Search Documents

By S. C. Robinson

International interest in storage and retrieval of geological data stems from a desire to tap this large and potentially valuable, but little-used resource. The data will be used primarily for development and testing of geological concepts and theory; secondarily as a basis for assessing mineral potential and even individual mineral deposits; thirdly for establishment of world-wide norms averages and standards; and fourthly as a search tool leading to sources of specific data and to repositories of specimens etc. International committee activities are designed to establish acceptable general standards for reference numbering, geographic location, geological terminology, coding etc. ; and to develop progressively the types of data (parameters) that should be recorded in specialized archival files in such fields of world-wide interest as palaeontology, mineral deposits, petrochemistry, stratigraphy, mineralogy, palaeomagnetism, physical geochronology etc. Establishment of world data banks analogous to those in oceanography may come later; for the present we hope to achieve some degree of agreed consistency in national and local data banks throughout the world, and to establish an international index to these banks as first steps in facilitating international exchange. For purposes of this paper, data are defined as facts, reproducibly measured or objectively described.

Jan 1, 1969

By R. C. Earlougher

Based on laboratory tests conducted with the use of fresh core samples as well as a considerable amount of field data obtained from numerous water floods in northeastern Oklahoma, it appears that for any given oil saturation there is a critical maximum velocity above which the oil-recovery efficiency falls off very rapidly. In effect, when a water flood is operated above this critical velocity, the injected water-oil ratio rises extremely fast, thus shortening the economic life of the flood and reducing the ultimate oil recovery. This critical velocity apparently varies considerably with the percentage of oil saturation of the sand, so that in effect the higher the oil saturation at the beginning of a flood the higher the velocity that can be used successfully. In reviewing several of the earlier floods in the Mid-Continent area, it is concluded that most of the failures were due to two things: (I) too low an oil saturation, such as 30 per cent, and (2) too high water-injection rates, Although considerably more field data are necessary to establish definite limits, it would seem that the proper field injection rate for a 330 by 330 or 440 by 440-ft. spacing varies from approximately I bbl. per foot of sand per day where the oil saturation is as low as 30 per cent up to 5 bbl per foot of sand per day when the oil saturation is as high as 45 to 50 per cent, Introduction With secondary recovery by water-flooding receiving more and more attention throughout the industry, a greater working knowledge of multiphase flow under field conditions becomes more and more necessary A great deal of research has been carried on in highly idealized laboratory conditions, from which certain trends have been indicated, but with few exceptions no direct application to field use has been reported. widely varying conclusions have been drawn from the mass of idealized laboratory experiments and often this divergence apparently was due to the neglect of connate or interstitial water. Since interstitial water is such an important factor in water-flooding operations, it then follows that any laboratory flooding experiment must necessarily take it into account; and since it is difficult to set up laboratory models to allow for interstitial water, the next best procedure is to use fresh core samples for such tests. Even this procedure has its difficulties, inasmuch as it is possible to run only one flooding test on each sample, as each sample differs somewhat in character from all other samples. However, this disadvantage can be overcome to a large degree by the use of an extremely large number of samples. The next question that arises is: "IS it possible to get uncontaminated core samples having a true oil and water saturation like that existing in the reservoir?" If the sand under consideration is still in the primary stage of production, with a normal or relatively high amount of gas still in solution in the oil, probably it is not possible to get a nonflushed core. On the other

