Muddy. A close study of older sedimentation in other Wyoming localities probably will point to an earlier structural history of local uplifts. The ancestral structures may be offset from their more robust Laramide progeny. End_of_Article - Last_Page 950------------

Cross-Bedding and Grain Size in the Lower Cretaceous Sands of East Anglia

AbstractThe cross-bedding of the Lower Cretaceous sands between Leighton Buzzard and Hunstanton has been studied. This paper describes new evidence which throws further light on the depositional environment and palaeogeography of these sediments.Both cross-bedding and grain size distribution were investigated in detail in the Woburn Sands (Aptian). These beds lie between Cambridge and Leighton Buzzard (Cameron, in Kirkaldy, 1939, p. 407), and are the youngest “;Lower Greensand” of East Anglia. Rather less attention has been paid to the pre-Barremian Sandringham Sands (Downham to Hunstanton). Unfortunately, the Carstone of Hunstanton shows no cross-bedding.

Developments in Canada in 1948

Developments in Canada in 1948

Recent Developments in Canada: ABSTRACT

Recent oil developments in Canada have been largely restricted to Alberta. Some exploratory work, including drilling, has been carried on in northeastern British Columbia, Saskatchewan, Manitoba, Ontario, and the Maritime provinces. Geophysical exploration in Alberta has reached an all time high with forty seismographs, nine gravity meters, one magnetometer and a number of core drills and stratigraphic drills operating. This work has been largely concentrated in the Central Plains, although the Southern Plains and foothills are receiving considerable attention. Recent important discoveries, in addition to the Leduc oil field which produces oil from two dolomite zones in the Upper Devonian as well as from a Lower Cretaceous sand, include the Gulf Pincher Creek Mississippia limestone gas and condensate discovery in the southern foothills, and Imperial's Redwater No. 1 well which appears to have found another Devonian oil field thirty miles northeast of Edmonton. Other recent finds include a small Lower Cretaceous sand discovery at Bantry jointly by California Standard and Imperial, several pool extensions in the Lloydminster oil field, a gas discovery in the Cretaceous Peace River sand of the Peace River district of northeastern British Columbia and northwestern Alberta by Pacific Petroleums Limited, and a small heavy oil discovery by Bata Petroleums near the Alberta-Saskatchewan boundary eighty miles south of Lloydminster in a Lower Cretaceous sand. One hundred and thirty wells were drilled in Alberta during the first six months of 1948. Using the A.A.P.G. classification, there were 110 completions, 74 of which were field development and 36 exploratory wells. Five field development wells were dry holes. Considering the exploratory wells, 5 outpost wells were successful and 5 were dry holes. Among the new field wildcats, Imperial's Woodbend No. 1, north of Leduc, discovered what is probably a new pool. Of the approximately 165,000,000 acres comprising the Province of Alberta, approximately 41,000,000 acres are currently held under lease or reservation. End_of_Article - Last_Page 2321------------

