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By John L. Lamont, Walter Crafts

STUDIES of the effect of composition of steel on hardenability by Grossmann,1 and as-quenched hardness by Field2 and by the authors,3 have made it possible to predict the results of quenching when the composition and cooling rate are known. In order to extend the application of the hardenability calculation to the quenched and tempered condition in which steel is finally used, a survey has been made of the hardness changes caused by tempering. From this study a method has been developed for the prediction of hardness and tensile strength of steel in the tempered condition. The method of calculation was developed from Rockwell C hardness tests on quenched and tempered Jominy specimens and is expressed in Rockwell C hardness units. It is of an additive type in which the degree of softening from as-quenched hardness is estimated. Tempered properties may be calculated within about plus or minus 5 Rockwell C hardness or plus or minus 15,000 lb. per sq. in. tensile strength. This degree of accuracy is less than that necessary for the control of heat-treatment, but is adequate for the comparative evaluation and selection of alloy steels. The formula indicates that tempered hardness is primarily dependent on as- quenched hardness and, as in the hardening reaction, the progress of tempering is controlled mainly by the carbon content- Alloys tend to retard softening by a secondary hardening mechanism in which the alloy appears to migrate from ferrite to the carbide phase. The factors for the effects of alloys in tempering vary so much from the effects of alloys in hardening that different steels of equivalent hardenability may, after lie heat-treatment, differ considerably in tensile strength. PROCEDURE In developing the method for calculating tempered Rockwell C hardness, simple and complex steels were tested over a range from 0.08-to 0.65 per cent carbon and up to 2.68 per cent manganese, 2.18 silicon, 3.50 chromium, 4.94 nickel, and 1.06 molybdenum. The steels were made as small induction-furnace heats at the Union Carbide and Carbon Research Laboratories, Inc. The accuracy of the method was finally checked on a variety of carbon, low-alloy and high- alloy types of heat-treating steels produced under commercial conditions. The method was based on a study of tempered Jominy bars, and its validity was tested by correlation with the center hardness and tensile strength of oil-quenched and tempered bars from ¼ to 4 in. in diameter. The method of calculation was derived from the differences in Rockwell C hardness between as-quenched and quenched and tempered Jominy specimens. Prenormalized Jominy hardenability specimens quenched from a normal temperature for austenitization were used to obtain a range of as-quenched Rockwell C

Jan 1, 1946

By D. L. Wood, J. H. Westbrook

The tensile behaviors of the CsCl structure compound AgMg are extensively documented in terms of strain, strain rate, temperature, composition, and metallurgical processing treatment. The observations lend themselves to presentation in terns of three regimes of deformation behavior; 1) low temperatures where deformation is primarily by slip; 2) intermediate temperatures where the deformation mode is also slip but with the detailed behavior dominated by dislocation interactions with solute atoms; 3) high temperatures where defomation is primarily by diffusion controlled processes. Of all the material groups of potential interest as high-temperature structural materials, the inter-metallics have been the least studied, particularly with respect to their mechanical behavior. Moreover, the application and processing of intermetallics for uses which exploit their often unique physical properties have been impeded by a lack of understanding of their mechanical properties. Previous work in this area* has been largely *For a recent review, see Westbrook.' exploratory, aimed on the one hand at the direct empirical development of materials of engineering utility and ,on the other at identification of the important parameters affecting the mechanical behavior of inter metallics. As a consequence, there has not been available, heretofore—for any inter-metallic—data, sufficient in extent or precision to provide an adequate phenomenological description of the effects of metallurgical variables on deformation behavior. Such documentation is prerequisite to intelligent application or processing design and is also necessary for testing present and future theoretical analyses of mechanical behavior. It was therefore an objective of the present investigation to document the deformation behavior of a simple ordered intermetallic over as wide a range as possible of all the usual metallurgical variables. The compound AgMg was chosen as the subject of this investigation because it met all of a group of desired criteria, namely: 1) congruent but moderate melting point; 2) simple crystal structure; 3) ordered structure persisting to the melting point; 4) broad solubilities for the component elements. The first and last criteria were expected to aid in the preparation of homogeneous single-phase specimens: the second and third to help simplify the

