Search Documents

By Charles H. Fulton

CHARLES H. FULTON, chairman, presided at the first session of the Mineral Industry Education Division on Wednesday morning. Reporting for the program committee, Edward Steidle, its chairman, pointed out that its function was not to arrange programs for meetings but to plan a program for the Division to follow in the development of its activities. This was appropriately followed by presentation and discussion of his paper, "Basic Trends in Mineral Industries Education," which, being available in printed form, was only presented in oral abstract. Jay A. Carpenter submitted interesting written discussion that was read, in his absence, by A. M. Smith. Most of the morning was devoted to the discussion of the paper, which was too extensive and ranged too widely to attempt to report in much detail. H. T. Mann, H. P. Hammond, Cadwallader Evans, C. H. Fulton, T. T. Read, D. F. McFarland and P. B. Bucky joined in the discussion, Mr. Hammond making a plea for more unification in mineral industry education, saying that in the study he made for the Society for Promotion of Engineering Education about 35 different curricula preparatory to work in the mineral industry were discovered to exist. He felt that most of the needs of the mining industry could he met by men who had had four years of engineering training of good enough basic quality to permit them to advance along special lines. However, there was apparently a growing demand, as reflected by the increasing number of candidates for the Master's degree in engineering, for men with more thorough training in the fundamentals.

Jan 1, 1933

By AIME AIME

ABOUT one hundred were in attendance when Donald M. Liddell opened the session* on non-ferrous metallurgy at 2 p. m. on Tuesday. F. F. Col- cord was vice-chairman. For the first part of the session the chair was turned over to Frank G. Breyer, who introduced G. L. Spencer, Jr., to read his contribution (T.P. 378), "High Silica Retorts at the Rose Lake Smelter," which was an account of the method of manufacture of high-silica zinc retorts at the Rose Lake smelter, and of the service given by these retorts. The materials used are, by volume, 50 per cent clay, 25 per cent silica flour and 25 per cent grog. Written discussion of the paper by E. M. Johnson, W. R. In- galls and M. M. Neale was read by Mr. Breyer. Mr. Johnson explained that their practice in manufacture differed very little from Rose Lake practice, but that their retorts did not last as long, possibly because Eagle-Picher does not use a hydraulic retort press or sintered ore. He ascribes the longer life of silica re- torts to the fact that they do not bend under heat. Mr. Ingalls pointed out that silica retorts are no better as heat conductors than clay retorts, but that they do have a superior rigidity in the furnace. The character of the retorts does not affect the density of the charge. Mr. Neale gave the procedure in the manufacture and use of high-silica retorts at the Donora zinc works, not

Jan 1, 1931

By Milton H. Fies

EARLY in 1945 the laboratories of the Southern Research Institute will begin active research investigations on behalf of industrial clients. This achievement has come after four years of planning by a group of Alabama businessmen, and is in partialanswer to an urgent need in the South. Those who conceived the Institute have long realized that a marked relationship exists between scientific research and the economic well-being of the several regions of the country. Clearly, technological research, generally absent in the South, is the medium through which are created new finished goods industries, and the increase of technological research is perhaps the most important long-range project in the South.