Jan 1, 1943

By R. C. Earlougher

Based on laboratory tests conducted with the use of fresh core samples as well as a considerable amount of field data obtained from numerous water floods in northeastern Oklahoma, it appears that for any given oil saturation there is a critical maximum velocity above which the oil-recovery efficiency falls off very rapidly. In effect, when a water flood is operated above this critical velocity, the injected water-oil ratio rises extremely fast, thus shortening the economic life of the flood and reducing the ultimate oil recovery. This critical velocity apparently varies considerably with the percentage of oil saturation of the sand, so that in effect the higher the oil saturation at the beginning of a flood the higher the velocity that can be used successfully. In reviewing several of the earlier floods in the Mid-Continent area, it is concluded that most of the failures were due to two things: (I) too low an oil saturation, such as 30 per cent, and (2) too high water-injection rates, Although considerably more field data are necessary to establish definite limits, it would seem that the proper field injection rate for a 330 by 330 or 440 by 440-ft. spacing varies from approximately I bbl. per foot of sand per day where the oil saturation is as low as 30 per cent up to 5 bbl per foot of sand per day when the oil saturation is as high as 45 to 50 per cent, Introduction With secondary recovery by water-flooding receiving more and more attention throughout the industry, a greater working knowledge of multiphase flow under field conditions becomes more and more necessary A great deal of research has been carried on in highly idealized laboratory conditions, from which certain trends have been indicated, but with few exceptions no direct application to field use has been reported. widely varying conclusions have been drawn from the mass of idealized laboratory experiments and often this divergence apparently was due to the neglect of connate or interstitial water. Since interstitial water is such an important factor in water-flooding operations, it then follows that any laboratory flooding experiment must necessarily take it into account; and since it is difficult to set up laboratory models to allow for interstitial water, the next best procedure is to use fresh core samples for such tests. Even this procedure has its difficulties, inasmuch as it is possible to run only one flooding test on each sample, as each sample differs somewhat in character from all other samples. However, this disadvantage can be overcome to a large degree by the use of an extremely large number of samples. The next question that arises is: "IS it possible to get uncontaminated core samples having a true oil and water saturation like that existing in the reservoir?" If the sand under consideration is still in the primary stage of production, with a normal or relatively high amount of gas still in solution in the oil, probably it is not possible to get a nonflushed core. On the other

Jan 1, 1943

By S. Wallden, R. Lindstrom

The electrolytic copper refining process is an excellent method for producing high-purity metal for electric conductors and other demanding applications. However, the process involves very high capital expenditure, especially the amounts of metals bound in the process. Efforts have therefore been made for many years to increase the production rate by increasing the current density, without impairing the quality of the copper. One of the approaches has been to diminish the polarization by mechanical means, while another was to "polish" the cathode surface by periodic brief reversals of the current. Reversed current electrolysis was first developed for electro- plating purposes and in 1952 Boliden AB and the Dept. of Electrochemistry at the Royal Inst. of Tech., Stockholm tested the method for copper refining with good results. However, no suitable electrical equipment for current reversal was then available. The thyristor-controlled silicon rectifier became available during the '60s and provided the scope for industrial application of the process and the first large-scale development was made by the Bulgarian copper refinery in Pirdop. Many copper refineries are now studying or adapting the reverse current process. Further lab and pilot investigations have been carried out at Boliden AB during the past 4 years and these were mainly aimed at studying the optimization of factors influencing the quality of copper. A production unit containing two tank sections with a total of 56 cells and equipped with a rectifier for cur- rent reversal has been installed and will be started during 1973.

Jan 1, 1973

J. M. HARTMAN, Philadelphia, Pa.: Mr. Fackenthal can remember some queer things that occurred at Durham, Pa., Aug. 3, 1876, while he was superintendent. The furnace was working stiff, i.e., blast-pressure 10 to 11 pounds, which was high pressure for those days. With this pressure there was some circulation through the stock. At 9 p.m., flushed cinder. After flushing, air was thrown off' for a moment to " bot up "; the keeper turned the lever and threw on air just as the scaffold dropped, which eased up the pressure to 4¼ pounds. The air-receiver is twice as large at Durham as at other places. The air from this receiver, added to the two seven-foot blowers, gave an extra large volume, which, rushing into the furnace, fired the finely-divided carbon, causing an explosion that threw part of the stock in the furnace out into the open air, threw up the bell-and-hopper with the tunnel-head plates, and gave off' a large volume of carbondust. The bell-and-hopper going up first, the stock followed, and, striking the bell-and-hopper, was deflected in a shower over the cast-house roof, breaking the slates. Sitting at the corner of the engine-house at the time, the stock pelted me, when I ran around the corner to get rid of it. Remembering there were two men at the furnace-top, I shut down the engines, and, running to the top, found them sitting in the hoist-house enjoying the fire-works. The explanation of this explosion is simple. There is in the blast-furnace a bed of fuel extending up, say, 16 to 18 feet above the tuyeres; in this bed of fuel some stray pieces of limestone are found, and a few pieces of unreduced ore; but, generally speaking, it is all fuel. On this bed of fuel is the zone of fusion. In this zone the descending stock is liquefied, except the fuel; the iron, melting, drops out of the ore, and the gangue unites with lime, forming cinder. The iron falls in the form of shot, and, with the cinder, trickles

