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By R. F. Lynch, J. D. Wood

The Al-1.0 pct Mg alloy 565 7 was studied using optical microscopy and electron microprobe X-ray analysis. Constituent particles were found to exist inter-dendritically in the as-cast material in a region of precipitate free a -aluminum. Five phases besides a fine precipitate and a-Al were identified in the cast structure: Fel3, Fe2Al7, Mg2Al3, CUMgAl2, and Cu2FeAl7. Thermal treatments conducted for 100 hr at 1180°, 1130°, 1080°, 1030°, 980°, and 880° F revealed a general dissolution and spheroidization of the in-terdendritic constituent network observed in the cast structure. The principal constituents present in the thermally treated structures were FeAl3 and Fe2Al7 with the relative amount of Fe2A17 to FeAl3 increasing with a decrease in the treatment temperature. The phases Present in the wrought structure were identical to those observed after the thermal treatments, with the constituent particles strung out in the direction of rolling. ALLOY 5657 is a nonheat-treatable commercial purity Al-1.0 pct Mg alloy utilized extensively because of its bright finishing characteristics. This investigation was conducted to determine the constituents present in 5657 alloy, and to study the effect of extended thermal treatments on morphology. Numerous studies have been carried out to establish the equilibrium diagrams for various aluminum systems,1-3 with phase identification based on X-ray analysis, morphology, and the etching response of relatively large particles. Phragmen4 conducted a study of the phases in aluminum eutectic systems and compiled a "corrected" table of etching responses, drawing on his work plus that of Schrader,5 Keller and Wilcox,6 and Mondolfo.7 A review of the original work of Keller and Wilcox, and Mondolfo, which was concerned with the constituents found in commercial alloys, reveals that in numerous cases their etching responses differ from those reported by Phragmen and from each other. These inconsistencies may occur because a specific constituent will react to a given etch in a varying manner depending upon its size, the elements dissolved in the phase, the other constituents surrounding a phase, and the solute content of the matrix. Work with a commercial orientation was conducted on alloys 2024 and 3003 by Sperry8,9 and on alloy 3003 by Barker,10 where the relationship between the phase diagram and the nonequilibrium structure of an alloy was examined. Backerud11 investigated the A1-Fe binary system and found that at high cooling rates the equilibrium eutectic reaction forming a-A1 and FeA13 is replaced by another lower temperature eutectic reaction forming a-A1 and metastable FeAl6, a constituent first identified by Hollingsworth et al.12 Most of the above mentioned studies were conducted on materials having a significantly greater alloy content than 5657 alloy, where the relatively small size and sparse distribution of second phase particles hinders the process of identifying constituents. EXPERIMENTAL PROCEDURE Material with a composition as given in Table I was examined in the as-direct chill cast, hot rolled and cold rolled conditions, and after thermal treatment of the cast structure. Thermal treatments were terminated by a water quench. Microscopic examination was conducted under various lighting conditions following the application of standard etchants as specified in Table 11. A semi-quantitative electron microprobe X-ray analysis was conducted for Al, Mg, Fe, Cu, Si, Zn, and Ti. RESULTS AND DISCUSSION Microstructure of the As-Cast Material. Particles of second phase material were found to exist inter-dendritically, principally in regions of precipitate free a-Al, as illustrated in Fig. 1. Adjacent to the ingot edge was a region of inverse segregation, resulting in an increased amount of second phase material containing large sized particles which aided in phase identification. Phase Identification. Cast Structure. Five phases besides a-Al and a fine precipitate were identified using optical microscopy and electron microprobe X-ray analysis, as presented in Tables II and III, respectively. FeA13 and Fe2A17 are often found with Fe2A17 forming a sheath around the core of FeAl3, resulting from an incomplete peritectoid reaction. These phases have a nearly identical appearance under white light, although they are easily differentiated under crossed polarizers, as characteristically illustrated in Figs. 2(a) and 2(b), respectively. Microprobe analysis con-