Jan 1, 1945

By P. Marier, T. R. lngraham

The kinetics of the sulfation of MnO,, MnzO3, and Mn3O4 in SO,, SO3, and O, mixtures was examined and the descending order of sulfation rates at temperatures near 400°C was found to be Mn,O3 > MnO, > Mn3O4. The respective activation energies for the thermal decomposition of MnO, and Mn,O, are 39 and 47 kcal. At 900°C, the thernzal decomposition of MnSO, to MnzO3 is slower than that to Mn3O4. The respective activation energies are 62 and 51 kcal, respectitely. MANGANESE is used to improve the hot workability of steel in the proportions of approximately 13.5 Ib of ferromanganese per ton of steel produced. This requirement accounts for about 95 pct of its large industrial market in North America. The remaining 5 pct is used in the battery and chemical industries. In most North American ores, the percentage of manganese and the manganese-to-iron ratio are not suitable for the direct production of ferromanganese. Hence, most of the North American requirements for manganese are satisfied by importing ore. Typically, many of the studies done on native low-grade manganese resources have been directed toward the production of ore substittes" and the recovery of manganese from open-hearth slags.3 Of the wide variety of processes which have been proposed, the most popular involve compounds in the Mn-S-O system. The thermodynamic properties of manganese and its compounds were reviewed by ah' in 1960 and, more recently, lngrahams discussed the thermodynamics of some of the reactions involved in the Mn-S-O system at normal roasting temperatures. The conditions for producing manganese sulfide during the reduction roasting of manganese sulfate are discussed by Fuller and Edlund.9 A novel scheme was proposed recently by zimmerley7 for utilizing waste sulfur dioxide from stack gases to recover the manganese from ocean-mined manganese nodules. Very little of the work published on manganese compounds has been related to reaction rates. Singleton et 1.' studied the rates of reaction on the MnO-C and Mn7C3-3MnO systems and observed linear and parabolic kinetics respectively in the systems. Tatievskaya et a1.' studied the low-temperature reduction of Mn&, MnO,, and Mn& in HZ and CO, and reported activation energies in the range 1628 kcal. In this paper, the rates of some of the decomposition and formation reactions involving MnSO4, MnOz, MnzO3, and Mn3O4 will be examined after the conditions for the thermodynamic stability of the individual compounds have been designated. CONDITIONS FOR STABILITY OF MnSO4, MnOz, MnZO3, AND Mn3O4 The areas of stability for h'hSO4, MnOz, MnzO3, and h3O4 were established from the data of Mah4 and Ingrahams and are shown in the predominance area diagram,10 logpq- logpsq, in Fig. 1. The diagram is drawn for two temperatures, 700°K, solid lines, and 1100°K, dotted lines. The sketch for the lower temperature includes the conditions likely to prevail in the Zimmerley patent7 when manganese nodules react with sulfur dioxide and that for the higher temperature indicates the conditions for recovering MnzO3 or Mn3O4 from MnSO4 during a roasting reaction. From the fact that the boundary between the areas of stability of MnOz and hSO4 at 700°K is parallel to the abscissa, it is evident that MnOz and SO2 should react together to produce MnSO4, irrespective of the oxygen pressure in the system. If the source of sulfur for sulfation were from waste flue gases, it is likely that the oxygen content of the gas stream would be more than sufficient to oxidize any MnsO4 to MnzO3, 107 atm of O2 required, or even to convert any Mnz03 to MnOz, 0.02 atm OZ required, prior to sulfation. At 1100°K, the diagram indicates that MnSO4 may be converted directly to either MnzO3 of Mn3O4, depending upon the prevailing partial pressure of oxygen. When the gas stream contains more than 1 pct Oz, logpq = -2, only MnzO3 would be recovered from an experiment done under equilibrium conditions. At oxygen partial pressures of less than 1 pct, one would expect to bring about a reversible exchange between MnSO4 and Mn3O4 by appropriate adjustment of the partial pressure of SOZ. These various reactions will be described in the subsequent kinetic experiments.

Jan 1, 1969

By R. G. Knickerbocker

A STURDY and consistent expansion of the metal industry occurred in 1947 exemplified by an increase of approximately 30 per cent in steel consumption over 1946. For this major reason, ferroalloy metals have seen their most useful and important peace-time year. The current domestic rate of consumption of high-grade ferroalloy ores, together with added consumption of new foreign producers as well as for eign nationals' restrictions on high-grade exports, makes very evident the increasing difficulties of obtaining sufficient high-grade ores. This accentuates the need for new and less expensive methods of production of ferro-alloy metals of higher purity from lower-grade domestic resources. As an important factor in preparedness, procurement of these high-grade, -critical ferroalloy minerals and metals for our nation's stock piles is a most important task. Also, this stock-piling can be the means of supplying incentive for the industrial development of the new metallurgical processes and plants necessary for the recovery of ferroalloy metals from our domestic low-grade deposits.

Jan 1, 1948

By H. P. Greenwald

IN the year just passed the Coal Division's Committee on Rock-Dusting reviewed the status of this safety measure in American coal mines and prepared a paper thereon which will be presented at the February meeting of the Institute. This paper supplements one appearing in Vol. 139 of the "Transactions," page 87 (1940). Because that paper will be issued soon, only a summary is given herein.