Jan 1, 1899

By O. W. Bilharz

Acid mine-water drainage is a serious problem with many mines in the Tri-State zinc and lead mining district. Particularly is this true when large volumes must be considercd in unwatering old mines that have refilled with water which has dissolved the products of oxidation and has become chalybeate in character. The experiences discussed in this paper have to do specifically with the unwatering of a comparatively small area west of the town of Baxter Springs, Kans., where the pumping job was complicated by water of this type and where the extremely high sulphate content particularly effected that phase of mine drainage having to do with stream pollution. Location, Geology and History The Baxter Springs area of the Tri-State mining field is situated just west of the town of Baxter Springs and is a northeasterly extension of the main mineralized zones of the Oklahoma part of the district (Fig I). The mining area is traversed with well defined shear zones which provide easy circulation of ground waters and the ore bodies are found along these shear zones as localized enrichments wherever the structural conditions are favorable (Fig 2). The ore-bearing strata is Mississippian with an overlain capping of shale of Penn- sylvanian age. This shale strata carries much pyrite and marcasite at its base and undoubtedly was a contributing factor to the subsequent high iron content of the water. The area originally contained a sulphide water which discharged as an artesian flow in springs within the town and gave Baxter Springs its name. These springs were famed for many years for their mineral water. This original sulphide water was first removed about 1917 and active mining was carried on west of the town during subsequent high metal price periods. Many small mines were opened, with each localized enrichment becoming a separate mine. During the depression mining ceased and all mines in the west Baxter area were allowed to flood. No serious effort was made to again unwater until higher prices caused from the demand for metal for World War II once more focused attention 011 this part of the field. Original Mining Results in Oxidation As plans for unwatering progressed, it soon developed that the mine-water pools had become strongly acid in character and carried large amounts of sulphates in solution. This occurred in the following way. When the original sulphide water was removed, shafts sunk, and mining carried on over a number of years, ferrous sulphate was formed by the spontaneous oxidation of the pyrite beds in contact with air admitted through churn-drill holes and mine openillgs. These products of oxidation can be seen today in the old mines of the district as crusts of crystalline sulphates

Jan 1, 1949

By George Smith

IN discussing present-day business and industrial troubles we easily drop into the habit of clinical diagnosis. Talk of this kind, with its emphasis on suspicious symptoms and abnormal tendencies, makes us all morbid. As an English essayist has put it, we may thus induce a melancholy, temper that simply in-vites the ministrations of social and political quacks. It is far better-because nearer the truth-for us to recognize that our condition is in no sense diseased, that our body politic, social and economic, is suffering merely from growing pains; that America is not de-cadent-indeed, that any lapses from staid normality are traceable to the, excesses of youth. Our chief .trouble, then, is only that our industrial state is still young; it may be that we have been growing too fast. The growth in the industrial development of our country from pioneer days to the present time has been marvelous. Too many of us, however, take all this as a matter of course-we credit this record of American progress to our American genius alone. Too often we overlook the fundamental relationship between resources and progress-that man is aided and even guided by Nature. The fact is, social advance, indus-trial progress, national prosperity all have their ma-terial basis in natural resources. In furnishing the needed mineral raw materials to the great manufac-turing industries of the United States there has been no halt, but rather a general acceleration. No other phase of American activity can show-equal advance. As the decades have passed, the winning of mineral wealth has progressed from the role of a stimulus for western exploration to that of the foundation for nation-wide business. In 1890 the Sherman law was passed; since then the population of the United States has about doubled. Since then, too, thevalue of the annual product of the mines of this country has increased better than eight-fold-from 650 millions to 51/ billions of dollars. Since then the four largest branches of the mineral industry, which supply the iron and copper, the bituminous coal and petroleum-the bone and sinew and the energy of all other American industries-have increased their annual output nearly ten-fold as to value and six-fold as to quantity. Such a growth in the volume of mineral output must be taken as a true measure of the ex-ceptional service rendered by the mines of the United States. Not only is this a much larger country than it was 38 years ago, but its growing mineral industry has met demands that have been out of all proportion to the growth of the population.