Status of German oil fields

The most active period in Germany's 85 years of oil-field development was the decade that ended with the close of World War II. Twenty-eight oil fields were discovered during that period and 62 per cent of Germany's total cumulative production obtained. About half of the new fields were found in the old Hannover producing district, from which has come more than three-fourths of all the oil produced in the country. The oil from the earliest of these new fields together with that obtained in extensions of the old Nienhagen field resulted in the annual crude production being more than doubled between 1935 and 1940. In the latter year an all-time peak of 7,393,309 barrels was reached. In spite of the discovery of II fields since, the production declined after 1940 and was onl 5,053,552 barrels in 1944 and 3,838,709 barrels in 1945. Most of Germany's crude oil comes from Lower Cretaceous and Jurassic formations on the flanks of salt structures which are the result of a combination of tangential folding, occurring during the late Jurassic and Cretaceous, and the upthrusting of Upper Permian salt beds. The oil in the Central Hannover district is in most places confined to narrow belts of tilted strata on the flanks of the salt structures, the thin producing sands being sealed in by uncomformities and faults. Only one important field--Reitbrook--has been found on the crest of the many deep-seated domes that have been discovered by geophysical prospecting in the region north and northwest of the Central Hannover district. It was formerly believed that large production would be obtained from the Hannover oil sands on the crest and flanks of these domes. Many of them have as yet not been adequately tested, but of the two score or so drilled only four have yielded oil chiefly from Upper Cretaceous chalks. The poor showing made by these domes evidently is due to the absence from the region of the Lower Cretaceous and Jurassic oil-bearing formations. The Pompeckj uplift, from which these formations were eroded, extends over a much greater area than was formerly recognized. Another disappointing development has been the failure to find important new production in the Middle Zechstein dolomites in central Germany. The discovery of oil from these dolomites at Volkenroda in the Thuringian basin in 1930 has led to no other commercial field being found in the region. These unsuccessful developments have been offset to some degree by the new discoveries at Heide in Schleswig-Holstein and near the Dutch border in western Germany. In the Heide fields oil is produced from Middle Zechstein dolomitic limestones and a pre-Neocomian scree breccia on the west flank of an elongate salt structure with a core of Rotliegend salt-bearing strata. The three fields discovered near the Dutch border in 1942 and 1943 produce from Lower Cretaceous sands and shell beds. They are situated on low folds unrelated to salt tectonics. These new developments, together with the possibility of discovering deeper sands on the flanks of salt structures, and the search for gentle folds between the salt structures, offer the best prospects of new discoveries. The Munich basin probably is the only region outside of the producing districts that justifies exploratory work.

Genesis of ground waters in the Coastal Plain of Virginia

The Coastal Plain province of Virginia consists of unconsolidated sediments of Cretaceous, Eocene, Miocene and Pleistocene age which dip gently seaward and thicken to more than 2,200 feet in the eastern part of the area. Lower Cretaceous sands are the most prominent water bearers south of James River but north of James River most deep wells end in Eocene strata.In the western part of the province, along the Fall Zone, water from deep wells is soft and has a low total mineralization. Eastward the water gains in mineral content and becomes a hard calcium-bicarbonate water. Still farther to the east it is softened by base exchange and is a soft sodium-bicarbonate water. In the vicinity of Chesapeake Bay this water is somewhat brackish and in places contains more than 1,000 parts per million of chloride.Soft water from the Fall Zone belt contains free carbon dioxide which dissolves calcium carbonate from the sediments as it moves eastward to form the hard calcium-bicarbonate water of the adjacent belt on the east. When the free carbon dioxide found in the Fall Zone water is consumed, gain in bicarbonate does not cease, and further accretions of bicarbonate are accounted for by chemical or biochemical breakdown of sulphate with liberation of carbon dioxide that subsequently forms bicarbonate.South of James River soft sodium-bicarbonate water from the Lower Cretaceous sediments commonly contains from 4 to 6 parts per million of fluoride. North of James River the Eocene sediments characteristically yield water containing from 1 to 3 parts of fluoride.The high chloride in the eastern part of the area is considered to be due to incomplete flushing of the sea water with which the sediments were once saturated. These slightly brackish waters have a somewhat lower hardness and a higher Ca/Mg ratio than would be expected of mixtures of sea water and soft sodium-bicarbonate water. It is thought that base exchange within the system occurs as sea water in the sediments becomes freshened; where saturated with sea water clays will adsorb mostly magnesium and sodium whereas when in contact with dilute solutions calcium and magnesium will be deposited and sodium liberated.