Jan 1, 1944

By C. Norman Bowers, Blaine B. Wescott

MARKED improvement in the serviceability of sucker rods has been effected in the last two years, partly because of the insistent necessity for greater economy in the operating costs of crude oil production growing out of the general industrial depression and partly because many of the recently developed fields have imposed more severe operating conditions upon both surface and underground equipment. The latter is particularly true of Kansas, where practically all of the oil produced. is associated with damaging amounts of hydrogen sulfide brine and where the method of establishing potential production demands equipment capable of being operated at maximum capacity without interruptions. The decline of flush production in the Oklahoma City field created new problems in deep-well pumping on a scale heretofore unequaled and the increased proportion of water it has been necessary to produce in the fields of the Greater Seminole area presented conditions that were acutely in need of betterment. The problem in the latter fields was complicated by the shift towards sulfide characteristics, which accompanied water encroachment, and it is probably true that nowhere, at the present time, are pump¬ing conditions generally as severe as in this territory. The Mid-Continent district, therefore, has become the proving ground for the numerous materials that have been proposed for sucker-rod fabrication. The information that ultimately will be obtained from an unprecedented amount of field experimentation will pay ample dividends when the decline of East Texas increases the demand for the vast reserves of sour crude in West Texas. It is a rare occurrence in industry that the use of such a simple piece of equipment as a sucker rod presents so complicated a problem for solution. As proof of this, it is only necessary to consider the numerous types of sucker rods on .the market at the present time and contrast this condition with that of less than four years ago, when it was the common aim of manufacturers to develop a single sucker rod for all conditions of

Jan 1, 1935

By C Woodward

AT the Belmont mine of the Anaconda Copper Min-ing Co., Butte, Mont., a new double-drum electric main hoist and a single-drum electric auxiliary hoist have recently been placed in operation to meet the demand for greater hoisting depths, and to replace a steam-driven hoist which was inefficient and inade-quate for the new conditions. The ease of operation, safety, and efficient consumption of power of the main hoist all tend toward improved hoisting conditions. It consists of a 2150 hp. d. c. motor, directly connected to a shaft carrying two drums equipped with clutches and brakes. The auxiliary hoist consists of a 1000 hp. d. c. motor directly con-nected to a single drum provided with the necessary brakes. Fig. 1 shows the general arrangement of the complete installation, with idler towers and head-frame. The headframe is built of Bethlehem H and G rolled sections, equipped with two 12-ft. dia. cast steel sheaves for the main hoisting ropes. The sheaves are mounted 129 ft., 6 in. above the collar of the shaft; and above them trolleys are provided for their removal or repairs. Between the headframe and the hoist machinery are two idler towers for supporting the ropes on 3-ft. man-ganese steel idlers provided with roller bearings which fleet on a fixed shaft. As a city street is between- the mine headframe, and hoists, it is necessary to protect the thoroughfare from drippings of the preservative compound used on the ropes which pass over the street. For this purpose, at the point where the hoisting ropes cross the street ,a bridge of trusses, supported on columns and roofed with corrugated iron, is provided from property line to property line. Since one of the idler, towers is set close to the street, a part of the structure is built in-tegral with the street covering. The general design of idler tower as well as the covering over the street is shown at A in Fig. 1.

Jan 9, 1927

By Frederick Laist

IN the course of the past 75 years the treatment of copper ores has undergone the most profound changes. To a lesser degree, this is true of all the nonferrous metals, but the rapid increase in the demand for copper due to the phenomenal growth of the electrical industry, and the discovery of vast new ore deposits in Michigan, Montana and Arizona, provided an exceptional incentive for improvements in smelting practice and for large-scale operations. Because these must perforce be carried on in regions where labor was scarce and wages high, the need for mechanization and larger smelting units soon became apparent. At a later date the porphyry coppers were discovered, with ores so low in grade that enormous tonnages had to be treated daily if they were to be made to pay at all. In some instances these ores were associated with, or overlain by, oxidized ores, which could not be concentrated mechanically and, of course, could not be smelted directly. This led to the development of the copper-leaching process. While the principles of the various smelting and leaching processes are for the most part of European origin, and have long been known, modern practice is essentially American and was evolved on this side of the Atlantic. The ores of copper may be divided into three general classes; viz, native copper, sulphide and oxidized ores. By far the greater number of commercially important ore deposits come under the classification of sulphides. Commercial deposits of native copper are limited to the Lake Superior

