Archer County Research Articles

The discrepancy between morphological and microanatomical patterns of anamniotic stegocephalian postcrania from the Early Permian Briar Creek Bonebed (Texas)

The histological framework of thirteen Early Permian tetrapod long bones from a single locality, the Briar Creek Bonebed in Archer County, Texas, USA, is described from a series of transverse sections through the midshafts. The bones were morphologically categorized and belong to one of three taxa: Eryops, Archeria, and Diadectes. However, five histotypes are recognized. The first category includes the juvenile bone. The second histotype is characterized by the presence of radial vascular canals. The third histotype is characterized by the numerous longitudinal canals arranged in regular rows. In the fourth histotype, there is strong remodeling in the deep part of the cortex, creating a distinct border with the external layer of lamellar bone. In the fifth histotype, the deep part of the cortex is progressively remodeled towards osteoporosis with distinct layers of large circumferentially arranged erosion cavities. For femora and humeri, histotypes match morphology. Histotype II is characteristic for Diadectes propodials, histotype III is characteristic for Eryops propodials, and histotype IV is characteristic for Archeria propodials. A discrepancy between morphology and histology is observed in the ulnae, fibula and radius. This discrepancy may be explained by interspecific or intraspecific variability.

A new method to determine volume of bromalites: morphometrics of Lower Permian (Archer City Formation) heteropolar bromalites

Lower Permian vertebrates from both terrestrial and aquatic organisms have been collected from Archer County, Texas, for over a century. These include preserved shark cartilage and spiral bromalites presumed to have been produced by freshwater sharks of the genus Orthacanthus. Specimens were collected in the newly named Archer City Bonebed V occurring in the Archer City Formation. Physical characteristics (length, width, height, mass, eccentricity, volume, and density) were measured and recorded for 300 spiral bromalites and compared by linear regression analysis. The spiral bromalites had an average length of 31.74 mm; width 14.43 mm; height 10.51 mm, and mass 7.971 g. Eccentricity ranged from 0.9 to 0.06. All of these values follow a normal distribution. In addition to the collection of this statistical data, a new formula is proposed to help determine the volume of these elliptical fossils when volume determination by water displacement is not an option. The percent difference between the observed volumes obtained by water displacement and calculated volumes ranged from 0.04 to 56 %. Ninety-five percent of the statistical sample had a percentage difference of <30. This data, if compiled with data from the analysis of specimens from other localities, may ultimately reveal size groupings that could reflect the presence of previously unknown taxa that possessed a spiral valve and coexisted with the Orthacanthus sharks.

Long bone histology indicates sympatric species ofDimetrodon(Lower Permian, Sphenacodontidae)

ABSTRACTThe Briar Creek Bonebed (Artinskian, Nocona Formation) in Archer County is one of the richest sources ofDimetrodonbones in the Lower Permian of Texas, USA. Based on size, a small (D.natalis), an intermediate (D. booneorum), and a large species (D. limbatus) have been described from this locality. It has been proposed that these traditionally recognised species represent an ontogenetic series of only one species. However, the ontogenetic series hypothesis is inconsistent with the late ontogenetic state of the small bones, as suggested by their osteology and degree of ossification. Histological analysis of newly excavated material from the Briar Creek Bonebed has resolved some of the discretion between these two competing hypothesis, confirming the coexistence of a small (D. natalis) with at least one largerDimetrodonspecies. An external fundamental system is present in the largest sampled long bones identified asD. natalis. The histology ofD. natalispostcrania is described as incipient fibro lamellar bone. This tissue is a combination of parallel-fibred and woven-fibred bone that is highly vascularised by incipient primary osteons. The species status ofD. booneorumandD. limbatusremain unresolved.

Eothyris and Oedaleops: do these Early Permian synapsids from Texas and New Mexico form a clade?