Jan 1, 1962

By Francisco Cadena

THE construction of Norris Dam, built by the Tennessee Valley Authority on the Clinch River, a tributary of the Tennessee River, involved the production of coarse and fine aggregate for approximately 1,000,000 cu. yd. of concrete. A hammer-mill plant for the manufacture of sand from quarried rock was indicated as the most economical method of providing this material. The abrasive character of the feed as compared to the average hammer-mill feed made it necessary to control operations rather closely, and this resulted in the accumulation of many data bearing on production and maintenance. This paper will deal only with three specific sets of data, accompanied by such general information as may be necessary to explain the conditions under which they were obtained and followed by discussions on the relation of silica content to hammer wear, comparative costs of slugger and stirrup hammers, and comparative costs of tool-steel and manganese-steel grate bars. Coarse Aggregate Aggregate for the concrete poured at Norris Dam came from a dolomite quarry within 2000 ft. of the west abutment of the dam. Geologically this rock is known as a Knox dolomite. A typical chemical analysis is given in Table 1. TABLE 1 .-Typica.1 Chemica1 Analysis [PER CENT H20,1100F ............................................ 0.0'2 Ignitionloss ............................................. 43.56 MgO .................................................. 19.19 CaO .................................................... 29.07 FezO .................................................... 0.39 A1203 .................................................... 1.94 FezO .................................................... 0.39 A1203 .................................................... 1.94 ..................................................... 5.75 SO2.. .................................................. Tr.] Rock was carried by 12-yd. dump trucks to a 42-in. gyratory crusher set at 6 1/2 in. The product of the primary crusher was taken by a belt conveyor to a double-deck vibrating screen followed by a 5 1/2-ft. cone

Jan 1, 1937

IT will be recalled that the first professor of metallurgy in the United States, appointed in 1855, never really gave any instruction in metallurgy and gradually turned into a professor of mineralogy. Metallurgy was included with mining in the early curricula, two students who took the B.S. in mining engineering from the Polytechnic College of Pennsylvania in 1863 wrote their graduation theses on the metallurgy of copper and zinc, respectively. Even after Columbia School of Mines established, in 1868, a separate curriculum leading to the Ph.B. degree in metallurgy, very few students elected it,* preferring to take the mining degree, since they received in its curriculum nearly all the metallurgical instruction they would have in the metallurgical curriculum. For many years a large proportion of the men who attained prominence in metallurgical enterprises had taken mining rather than metallurgical degrees. METALLURGY Clifton Sorby's study of thin sections of rocks under the micro- scope, beginning in 1850, and its subsequent development by Zirkel and others, had made microscopic petrography a recognized department of, geological research as early as 1873. It was inevitable that the idea of studying polished metal surfaces under the microscope by reflected instead of transmitted light would occur to investigators. Sorby himself did it in 1864, and Adolph Martens and Floris Osmond may be especially named ', among the many European workers who, by the late eighties, had so developed the necessary techniques that they were able to photograph polished metal surfaces at magnifications as high

Jan 1, 1941

LANS are underway for the annual meeting of AIME, to be held in New York, February 17 to 21. The technical program includes meetings of all divisions of all three branches, Mining, Metals, and Petroleum. The bulk of the technical sessions will be held at the Statler Hotel, and the annual banquet will be held at the Waldorf-Astoria, Wednesday evening, February 20. The technical program of the Mining Branch activities is included in this issue. While it is not complete in every detail, it shows general interest groupings as well as subjects to be discussed. The program for each division is shown separately to facilitate following the activities of these special interest groups. Then, after a full scale and possibly somewhat strenuous technical meeting, a post-meeting feature will appeal to many of the members. A restful cruise to Bermuda and Nassau is offered at special rates to AIME members and friends. The schedule is a 3:00 pm departure from New York on the Queen of Bermuda on Saturday, February 23; arrival at Bermuda at 7:00 am Monday, February 25; arrival at Nassau at noon, Wednesday, February 27; and the trip ending again in New York at 9:00 am, Saturday, March 1. Rates begin at $202.10 per person, with higher rates depending upon accomodations desired. The base rate includes outside room with private bath and all meals, as well as Federal, Bermuda and Nassau taxes. Reservations for the trip should be made immediately through Leon V. Arnold, 36 Washington Square West, New York 11, who is in charge of arrangements.