Status of German Oil Fields

The most active period in Germany's 85 years of oil-field development was the decade that ended with the close of World War II. Twenty-eight oil fields were discovered during that period and 62 per cent of Germany's total cumulative production obtained. About half of the new fields were found in the old Hannover producing district, from which has come more than three-fourths of all the oil produced in the country. The oil from the earliest of these new fields together with that obtained in extensions of the old Nienhagen field resulted in the annual crude production being more than doubled between 1935 and 1940. In the latter year an all-time peak of 7,393,309 barrels was reached. In spite of the discovery of II fields since, the production declined after 1940 and was onl 5,053,552 barrels in 1944 and 3,838,709 barrels in 1945. Most of Germany's crude oil comes from Lower Cretaceous and Jurassic formations on the flanks of salt structures which are the result of a combination of tangential folding, occurring during the late Jurassic and Cretaceous, and the upthrusting of Upper Permian salt beds. The oil in the Central Hannover district is in most places confined to narrow belts of tilted strata on the flanks of the salt structures, the thin producing sands being sealed in by uncomformities and faults. Only one important field--Reitbrook--has been found on the crest of the many deep-seated domes that have been discovered by geophysical prospecting in the region north and northwest of the Central Hannover district. It was formerly believed that large production would be obtained from the Hannover oil sands on the crest and flanks of these domes. Many of them have as yet not been adequately tested, but of the two score or so drilled only four have yielded oil chiefly from Upper Cretaceous chalks. The poor showing made by these domes evidently is due to the absence from the region of the Lower Cretaceous and Jurassic oil-bearing formations. The Pompeckj uplift, from which these formations were eroded, extends over a much greater area than was formerly recognized. Another disappointing development has been the failure to find important new production in the Middle Zechstein dolomites in central Germany. The discovery of oil from these dolomites at Volkenroda in the Thuringian basin in 1930 has led to no other commercial field being found in the region. These unsuccessful developments have been offset to some degree by the new discoveries at Heide in Schleswig-Holstein and near the Dutch border in western Germany. In the Heide fields oil is produced from Middle Zechstein dolomitic limestones and a pre-Neocomian scree breccia on the west flank of an elongate salt structure with a core of Rotliegend salt-bearing strata. The three fields discovered near the Dutch border in 1942 and 1943 produce from Lower Cretaceous sands and shell beds. They are situated on low folds unrelated to salt tectonics. These new developments, together with the possibility of discovering deeper sands on the flanks of salt structures, and the search for gentle folds between the salt structures, offer the best prospects of new discoveries. The Munich basin probably is the only region outside of the producing districts that justifies exploratory work.

The Delhi, West Delhi and Big Creek Fields: ABSTRACT

The Delhi, West Delhi, and Big Creek fields are in northeastern Louisiana in parts of Richland, Madison, and Franklin parishes. Production is from Tuscaloosa in Upper Cretaceous and Paluxy in Lower Cretaceous. Sands within a common reservoir constitute the most prolific producing zone. These sands consist of a basal Tuscaloosa sand and various underlying Lower Cretaceous sands in contact at the unconformity. Other producing sands in the Tuscaloosa are lenses in the marine Tuscaloosa above the basal sand. The Big Creek field produces from several lenticular sand members in the marine Tuscaloosa with the basal sand having been overlapped and not being present. As of July 1, 1946, 236 wells had been drilled in the Delhi, West Delhi, and Big Creek fields, of which 197 were oil-producing, four gas, and 35 were dry and abandoned. The present productive area approximates 7,000 acres. The fields are in stages of development and the ultimate productive area is as yet unknown. The estimate of total recovery is in excess of 200,000,000 barrels of oil at the present stages of development. The Delhi field was drilled on a seismic structure but subsequently it was found that the accumulation of the oil was due to a stratigraphic trap with structure playing but a small part. The discovery well primarily was located on the theory of a Tuscaloosa pinch-out; the small seismic structure was of secondary importance only. End_of_Article - Last_Page 1967------------

