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By B. S. Gottfried

A generalized mathematical model is presented, which describes the thermal recovery of oil in linear systems with convective external heat loss. Three-phase fluid flow, conduction-convection heat transfer, chemical reaction between oxygen and oil and aqueous phase change are included, making the model applicable to a variety of thermal recovery processes. The complexity of the model requires that numerical solutions be obtained with a digital computer. The numerical approximations of the partial differential equations are presented and the algorithm is discussed in detail. The analysis is applied to the detailed simulation of a forward-combustion laboratory tube experiment. The results of the simulation exhibit with reasonable accuracy all of the principal thermal and bydrodynamic characteristics observed in the laboratory (i.e., the propagation of a combustion zone, a steam plateau, and oil and water banks). Numerical variations in the parameters appearing in the external heat-loss term, the aqueous phase-change term, and the Arrhenius combustion term are examined, and their effects on the predicted temperature profiles, oil and water production histories, and the air-oil ratio are presented. In spite of an oversimplification in the chemical reaction mechanism and the considerable computer time required to obtain solutions, the model represents a major advance in the ability to simulate the phenomena observed in thermal recovery experiments. INTRODUCTION Thermal oil recovery refers to a class of recovery processes where heat is supplied to a reservoir to provide the necessary expulsive energy. This thermal energy can be supplied externally as steam or hot water, or it can be generated in situ by forward or reverse combustion. In either case, however, thermal recovery processes are charac- terized by the simultaneous flow of two or three fluid phases in a variable - temperature field, accompanied by possible chemical reaction or phase-change effects.2-5, 7- 10, 14,16-18,20-22 Although a physical understanding of the thermal recovery processes is far from complete, it is possible to construct mathematical models which describe approximately all of the principal physical and chemical phenomena. However, attempts to solve such models, even with high-speed computers, involve formidable mathematical difficulties. Consequently, theoretical solutions have been obtained only for idealized cases in which important physical phenomena are neglected. For example, consider the process of forward in situ combustion. All such theories which have been developed consider only certain aspects of the process, such as heat transfer, 2-4,8,9,l6,l8 heat transfer with phase change,10 heat transfer with chemical reaction,7 or the hydrodynamics of three-phase flow.21 A general theory including all of the above phenomena has not been developed to date. This paper presents a unified theory of thermal recovery processes in linear systems. A mathematical model is developed which explicitly includes conduction-convection heat transfer with convective external heat loss, chemical reaction between air and oil, aqueous phase change, and the hydrodynamics of three-phase flow. A system of equations is developed which can be solved numerically on a high-speed digital computer, resulting in predicted temperature, pressure, and saturation histories in space and time. The model allows a more detailed simulation of thermal recovery tube experiments than had previously been possible. THEORETICAL DEVELOPMENT Consider the linear flow of gas, water and oil in a homogeneous porous medium. Assume that the oil will react with gaseous oxygen, and that mass is transferred between the water and gas phase by evaporation or condensation. In the absence of hydrocarbon phase change, intraphase diffusion,

Jan 1, 1966

By Dean F. Winchester, C. D. Johnson

The so-called Rocky Mountain region is here made to include Colorado, Idaho, Montana, northern New Mexico, Utah and Wyoming, an area of great distances and relatively sparse population. Conditions of distance, transportation and markets have had their retarding influence on devolopment and production but the increase in facilities and markets in recent years has provided additional incentive for more thorough search for new productive areas and the more complete development of the known fields. The low prices of crude during the past year have offset, to a certain extent, the desire for increased production and much of the effort has been directed therefore to outlining new areas rather than to attempts to increase production from known fields and thereby add to the already sufficient supply above ground. During the year just closed the Rocky Mountain region has seen consistent efforts to outline new areas and these efforts have been reasonably successful. In this area a very large part of the land is government property, and by cooperation between the government, the private owner and the company it has been possible to carry on development in a scientific manner, providing for the maximum recovery of valuable products at least cost and at times when prices were best. Due to the fact that in the Rocky Mountain region costs of exploration and development are relatively high because of natural circumstances, it has been the policy of operators to drill test wells only on structures where they controlled a large proportion of the land. Even community lease programs have been effected in certain areas, thus obviating the necessity of offset drilling and the attendant uneconomical and even wasteful production. Oil production in the Rocky Mountain states has shown a slight increase during the year, the average daily production for November being 78,124 bbl. as against an average in January of 76,681 bbl. The total production during the first 11 months of the year, according to the U. S. Burcau of Mines, was as follows:

Jan 1, 1929

By Walter Crafts

Tests carried out at the Union Carbide and Carbon Research Laboratories, Inc., on the effects of grain-refining deoxidizers are in substantial agreement with the data presented by Mr. Comstock. Notable is the observation that, although boron and aluminum increased hardenability, the steel was of poor quality in comparison with the other boron-treated steels to which at least two grain refiners were added. The effect of zirconium in improving the ductility of the chromium-nickel steel is in agreement with our experience that zirconium is specifically beneficial to chromium steels. In order to amplify Mr. Comstock's results and to indicate some of the basic principles of special deoxidation, the primary observations of our study have been summarized. The effect of boron in increasing hardenability was described by R. Walther, U. S. Patent No. 1519388, Dec. 16, 1924, but effective amounts in incompletely deoxidized steel are sufficient to harm hot workability and room-temperature ductility. Work at the Union Carbide and Carbon Research Laboratories, Inc., has shown that in order to obtain deep hardening without using such large amounts of boron as to result in impairment of ductility, the steel must be thoroughly deoxidized. This may be accomplished by a high silicon content or a grain-refining addition of strong deoxidizers. The degree of grain refinement and hardenability are inclined to be erratic when only one grain-refining element is used, although aluminum, zirconium, titanium, and vanadium have been used singly and resulted in increased. although somewhat erratic, hardenability. The ductility likewise was inclined to be inconsisterlt when only one grain-refining deoxidizer was added. By combinations of grain-refining elements, it was found possible to combine the specific virtues and counteract some of the defects of each clement. In addition, the complex deoxidizers gave more consistent grain refinement and hardenability. When used in combinations, each element adds its own specific influence as well as modifying the character of the other elements. The function of aluminum is primarily to give consistent results and to minimize abnormalities resulting from too

Jan 1, 1943

By Walter Crafts

Tests carried out at the Union Carbide and Carbon Research Laboratories, Inc., on the effects of grain-refining deoxidizers are in substantial agreement with the data presented by Mr. Comstock. Notable is the observation that, although boron and aluminum increased hardenability, the steel was of poor quality in comparison with the other boron-treated steels to which at least two grain refiners were added. The effect of zirconium in improving the ductility of the chromium-nickel steel is in agreement with our experience that zirconium is specifically beneficial to chromium steels. In order to amplify Mr. Comstock's results and to indicate some of the basic principles of special deoxidation, the primary observations of our study have been summarized. The effect of boron in increasing hardenability was described by R. Walther, U. S. Patent No. 1519388, Dec. 16, 1924, but effective amounts in incompletely deoxidized steel are sufficient to harm hot workability and room-temperature ductility. Work at the Union Carbide and Carbon Research Laboratories, Inc., has shown that in order to obtain deep hardening without using such large amounts of boron as to result in impairment of ductility, the steel must be thoroughly deoxidized. This may be accomplished by a high silicon content or a grain-refining addition of strong deoxidizers. The degree of grain refinement and hardenability are inclined to be erratic when only one grain-refining element is used, although aluminum, zirconium, titanium, and vanadium have been used singly and resulted in increased. although somewhat erratic, hardenability. The ductility likewise was inclined to be inconsisterlt when only one grain-refining deoxidizer was added. By combinations of grain-refining elements, it was found possible to combine the specific virtues and counteract some of the defects of each clement. In addition, the complex deoxidizers gave more consistent grain refinement and hardenability. When used in combinations, each element adds its own specific influence as well as modifying the character of the other elements. The function of aluminum is primarily to give consistent results and to minimize abnormalities resulting from too