Jan 1, 1952

By Walther Mathesus

INTRODUCTION THE use of high blast heats on furnaces melting Mesaba ores is still the exception, the average blast temperatures carried on Mesaba stacks seldom reaching 1,100° F. Some 15 years ago, when the use of fine Mesaba ores in larger proportions to the total burden first came into practice, it was found difficult to employ even those blast heats which it had been possible to carry with the Old Range ores. The furnaces refused to "take" high heats, and would persistently labor with irregular stock movement, which impaired the practice and increased the coke consumption. By lowering the blast temperature, the working of the furnace became smoother, and experience taught that with the softer and more easily reduced Mesaba ores, satisfactory practice could be obtained with comparatively low blast heats. Therefore a large number of Mesaba furnaces have ever since been operated on very low blast temperatures, ranging between 800° and 1,000° F. In the face of these difficulties, furnace men were slow to recognize that furnaces could be so designed as to permit a free movement of the charges in combination with the use of higher heats. Since higher blast temperatures did not seem to offer great advantages in the smelting of Mesaba ores, investments in hot-blast stoves were not as attractive to the furnace man as labor-saving devices and means of obtaining greater tonnages. The effect of this preference is keenly felt at the present time. It has brought about the peculiar situation, that the majority of our furnace plants (among them some of the most progressive) lack modern and efficient stove equipment. The result is that, even where the proper furnace lines have been adopted and conditions are now favorable to the successful employment of higher blast temperatures, the heats required for the greatest fuel economy are not available.

Jan 3, 1915

By R. G. Mallon, R. L. Braun

Primary copper-sulfide ore deposits that are well below the water table can be chemically mined by in-situ high-pressure leaching. The leaching is accomplished by pumping oxygen gas into the bottom of a large underground flooded column of rubblized ore. Part of the injected oxygen dissolves under the high hydrostatic pressure in the column. With a high enough injection rate, the excess oxygen gas induces a convective circulation of oxygenated solution within the rubble column, which transports dissolved oxygen throughout the system. At elevated temperatures, this results in a relatively rapid dissolution of the copper minerals. A method of calculating the leaching rates is presented. The calculation is done by means of a finite-difference computer code that couples all of the processes relating to copper leaching, convective circulation, and the injection, dissolution, and consumption of oxygen. Results of the calculation for a typical case show that over 70% of the copper can be extracted in less than six years with good efficiency in oxygen utilization.

Jan 1, 1976

[based on o report by HUBERT E. RISSER] There is a tendency among laymen to relegate America's coal industry to Pennsylvania and West Virginia, completely overlooking-or unaware of- the vast reserves, both those developed and those untapped, situated in the 1.4 million square miles between the Appalachians and the Rockies. At the 1965 AIME Annual Meeting, Hubert E. Risser, Principal Mineral Economist of the Illinois State Geological Survey, presented an interesting picture of the wealth of mineral fuels occurring in that area. In his talk entitled "Trends in Mineral Fuels in the Central United States", Mr. Risser underscored the fact that "more than half of the nation's known reserves of each of the three major fuels-oil, gas and coal-lie within the Central area." The highlights of his speech, with emphasis on the coal situation, are excerpted below.

Jan 6, 1965

By D. B. Hobbs, H. O. Burrows, T. D. Stay

Aluminum which has lost its original identity as to source may be considered as secondary. This would include scrap originating in the fabrication of aluminum, which is not consumed at the plant of fabrication, and all material resulting from fabrication, which has lost its original identity regardless of whether it be consumed at the plant of fabrication or not. In general, secondary aluminum may be divided into two classes, commercially pure and alloyed. The chief impurities found in commercially pure aluminum are copper, iron, titanium and silicon; while in aluminum alloys, copper, iron, titanium, silicon, zinc, manganese, magnesium, nickel, or tin, may be present in varying proportions. Occasionally lead and antimony are found in secondary aluminurn alloys, especially if the alloy results from remelting vender's automotive scrap. Such alloyed elements as are found in the scrap cannot be removed on remelting. In this, the remelting of secondary aluminum differs from the smelting of secondary copper or most other secondary metals. The majority of secondary materials reach the consumer in the form of remelt ingot or remelt No. 12 ingot. This ingot varies greatly in quality, depending upon the source of the material, and the manner in which it is refined and blended. The principal differences between primary and secondary ingot are: 1. The composition of secondary ingot may be more or less inclcfinite. 2. Secondary ingot may contain more dross and oxide. Secondary ingot may, however, be used successfully in a great itiany products. Relation of Primary Production to Secondary Production Table 1, compiled from data published by The Ameriran Metal Market, gives an approxirnatc idea of the relation of primary to srcondary production. Information obtained from other sources leads the authors to believe that the figures for secondary production are somewhat low.