Jan 1, 1970

By A. M. Gaudin, R. T. Hukki

Previous work on the principles of comminution has shown: (I) that the surface produced is proportional to work input (Rittinger law,1a-3); (2) that there is regularity to the weight distribution of the fragments according to size.4-10 In this paper it is brought out that the surface on the fragments is distributed in definite and simple relation to size. The experimental work has involved: I. Construction of an apparatus capable of measuring the surface of mineral fragments independently of the chemical composition of the fragments and independently of the site of the surface; 2. Refining the methods available for measurement of particle size; 3. Designing and building a crusher capable of operating on very small quantities of mineral, if necessary on single crystals, and in such fashion as to minimize handling losses of material. Complete experiments have been carried out with massive quartz and individual quartz crystals. partial experiments, lacking surface measurements, have been made with glass spheres, galena, sphalerite, fluo-rite, salt and coal. Introduction The existence of regularity in weight distribution with size was noted many years ago, especially by A. 0. Gates;' the subject was also studied in detail by one of us.6 In the latter paper it was shown that rocks can be divided into two classes: homogeneous rocks, which show no preferential breaking, and heterogeneous rocks, which show preferential breaking at the grain size of the rock. It was shown, furthermore, that the fragments obtained by rupturing a homogeneous rock occur (in the fine range) in such abundance as to permit the writing of a relatively simple equation to relate the weight retained on a screen to the screen opening. With screens of which the openings are in constant ratio, the weight retained, w, is related to the screen size x by the equation w = Cxm [I] In this equation C and m are experimental constants. A plot of weight retained against particle size is a straight line of slope m if the scales for x and w are both logarithmic. In the fine range, the slopes of the size-distribution graphs plotted according to the method described above vary within a limited range. An inspection of a number of size-distribution data by various experimenters indicates that the slope very seldom exceeds 1.0, but is usually greater than 0.7. More recently, schuhmann8 proposed a method of charting that has so many advantages of its own that it has been used primarily in this work. For fine particles Schuhmann has found that the data are represented by the equation (x)m k [2]

Jan 1, 1947

By B. F. Fackenthal

One of the practical questions presented to the blast-furnace manager, with regard to which little help can be obtained from existing technical literature, is the manner of filling and blowing-in. This operation is often performed according, more or less, to traditions which have come down from earlier practice, and which, if not positively detrimental when followed with the large modern furnace, may at least be greatly improved, just as the running of the furnace itself, while in blast, has been improved. It is not necessary, as many of the old furnace-men believed, to make a lot of white or silver-gray iron at the start, or to spend many weeks, or months even, in bringing the furnace to its normal burden. It has seemed to me that the publication of carefully-recorded data of practice on this point may be interesting to the members of the Institute engaged in the management of blast-furnaces. The enlarged blast-furnace at the Durham Iron Works, Riegelsville, Pa., owned by Messrs. Cooper & Hewitt, of New York City, was first put in blast February 21, 1876, since which time it has made seven blasts, and is now running on the eighth. A description of the furnace-plant, together with a record of the fifth blast, was given in my paper read at the Chattanooga meeting, May, 1885 (Transactions, xiv., 130). After some of the early blasts the furnace-lines underwent considerable change, and I have thought best to accompany this paper with drawings showing the lines and the tuyere-arrangement (see Plates I. and II.), and to give also the following summary of the conditions and results of each blast. During the first and second blasts no coke was used, and the furnace ran very irregularly, showing a constant tendency to scaffold, which was attributed, in great part, to the small hearth and other defective lines. The large proportion of air required at this furnace is accounted for by the fact that the engines are defective, and do not deliver into the furnace the amount of air indicated by the pistondisplacement.

Jan 1, 1890

By Roy L. Zuber

Identification and analysis of mining hazards involves the correlation of accident, injury and illness information from all segments of the mining industry. It would not be feasible to process the volume of data involved without substantial reliance upon a computerized information system similar to that maintained by the Health and Safety Analysis Center. Numerous statistical programs are applied to the computerized accident-injury-illness data base to identify those mining tasks and associated activities which are responsible for most of the injuries and occupational illnesses. These programs are used to flag those mining tasks or conditions at specific mines or segments of the mining industry where either a significant increase in the injury/illness trend has been reported or where the number of injuries/illnesses related to specific mining tasks or conditions are high. Upon identification of those mining hazards which warrant further analysis, a computerized search of the coded accident data is performed to correlate the predominant categories by cause of injury or illness, source of injury, nature of injury, type of accident, etc. From this correlation, those factors most common to the conditions responsible for the hazard may be identified. Based upon analyses of this form, recommendations are made regarding the appropriate engineering, training, and/or operational improvements necessary to alleviate the hazard. In addition to mining hazard analysis, the computerized data base also has application in the area of optimum resource allocation. Computer programs have been developed to assist management in allocating resources based upon organizational requirements and historical accident - injury trends.