Jan 8, 1928

By Paul B. Crawford, Bobby L. Landrum

Electrical model studies have been made of the effect of unsymmetrical vertical fractures on production cnpacity. The study war restricted to the case of two vertical fractures originating at the well and extending out into the reservoir for various distances and orientations. The ratio of the short fracture length to the long fracture length was varied from 0.1 to 1.0 in successive studies. The angle separating the two fractures was varied from 0 to 180 degrees. The most effective fractured patterns were obtained when the fractures were oriented 180 degrees. It was found that when the total fracture length was equal to 0.2 of the drainage radius, the increase in production capacity may vary from approximately 1.55 to 1.95. depending upon the ratio of the short fracture length to the long fracture length and the angle separating the two fractures. If the total fracture length were 0.5 of the drainape- radius. poroduction cavacitv., increases varving 1.95 to 2.65 were observed, depending on the angle between the fractures and the ratio of the .short fracture length to the long fracture length. The fractured well production capacity decreased aPproxin?ately I to 10 per cent as the angle separating the fractures was varied from 180 to 90 degrees. It was dependent on the particular fracture. The commercial application of reservoir fracturing techniques has caused an interest to be expressed in the effect of vertical and horizontal fractures on production capacities. Some data have indicated that substantially vertical fractures may be created in some reservoirs. It is believed that the fractures are possibly unsymmetrical, that is, one fracture may extend due north 100 ft and a second fracture on the opposite side of the well may extend south or southeast only 50 ft. The total fracture length, ratios of the lengths and angles of separation may vary considerably. For this reason variations in these factors were considered. The study was restricted to the case of two vertical fractures originating at the well and extending out into the reservoir. It is not known that such will occur in a reservoir, but the results may be of value in interpreting or studying fracturing applications. PROCEDURE An electrical model was used in this study of the effect of unsymmetrical vertical fractures on production capacity, A wooden tank 30 in. in diameter and approximately 2 in deep was coated with paraffin wax. A copper band was situated at the periphery and a single wire electrode was positioned at the center of the tank. The ratio of the reservoir radius divided by the

Jan 1, 1956

By C. D. Hunter, I. B. Browning, Ralph Thomas

Production of oil in Kentucky during 1938 was 5,566,154 bbl., showing a substantial increase over that of the year 1937; while in the gas areas development was somewhat retarded although deliveries were similar to those of 1937. In eastern Kentucky there was an oil increase during 1938 of over 150,000 bbl. above that of 1937. No new pools were developed and the increase was almost entirely due to the installation and expansion of secondary recovery methods and to the further development of the Maxon and Big Lime, Mississippian pools in Floyd and Martin Counties. With this development eastern Kentucky reached a level near that of 12 years previous, when the development of several large producing areas had just been completed. In eastern Kentucky during 1938 not over 50 gas wells were completed. Although the pipe-line deliveries were approximately the same as during 1937, development was retarded because of an excess of gas already developed and the intensive development of the Oriskany fields in West Virginia. In western Kentucky, in the part of the Illinois Basin lying in the state and known in Kentucky as the Western Coal Basin, the increase was due to the discovery of a number of new pools, the largest and the one producing the biggest wells being known as the Birk City pool. In fact, the discovery of this pool with the McClosky "sand" (St. Genevieve limestone) as the producing formation was in a large measure responsible for the increased activity, which in turn brought the discovery of the other areas. The discovery well in this pool is the C. T. Blackwell, which came in flowing 1000 bbl. daily from the McClosky sand at a depth of 1870 ft., drilled in April 22, 1938. This discovery, coming at a time when the major companies and many others were conducting an intensive leasing campaign and making extensive subsurface and geophysical surveys in the deeper part of the basin, resulted in renewed activity over the entire area and brought much new drilling. It also brought to Kentucky for