By William Fink

THE constitution of the aluminum-cobalt alloys has been the subject of relatively few investigations. Brunck1 analyzed the residue which remained after treating the 17 per cent cobalt alloy with dilute hydrochloric acid. The results of the analyses indicated the existence of a compound Co3Al13. Guillet2 published a liquidus for the aluminum-cobalt system which contained two maxima corresponding to CoAl6 and CoAl2 and two eutectic points at 30 and 74 per cent Co. The most extensive investigation of the system was carried out by Gwyer,3 whose results are summarized in Fig. 1. It will be noted that at the aluminum end there is a suppressed eutectic at 644° C. By extrapolation of the duration of the eutectic arrest to zero, the composition of the compound was placed at Co3Al13. Another thermal arrest was noted at 550° C., which Gwyer attributed to a peritectic reaction. The present investigation of the aluminum end of the aluminum-cobalt system is the eleventh of a series dealing with the constitution of aluminum; rich alloys prepared from electrolytically refined aluminum.4 Preparation of Alloys.-The alloys used in this work were all prepared from electrolytically refined aluminum, the analysis of which is shown in Table 1. In preparing some of the alloys, metallic cobalt (98 to 99 per cent) was used either directly or in the form of an intermediate alloy, the composition of which is given in Table 1. In order to obtain alloys of higher purity, cobalt was introduced into some of the alloys by means of chemically pure cobaltous chloride which was readily reduced by the aluminum. A small electric furnace with nickel-chromium heating elements was used in the preparation of the alloys.

Jan 1, 1932

By John S. Crout

TWENTY-FIVE years ago the training of an engineer was of interest solely to the educator and to the student entering the field. At that time the engineer's position in society was relatively simple. His training emphasized design and operation and he expected to enter industry to handle the engineering problems of raw materials production, mechanical and product design, and the operation of power plants, factories, transportation and communication systems, and similar phases of industrial activity. He was not concerned with or particularly interested in the problems of management, administration, sales, publicity, industrial relations, or of legislation. To a large degree he was content to leave these matters to self-made businessmen, or men trained in law, finance, or commerce. That period in the evolution of the engineer is now history. It is generally conceded that the modern world is dependent upon engineering technology for its day-to-day survival. The continued operation of facilities on which mankind relies is dependent upon the functioning of mines, utilities, chemical plants, and other factories, all of which require the knowledge and the skills of trained engineers. Thus from a purely mechanical point of view, the engineer has become indispensable to

Jan 1, 1947

By H. S. Rankin, E. C. Houston

OLIVINE is considered a valuable potential source of metallic magnesium in the chloride electrolytic process. Treatment of olivine with hydrochloric acid can be carried out under conditions that prevent the formation of gelatinous silicic acid, which would inhibit the reaction by forming a covering around the ore particles. It is our hypothesis that the formation of gelatinous silicic acid is avoided by the dehydrating action of the magnesium chloride, which takes up water to form a series of hydrates and leaves the silicic acid in granular condition. Leaching serves to separate the magnesium chloride from the silicic acid and unattacked ore, which can be treated with fresh acid in successive steps until extraction is essentially complete. The leach solution can be purified by the addition of caustic magnesia and the precipitated impurities removed by decantation or filtration. The resulting magnesium chloride contains: Fe, less than 0.001 per cent; Mn, 0.012 per cent; Ni, none. Chlorination[f] of olivine has two major defects: (1) a large part of the chlorine goes to form silicon and iron chlorides, (2) the anhydrous magnesium chloride is held by absorption in the finely divided silica. SUPPLY It is well known that olivine, a silicate of magnesium and iron, is present in large amounts in several localities in the United States. The largest deposits occur in the southeast and on the Pacific Coast.1 The southeastern deposits were surveyed by Lewis2 in 1896 and by Hunter3 in the period 1933-1940. It is estimated that high-grade olivine, conveniently located with regard to transportation and power, is present in excess of 230 million tons above local drainage level in western North Carolina and north Georgia. PREVIOUS TECHNICAL WORK In the past few years, olivine has attracted considerable attention in the refractory field. In the chemical processing industry, however, it has long been thought axiomatic that the cost of processing silicates is an economic barrier to their utilization, especially where more reactive minerals, such as carbonates, oxides or salts, are available. This attitude is not entirely justified in connection with olivine. Unlike most silicates, olivine is readily attacked by acids, chlorine and other reagents without resorting to fusion to break down the silicate structure. Olivine has been suggested as a raw material for making epsom salt by roasting with pyrites.4 Other processes include acid treatment5 and digestion with calcium chloride.6 Recently a small plant was built near Webster, N. C., for making epsom salt from olivine by treatment with sulphuric acid. This plant is now in commercial operation, producing approximately two tons per day. Olivine is also receiving attention from the fertilizer industry as an inexpensive source of soluble magnesium.