Jan 1, 1943

By D. G. Westlake

Resistance was measured as a function of temperature, 77° to 350°K,for niobium with hydrogen concentrations up to 3.76 at. pct. Cooling curves exhibited a discontinuity in slope that was attributed to the initiation of hydride formation. A thermal hysteresis was explained in terms of diffusion and the effects of mechanical constraint on nucleation and growth. The heat of solution of hydrogen in saturated Nb-H solid solution was 2. 737 * 0.045 kcal per g-atom, including an unknown stress contribution. The critical ternperatures for hydride formation during cooling and for embrittlement are correlated but not coincident. This, too, has been explained in terms of mechanical constraint and stress-itlduced tratzsfomtation. Nb-H alloys undergo a ductile-brittle transition with decreasing temperature.'-3 Similar behavior has been noted for v-H.1,5 For the latter system, there is evi-dence6 suggesting coincidence of the temperature of minimum ductility and the critical temperature T, for initiation of metal hydride precipitation during cooling. A decrease in ductility due to the presence of brittle hydride particles is readily explainable. The fact that ductility begins to decrease at some temperature higher than T,4,5 has led us6 to suggest that precipitation may be strain-induced locally during tensile testing. Wood and Daniels' have reported that a plot of temperatures for 10 pct reduction in ductility vs hydrogen concentration in niobium is not coincident with, but parallels, the solvus.7,8 They believe this indicates a correlation of precipitation and embrittlement. Unfortunately, the two reported solvuses 7,8 to which Wood and Daniels refer are not in agreement with each other. Furthermore, neither solvus was determined experimentally: each was a plot of calculated solubilities. Thus. neither is highly dependable for determining whether embrittlement coincides with initiation of hydride precipitation. Longson 9 studied phase relations in the Nb-H system between 77° and 473°K by dilatometry. Comparison with metallographic observations convinced him that discontinuities in the slopes of his dilatometric plots were coincident with the initiation of hydride precipitation. Plotting the logarithm of the hydrogen concentration vs the reciprocal of the temperature at which precipitation was initiated during cooling, he obtained a straight line shown in Fig. 1. Walter and chandler,'' using X-ray techniques to detect the for mation of a second phase? have obtained three experimental points in the temperature range 295° to 338°K which fall within Longson's experimental error for this plot. A similar plotg of temperatures at which dissolution was completed during heating was a parallel line shifted toward higher temperatures. A straight-line plot was obtained, also, for the temperatures of the ductile-brittle transitions,9 but it was shifted toward still higher temperatures. Longson calculated an activation energy of 2.980 * 0.300 kcal per mole for the hydrogen embrittlement mechanism, compared with 3.180 * 0.400 kcal per mole for hydride formation. Despite this agreement, he concluded, "It seems unlikely that embrittlement results from hydride formation..." because hydrogen embrittlement was observed at temperatures above the solvus. It is our contention that embrittlement is correlated with precipitation of the hydride.6 Because only Longson has investigated Nb-H phase relations at sub-ambient temperatures, we deemed it advisable to re-determine the temperature dependence of the solubility using the resistometric technique already proven successful for the V-H system.6 Coincidence of our solvus with temperatures for embrittlement would

Jan 1, 1970

By A. B. Parsons

Not so many years ago the interest of the average mining engineer in money matters-aside from his pay check or his consulting fees-was confined to the per-ton cost of mining and beneficiating ore and to the amount of capital that would be required to erect the plant necessary to carry out such operations on a prescribed scale. The so-called "business men" assumed that questions of marketing the products, of profits, and of dividends were in their exclusive sphere-matters too intricate or, perhaps, too practical for the mere engineer! In the case of a new enterprise, the promoter shouldered the entire responsibility for raising the necessary funds, and incidentally he got the lion's share of profits. In fact, he frequently profited handsomely even though the mine earned little or nothing. Occasionally the engineer turned promoter or entrepreneur--conspicuous examples are Herbert Hoover, D. C. Jackling, William Braden and F. W. Bradley- but by and large he remained in a sphere of his own. To what extent this condition of affairs has changed is difficult to say. It might be argued that it were better that it be not changed; and yet I cannot help feeling that in mine promotion lies a distinct opportunity for the