Jan 1, 1939

By C. D. Hunter, I. B. Browning, Ralph Thomas

Production of oil in Kentucky during 1938 was 5,566,154 bbl., showing a substantial increase over that of the year 1937; while in the gas areas development was somewhat retarded although deliveries were similar to those of 1937. In eastern Kentucky there was an oil increase during 1938 of over 150,000 bbl. above that of 1937. No new pools were developed and the increase was almost entirely due to the installation and expansion of secondary recovery methods and to the further development of the Maxon and Big Lime, Mississippian pools in Floyd and Martin Counties. With this development eastern Kentucky reached a level near that of 12 years previous, when the development of several large producing areas had just been completed. In eastern Kentucky during 1938 not over 50 gas wells were completed. Although the pipe-line deliveries were approximately the same as during 1937, development was retarded because of an excess of gas already developed and the intensive development of the Oriskany fields in West Virginia. In western Kentucky, in the part of the Illinois Basin lying in the state and known in Kentucky as the Western Coal Basin, the increase was due to the discovery of a number of new pools, the largest and the one producing the biggest wells being known as the Birk City pool. In fact, the discovery of this pool with the McClosky "sand" (St. Genevieve limestone) as the producing formation was in a large measure responsible for the increased activity, which in turn brought the discovery of the other areas. The discovery well in this pool is the C. T. Blackwell, which came in flowing 1000 bbl. daily from the McClosky sand at a depth of 1870 ft., drilled in April 22, 1938. This discovery, coming at a time when the major companies and many others were conducting an intensive leasing campaign and making extensive subsurface and geophysical surveys in the deeper part of the basin, resulted in renewed activity over the entire area and brought much new drilling. It also brought to Kentucky for

Jan 1, 1939

By H. J. French

Within the past few years, particularly because of the rapid growth of the airplane industry during the war, considerable attention has been paid to the manufacture of light-wall cold-drawn seamless and welded steel tubing for structural purposes. While the manufacture of such tubing is not, in itself, a difficult matter, some difficulties have been encountered in producing the same under specifications requiring definite physical properties. It is the purpose of this paper to describe the methods of manufacture and the properties that may be obtained by such methods for tubing coming within about 1/2 to 2 in. (12.7 to 50.8 mm.) outside diameter and 10 to 22 Birmingham wire gage (0.134 to 0.028 in. wall thickness). Such tubing is largely used as structural material in the aircraft industry, and it is of the utmost importance that the physical and chemical properties should be known, and also that the various factors entering into the manufacture should be under such control as to allow these properties to be varied and held within definite limits. In general, tubing may be divided into four classes: namely, specialty tubing, such as riveted-sheet or plate, lock jointed, etc.; brazed tubing; welded tubing; and seamless tubing. Welded tubing may be divided into hot product, such as lap welded and butt welded, and cold product, such as acetylene and electric welded. Seamless tubing may be hot rolled or cold drawn. Specialty Tubing The first two classes present mainly mechanical or structural engineering problems. A simple form of tube is made by riveting together the overlapping edges of rolled sheets or plates formed into a cylinder. Because of the nature of its construction, such a tube is necessarily limited to relatively large sizes. Lock-jointed tubing is produced by passing low-carbon strip through a forming machine having suitable rolls and dies, its manufacture is almost entirely a question of design of the forming machine and its satisfactory operation. The chief application of such tubing is in the manufacture of bedsteads.