Jan 1, 1942

By Frank Van Horn

IT is customary to ascribe two general modes of occurrence to natural gas, namely shale. gas which, as the name indicates, is found in' shale, and reservoir gas, which occurs ill sandstone, conglomerate and dolomitic limestone. Both of these types are found in the Cleveland district. The shale gas has been produced on a small scale for a long period of years, probably dating back as far as 1883. Shale gas is a low-pressure gas, small in volume with variable pressure, and is limited to no definite horizon. It is generally independent of oil, may last for a long time, and is not dependent to any great extent on the structure of the rocks. There are many such wells in the district which range from 400 to 1,840 ft. in depth, although most have been completed at about 800 ft. This indicates that the wells pass through the Cleveland and Chagrin shales into the Huron or Portage shale of the Upper Devonian. During the last 2 years great interest has developed in a deeper-seated reservoir gas. What is commonly called reservoir gas is generally a high-pressure gas occurring in large volume at a definite horizon. Oil may, or may not, be associated with the gas, and in most regions in which reservoir gas is found, the geological structure is of great importance. This type of gas occurs in all large fields such as those of West Virginia which have been supplying Cleveland until the recent discovery of local gas at great depths in commercial amounts.

Jan 1, 1917

By Glenn Allen

SAN FRANCISCO Mines of Mexico, Ltd. owns and operates an extensive group of claims in the San Francisco del Oro-Santa Barbara district, about 15 miles southwest of Parral, Chihuahua. The property comprises the mines, aerial tramways, flotation mill, power plant, shops, offices, assay and testing laboratories, modern hospital, water and sanitary system, quarters for miners, mechanics and operators, a well housed colony for Mexican staff employees and residences for foreigners. Each colony has a club house and mess and tennis courts. The employees have constructed a nine-hole golf course. In other words, the property is self-contained and completely integrated for production of lead and zinc concentrates from complex sulfide ores.

Jan 1, 1930

By Robert Linton

The Sierra Consolidated Mines Co., organized in 1909, owns, together with other holdings, practically all of the productive mineral area in the Ocampo district. Lying within this area are 15 mines, large and small, that hid previously been worked and appear to have yielded, since the discovery of the camp, about 100 years ago, bullion of a total value of over $50,000,000. The deepest mine, the Santa Juliana, had been worked to 1,100 ft. below the outcrop. The reopening of the mines involved, first, extensive and thorough development to open up the known ore shoots at greater depth and explore the ledges for additional shoots, and, second, a revision of existing equipment and methods, so as to increase output and reduce cost of production. This paper will give some account of the metallurgical treatment and a description of the new mill to be built at El Salto. The Ore The ore is practically all argentite, Ag2S, with some associated gold, and carried in a siliceous gangue. The typical ledge matter is an ande-sitic breccia cemented with quartz, or quartz stockwork in andesite.l The proportion by weight of silver to gold averages about 60 to 1. The silver sulphides occur ordinarily in rather fine. dissemination, sometimes not being easily discernible with the naked eye, even in ores of very good grade. The ledges also contain considerable pyrites, which as a rule is barren. "Bronce" is the local term applied to such barren pyrites, and "Pasta" to such as carries values.