Jan 1, 1932

By Richard P. Hight

Abrasives include the substances, natural or artificial, that are used to grind, polish, abrade, scour, clean, or otherwise remove solid material, usually by rubbing action but also by impact (pressure blasting for example). They do not include abrasive tools, for instance, lathe tools and files--or polishing agents such as waxes, which act by filling pores. Detergents and cleaners whose action is chemical rather than physical are omitted al- though some chemical-action polishes and cleaners may also contain solid abrasives, for example, many automobile and metal polishes. General Considerations The most important physical properties of materials that qualify them for use as abrasives are hardness, toughness (or brittleness), grain shape and size, character of fracture or cleavage, purity or uniformity. For making bonded abrasive products such as grinding wheels, additional important factors are stability under high heat and bonding characteristics of grain surfaces. The economic factors of cost and availability are always important. No one single property is paramount for any use. For some uses extreme hardness and toughness are needed, as in diamonds for drill bits; for others, the factors of greatest importance are hardness and ability to break down slowly under use, to develop fresh cut- ting edges when grains become worn-for example: in garnet for sandpaper neither highly cleavable or friable grains nor extremely tough grains are wanted. For still other uses, great hardness is objectionable; for example, abrasives for dentifrices and for glass-cleaning soaps. For the most efficient use in the more critical applications, the different types of abrasives are rarely completely interchangeable; thus, while crushed quartz and garnet are both used in sandpaper, the papers are not at all interchangeable in their use applications. In the last analysis, the choice of a high grade abrasive depends upon the quality and quantity of work done by the abrasive per unit of cost. Initial cost of an artificial abrasive may be much greater than that of a natural abrasive but the artificial abrasive may do so much better work than the natural one, and do it so much faster that the ultimate cost will be less. It is for this reason that artificial abrasives have largely replaced natural abrasives. Abrasive Value Mineralogical hardness or "scratch" hardness as expressed in Mohs' scale is an important property in evaluating abrasive materials, but, as noted before, it is only one of several essential properties. The mineral hardness of pure crystal almandite garnet is about 7.5, but if the crystal is crossed by incipient fracture planes, or if it contains inclusions of other minerals, the apparent or useful hardness may be much lower. While the quartz grains in a sandstone have a hardness of 7, the bond holding the grains together may be so weak that the stone is valueless as a commercial abrasive. In artificially bonded wheels and stones, the hardness, strength, and character of the bond are fully as important as the hardness of the abrasive grains. Thus, in an overall consideration of abrasive hardness of loose abrasive grains, both "scratch" hardness and toughness must be considered. In naturally or artificially bonded abrasive stones, bond characteristics are a third factor, which is most important. The problem of abrasive hardness is further complicated by the inadequacies of methods of testing hardness and of expressing relative values. The Mohs' scale is inadequate both because the methods of testing are very crude and

Jan 1, 1975

By H. Guyod

The response of the Guard Electrode sonde (LL3) and the Laterolog (LL7) can be mathematically computed only for cases that do not represent realistic conditions. A resistance network analogue that simulates a number of typical—although idealized—formations was used instead to obtain, for both devices, a large number of resistivity logs and current distribution maps. From these data, charts were prepared for estimating true resistivities under a number of conditions. Some of these charts and current distribution maps are presented. INTRODUCTION Two main benefits are expected from a resistivity log: (1) obtaining geological information for mapping and other purposes, and (2) obtaining petrophysical data, based on true rock resistivity. The geological information can be derived from any resistivity curve having sufficient vertical detail, but true rock resistivities frequently are difficult to determine with desired accuracy because we do not have sufficient interpretation data. This is particularly true for the records given by the Laterolog tools. The object of this paper is to throw some light on the factors affecting the responses of these tools so that better resistivity data can be obtained from Laterologs. LATEROLOGS Laterolog measuring systems are of two types: the LL3 sonde, frequently called "Guard", and the LL7 sonde. Both measure the resistance between a single exploring electrode placed in the borehole and a faraway return electrode whose influence will be assumed here to be negligible. Although the principles of these tools have already been outlined,1-3 it is desirable to review them briefly in this article. LL3 Fig. 1, left side, represents a long cylindrical, vertical current electrode placed in a medium of uniform resistivity. The current leaving the center section of the electrode flows essentially along horizontal lines, delineating a surface having the shape of a biconcave lens. It is the elec- trical resistance offered to this particular group of current lines that is measured by the Guard tool. This is done in practice by having a long cylindrical electrode consisting of three sections physically and electrically separated by thin insulating washers, as shown in the center of the figure, and keeping the three sections at the same potential. It is obvious, for all practical purposes, that the current and potential distributions about this electrode are the same, as if we had a continuous electrode of same dimensions. Because the three sections are electrically separated, the resistance seen by the center section E can be independently measured. This section will be called the exploring electrbde, or E electrode. Its height generally is from a few inches to 1 ft. The outer sections are the guards G, which are several feet long. The combined length of the three sections is from 10 to 12 ft for the tools currently used in the petroleum industry. Let V denote the potential difference between E and the faraway return electrode, and I be the current flowing between these two electrodes. The resistance (Re) seen by the exploring electrode is VII, and the corresponding apparent resistivity is Ra = k(Re),............(1) where k is the tool calibration factor. The previous description establishes that the Guard tool uses that central portion of the sonde from which, in a uniform medium, the current follows essentially horizontal paths. When the formation being logged is fairly uniform, and when its resistivity is of the same order as