Jan 1, 1983

By Harry A. Perry

The Highlad underground uranium mine is located in the southern Powder River Basin, Converse County, Wyoming. Development by Exxon Minerals Company began in 1973 and average production from the complex roll- front deposit ranges from 500 to 600 stpd. A staff of six eight grade control technicians work within the Geology Department to guide and monitor production, to minimize waste and to account production to reserve estimates. A thorough knowledge of the complex roll- front deposit aids in accounting production to reserve estimates. Grade control technicians assist the mine geologist in making geologic cross sections, in estimating reserves, and in predicting monthly and quarterly production grades.

Jan 1, 1980

THE SECRETARY The year 1917 has been a notable one in Institute affairs. The usual activities, including meetings, publications, local section interests, library service, and so-forth, have been continued on at least the same scale as previously, and in addition the resources of the Institute have been placed without stint at the service of the Nation, not only for the active prosecution of the military side of the war, but even more especially in the industrial operations which form the very basis of modern warfare. The officers and directors of the Institute have labored both officially and individually, while the Institute as a body, through committees of, prominent members, and through many individual members, has given freely. Finally, Institute funds have been appropriated to an amount exceeding $5000 to accomplish the cooperation with Government bureaus, and provide committee expenses necessary for performing the services that have been given. The President of the Institute had a very large personal share in many of these activities, which will be described in the following pages, as well as in the President's own report. Many of the Institute's members are giving their whole time for. $1 a year, or less, and especial mention should be made of Herbert C. Hoover, Food Administrator, W. L. Honnold, Head of the Commission for Relief in Belgium, Mark L. Requa, Petroleum Administrator, Edgar Rickard and Charles W. Merrill of the Food Administration, S. A. Taylor of the Fuel Administration, W. L. Saunders, B. B. Thayer and Joseph W. Richards who .are giving a. large share of their time to the Naval Consulting Board, W. Y. Westervelt, W.0. Hotchkiss and Harvey S. Mud of the War Minerals Committee, David W. Brunton of the War Committee of Technical Societies, and hundreds of others whose names are mentioned in the Honor Roll of Members. It has also been a notable year in cooperation with sister-societies. The most important event under this head was the accession of the American Society of Civil Engineers into the fraternity of Founder Societies.

Jan 2, 1918

By H. V. Fairbanks

Efforts were made to determine the amount of increase in the drying rate which could be obtained through acoustic treatment of ultra fine coal under various conditions, and to test the feasibility of using a rotary kiln and multitiered vibrating screens as a means for continuous drying of coal fines. Introduction of acoustic energy during the rotary kiln experiments increased the drying rates from 10-40%, depending upon the experimental condition. The use of a drying assembly consisting of multitiered vibrating screens produced better results than the rotary kiln and has definite possibilities of providing an effective means of drying coal fines in relatively large quantities.

Jan 1, 1973

By T. Sterry Hunt

IN my address on the " Geognostical Relations of the Metals," delivered before the Institute on the 20th of February last (Vol. I Transactions, p. 331), I spoke of the rocks in the vicinity of Thunder Bay, Lake Superior, where I indicated two series of uncrystalline rocks resting upon the Huronian schists, the lower one consisting of dark-colored argillites and sandstones overlaid, apparently in slight discordance, by nearly horizontal red and white sandstone and marls, which were compared with those of Sault Ste. Marie, and those of the Portage Lake district, on the south shore. These latter sand-stones, according to Brooks and Pumpelly, overlie unconformably the Keweenaw series of copper-bearing amygdaloids, sandstones, and conglomerates, and are in turn overlaid by the Trenton limestone. I then proposed to call this lower series of Thunder Bay, that is to say, the dark-colored argillites and sandstones which are traversed by the silver-bearing lodes of that region, the Animikie group. Shortly after the publication of that address I received an abstract of a paper on the geology of that region by Professor Robert Bell, read before the Montreal Natural History Society, February 24th. He there confirms the statement made in my address that the gold of Lake Shebandowan occurs in the Huronian, which is also seen to be cut by the silver-bearing lodes just mentioned. Professor Bell, in this paper, proposes to designate both what I have called the Animikie group, and the overlying red and white sandstones, by the name of the Nepigon group, for the reason that the upper series is best displayed about Lake Nepigon. This latter series is by Logan supposed to be overlaid by the copper-bearing amygdaloids with conglomerates and sandstones of the north shore (apparently identical with those of Keweenaw) ; and the whole together, including the Animikie group, constitute his Upper Copper-bearing group. These copper-bearing strata are by him supposed to be overlaid by the red and white sandstones of St. Mary, which are apparently the same with those sandstones which, according to Brooks and Pumpelly, overlie unconformably the similar cupriferous rocks of Portage Lake, and are, in their turn, overlaid by the Trenton limestone. Thus the sandstones which at Thunder Cape overlie the Animikie group are by Logan placed in the midst of the Upper Copper-bear-