ABSTRACT The monospecific genera Eothyris (Petrolia Formation, Leonardian, Archer County, Texas) and Oedaleops (Abo/Cutler Formation, Wolfcampian, Rio Arriba County, New Mexico), known solely from cranial remains, are confidently assigned to the monophyletic Caseasauria based on cranial and dental characters. In addition, Eothyris and Oedaleops comprise the monophyletic Eothyrididae based on nine cranial and dental characters. In contrast to the medium to large sized herbivorous caseids, the small eothyridids exhibit dental features that indicate that they were faunivores. The presence of well-developed caniniform teeth suggests that they were predators. Both Eothyris parkeyi Romer and Oedaleops campi Langston exhibit a suite of plesiomorphic cranial characters that identify them as basal synapsids. Thus, the eothyridids are better representatives of the primitive synapsid cranial morphotype than the often-used ophiacodontids. Although they appear relatively late in synapsid evolution, both eothyridids are significantly older than all other caseasaurs, forcing the establishment of a long unrecorded lineage for caseids.

New information on the pectoral girdle and vertebral column in Lupeosaurus (Reptilia, Pelycosauria)

UCLA VP 1651, a new specimen from the Lower Permian Admiral Formation of Archer County, Texas, provides information on heretofore unknown portions of the postcranial skeleton of the large pelycosaur Lupeosaurus. Presacral neural spines are elongate and have a subcircular cross section. Laterally directed tubercles are not present on any of the neural spines. Cervical vertebrae appear to have elongate neural spines and sharply keeled centra. Transverse processes are positioned relatively high above the bases of the centra through the length of axial column. The pattern of tilting of the neural spines is similar to that in the primitive edaphosaur Ianthasaurus hardestii. The proximal end of the first sacral rib contributes significantly to the intervertebral articular facet usually formed by the centra. The sacral ribs do not appear to fuse with one another distally. The ventral clavicular plate is greatly expanded anteriorly. The posterior edge of the subcoracoscapular fossa is very well defined. The available morphological information does not warrant a separate familial designation for the genus Lupeosaurus. Despite the lack of laterally directed tubercles of the neural spines, Lupeosaurus appears to be referrable to the Edaphosauridae. However, in the absence of cranial materials, this association must remain tentative. Although this description adds new information for only a restricted portion of the skeleton, it does appear to confirm the existence of a distinct, albeit rare, pelycosaur from the extensively studied fauna of the Lower Permian.

Early permian depositional environments and pond bonebeds in central archer County, Texas

The Lower Permian redbeds of North Texas contain the oldest abundant non-aquatic vertebrate fauna. In the past, collecting of fossils and study of their paleozoology has been emphasized. With the exception of the pioneering work of Olson (1958, 1977) little attention was paid to sedimentological, paleoecological, and taphonomical aspects of the fauna. This study focuses on the sedimentary framework, paleoenvironment, fossil content, and taphonomy of the most common type of fossil occurrence — the pond bonebed. Five sedimentary facies are recognized: meanderbelt sandstones, large straigt channel fill sandstones, small straight channel fill sandstone, interbedded facies, and floodplain mudstone. These are the components of small meandering river systems with local tributaries and crevasse splays. Pond bonebeds occur as gray claystone lenses in red floodplain mudstones, deposited in oxbow lakes or swamps. The fauna is largely aquatic ( Orthacanthus, Ectosteorhachis, paleoniscoids, Sagenodus) or semiaquatic ( Eryops, Trimerorachis, Archeria, Edaphosaurus) with subordinate terrestrial elements ( Diadectes, Dimetrodon). Fossil plants, found as impressions, petrifactions, and charcoal, are indicative of swamps ( Psaronius) and well drained soils (conifers). All of the organic debris accumulated gradually by biological and physical processes. Occasional isolated but complete vertebrate skeletons are found in the floodplain mudstones.