Jan 1, 1965

By Robert A. Rapp, Jan E. Verfurth

From the measurement of internal-oxidation band widths in Ag-In and Cu-A1 alloys, products for the solubility No and the diffusivity Do of oxygen in silver and apparent NODo products in copper have been obtained over a range of temperature. The NODO products for silver are in agreement with the product of the individually determined No and Do values of Eichenauer and Müller. Although interstitial diffusion of oxygen in silver is expected, the temperature-independent factor Do of the diffusion coefficient does not agree well with the theory of Wert and Zener. For Cu-A1 alloys internal oxidation does not follow the expression derived for ideal kinetics, since the apparent NODo product calculated from internal-oxidation measurements is a function of the alloy content in the specimen. Thus, unequivocal values for No or DO or even the product NODO in copper are not available from the literature. RELIABLE values for the saturation solubility NO and diffusivity DO of oxygen in fcc metals are lacking and difficult to determine, partially because internal-friction measurements are not applicable. Permeability experiments and Sieverts7-type adsorption -desorption methods3 have met with difficulty; however, Eichenauer and Müller4 have recently reported on the solubility and diffusivity of oxygen in silver as determined by the latter technique . Rhines, Johnson, and Anderson,5 and independently Meijering and Druyvesteyn,' introduced the possibility of deriving values for the product NODO in a metal from measurements of the widths of internal-oxidation zones (subscales) formed during the internal oxidation of alloys. In addition to these authors, several other investigators7-9 have made such measurements in various silver and copper alloys at various temperatures, mostly using me- chanically polished specimen surfaces. The purpose of this investigation was to determine over a range of temperature the calculated products NODO in silver and copper from systematic measurements of the widths of internally oxidized zones in Ag-In and Cu-A1 alloys, using specimens with electro-etched surfaces. Consider the internal oxidation of a dilute solid-solution alloy in which the base metal is not oxidized. If diffusion of oxygen is the rate-controlling step, then the depth 5 of the internal-oxidation zone is given by where y is a dimensionless parameter and t the oxidation time. Based on the solution of the diffusion equation, wagnerl0 has shown that under certain conditions several mathematical simplifications may be used in the evaluation of y, so that Eq. [I] may be expressed for the case that y « 1, and y(Do/DB) 1, where N(so)the is the equilibrium solubility (mole fraction) of oxygen in the solvent metal for the given oxidizing atmosphere, is the mole fraction of the solute metal in the bulk alloy, 4 is the diffusivity of the solute in the base metal, and v is the ratio of oxygen atoms to solute atoms in the precipitated oxide BO,. Rearranging Eq. [2] Maak' has derived an expression analogous to Eq. [3] for the case that an external-oxide scale, in addition to an internal-oxidation zone, is formed. For this combined external and internal oxidation for the case that 5/2 where 5 is the distance of the internal-oxidation front from the original external s.urface, and X is the distance of the external oxide/metal interface from the original external interface. The function F is defined by the expression