Jan 1, 1874

By B. T. Brady, Wilson Blake

One of the more widespread experimental procedures currently used in experimental rock and soil mechanics work involves the use of a short circular cylinder loaded axially between nonrigid end plates1-5 (Fig. 1a and b). It is widely recognized 6 that a number of undesirable features are connected with this test procedure ; the most noteworthy of these is the development of a nonuniform stress distribution throughout the specimen resulting from an elastic mismatch between the specimen and the end plates. In general, the end plates and specimen possess different elastic properties. As a result of this elastic mismatch, the uniform distribution of stress and strain applied to the end plates is altered at the interface, the degree of which is dependent not only on the magnitude of the elastic mismatch but also on whether there is any relative movement between the specimen and the end plate. A convenient measure of the elastic mismatch is the ratio (vp/Ep) / (v8/E3), where v and E are Poisson's ratio and Young's modulus and the subscripts s and p refer to the specimen and end plate, respectively. For most tests that use steel end plates, (v8/E8) is greater than (vp/Ep) ; i.e., the specimen tends to expand or contract laterally more than the end plates. Because of the frictional restraint offered by the end plates, shearing stresses are developed at the interface that, for compression testing, act inward producing a "clamping" effect (Fig. lc). The effect of this "clamping" is to produce a state of triaxial stress throughout the specimen. Fig. Id illustrates the coordinate system and stress nomenclature used. In a homogeneous, elastic two-dimensional plate loaded uniaxially at the edge, a uniform stress distribution is obtained at a distance from the

Jan 1, 1972

By P. Duwez, L. Zwell

In recent years, the problem of pressing metal powder in a die has received much attention. The question has been the object of a Symposium held in New York in March 1947 under the sponsorship of the AIME; an excellent review of the subject may be found in Ref. 1. Various experimental techniques have been used to study the behavior of the powder in a die cavity. Two methods have been particularly successful; one consists of measuring the density distribution²,³ and the other makes use of a lead grid in the powder during pressing.4 In the present study, the pressure at various points on the bottom and the sides of a die 1.50 in. in diam was measured by means of small piston dynamometers and resistance sensitive strain gauges. In order to correlate the results with previous investigations, the pressure distribution inside the compact has also been determined by an indirect method based on density measurements. Strain Gauge Measurements of Pressure on Side and Bottom of Die A schematic drawing of the die used for measuring side pressures is shown in Fig 1. The pressure gauge consists of a 0.25-in. diam piston A which transmits the pressure to a dynamometer B, on which two Baldwin Southwark type 4-14 strain gauges are fastened 180" apart. Because the installation of several dynamometer assemblies along the side of the die would have been difficult, the pressure distribution was obtained in successive tests in which the distance from the gauge to the bottom of the compact was adjusted to different values by changing the length of the bottom piston. The dynamometer, disassembled from the die, was calibrated under compressive loads and showed a 1.00 ohm change of resistance for every 15,300 psi change of pressure (750 lb load change). All the strain gauge measurements were made with a null type Leeds and Northrup Wheatstone bridge. The sensitivity of the method was better than 1 pct and the accuracy was within 2 pct. These values were considered satisfactory in view of the rather large scatter in the measurements introduced by the random variation in packing the powder in the die. The stable ambient conditions and short time involved in the taking of observations made temperature compensation unnecessary-. The pressure distribution on the bot-