Jan 1, 1920

By Ellsworth Daggett

The Berlin gold-quartz mine is situated in Nye county, Nevada, on the west flank of the Shoshone range, about 40 miles south and 30 miles west from the town of Austin, the county-seat of Lander county. The distance from Austin is about 60 miles by stage-road. The outcrop of the vein, at the top of the incline-shaft, is situated just at the base of the mountain proper, almost exactly at the intersection of the mountain-side with the gravelly bench that slopes for about three-quarters of a mile to the flatter sage-brush plain, or desert valley, below. The vein itself consists almost entirely of quartz, with perhaps 2 per cent. of sulphide of iron, copper, lead, zinc and antimony, and perhaps a trace of some of the compounds of tellurium with gold and silver, although none of the latter have been as yet positively identified. The relative proportion, by weight, of silver and gold in the ores, varies in different parts of the vein, from 12 silver for 1 of gold, to 7 silver for 1 of gold. The quartz vein-filling is usually frozen fast to the walls, and is very hard and compact, seldom showing the friable, fissured, or shelly structure often to be found in quartz-veins. Comparatively little evidence of relative motion of one wall of the vein upon the other is to be found—a fact indicating that during the formation of the vein, and prior to the extensive movements herein described, little disturbance had taken place. No evidence whatever of metasomatic origin has been observed. On the other hand, occasional occurrences of comby structure, in which the axes of the quartz-crystals are at right angles to the plane of the vein, rather indicate deposition from solution in a pre-existing fissure. Spurs, or branches, and small parallel veins, while not en-

Jan 1, 1908

Jan 1, 1908

Jan 1, 1927

By William P. Blake

In the recent litigation for the possession of franklinite by one party and of zinc-ore by the other party, it was shown by the evidence of experts familiar with the original condition of the outcrops that at Mine Hill a more or less disticctly defined layer of red zincore underlay the heavier and larger body of the franklinite, so-called ; this layer or bed of zinc-ore dipping under the franklinite upon the western cropping, while at Stirling Hill, two miles south, the conditions were apparently reversed, the zinc-ore overlying the franklinite. An explanation being required, it was shown, first, that at both places, at Mine Hill on the north and at Stirling Hill on the south, the ore-bed lies in a synclinal or trough-like fold with the red zincore under the franklinite; and secondly, that at Mine Hill, we see chiefly the outcrop of the western part of the folded bed and at Stirling Hill the eastern part; the Mine Hill cropping being on the western slope, and the Stirling Hill cropping on the eastern slope of the hill. Thus the ''back vein" at Stirling (the western outcrop) corresponds with the front-vein at Mine Hill, and, like it, has the red zinc-ore on the foot-wall, while the front-vein or eastern cropping at Stirling corresponds to the back-vein or eastern cropping at Mine Hill in the part of the bed generally known as the " buckwheat-field vein." If the ore-bed were continuous in one synclinal trough between the two localities, no further explanation would be required. But it is not so ; and the synclinal folds at both places pitch steeply to the north, bringing the beds to the surface in horseshoe-like curves at their southern ends or croppings, and carrying the beds far below the surface northwards. This justifies a doubt

Jan 1, 1895

By John Primrose

Tube stills having demonstrated their usefulness for refining operations, the later developments in their design have been in the direction of improved thermal efficiency. The earlier designs operated with low furnace temperatures and large volumes of furnace gas because the fuel was burned with much excess air. It was quite possible to provide sufficient heating surface to lower the temperature of the flue gas to within 150" of the temperature of the inlet oil, or when inlet-oil tempera-tures were high to have the flue gas escape at 300" or 350" F. by using the heat remaining in the flue gas from the still to preheat the air supplied for combustion. But even so, the thermal efficiency was low because of the large quantity of air used for combustion. The large quantity of excess air was required to burn the fuel in the furnace at a temperature low enough to prevent overheating the furnace walls and overheating of the oil. Supplying heat to the tubes of the heating surface at a rate beyond the capabilities of the oil to absorb, except with a considerable difference between the temperature of the inside of the tube and oil passing through, would result in overheating the tubes and the oil in contact with them. For these reasons it was very necessary in the older types of tube stills to burn the fuel with large quantities of excess air, resulting in low thermal efficiency despite the low flue-gas temperature. Neglecting loss by radiation, the thermal efficiency could be improved only by burning the fuel with less excess air, but it was necessary to accomplish this without upsetting the furnace temperature conditions existing when large quantities of excess air were used. There are several methods of bringing this about, such as controlling the furnace temperature by returning a proportion of the flue gas to the furnace, or by exposing direct to the fire a heat-absorbing surface so located and proportioned that sufficient heat will be absorbed by radiation to prevent excessive furnace temperatures.