Jan 1, 1964

By C. F. Rust

Experimental evidence is presented showing that reproducible formation resistivity factor measurements and resistivity index determinations on reservoir core samples map be made utilizing either the two- or four-electrode methods. Equipment is described which permits the application of either technique to the core specimen without loss of time and with a minimum amount of effort. Since electrical resistivity measurements on reservoir rocks are important not only in electric log interpretations, but also in the study of fundamental rock parameters, it was considered desirable to compare the applicability of both techniques of resistivity measurement. INTRODUCTION The techniques employed in the measurement of electrical resistivity on reservoir rocks, as practiced in the petroleum industry, may be reduced to two fundamental methods: one utilizing two electrodes only, usually referred to as the two-electrode method; the other using two additional electrodes and commonly known as the four-electrode method. In the former, the core sample whose resistivity is to be measured is mounted between two electrodes, usually metal discs, which serve to pass a current of known magnitude through the saniple. The potential drop across the sample, measured between these same two electrodes, and the core dimensions furnish the necessary data to compute he resistivity of the sample. In the four-electrode technique the end plates, again usually ol metal, still serve as current electrodes. Additional probes or electrodes dispersed along the sample are utilized to measure the potential drop. Both methods are used in practice1,2 and it is the purpose of this paper to compare the two techniques as applied to the determination of formation reiistivity factors and the resistivity index exponent n, in Archie's empirical equation I = p/po = Sw 11. To evaluate the two techniques it is desirable to point out the experimental precautions which must be taken to insure reliable results. It is evident from the electrode arrangements of the two- and the four-electrode methods that, for a given sample, the volume of sample included by the four-electrode method is less than the volume included by the two-electrode method. One of the prime difficulties associated with the two-electrode method is the possible occurrence of an abnormally high resistance between the electrodes and the brine-saturated sample, which results in erroneous resistivity values for the core sample itself. Attempts to alleviate this difficulty meet varying degrees of success. Methods used in the past employ such absorbent materials as brine-saturated Kleenex: chamois, or felt. A technique described by Morgan, Wyllie, and Fulton,1 appears to be more satisfactory. Their method consists of spraying or painting the end areas of a core sample with conductive silver paint. This technique reduces contact resistances between the porous medium and the electrodes to a value which is generally negligible as compared to the resistance of the sample itself. In the four-electrode method these requirements are not as stringent since separate probes are used to measure the potential difference acrozs a portion of the sample. In this case, contact resistance occurring at the current electrode; are of no consequence. and those appearing at the potential

Jan 1, 1952

By Donald E. Grimes

In conjunction with Inland Steel&apos;s development of lead-bearing steels possessing improved machin-ability because of tellurium and/or selenium additions, it was decided to determine liquidus and solidus temperatures in the Pb-PbTe-PbSe sub-ternary system. With the exception of alloys in the PbTe-PbSe system, it is believed that no previous study of this subternary has been performed. Thermal analysis was employed in a general survey of the subternary. In addition to PbTe, PbSe, and pure lead, ten ternary compositions were selected at intervals of ten at. pct. Sixty-gram alloys were prepared by sealing an appropriate mixture of the elements in quartz crucibles with a central thermocouple-well under a vacuum of less than 10 p. All three elements were 99.999+ pct pure with only trace impurities detected by spectroscopic examination. After the alloys had been heated at least 20°C above the liquidus in a Kanthal furnace, cooling and heating curves were obtained. Two or more cooling curves were employed both for the determination of each alloy liquidus and for the solidus of those al- loys containing greater than 50 at. pct Pb. Cooling rates were 0.5° to 3.5°C per min during the 5 min immediately prior to the start or end of solidification. For those ternary alloys containing 50 at. pct Pb, the solidus was determined from heating curves. Temperatures were measured with a Pt/Pt-10 pct Rh thermocouple which was calibrated in the same apparatus against the freezing points of zinc (A. D. MacKay—99.999 pct), antimony (A. D. MacKay-99.999 pct), and copper (ASARCO—99.999+ pct) both before and after the experimentation. The only interruptions in the continuous strip-chart recording of the temperature occurred for brief periods at significant points of interest when direct readings were made with a Rubicon Type B potentiometer sensitive to * 1 µv. The average liquidus and solidus temperatures obtained in this investigation are listed in Table I together with probable errors based on the accuracy of the thermocouple calibration and the reproduci-bility of the data. No chemical analyses of the alloys were performed because the synthetic or as-charged compositions were felt to be reliable. The melting points obtained for PbTe (924.7° ± 0.7°C) and PbSe (1084.0° ± 0.6°C) compare favorably with recent findings of other investigators.&apos;-&apos; As indicated in Table I, both the liquidus and solidus temperatures increase as selenium replaces tellurium for a constant atomic percent lead. As a result, the ternary liquidus and solidus temperatures for a given percent lead lie between the corresponding binary temperatures published in the literature. It should be noted that those ternary alloys containing 50 at. pct Pb exhibit a relatively narrow liquid-plus-solid region (<80°C) when compared with alloys containing greater than 50 at. pct Pb. Alloys with 60, 70, or 80 at. pct Pb not only have a much wider liquid-plus-solid region (>500°C) but also exhibit considerably lower and approximately constant solidus temperatures which thus form a virtually isothermal solidus "plane" slightly below the melting point of pure lead (327.3°C). For these alloys