Taphonomy of the Lower Permian Geraldine Bonebed in Archer County, Texas

Lower Permian Admiral Formation redbeds in north Texas are famous for their vertebrate fauna. This paper provides a detailed taphonomic analysis of the Geraldine Bonebed in central Archer County, Texas, one of the most important fossil vertebrate occurrences in the region. The Geraldine Bonebed is situated in the floodbasin facies (red and gray mudstones with abundant Psaronius roots) of a small meandering river system. Such basins were covered with a dense swamp forest with a high diversity of vertebrates. The Geraldine Bonebed has yielded, from an area of 30 m 2, 44 partly articulated skeletons of four genera of tetrapods and the remains of another eight vertebrate taxa. The bones lie on a layer of fern, and conifer foliage and wood intermingled with fossil charcoal. The sediment, the occurrence of “Wasserleichen”, and the skeleton orientation indicate post-mortem transportation and deposition in water. A single mass death event, which could have been a forest fire, drove the animals into a pond where they perished. Carcasses floating in water together with plant debris were concentrated by wind-induced drift into this exceptional fossil deposit. A recent example of this process of bonebed formation after mass death was described by Weigelt (1927) from the Texas Gulf Coast.

A Permian-?Pennsylvanian Chondrichthyan Microfauna from Lowermost Wichita-Albany Group in North-Central Texas: ABSTRACT

End_Page 941------------------------------The age of the vertebrates from the Rattlesnake Canyon locality in western Archer County is currently considered to be latest Wolfcampian-earliest Leonardian or latest Gearyan (latest Pennsylvanian). Comparison of the shark teeth obtained by bulk-sediment sampling with those obtained in a similar manner from younger Loenardian localities in the same region and from Pennsylvanian (Virgilian) localities in Nebraska and the Dunkard basin favors a Permian age, but with reservations due partly to the coexistence of taxa with freshwater and marine affinities. Three species of xenacanthodiids occur here (two are rare) and in younger deposits; they are unknown from the older deposits. A new species occurs in Nebraska. Six new species of hybodontoids occur in the Texas deposits, but only two occur at Rattlesnake Canyon (one exclusively); at least five of them occur in Nebraska, but all remain unknown from the Dunkard basin. One species (new) of helodontid occurs in the Texas localities; it is rare at Rattlesnake Canyon, known only from the Wolfcampian in the Dunkard basin, but many occur in the Nebraskan Virgilian. Iniopterygians have previously been reported only from the Pennsylvanian, including the Nebraska locality, but not from the Dunkard basin; a new genus occurs at Rattlesnake Canyon, but the group is absent from younger deposits. Cte acanthoids and petalodontiids are too rare and poorly understood taxonomically to permit a significant analysis. End_of_Article - Last_Page 942------------

Curry Unit: A Successful Waterflood in a Depleted Carbonate Reservoir With High Gas Saturation