Jan 1, 1915

By Harold H. Goe, Louis V. Bender

The recovery of arsenic was started at the Washoe Reduction Works (later called the Anaconda Reduction Works) in 1904, when an arsenic plant was constructed adjacent to the lower end of the 60-ft. main flue.' This plant originally consisted of a Brunton roasting furnace for treatment of flue dust and a small reverberatory furnace for treating the crude arsenic produced in the roasting operations, together with the necessary kitchens for condensation of the fumes and grinding and barreling apparatus for preparing the refined white arsenic for market. The Brunton furnace was fired with wood. It was 14 ft. 6 in. in diameter with two outside fireboxes. The hearth revolved upon a central shaft. The charge was fed through a dust-tight hopper on to the center of the hearth and slowly moved to the outer edge of three rows of stationary rabbles fastened in the roof of the furnace. There was a 3-ft. space between the hearth and roof. A crude arsenic was condensed from this furnace. The hot flame from the fireboxes passed directly over the charge, vaporizing the As203 that was carried through brick flues to the condensing chamber. This chamber was 8 ft. high, 16 ft. wide and 240 ft. long, divided into small kitchens by partitions spaced every 7 ft. It was connected with the main flue system to provide draft and to receive any losses from the chamber. The small kitchens were connected by openings in such a way that the fumes took a zigzag course, causing them to come in contact with the cold walls and ceiling and condense the arsenic. There was an opening from the outside into each kitchen, for the removal of the deposited arsenic, which was closed by a wooden door. The refining furnace was a small coke-fired reverberatory having a hearth 10 by 20 ft. in dimensions. It had three hoppers through which the crude charge was introduced, and one firebox placed at one end. The hot gas from the burning coke passed over the charge, volatilizing the arsenic and carrying it to the kitchens.

Jan 1, 1934

By E. P. Burtchaell

A method is presented for evaluating the effect of gravity drive upon the reservoir performance of a high relief pool. Conventional forms of reservoir analysis do not consider the alterations in the basic material balance data caused by gravity segregation of reservoir fluids. A procedure is outlined for structurally weighting physical and chemical data for use in the material balance equation. It is demonstrated how actual pool performance data can be utilized to evaluate the future reservoir performance of a gravity drive pool. INTRODUCTION Conventional reservoir engineering. procedure is inadequate for the analysis of an oil pool which has considerable structural relief, steep dips, and good permeability development. In, pools of this type, gravity drainage has an important part in the movement of oil to the wells and the effects of gravity on the overall pool performance should be included in any analysis of reservoir behavior. Many engineers have the opinion that the force of gravity in the movement of oil is not important until the later life of a pool.' Probably the basis for this belief is that gravitational effects may not be readily discernible until a pool is nearing depletion. This would be especially true for pools not having a high degree of structural relief and permeability development. Actually the effects of gravitational forces are at a maximum when the pool pressure is high, for during this period the hydrostatic head of the oil column is at a maximum and the viscosity of the oil is at a minimum. Oil recoveries from pools having favorable gravity drive characteristics may equal or even exceed recoveries which might be expected from water displacement. Field evidence indicates that in some reservoirs gravity drive has resulted in recoveries greater than that which could have been expected from gas expansion or water drive.'.3 Unfortunately, the possible effects of gravity drive on pool performance have been underestimated and other reasons have been sought to explain the high recoveries obtained. There are unquestionably many reservoirs to which the principles of gravity drainage can be effectively applied. It is the purpose of this paper to illustrate one method whereby gravity drive is included in the reservoir analysis of an oil pool. A hypothetical pool, typical of many California reservoirs, is used as an example. As used in this paper, "gravity drive" is defined as the overall effect of gravitational influences on the recovery of petroleum from the reservoir; "gravitational segregation" as the gravity separation of oil and gas within the reservoir; and "gravity drainage" as the downward movement of oil as caused by the force of gravity. SAND VOLUME DATA Fig. 1 presents a structural contour map of the pool under study. Maximum closure is 1950 feet with dips on the south flank approaching 45". The original gas-oil interface was set at -5200 feet. Average thickness of the producing sand was 200 feet. For use in subsequent calculations ill this paper, the pool was subdivided into 100-foot vertical increments and the sand-volume content of each increment was obtained. If the gross sand thickness is small, under 100 feet, the sand-volume content can be obtained by superimposing an isopachous map upon a structural contour map and planimetering the average thickness of each 100-foot increment. For sand thicknesses over 100 feet, one approacli would be to construct a sufficient number of cross-sections of the pool from which the weighted sand-volume of each 100-foot increment could be obtained. Variations in the sand body with depth, as determined by core data, can also be included in the above process. Table I presents a summary of sand-volume calculations, core data, and the original distribution of reservoir hydrocarbons in the pool. Fig. 2 illustrates the structural distribution of the sand-volume content. A total of 171,398 acre-feet is contained within the productive limits of the pool. Assuming an average porosity of 25% and an interstitial water content of 20%, the original hydrocarbon content was computed to be 227,075,000 barrels. DEPTH-PRESSURE DATA The determination of the initial vertical pressure arrangement in the pool is necessary for PVT and material balance calculations. Whenever sufficient data are available, a plot of pressure versus subsea depth of measurement should be made. From this plot a representative fluid pressure gradient can be established. Lacking sufficient initial pressure data, an initial pressure gradient may he estimated or calculated from avail-