Jan 1, 1965

By Newell Hamilton

Some years ago, in the manufacture of seamless tubing from an alloy steel containing 0.07 per cent maximum carbon, 18 per cent chromium and 8 per cent nickel, at the plant of The Babcock & Wilcox Tube Co., a peculiar type of piercing defect was noticed. This defect was definitely associated with certain heats of the alloy and was independent of any of the variables of mill operation and billet-heating condition. A thorough analysis of the defective material yielded but one clue to the reason for its abnormal behavior in piercing and that was its oxygen content as determined by the vacuum fusion method. The oxygen content of the defective 18-8 alloy was found to be from two to three times that of the material that had pierced satisfactorily, and this incited an active interest in the vacuum fusion method for the analysis of alloy steels. After a critical survey of the literature on this subject, and considerable experimentation, an apparatus and technique were evolved that gave a fairly rapid, simple and reliable method of analysis. Samples selected from six years of tube production of 18-8 and other corrosion-resistant alloys were analyzed by this method. This paper describes the procedure and gives a correlation of the oxygen, hydrogen and nitrogen contents of a number of alloy steel samples representative of good and bad tube-piercing quality. The Apparatus Basically the apparatus used in this work was that of Jordan and Eckman,&apos; employing a high-frequency induction furnace and the gravimetric method of analyzing the evolved gases, nitrogen being excluded from the determination. In addition, a magazine-type cap and a large-

Jan 1, 1934

SEC. 1. The membership of the Institute shall comprise seven classes, namely: 1. Members; 2. Honorary Members; 3. Senior Members; 4. Associates; 5. Junior Members; 6. Rocky Mountain Members; 7. Junior Foreign Affiliates. All shall be equally entitled to the privileges of membership, excepting that no member of any class whose residence shall be outside of the United States of America, except those residing in Mexico and Canada, shall be entitled to vote. SEC. 2. Members: A person to be eligible for election or transfer into the class of Member must be at least 27 years of age and must have had at least six years&apos; employ¬ment in the practice of engineering, mining, geology, metallurgy, or chemistry, during at least three years of which he must have held positions of responsibility in one or more of these fields. This shall not apply to Rocky Mountain members. SEC. 3. Honorary Members: Each candidate for Honorary Membership must be recommended by at least ten Members and must be elected by ballot at a meeting of the Board of Directors by the unanimous vote of the Directors present; provided, how¬ever, that the number of Honorary Members shall at no time exceed twenty. Such election shall automatically act as a transfer of such member from any other class of membership to which he may belong. SEC. 4. -Senior Members: The Directors may in their discretion place on the Honor Roll of Senior Members and transfer from any other class of membership other than Honorary Membership the name of any Member or Associate who has reached the age of seventy years and who has paid dues for thirty years, and for good reasons in special cases may vary the age or number of years. SEC. 5. Junior Members: A person to be eligible for election to the class of Junior Member must be qualified through education or experience to hold a subordinate position in engineering, mining, metallurgical, geological or chemical work. He shall be not more than 33 years of age at the time of election. SEC. 6. Associates: A person eligible for election or transfer into the class of Associate shall be one, who, in the opinion of the Committee on Admissions and the Board of Directors, is suitable for such election or transfer by reason of his interest in or connection with mining, geology, metallurgy, or chemistry. SEC. 7. Rocky Mountain Members: Membership in a special class of life member¬ships without annual or other dues and without right to receive the printed literature distributed to other members or the right and privilege of wearing the official badge of technical members, is given to all members of the Rocky Mountain Club at the time of consolidation. These special Rocky Mountain memberships shall be claimable by any member of the Rocky Mountain Club, not already a member of the Institute, availing himself of the privilege within ninety days after mailing of notice to him, by the Secretary of the Institute. SEC. 8. Junior Foreign Afliate: Upon appropriate action by the Board of Direc¬tors and with its approval, members in good standing of any technical society having its headquarters outside of the United States of America, Canada, or Mexico,