When waterflooding was begun in 1966, most of the wells in the old Curry Pool had been abandoned and a vacuum had been pulled for some 30 years. The pilot injection program was expanded and in 1971 the fieldwide flood pattern was changed to a five-spot on 40-acre spacing. Production increased from 80 BOPD in 1966 to 3,650 BOPD in 1972, and Production increased from 80 BOPD in 1966 to 3,650 BOPD in 1972, and the incremental oil recovery due to waterflooding is estimated at 7.5 million barrels. Introduction The Curry Unit waterflood project is about 4 miles southwest of Breckenridge, Stephens County, Tex. (see Fig. 1). The reservoir formerly known as "Curry Pool" is currently classified as the Stephens County Pool" is currently classified as the Stephens County Regular field by the Texas Railroad Commission. The producing formation is Caddo Reef, which lies at an average depth of 3,200 ft. The field is about 3.6 miles long and about 2.5 miles wide and encompasses more than 3,200 productive acres. The field was discovered in 1918, and by 1925 there were about 195 wells producing from this reservoir. The initial potentials ranged from 15 to 2,000 BOPD. The early wells were drilled by cable tools and completed open hole. Each contained several strings of uncemented casing. The wells were stimulated with 80 to 250 qt of nitroglycerine. Remedial work consisted of clean-out, shooting with nitroglycerine, and acidizing. Many of the wells were plugged in the late 1930's and early 1940's, but how and with they were plugged is unknown. In the 1950's a number of wells were drilled. Their potentials ranged from 10 to 55 BOPD, and as far potentials ranged from 10 to 55 BOPD, and as far as the primary production is concerned, they were economic failures. The reservoir properties (high porosity, low water saturation, low oil viscosity) do indicate a good candidate for waterflood. However the gravity drainage was the main producing mechanism at the start of the waterflood and the gas saturation was thought to be dispersed throughout the formation. This was substantiated by the fact that throughout the reservoir, regardless of the structural position or vicinity of the original gas-cap area, the GOR's were high. In addition, a number of wells produced water that was suspected to be from the lower limestones or from shallow water sands through casing leaks or channels behind casing. The field had to be practically redrilled, requiring significant capital investment. Thus conditions were not conducive to instituting a waterflood in this reservoir. The reservoir thickness was estimated mostly from driller's logs and secondary recovery was estimated with an empirical resaturation equation. The performance to date indicates that the recovery estimate performance to date indicates that the recovery estimate is still valid. Geology and Reservoir Description The Bend Arch is the main structural feature controlling the occurrence of oil in the North Texas area. The Bend Arch is a broad anticlinal feature dipping to the northwest and extending from the Llano-Burnet uplift in Central Texas to about the center of Archer County in North Central Texas. It separates the West Texas Permian Basin to the west from the Fort Worth Syncline to the east. JPT P. 1359

DeMoss Flood Handles Early Water-Breakthrough Problem

Introduction The DeMoss field located in Archer County, Tex., 7 miles southeast of Archer City, is being water flooded under a unitized program (Fig. 1). The correct name for the unit is "Strawn (Basal) Sand Reservoir Unit"; however, for brevity and convenience it will be called the DeMoss flood in this paper. The purpose of this report is twofoldit is a case history of waterflood operation, andit shows how the profit and ultimate oil recovery were increased by the use of equipment designed to handle large volumes of fluid. Two features,very high vertical permeability andhigh horizontal-permeability variation in portions of the pay zone, are believed largely responsible for early and excessive water breakthrough during waterflood operations. The possibility that this solution to the problem of excessive water production in water floods could be instrumental in the development and production of waterflood reserves, which otherwise may be uneconomical, has been an added stimulus in the preparation of the paper. Primary Development and Production History The discovery well, A.J. DeMoss No. 1 (Unit Well No. 3–1) was completed in Nov., 1949, in open hole from 3,598 to 3,608 ft, flowing 302 BOPD and no water. Rapid development on 10-acre spacing followed, resulting in 27 producers by June, 1950 (Fig 2). General completion practice was to drill a few feet into the pay section with rotary tools, run electric logs, set and cement either 5 - or 7 in. production casing in a lime cap over-laying the pay zone. The wells were then swabbed-in on a flowing status. Very few of the wells had the entire pay zone penetrated by the wellbore. Production by solution-gas drive first began to decline in Nov., 1950; consequently, small hydraulic-fracture treatments were applied to a majority of the wells during Jan., 1951. Primary production peaked at 35,674 bbl of oil in April, 1951, as a result of the frac jobs; then, it declined to a low of 3,150 bbl of oil by Jan., 1957 (Fig. 3). Primary recovery to Jan. 1957, was 1,101,039 STB. An investigation of records revealed that the A.J. DeMoss No. 14 (Unit Well No. 3–14) probably produced 35 per cent of the accumulated, total primary recovery. This high one-well recovery figure is a result of a mildly active water-intrusion in this area acting on this well only. During the primary life of the field, the water encroached updip toward this well, thus sweeping a reservoir area greater than the normal well location. This will logically explain the very high recovery figure for the well.