Jan 1, 1950

By E. P. Klier, S. M. Grymko

The transformations in eutectoidal systems have been extensively studied as they occur in steels.&apos; As a consequence of these studies the martensite, bainite and pearlite reactions found for most steels are widely recognized. Further, because of the work of Smith and Lindlief2 and of Greninger and Troiano3 these reactions, except for the bainite reaction, are considered as typical for all eutectoidal systems. The primary alloy studied by Smith and Lindlief2 was a CuAl alloy of near eutectoid composition as was the alloy more recently studied by Mack.4 The transformations in these alloys were, for the most part, studied metallo-graphically, while an X ray analysis of structures was essentially wanting. It has appeared desirable, therefore, to investigate selected CuAl alloys at and slightly away from eutectoid composition. For this purpose three alloys were prepared containing 10.5,11.9 and 13.5 pct A1 respectively. The results of a metallographic and X ray analysis of structures obtained for isothermal transformation of the ß-phase are reported here for the 11.9 and 13.5 pct A1 alloys. Introduction The phase equilibria in the CuAl alloys of immediate concern are indicated in the equilibrium diagram section presented in Fig 1.5 The equilibrium and transition structures which have been reported in this system are as follows: a = copper rich terminal phase (f.c.c.) ß = high temperature eutectoidal phase (b.c.c.) r2 = aluminum-rich intermediate phase (r-brass structure) a&apos; = modified a-phase postulated by Bollenrath and Bungnrdt.26 ß1 = ordered ß (b.c.c.) ß&apos; = martensite structure: A1 < 13 pct (near h.c.p.) ß" = ß&apos; of Smith and Lindlief2 7&apos; = martensite structure: A1 > 13.5 pct (h.c.p.); ß2 of Bollenrath and Bungardt.26 The eutectoid transformation can be suppressed at sufficiently high cooling velocities. The ß-phase is then retained to about 500°C where ordering sets in. The ordering interval is not satisfactorily known but indirectly appears to be non-suppressible. Subsequent to the ordering reaction and consequently at lower temperatures, the ordered ß1 decomposes to a marten-sitic structure. The kinetics of these reactions and in particular those of the martensite reaction have an important bearing on the results obtained in this investigation. Since some confusion exists concerning certain reported aspects of these reactions, they will be considered in some detail. THE MARTENSITE REACTION The martensitic structure is formed on cooling through a critical range6

Jan 1, 1950

By Frederic P. Dewey

The improvement in leaching introduced by the Russell process has stimulated the development of processes for refining lixiviation-sulphides. In the early days several processes for dealing with the sulphides were proposed, and some of them were tried more or less ; but the business finally settled down to sending the sulphides to the smelters, although this was known to be both troublesome and expensive. In 1891 Mr. C. A. Stetefeldt* introduced at the Marsac mill, Park City, Utah, an unpatented process, built up out of the general fund of information available. It consisted in matting the sulphides, grinding, roasting, grinding again, and dissolving the copper out in diluted sulphuric acid, then melting the silver and crystallizing the bluestone. It did not yield fine bullion, hence the bullion had to be refined as well as parted; besides, there was some loss. This process was thoroughly tried at the Marsac refinery and then a year&apos;s run was made, the net result of which was that it did not prove sufficiently better than the sending of the sulphides to the smelters to warrant its substitution for that practice. In 1893 the Dewey-Walter Refining Company undertook the refining of the Daly sulphides in the Marsac refinery by the sulphuric acid process, upon which two United States patents ? have been issued to the writer. Naturally, difficulties were encountered in starting a new process, and most of 1893 was taken up in getting it into smooth working order; but in 1894 a run was started, in which all the regular sulphides produced by the

Jan 1, 1897

By J. W. Harden

THE observations here following are the result of an examination made as to the feasibility of extending the South Mountain Railroad from Pine Grove to Waynesborough, and of the commercial value of the ore through which such extension would be made to pass. The road at present built and in operation has a junction with the Cumberland Valley Railroad, half a mile east of Carlisle, and extends southward to Pine Grove, a distance of 172 miles. The extension proposed will add to it near 27 miles, making its total length 442, more than 23 of which will run through, or in close proximity to, beds of ore. Along the route taken there are a number of openings at which the ore is gotten, of which the Craighead bank, Huntzinger&apos;s bank, Lowrey&apos;s bank, Wenkoop&apos;s bank, the Henry Clay bank, the Fuller

Jan 1, 1873

By Mason J. Christner

Geology has become increasingly quantitative in the last 20 years. This trend has been accelerated by computer capability in the manipulation of data. The mining industry has been relatively slow to harness computer power, but the larger companies have moved in this direction in the past few years. Among the leaders in this progression is the White Pine Copper Co., and the following is a brief description of their computer system for processing, managing, and utilizing geologic data. Geology The White Pine mine is in the Upper Peninsula of Michigan, 6 miles south of Lake Superior and 80 miles west of the Houghton-Hancock area, center of the famous Copper country. The ore body of chalcocite, native copper, and minor native silver, is a tabular body in the basal 25 ft of the flat lying Nonsuch Shale and the top part of the underlying Copper Harbor Conglomerate. Twelve or more