Jan 1, 1928

By J. T. Hayward

Studies of the forces and conditions governing the recovery of petroleum from natural reservoirs indicate that a low gas-oil ratio increases ultimate recovery, retards the encroachment of water and tends to reduce lifting costs. Methods for controlling and reducing gas-oil ratios in producing wells consequently have been given considerable attention during the past few years. However, during this same period, the production from wells in nearly all fields has been fixed by proration agreements and it is the opinion of the writer that where a well is required to produce steadily at a predetermined rate, less than its "potential" or maximum capacity, the gas-oil ratio will depend only upon the rate of production, and will be independent of the method of production and of the design of equipment in the well. If no change in the rate of production is contemplated, efforts directed to improving the gas-oil ratio by altering the diameter of the flow string, changing the position of the choke, assisting the flow with gas-lift or pump, etc., will be unsuccessful. This viewpoint is not new. It was presented by H. N. Marsh and B. H. Robinson in 1929,' but it has not been generally accepted. Although engineers believe that the rate of withdrawal and not the equip ment used governs the water-oil ratio, a similar opinion regarding the gas-oil ratio is not so commonly admitted. The rates of flow of oil and gas into the base of an oil well depend upon the following conditions: 1. The characterist-ics of the oil and gas. 2. The characteristics of the underground reservoir. 3. Temperature and pressure conditions in the reservoir. 4. The back-pressure held against the face of the sand. In operating a well, the only one of these conditions over which control may be exercised through operating procedure and the use of equipment above the sand is the back-pressure at the face of the sand. Strictly speaking, the back-pressure varies over the face of the sand, owing

Jan 1, 1932

By P. H. Royster, T. L. Joseph

In a study of the blast-furnace process, the Bureau of Mines has made many experiments for the purpose of determining the exact nature of the combustion of coke in the neighborhood of the tuyeres. Two papers1 presented at a meeting of this Institute discussed somewhat the practical aspects of coke combustibility in its relation to the operation of the blast furnace. In a later paper,2 Sherman and Kinney discussed the possible effect of variations in the combustibility of cokes on the furnace operation, and find that the "reoxidation theory" of Koppers and the "heat concentration theory" of Brassert³ are insuffcient to explain the variation in the conduct of different cokes that has been observed by furnace operators. In their report to the D-5 Committee of the American Society for Testing Materials, with which the Bureau of Mines has been cooperating, Perrott and Fieldner4 seem to agree with Sherman and Kinney that, for practical purposes, the nature of the combustion of coke at the tuyeres of any furnace is constant and is affected neither by the physical properties of the coke nor by the nature of the furnace operation. They omit as unimportant any tests on the combustibility of coke from their proposed methods for standard tests on coke. In the last two papers, it is pointed out that performance tests, in which all other factors except coke quality are kept constant, are to be desired and

Jan 1, 1924

Jan 1, 1939

By A. Sainato, E. Baker, J. Cervik

In Europe, water infusion is used widely to reduce generation of respirable dust during mining. Its use in the US is limited to a few plow operations in the deeper parts of the Pocahontas No. 3 Coalbed. The technology for infusing water into retreating longwalls is described and results of a recent Bureau test in the Lower Sunnyside Coalbed demonstrated dust reductions ranging from 47% to 64%. Because water infusion increases moisture content of the coalbed, face air velocities in excess of 2.5 m/s (500 fpm) are possible, further diluting dust levels before dust entrainment occurs. An economic analysis shows a 23% reduction in operating costs when coal production is increased by changing from unidirectional to bidirectional mining with water infusion.

Jan 1, 1986