Developments in North and West-Central Texas in 1949

During 1949, production in the North and West-Central Texas district increased to 69,562,241 barrels of oil, bringing the cumulative total for the district to 1,585,125,415 barrels; gas production totaled 94,819 MCF for the year. There were 4,732 wells drilled in the 37 counties which comprise the North and West-Central Texas district. In all, 1,547 exploratory tests were drilled, of which 344 were producers, a success of 22 per cent. One hundred thirty-eight new fields were discovered. Among the more important discoveries were: (1) Mississippian reef limestone discovery in Comanche County; (2) development of Strawn sand production from structural traps in the McGregor area and DeMoss field in Archer County; (3) development of Strawn sand production in several localities f Haskell County; and (4) the Ellenburger discoveries in the Boyd, Killen, and Post Oak areas of Jack County and in northeastern Fisher County. The seismograph continued as a leading exploration tool, being credited with 50 discoveries. Seismic work was concentrated in Jack, Wise, Haskell, Throckmorton, Knox, Stonewall, Fisher, and Nolan counties and in the southern part of the Fort Worth basin. Major leasing activity was confined to Stonewall, Knox, Haskell, and King counties and to the counties in the southern part of the Strawn basin. Much of the acreage leased was purchased before exploration.

Developments in North and West-Central Texas in 1948

During 1948, production in the North and West-Central Texas district increased to 71,469,000 barrels of oil as compared with 62,127,000 barrels produced in 1947. Wichita was the leading producing county with 10,600,000 barrels, followed closely by Archer County, with 9,400,000 barrels. Drilling activity also showed a gain with a total of 4,009 tests drilled in 1948, of which 2,150 were productive. This represents a drilling increase of 34 per cent over the previous year. Of the total wells drilled, 1,113 were exploratory, which resulted in 202 new producing discoveries as against 144 discovered in 1947. These new discoveries include wildcat pools, deeper producers, and extensions. Among the more important developments and discoveries in the district were: (1) the continued development of the Sherman field in Grayson County; (2) the development of the Chico field and the discovery of distillate in the Signal Oil Company's Daily Well No. 1 in Wise County; (3) Strawn conglomerate discoveries in northeastern Jack County and central Wise County; (4) the discovery of a producing sand and the extension of the Canyon Reef zone in the Round Top field in Fisher County; (5) the development of the Bartlett field in southwestern Jones County; and (6) the development of the Kirk pool in Comanche County. Surface mapping, subsurface, and the use of the reflection-seismograph continued to play the leading roles in exploratory methods.