Jan 1, 1947

By R. G. Bowman

DISCUSSIONS of processes for the manufacture of white lead generally open with the statement that white lead is the oldest chemical pigment known to man. This fact is of more than historical interest; in the light of the present extensive use of white lead, ii indicates that the .compound possesses characteristics that make it unique among white pigments, and superior to all ;in its particular field. A greater variety of processes have been proposed for manufacturing white lead than for any other one chemical compound. Only a few of these processes have come into commercial use, however, and a large part of the present production here and abroad is made by the process used in ancient times. The outstanding disadvantages of the old process are that it is slow and laborious, affords no control of the product, and yields at best an impure material lacking in uniformity. Improved processes, sometimes classed all together as "quick processes," have had as their main object the shortening of the time required. Most of them accomplish this and some have yielded a superior product as well, but only two or three are now in use commercially. For centuries the manufacture and mixing of paints has been treated as an art, and the practice has been much influenced by tradition and precedent. There is a reluctance to abandon old materials for this purpose, and as few new uses for white lead have been developed, the adoption of the quick processes has been slow. The electrolytic production of white lead is not-new, a large number of processes and forms of apparatus have been proposed and patented within the past 25 years, all directed toward the, production of white lead, wholly or in part, by electrolysis. One or two of these processes were tried commercially but proved unsuccessful.

Jan 9, 1925

By C. Norman Bowers, Blaine B. Wescott

Marked improvement in the serviceability of sucker rods has been effected in the last two years, partly because of the insistent necessity for greater economy in the operating costs of crude oil production growing out of the general industrial depression and partly because many of the recently developed fields have imposed more severe operating conditions upon both surface and underground equipment. The latter is particularly true of Kansas, where practically all of the oil produced is associated with damaging amounts of hydrogen sulfide brine and where the method of establishing potential production demands equipment capable of being operated at maximum capacity without interruptions. The decline of flush production in the Oklahoma City field created new problems in deep-well pumping on a scale heretofore unequaled and the increased proportion of water it has been necessary to produce in the fields of the Greater Seminole area presented conditions that were acutely in need of betterment. The problem in the latter fields was complicated by the shift towards sulfide characteristics, which accompanied water encroachment, and it is probably true that nowhere, at the present time, are pumping conditions generally as severe as in this territory. The Mid-Continent district, therefore, has become the proving ground for the numerous materials that have been proposed for sucker-rod fabrication. The information that ultimately will be obtained from an unprecedented amount of field experimentation will pay ample dividends when the decline of East Texas increases the demand for the vast reserves of sour crude in West Texas. It is a rare occurrence in industry that the use of such a simple piece of equipment as a sucker rod presents so complicated a problem for solution. As proof of this, it is only necessary to consider the numerous types of sucker rods on the market at the present time and contrast this condition with that of less than four years ago, when it was the common aim of manufacturers to develop a single sucker rod for all conditions of

Jan 1, 1935

By R. H. Richards

In October, 1891,I read a paper before the Institute on a "A HandTelescope for Stadia-Work" (Bans., xx., 732), and promised to report at an early date some results showing the degree of accuracy attained with the instrument. I am now able to report on these results and also on certain improvements that I have made in the target since the first paper was read. I may say that I prefer the title, "Prismatic Stadia-Telescope," to that used in my earlier paper, for while the instrument can be used with perfect satisfaction for short sights up to, say, 300 to 600 feet when held in the hand, it is impossible to read milch longer distances without the use of a tripod, as a steady support for the instrument. Results are here given upon four combinations of prism and telescope. No. 1. A telescope made by Alvan Clark & Sons, 3-inch objective, 28 inches focal length, magnifying 60 diameters, the prism covering half the objective: Feet measured Reading of Distance reduced Reeding of rod pro by tape. the rod. to feet. portional to 100 ft. 127.66 1.1825 100 .92629 211.35 1.9585 100 .92666 326.59 3.0265 100 .92669 484.88 4.4925 100 ,92652 606.91 5.6225 100 .92641 Average,,92651 The value of this prism therefore is .92651 feet on the rod for 100 feet of distance, or 1 foot on the rod corresponds to 107.931 feet of distance. No. 2. A Bardou telescope having a 1-inch objective, magnifying 20 diameters, and a prism covering half the objective:

Jan 1, 1893

By N. W. Wickersham, Ward B. Blodget, Roberts R. Boyd

The year 1926 has seen few radical changes or developments in methods of drilling and handling oil wells, but it has been a year of steady progress and development in deep drilling and production methods. Probably the outstanding development of the year was recognition by the directors of the American Petroleum Institute of the importance of natural gas in the production of oil, and the Institute directors' resolutions in December, 1926, regarding regulation of gas production with oil by state legislation. This matter is extremely important and will receive the attention of the industry in 1927. Advances in Drilling Equipment The history of the progress of deep well drilling is the solution of problems as they have confronted the operator. As the prospects for deeper production have become apparent, methods of penetrating the earth to greater depths have been devised. Rotary Equipment Improvements in the construction and in the methods of operation of rotary drilling equipment have practically caused elimination of cable tools in California for all but shallow work. The rotary drill, from 1910 when it began to be a practical factor in California, has been making steady advances, first displacing cable tools for drilling to the oil sands in proved fields and later displacing the cable-tool outfit entirely. With the perfection of machinery for taking core samples of the formation penetrated, the rotary drill has become generally used for wildcat work, continuous coring being practiced when desirable. Deep Holes The use of the rotary drill has made commercially feasible the opening of oil fields at greater depths than was considered possible with cable tools. Heavier equipment has been promptly supplied as occasion has

Jan 1, 1927

By John Johnston

ONLY two of the Institute's 26 Local Sections were unrepresented at the delegates' three sessions, held on Monday morning and afternoon and Thursday afternoon of the annual meeting. The Philadelphia and Wyoming Sections alone sent no delegates. In all, seven hours were spent most profitably in reviewing the work done by the Institute at headquarters and in the field, comparing ideas and practices in varied activities, and in establishing personal contacts. Cordiality and the co¬operative spirit marked the meeting and apparently no one had any serious grievances to air. Four motions were introduced and unanimously passed. The first, which was introduced by B. L. Sackett, was a recommendation by the delegates that a national committee be appointed to cooperate with Local Sections in the matter of student activities, to promote Institute welfare. It was agreed that this recommendation be made simultaneously to the Board of Directors and to the Mineral Industry Education Division. A subsequent resolution by A. M. Smith was passed asking that a part of the duties of this committee be to secure the opinions of Local Sections as to the most desirable methods of interesting students in the preparation of technical papers, by giving prizes or otherwise, and to report their findings at the Section Delegates' meeting next year.

Jan 1, 1933

By R. E. Holmes, T. W. Leland

The solution to the unsteady-state mass- and heat-transfer equations describing the adsorption of a dilute component from a gas stream flowing through a packed bed is readily applicable to the design of hydrocarbon recovery units. The solution to these equations depends on the assumption of a linear equilibrium equation to relate concentrations on the surface to concentrations in the gas. This assumption is shown to be justifiable for components which are very dilute in the gas stream. This approach permits the prediction of the effects of bed shape and size, cycle time, and gas mass velocity on the recovery of each component. It also allows the time and gas flow rate needed for regeneration to be determined. The equations involve a constant for each component and another constant characterized by the type of adsorbent. These constants must be evaluated from operating data. Values of these constants determined for silica gel are presented. This paper points out the type of experitrrental data needed for a thorough design of hydrocarbon adsorption units. INTRODUCTION The growing importance of adsorption processes to recover hydrocarbons from natural-gas streams has created an urgent need for better methods to design and predict the performance of these processes. Since the original use of solid adsorbents in natural-gas processing was for dehydration, most of the current design methods for hydrocarbon recovery re extensions of those developed earlier for dehydration. These methods are based on an adsorptivity or bed loading factor defined as the amount of a particular component adsorbed per unit weight or per unit volume of the packed bed. The recovery of a given component is then expressed as an empirical function of its adsorptivity on a given adsorbent. In spite of the simplicity and initial utility of these methods, they are not completely satisfactory in that they do not predict the effect of the dimensions of the bed in relation to flow rate and cycle time, and do not predict the distribution of various components along the length of the bed. It is possible, however, to make a considerable improvement in the design of these processes by applying the basic equations of mass and heat transfer applicable to gases containing small concentrations of adsorbing components flowing through granular beds. These equations have been developed and solved by Anzelius,' Furnas,% nd Hougen and Marshall." where G = mass velocity of the inert constituents (assumed to be methane), lb/hr-sq ft, y = weight of an adsorbing component in the gas per unit weight of inert, lb of a given constituent per lb of methane, x = bed length, ft, p, = packed bed density, lb/cu ft, P, = gas density, Ib/cu ft, f = void fraction in the bed, t = time, hours, and w = weight of a given component adsorbed per unit weight of adsorbate free solid, Ib/lb pure adsorbent. The term on the left side of Eq. 1 represents the flow rate per unit bed volume of a component entering less the flow rate per unit bed volume of that component leaving the differential bed length. The terms on the right side represent, respectively, the accumulation rates per unit bed volume on the solid and in the gas phase within the differential bed section. The last term is negligible for this application since pgfv is quite small in comparison with p, and G. The partial differential is determined by the mass-transfer rate between gas and solid in the differential section.