Jan 1, 1972

By L. R. Duncan, O. M. Wicken

Magnesium, the eighth most abundant element in the earth&apos;s crust, is found widely distributed in a variety of minerals. Among the more commercially important ones are magnesite (MgCO,), brucite (Mg[OH],) , dolomite (CaMg[CO,],), and the salts magnesium sulfate and chloride often found in natural brines. Among other commercially important magnesium-containing minerals are olivine ([MgFe],- SiO,) , talc (H,Mg,[SiO,],) , and serpentine (H,Mg,Si,O,) . These are valuable because of desirable characteristics given them by the magnesium content and its placement in the particular crystal structure. These minerals are the raw materials for a host of products including magnesium metal and several grades of magnesia or magnesia- containing materials for refractories, fluxes, fillers, insulation, cements, decolorants, fertilizers, and chemicals. Considering only those minerals valued for their magnesia or magnesium content, over 85% of the material tonnages are processed to be used as refractories. Dolomite, which is used in enormous tonnages for its physical properties in construction, has an important use as a refractory raw material in its own right and, after calcination, as a precipitant for magnesium hydroxide, which is an intermediate for the production of magnesia or magnesium metal. Magnesia from the reaction of calcined dolomite (or limestone) with sea-water or magnesium-containing brines has supplanted much of the production of magnesia from mined magnesite, particularly in the United States. The best known of the minerals directly and widely exploited for magnesia content is magnesite, one of the calcite group of rhombo- hedral carbonates which includes calcite (Ca- CO,) , siderite (FeCO,) , and rhodocrosite (MnCO,) among others. The members of this group enter into a wide range of substitutional solid solutions when the positive ions have similar radii. The radii of magnesium and iron ions are within 6% of each other; hence, magnesite and siderite form a complete series of which breunnerite (ferroan magnesite) is a well-known end member. However, the radius of calcium ion is 36% larger than that of magnesium ion, and only limited substitution exists at each end of the MgC0,-Cam, series. Dolomite is not a member of the calcite group, but results when calcium and magnesium ions alternate in equal number in an ordered structure among carbonate ions. The result of these relationships is that calcite and dolomite, often found intermixed with magnesite, occur commonly as identifiable crystal entities which can often be separated to a varying degree from the magnesite by various beneficiation techniques. Magnesite, when pure, contains 47.8% MgO and 52.2% CO,. The pure mineral is sometimes, but rarely, found as transparent crystals resembling calcite, but, preponderantly, magnesite contains variable amounts of the carbonates, oxides, and silicates of iron, calcium, manganese, and aluminum. Magnesite may be either crystalline or "amorphous" (cryptocrystalline). The crystalline form has a hardness of 3.5 to 4.0. The color may range from white to black with shades of yellqw, blue, red, or gray. The color is not a fundamentally significant indicator of purity, but in a given deposit, an experienced person can often roughly grade magnesite by assessing color and crystallinity. The crystalline form of magnesite occurs in