Jan 1, 1949

By I. S. Levy, J. L. Brimhall, B. Mastel

Specimens of' Hastelloy X-280, a low-cobalt version of the solid-solution- hardened nickel-base alloy Hastelloy X, were given a series of thermomechanical treatttzents. They were then Lensile-tested at room temperature and 1350°F. The Microstructures of the specimens tested at 1350°F were studied by electron Microscopy. Microscopy showed that dislocation tangling, caused by the cold working, mas still in evidence after aging-for 24 hr to temperatures as high as 1550oF. (Cr, Mo)23 C6, (Fe, Mo)6 C'. as well us an unidentifiable phase precipitale due to the combination of the thermomechanical treatments and subsequent tensile strain. The room -temperature and 1350°F tensile properties show a general increase ill strength and decreccse in ductility with increusing cold-work level. This is due to the dislocation taangling-. PerLurbatiot~s to this general trend occur- due to solid-solution weakening at the higher cold-work levels as a direct result of the preciplitation reactions. THE requirements for corrosion resistance and high-temperature strength place nickel-base alloys among the more promising materials for advanced nuclear reactor applications. However, when these alloys are irradiated at service temperatures, they generally suffer severe embrittlement'" and reduction in rupture life.3 Certain experimental treatments resulted in improvements in the tensile and stress-rupture properties of Hastelloy X-280, a solution-hardened nickel-base alloy.' To provide a basis for understanding these improvements, unirradiated tensile specimens were examined by electron microscopy. The results are reported in this paper. EXPERIMENTAL DETAILS Material. Hastelloy X-280, a low-cobalt version of Hastelloy X, is a member of the solution-hardened class of nickel-base alloys. The Hastelloy X-280 was obtained from 4- and 1-in: thick plates in the mill -annealed condition. Table I gives the chemical composition of the material as reported by the National Spectrographic Laboratories. ~x~erimental Treatments. Plates of suitable size, 12 by 3 by 1 in., or by + in., were cut under a water jet from the stock material and examined ultrasonic -ally for homogeneity of grain size and absence of voids. The acceptable plates were solution-treated at 2150°Ffor 1 hr and air-cooled. These plates were then reduced in thickness by cold rolling 0, 10, 15: or 20 pct along the original rolling direction. The plates were machined into buttonhead tensile specimens with a gage diameter of 0.125 in., with a gage length of 1.125 in., and with their tensile axes parallel to the rolling direction. The specimens were examined for quality of finish with a penetrant dye, ultra son ically checked for voids, and finally given a dimensional tolerance check with an optical comparator. The acceptable specimens were aged for 24 hr at either 1000" or 1500 F and air-cooled. These specimens were then held at 540°F in a water loop for approximately 18 days to qualify as controls for similar specimens irradiated under the same conditions of time, temperature, water chemistry, and flow rate. Table U summarizes the treatments. These treatments were investigated to establish whether prior precipitation and stabilization of carbide phases at strain sites within the matrix could reduce the amount of carbides available for precipitation at grain boundaries during service. Tensile-Test Conditions. Specimens were tested to fracture at room temperature or 1350 F in air on an Instron tensile-testing machine at a crosshead speed of 0.05 in. per min. The time for the furnace to reach equilibrium at 1350°F was approximately 30 min; soak time prior to testing was 15 min; and test duration was approximately 5 min.