By AIME AIME

EVEN the weather man joined in a friendly conspiracy to make the fall meeting of the Industrial Minerals Division at Rolla, Mo., Oct. 23-25. the splendid surges that it was. Following weeks of rain, the foliage of the Ozarks was still green, merely enlivened here and there by splashes of autumn coloring. In contrast to the tranquil beauty of the School of Mines campus under smiling Indian summer skies, the pace of the meeting was lively. Registration was larger than at any previous meeting and included an unusual number of prominent names and delegates from all over the country. From 125 to 150 were present throughout the three technical sessions, at the Thursday evening smoker, and also at the banquet on Friday; when students trooped in to the technical sessions the audience was augmented occasionally to over 200.

Jan 1, 1941

By R. T. Gallagher

FOLLOWING recent precedent, the Mineral Industry Education Division opened its first session on Sunday afternoon at the Columbia University Men's Faculty Club with an unexpectedly large attendance. The first session was presided over by the Division Chairman, A. F. Greaves-Walker. The first paper, a preliminary report on college enrollments in mineral technology curricula, by W. B. Plank, though incomplete, pointed to a general over-all reduction of 38 per cent in enrollment in mineral industry curricula. Following that, A. C. Callen's paper elicited many comments. It presented the results of a survey (no direct questions asked) addressed to officials in the mining industry. J. L. Bray spoke on war production drive methods and results and his slides gave visible evidence (and much laughter) of the success of the drive. C. L. Wilson's able presentation covered not so much present status but the future status of accelerated mineral technology programs after the war. The last paper of the first session by Edward Steidle, was handed out in mimeographed form.

Jan 1, 1943

Discussion of the paper of GEORGE S. Rice, presented. at the Pittsburgh meeting, October, 1914, and printed in Bulletin No. 94, October, 1914, pp. 2459 to 2492. WILLIAM GRIFFITH, Scranton, Pa.-I notice in the discussions and literature that emphasis is placed on rock dust, shale dust, and limestone dust, and I infer that these different. sorts of rock are ground up to produce this dust. -Is that right? MR. RICE.-That is correct, but we do not have to grind the limestone dust we are using in the experimental mine, as that is obtained from a quarry, and is used just as it comes; we can get it very cheaply, as it is a by-product of the quarries. MR. GRIFFITH.-Have any experiments been made with ordinary dirt out of the fields; could not that be used as ground dust? MR. RICE.-If you dry it and powder it enough so it will float in a, strong air current it might be all right for the barriers, but if it is damp there will be a tendency for it to mat together; then it would be quite useless for making a dust cloud. There might also be another disadvantage if used through the whole mine, if it had very much free silica in it, which is bad for the lungs. Limestone and selected shale dust would not affect the health of miners. MR. GRIFFITH.-In order to do very much good with any of those barriers, they ought to be rather extensively used throughout the mines, and there are few mines that have facilities for grinding up this rock into such a fine dust. If the ordinary earth from a plowed field could be used, even if it were not quite so good, it is more accessible and very much cheaper; therefore, in using it, with the universality of the supply through-out the country, it would tend to stop explosions. MR. RICE (communication to the Secretary*).-In closing, it is well to again emphasize that I do not advocate barriers being a "cure-all" for explosions. It will be generally agreed that prevention is best, not only by means of improved methods of using explosives, and ventilation to prevent accumulations of firedamp, but also by either thoroughly wetting the dust throughout the mine, or else so treating it with rock dust or other inert dust that an explosion cannot start. From my observations I believe that rock dusting. is a practicable method, and has the merit of visibility, and remaining effective for considerable periods, whereas the watering method has to be daily followed up, and if neglected for a short period the mine may become in a dangerous condition. The Germans