Jan 1, 1975

By M. Sheffield

This paper presents a technique lor predicting the flow of oil, gas and water through a petroleum reservoir. Gravitational, viscous arid capillary lorces are considered, and all fluids are considered to be slightly compressible. Some theoretical work concerning the fluid flow in one-, two- and three-space dimensions is given along with example performance predictions in one- and two-space dimensions. INTRODUCTION Since the introduction of high speed computing equipment, one of the goals of reservoir engineering research has been to develop more accurate methods of describing fluid movement through underground reservoirs. Various mathematical methods have been developed or used by reservoir engineers to predict reservoir performance, 193-5,7,8 The work reported in this paper extends previously published work on three-phase fluid flow (1) by including a rigorous treatment of capillary forces and (2) by showing certain theoretical mathematical results proving that these equations can be approximated by certain numerical techniques and that a unique solution exists. DISCUSSION The method of predicting three-phase compressible fluid flow. in a reservoir can be summarized briefly by the following steps. 1. The reservoir, or a section of a reservoir, is characterized by a series of mesh points with varying rock and fluid properties simulated at each mesh point. 2. Three partial differential equations are written to describe the movement at any point in the reservoir of each of the three compressible fluids. All forces influencing movement are considered in the equations. 3. At each mesh point, the partial differential equations are replaced by a system of analogous difference equations. 4. A numerical technique is used to solve the resulting system of difference equations. Capillary forces have been included in two-phase flow calculations.1,4,8 The literature, however, does not contain examples of prediction techniques for three-phase flow that include capillary forces. Where capillary forces are considered, each of the three partial differential equations previously discussed has a different dependent variable, namely pressure in one of the three fluid phases. Therefore, three difference equations must be solved at each point in the reservoir. Where large systems of equations must be solved simultaneously, an engineer might question whether a unique solution to this system of equations actually exists and, if so, what numerical techniques may be used to obtain a good approximation to the solution. It is shown in the Appendix that a unique solution to the three-phase flow problem, as formulated, always exists. It is also shown that several methods may be used to obtain a good approximation to the solution. The partial differential equations and differenceequations used are shown in the Appendix. Matrix notation has been used in developing the mathematical results. Two sample problems were solved on a CDC 1604. They illustrate the type of problems that can be solved using a three-phase prediction technique. SAMPLE ONE-DIMENSIONAL RESERVOIR PERFORMANCE PREDICTION A hypothetical reservoir was studied to provide an example of a one-dimensional problem that can be solved. Of the several techniques available, the direct method of solution as shown in the Appendix was used. The reservoir section studied was a truncated, wedge-shaped section, 2,400 ft long, with a 6&apos; dip. (A schematic is shown in Fig. 1.) This section was represented by 49 mesh points, uniformly spaced at 50-ft intervals. The upper end of the wedge was 2 ft wide, and the lower end was 6 ft wide. The section

Jan 1, 1970

By R. H. Jacoby, V. J. Berry, R. C. Koeller

The experimental phase behavior of several field gas-condensate systems, one field volatile oil system, and a series of synthetic systems having gas-oil ratios from 2,000 to 20,000 scf/bbl stock tank oil was measured. The data were used to calculate the depletion performance of the field systems at their respective reservoir temperatures and of the synthetic systems at various temperatures. The results of the performance calculations were used to prepare correlations of total stock tank oil and separator gas in-place, and the amount of each recovered by primary depletion. Data needed to use the correlations are initial gas-oil ratio, initial tank oil gravity, reservoir temperature and reservoir pressure. The correlations presented should be useful for estiinating recovery from reservoirs producing volatile oils or rich gas condensates having gas-oil ratios from about 2,000 to 30,000 scf/bbl of stock tank oil. INTRODUCTION Prediction of depletion performance for gas-condensate reservoirs usually requires extensive laboratory work or lengthy phase-behavior calculations. For many small gas-condensate bearing zones the expense of such work is often not justified. Furthermore, where large holdings are involved, it is useful to have estimates of future oil and gas production in advance of the results of a laboratory analysis, even if such work is ultimately planned. For these reasons, it would be of value to have a method for rapidly estimating the depletion performance of gas-condensate reservoirs from the type of field data usually available. Few data on the reservoir depletion performance are available for the purpose of developing correlations. The increasing number of gas-condensate discoveries and the advent of high-speed computers have stimulated the development of methods for predicting performance. Such calculated performance data have been shown to be reliable and are becoming accepted as a basis for reserve estimates and for engineering studies. It therefore seems satisfactory to use results of performance predictions themselves for the purpose of developing the desired correlations. Such an approach is described in this paper. Several rich natural gas-condensate systems (gas-oil ratios of from about 3,600 to 60,000 scf/bbl) and one natural volatile oil system were studied (2,363 scf/bbl). In addition, to provide a more systematic basis for correlating purposes, a series of related, synthetic reservoir fluid mixtures was also studied (GOR&apos;s from about 2,000 to 25,000 scf/bbl). The purpose of this paper is to show how the recovery of oil and gas by primary depletion may be estimated from surface gas-oil ratio, reservoir temperature and pressure, and tank oil gravity. procedure Experiments Companion samples of gas and oil were collected from the high pressure separators in nine different fields at the time of their discovery. These samples were each recombined in accordance with the respective producing GOR to reproduce the reservoir fluids. Eight of these fluids, designated F-2 through F-9, were rich gas-condensate systems at the respective reser-