Geology of Black Knob Ridge, Oklahoma

Black Knob Ridge is situated at the west end of the Ouachita Mountains, near Atoka, and about 15 miles east of the east end of the Arbuckle Mountains. It is the westernmost area that reveals the facies of pre-Pennsylvanian rocks characteristic of the Ouachita Mountains. The strata in Black Knob Ridge dip eastward beneath the Pennsylvanian Stanley shale, which is overlain by the conformable sequence of the Jackfork sandstone, Johns Valley shale, and Atoka formation, all of which are of Pennsylvanian age. At the south end of Black Knob Ridge the Paleozoic strata are overlapped by beds of the Lower Cretaceous Trinity sand of the Gulf Coastal Plain, which dip gently southward. On the west side of Black Knob Ridge, south of Stringtown, the Caney shale, Springer formation, and toka formation of the facies or sequence characteristic of the Arbuckle Mountains are exposed. Northwest of Black Knob Ridge, north of Stringtown, undifferentiated shales and sandstones of Pennsylvanian age are exposed. The rocks of Black Knob Ridge are composed of clastic siliceous sediments together with some siliceous limestones. They are almost identical in lithologic and faunal characteristics with rocks of the same age in the Potato Hills, Oklahoma, and are only slightly different from rocks of the same age in McCurtain County, Oklahoma, and the Arkansas part of the Ouachita Mountains. The rocks differ greatly in both lithologic character and fauna from rocks of the same time interval in the Arbuckle Mountains, but pronounced similarity between rocks at several horizons in Black Knob Ridge and rocks of equivalent age in the Arbuckle Mountains suggests that the basin of deposition of the rocks of Black Knob Ridge and the similar rocks farther east in the Ouachita Mountains was connected at least intermittently with the basin of deposition of the rocks characteristic of the Arbuckle Mountains. The greater abundance of limestone in the Bigfork chert in Black Knob Ridge than in the areas of its occurrence farther east suggests that the change from the Bigfork chert of the Ouachita Mountains to the Viola limestone of the Arbuckle Mountains was gradual within the basin of deposition; however, later northwestward thrusting of the rocks of Black Knob Ridge has moved them closer to the areas of deposition of the rocks of the Arbuckle Mountains and has therefore accentuated the two different sequences, one typically developed in the Arbuckle Mountains, and the other in the Ouachita Mountains. Black Knob Ridge lies at the west side of the Oklahoma structural salient of the Ouachita Mountains and is made up of a series of rocks that dip steeply eastward and End_Page 1------------------------------ are bounded on the north and west by the Ti Valley and the combined Ti Valley and Choctaw faults. Along these faults the strata in Black Knob Ridge have been thrust northwestward 20 miles or more. The presence of several minor thrust faults and folds in Black Knob Ridge indicates that the movement along the Ti Valley fault was not entirely normal to the strike, but was in part parallel with the strike in a northerly direction. The overthrusting has moved the Black Knob Ridge rocks westward to within 15 miles of the Arbuckle Mountains over strata that, prior to the thrusting, were exposed in an uplift near the present position of Black Knob Ridge. The rocks in this uplift are similar to the sequence of the Arbuckle Mountains and are thus dissimilar to the overthrust rocks which belong o the sequence of the Ouachita Mountains.

On some Recent Borings through the Lower Cretaceous Strata in East Lincolnshire

The information on which this communication is based has been in my possession since 1889, but pressure of other work had prevented me from preparing it for publication until the present time. The results of the borings which are here described are important, because they give information concerning the geological structure of the platform which underlies the Glacial Drift on the eastern side of the southern part of the Lincolnshire Wolds. We learn from them that the outcrop of the Lower Cretaceous sands and clays extends much farther northward beneath the Drift on this side of the Wolds than there was any reason to suspect at the time when I mapped the area for the Geological Survey. §1. The Boring at Willoughby (1887). Willoughby is a village between the towns of Burgh and Alford, and the site of the boring ,is at the station on the East Lincolnshire Railway, which is the junction for the new branch-line to Sutton. The boring was made for the Railway Company in 1887, and a good supply of water was procured at a depth of 245 feet. For information regarding the beds passed through I am indebted, in the first place, to Mr. H. Cheetham, the engineer of the railway ; but the description of the strata furnished by him being only a well-sinker's account, and not sufficiently accurate to enable me to identify the strata, I wrote to my friend, Mr. Meaburn Staniland, F.G.S., asking if he could take an opportunity of looking the