Coleman Pool Discovery, Archer County, Texas

Coleman Pool Discovery, Archer County, Texas

Developments in North-Central and West-Central Texas, 1938

New developments and discoveries in north-central Texas during 1938 have materially increased the importance of the Strawn formations as major producing zones in the north-central district and have increased the scope of the Canyon and Cisco in the west-central. The most important Strawn discovery in the north-central district was the Hull-Silk pool in north Archer County. Of smaller proportion, but highly significant, was the Adams Oil Company Moer No. 1 well near the town of Scotland which was completed from the Finley zone (one of the Hull-Silk pool zones) for approximately 115 barrels per day pumping. Important extensions were made east and west of the K.M.A. field. The producing area was increased from about 10,000 acres in 1937 to 32,000 acres in 1938. This field, which was discovered in 1931 and had only five producing wells in 1935, began the year with 89 producers and ended with 890. Sinclair-Prairie opened a new pool in the Delaware Bend area of Cooke County with its Best No. 1, and Rogers and Rogers another near the town of Nocona, Montague County, with the completion of their No. 1 Burnett. Both of these are lower Strawn in age. Madden and Goldsmith and King Oil opened a new Canyon pool (Chalk Hill zone) in the Holliday district, Archer and Wichita counties. New Canyon production in Wilbarger County was also developed in the Castlebury pool from the Landreth limestone. A small Bend pool was opened by Continental and Petroleum Producers on the State Asylum Lands on the outskirts of the town of Wichita Falls. Important extensions to the James and Sims pools in southeast Young County, discoveries by Anzac Oil Company and R. V. Tidwell in southwest Young and the Wray pool in central Young served to keep interest active in the Bend areas of Young, Jack, and Throckmorton counties. A new feature of this area is the discovery of commercial Mississippian production in south Young County. In the west-central district, two new pools, Irvin and Chittenden, were discovered in western Jones County in the Swastika sand underlying the Gunsight limestone, and new, deeper production was found in this zone in the Noodle Creek field. In eastern Jones County the Avoca pool, producing from the lower Canyon limestone (Avoca pay), was extensively developed. A new pool, the Griffin, was discovered in this same zone, and three new pools, Steffens, Fox, and Akard were discovered in shallower Cisco zones. Although about the same number of wells were drilled in 1938 as in 1937, practically double the number of new pools and important extensions were reported. This was the result of more intensive application of geological and geophysical methods of exploration. In spite of the larger amount of new production in 1938, the total production for the year was slightly less than in 1937. This was the direct result of the drastic proration conditions which were in effect during 1938. End_Page 844------------------------------

Effect of Repressuring Producing Sands during the Flush Stage of Production

The repressuring of oil-producing formations during the flush stage ofproduction, although requiring primarily the same procedure as operations onformations where the gas pressure has been depleted, offers several advantagesof major importance, the value of which has not heretofore been demonstrated.It is the purpose of this paper to present an account of some recent operationsof this character and the economic effects on the properties where they wereapplied. The principal objective in all repressuring operations is to secure aneffective diffusion of the input energy to all parts of the producing sand. Ifthis can be accomplished, success is assured during the remainder of the lifeof the property; if not, it will be temporary only and will be followed bydifficulties, and the maximum possible recovery will not be obtained. During the past year in Texas, the Cook pool in Shackelford County, and theTurbeville pool in Archer County, while still in their flush stage ofproduction, have been subjected to repressuring operations to observe theirreaction to this process during the early stage of their productive periods.The repressuring operations carried on in each of these pools will be discussedseparately in this paper in order to show peculiarities which were present inone pool but were not observed in the other. Turbeville Pool The Turbeville pool is in Archer County, about 30 miles south of WichitaFalls. The productive sand varies in thickness from 10 to 30 ft., the averagebeing about 16 ft. The depth of the sand varies from 1450 to 1530 ft. Thedeveloped productive area to date is approximately 200 acres, but the limits ofthe pool have not yet been proved. The sand varies considerably in differentparts of the pool with respect to both porosity and permeability. The gravityof the oil varies from 39 to 41? A. P. I. There were some wells which flowedfor a few days after completion but during 1927 all production was secured bypumping.

The Geology and Oil Fields of Archer County, Texas

Within the last three years Archer County, Texas, has risen from a position of relative unimportance as a producing area to one of the principal productive districts in the Mid-Continent field. At the present time there are 34 producing areas varying in size from pools of one or two wells to fields covering as much as 1,200 acres. Practically all of the production is confined to sand zones in the lower part of the Cisco group (Pennsylvanian) which are regionally persistent but locally very erratic. Development and operating costs are low, the oil is of high gravity (39-42 Baume), and the wells are relatively long-lived. The paper discusses the origin and accumulation of the oil as well as problems of porosity, ultimate yield, etc., of this particular district. Various tables show pertinent facts regarding individual fields and the relationship of surface to subsurface structure. Cross-sections show stratigraphic relationship of the fields and of the county to adjoining areas.

The Recent Discovery in Archer County, Texas: GEOLOGICAL NOTES

The Recent Discovery in Archer County, Texas: GEOLOGICAL NOTES