AS If see it, then, the engineering advances of which yob have studied here at Golden, the continued growth of. industry that you see about you here in Colorado, and the country-wide progress that I have not time to discuss-these illuminating facts should clear away any doubts as to your future. You have little license to ask, "Where is the call for engineering or what the need? Yankee fashion I might ask you by way of reply, "Have all the mines been opened? Have all the power-houses and transmission lines been built? Have the last improvements in. mill and smelter been in-stalled?" We know that the general answer is No, and the rest of the answer, which tells where are those mines and power plants and what are the new methods and processes in mining and metallurgy, must be sup-plied by you engineers of the future. And anyone who has even casually observed what recent years have brought forth in our profes- sion cannot but envy you your job. Our reconnaissance excur-sion into your future should not be much longer extended, but before turning back there are four landmarks that I would like to point out-not lofty peaks but useful tie points that are worthy of your attention as you traverse the territory of your future work. Two of these are in fact low spots or depressed areas which call for engineering activity; these are commonly called "waste" and "average." The other two are of larger significance and are rather extensive regions in the domain you are to enter and occupy. These larger tracts bear the suggestive place names "fact-finding" and "human engineering" and perhaps will prove to be the heights from which the broadest outlook is to be had in this "pilgrim&apos;s progress:" In the first place, waste deserves your attention, al-though I realize that it is possibly the most unpopular word anyone hailing from Washington can publicly utter. Its unpopularity naturally follows from its overuse in the somewhat strong charges made against the industrial and business world some years ago, when the doctrine of conservation was first preached in the land. But waste is a word to be used in an engineering sense as well as for political effect. Properly used, waste is not a word to shy at-rather it is a challenge to the engineer. For example, at present, the loss of 1 kilowatt-hour to every 5 sold is a clarion call to the electrical engineer. Waste is your target to shoot at, the obstacle for you to surmount, the giant for you to slay.

Jan 7, 1928

By J. T. Brown

AS far as could be ascertained, no one had previously investigated the creep strength of silicon poly-crystals. Literature has appeared showing evidence for plastic deformation in silicon single crystals and whiskers.*1"6 Also the fact that germanium, a material of similar crystal structure to silicon undergoes plastic deformation under stress at temperatures above about 60 pct of its melting temperature, has been known for some time.2"4&apos;7 This investigation was performed for the purpose of determining the strength and ductility of silicon polycrystals under creep conditions that would give fairly long times to rupture. PROCEDURE The silicon specimen blanks were obtained by first placing granulated transitor grade silicon (99.999 + pct pure) in a silica crucible. The crucible was surrounded by a graphite susceptor, and induction heating was used for melting the silicon in a vacuum furnace. Blank specimens were formed by freezing molten silicon onto a polycrystalline seed of silicon in a vacuum furnace. The seed was attached to a motor driven revolving rod. As silicon solidified, this rod was gradually withdrawn from the melt. A shape with a contracted center section was obtained by varying the rate of withdrawal from the melt. Specimens for the creep-rupture tests were ground from these "pulled" blanks. Creep-rupture tests were performed in spring loaded machines under constant load at 1800" and 2000° F. RESULTS AND DISCUSSION A test specimen which was sectioned longitudinally is shown in the photomacrograph in Fig. 1. Very little deformation has taken place in the portion of the specimen shown, however, slip lines from several slip systems within the same grain, and deformation band formation was seen. The elongated appearance of the grains is due to the method of growing the specimens. One of the most interesting aspects of the results obtained from the creep-rupture tests was the high strength and the accompanying large amount of ductility. The data obtained is listed in Table I which shows the stress to rupture in 100 hr at 2000°F is between 8000 and 9000 psi. This indicates that silicon&apos;s strength at 2000°F is about equal to that of the best commercial super-alloys. It is important to mention that silicon has less than 1/3 the density of iron-, nickel-, and cobalt-base alloys. The usual type alloys for high-temperature applications

Jan 1, 1960

By J. H. Allen

The air lift method of pumping water is discussed. A review of several large diameter hole drilling projects that used reverse- circulation air-lift techniques is presented. Proposals are made for reverse circulation flow rates for slow rates of bit penetration (5 fph) as well as reverse-circulation flow rates for faster rates of bit penetration (10 fph). The Ingersoll-Rand air lift equations are modified for rotary drilling operations. By establishing minimum reverse circulation flow rates and utilizing the modified air lift equations, the establishment of minimum circulation equipment sizes and a more definitive requirement for improved bit body design should result.

Jan 1, 1978