Jan 1, 1968

By E. P. Burtchaell

A method is presented for evaluating the effect of gravity drive upon the reservoir performance of a high relief pool. Conventional forms of reservoir analysis do not consider the alterations in the basic material balance data caused by gravity segregation of reservoir fluids. A procedure is outlined for structurally weighting physical and chemical data for use in the material balance equation. It is demonstrated how actual pool performance data can be utilized to evaluate the future reservoir performance of a gravity drive pool. INTRODUCTION Conventional reservoir engineering. procedure is inadequate for the analysis of an oil pool which has considerable structural relief, steep dips, and good permeability development. In, pools of this type, gravity drainage has an important part in the movement of oil to the wells and the effects of gravity on the overall pool performance should be included in any analysis of reservoir behavior. Many engineers have the opinion that the force of gravity in the movement of oil is not important until the later life of a pool.' Probably the basis for this belief is that gravitational effects may not be readily discernible until a pool is nearing depletion. This would be especially true for pools not having a high degree of structural relief and permeability development. Actually the effects of gravitational forces are at a maximum when the pool pressure is high, for during this period the hydrostatic head of the oil column is at a maximum and the viscosity of the oil is at a minimum. Oil recoveries from pools having favorable gravity drive characteristics may equal or even exceed recoveries which might be expected from water displacement. Field evidence indicates that in some reservoirs gravity drive has resulted in recoveries greater than that which could have been expected from gas expansion or water drive.'.3 Unfortunately, the possible effects of gravity drive on pool performance have been underestimated and other reasons have been sought to explain the high recoveries obtained. There are unquestionably many reservoirs to which the principles of gravity drainage can be effectively applied. It is the purpose of this paper to illustrate one method whereby gravity drive is included in the reservoir analysis of an oil pool. A hypothetical pool, typical of many California reservoirs, is used as an example. As used in this paper, "gravity drive" is defined as the overall effect of gravitational influences on the recovery of petroleum from the reservoir; "gravitational segregation" as the gravity separation of oil and gas within the reservoir; and "gravity drainage" as the downward movement of oil as caused by the force of gravity. SAND VOLUME DATA Fig. 1 presents a structural contour map of the pool under study. Maximum closure is 1950 feet with dips on the south flank approaching 45". The original gas-oil interface was set at -5200 feet. Average thickness of the producing sand was 200 feet. For use in subsequent calculations ill this paper, the pool was subdivided into 100-foot vertical increments and the sand-volume content of each increment was obtained. If the gross sand thickness is small, under 100 feet, the sand-volume content can be obtained by superimposing an isopachous map upon a structural contour map and planimetering the average thickness of each 100-foot increment. For sand thicknesses over 100 feet, one approacli would be to construct a sufficient number of cross-sections of the pool from which the weighted sand-volume of each 100-foot increment could be obtained. Variations in the sand body with depth, as determined by core data, can also be included in the above process. Table I presents a summary of sand-volume calculations, core data, and the original distribution of reservoir hydrocarbons in the pool. Fig. 2 illustrates the structural distribution of the sand-volume content. A total of 171,398 acre-feet is contained within the productive limits of the pool. Assuming an average porosity of 25% and an interstitial water content of 20%, the original hydrocarbon content was computed to be 227,075,000 barrels. DEPTH-PRESSURE DATA The determination of the initial vertical pressure arrangement in the pool is necessary for PVT and material balance calculations. Whenever sufficient data are available, a plot of pressure versus subsea depth of measurement should be made. From this plot a representative fluid pressure gradient can be established. Lacking sufficient initial pressure data, an initial pressure gradient may he estimated or calculated from avail-

Jan 1, 1949

By AIME AIME

MEXICO embraces one of the great metal and petroleum producing provinces of the world. In this respect its history dates back to the overthrow of the Aztec empire by a Spanish force under Hernando Cortes between 1519 and 1.521. Even before then, its richness in silver and other minerals was not unknown. But it was a treasure house for the Spanish conquerors until the country became independent in 1821. It has been computed that in the 400 years following 1521, Mexico yielded 1.55,000 metric tons of silver, worth $3,000,000,000, two-thirds of the entire world production. In 1935 the country accounted for 36 per cent of the world's silver output, 14 per cent of its antimony (in 1934), 13 per cent of its lead, 3 per cent of its zinc and copper, and 21/2 per cent of its petroleum. Contrary to the impression of some, its gold output is now comparatively small, though important in the past. Its oil, as well, formerly hulked much larger than now, in 1921 being one-fourth of the world output.

Jan 1, 1936