Jan 4, 1915

By T. C. Boberg, R. B. Lantz

This paper presents a method for calculating the producing rate of a well as a function of time following steam stimulation. The calculations have proved valuable in both selecting wells for stimulation and in determining optimum treatment sizes. The heat transfer model accounts for cooling of the oil sand by both vertical and radial conduction. Heat losses for any number of productive sands separated by unproductive rock are calculated for the injection. shut-in and production phases of the cycle. The oil rate increase caused by viscosity reduction due to heating is calculated by steady-state radial flow equations. The response of successive cycles of steam injection can also be calculated with this method. Excellent agreement is shown between calculated and actual field results. Also included are the results of several reservoir and process variable studies. The method is best suited for wells producing from a multiplicity of thin sands where the bulk of the stimulated production comes from the unheated reservoir. The flow equations used neglect gravity drainage and saturation changes within the heated region. INTRODUCTION This paper presents a calculation method which can be used to predict the field performance of the cyclic steam stimulation process. The calculation method enables the engineer to select reservoirs that have favorable characteristics for steam stimulation and permits him to determine how much steam must be injected to achieve favorable stimulation. While the calculation represents a considerable simplification of physical reality and the results are subject to numerous assumptions which must be made about the reservoir, it has been found that realistic calculations can be made of individual well performance following steam injection. The duration of the stimulation effect will depend primarily on the rate at which the heated oil sand cools which, in turn, is determined by the rate at which energy is removed from the formation with the produced fluids and conducted from the heated oil sand to unproductive rock. A complete mathematical solution to this problem is a formidable task, and finite difference techniques would undoubtedly have to be used. The calculation method pre- sented here utilizes analytic solutions of simple related heat transfer and fluid flow problems. The method is sufficiently simplified that it can be used as a hand calculation, although the calculations are somewhat lengthy and laborious. For that reason, the analysis was programmed for an IBM 7044 digital computer. Well responses observed at the Quiriquire field in eastern Venezuela&apos; have been matched using this program after making suitable approximations for reservoir and wellbore conditions. One of the most valuable uses of this calculation method is to assess the effect of reservoir and proc-cess variables on the stimulation response. This paper contains results of several studies made of key reservoir and process parameters. Among the most important of these is the influence of prior wellbore permeability damage. If a well is severely damaged prior to stimulation, a higher stimulation response will be observed than if it is undamaged. If a portion of this damage is removed, a permanent rate improvement will occur. THEORY I)ES(:KJJ&apos;TION OF CALCULATION METHOD The process of cyclic steam stimulation is essentially one of reducing oil viscosity around the wellbore by heating for a limited distance out into the formation through the injection of steam. Suitable modifications of the calculation technique presented here can be made so that stimulation of wells by hot gas injection or in situ combustion can also be calculated. A schematic drawing of the heat transfer and fluid flow considerations included in the calculation method is shown in Fig. 1. In brief, the calculation assumes that the oil sand is uniformly and radially invaded by injected steam. For wells producing from several sands, each sand is assumed to be invaded to the same distance radially. In calculating the radius heated rn energy losses from the wellbore and conduction to impermeable rock adjacent to the producing sands are taken into account. After steam injection is stopped, heat conduction continues and oil sands with r < ra cool as previously unheated shale and oil sand at r > r, begin to warm. The effect of warming of oil sand out beyond r, has little effect on the oil production rate compared to the effect of cooling of the oil sand nearer the wellbore than ra. Thus, in computing the oil production rate, an idealized step function temperature distribution in the reservoir is assumed where the original temperature exists for r > rn and where an average elevated temperature exists for r < rn. The average temperature in the oil sand for the region r < rn is computed as a function of

Jan 1, 1967

By AIME AIME

A SIDE from the technical sessions held as noted elsewhere, the chairman of the various sub-committees of the Mining Methods Committee, together with a few other specialists, were invited to a conference with President Bradley, which was held on Wednesday afternoon, Feb. 20. The general plan of a comprehensive series of comparable papers descriptive of mining practice in various parts of the country, launched by this committee some seven years ago having been adopted by the U. S. Bureau of Mines, the feeling was general that the Committee could safely 1eave.that part of its work in these capable hands and turn its attention to other matters. The plans of the Bureau were presented as below by Charles William Wright of the Bureau.

Jan 1, 1929