Jan 1, 1937

By J. A. Hren, G. Thomas

A high-temperature stage has been used to study precipitation and dissolution in thin foils of Al-20pct Ag alloy directly in the electron microscope. The results show that the aging characteristics are similar to those observed for bulk materials, and in addition, direct evidence is presented for clustering at the solid solution temperature. The limit of solubility of G. P. zones is-350°C. The heterogeneous precipitation, the growth and dissolution of ?&apos;have been studied in detail. Growth of ?&apos; parallel to the basal planes, occurs by continuous motion of inter -facial partial dislocations. Growth stops at intersecting particles due to formation of sessile a/6 <110> interfacial dislocations. Growth normal to the habit plane occurs by the spontaneous nucleation of partial dislocations on alternate (111) planes and the thickening rate is --10-3= times the lengthening rate. The precipitates dissolve in layers and the final product is a whole a/2 <110> dislocation . The nucleation -growth -dissolution processes are thus completely reversible. Kinetic data obtained from the dissolution rates of ?&apos;particles enable the diffusion coefficient to be determined and the activation energy is found to be 37.5(±4) kcal mol-1, which is that expected for dzffusion of silver in aluminum. The velocity of the interfacial dislocations is thus dependent solely on the rate of diffusion of silver atoms. RECENTLY it was demonstrated that a high-temperature stage could be effectively used in the electron microscope to follow directly the processes of precipitation and dissolution in thin foils of A1-4 pct Cu alloy.&apos; These experiments also provided kinetic data which enabled the diffusion coefficient to be estimated. This new development of electron metallography opens up many fruitful areas of research and it was decided to investigate the aging behavior in thin foils of A1-20 pct Ag alloy, particularly the mechanism of heterogeneous precipitation (i.e., precipitation on lattice defects). This system was chosen because the aging characteristics of bulk specimens are now well known,2"7 and because we wished to obtain more details of the role played by partial dislocations and stacking faults in the nucleation growth and dissolution of the hcp ?&apos; phase. This is of interest for the general case of fcc-- hcp transformations. Part of the A1-Ag phase diagram is shown in Fig. 1. The use of a high-temperature stage also enables a study to be made of the clustering process (formation of G. P. zones) and to determine the structure of the solid solution prior to the usual quenching and aging procedures. It is also possible to obtain kinetic data from measurements of the rates of dissolution of precipitate particles. Unlike the results of previous experiments on A1-4 pct CU 1 where much of the initial precipitation occurred on the foil surfaces, the results on the A1-20 pct A1 alloy were identical to those reported for bulk specimens6,7 and no surface precipitation was ever observed. Thus, it was possible to follow the aging sequence: G.P. zones — ?&apos; — ? directly in the thin foils. This paper is concerned with the formation and dissolution of zones and the ?&apos; phase, and no attempt has been made so far to follow the mode of discontinuous precipitation of ?. I) EXPERIMENTAL DETAILS The high-purity A1-20 pct Ag alloy was prepared by the Aluminum Co. of America in the form of 0.001-in.-thick sheets. These were cold rolled with intermediate anneals to a thickness of 0.0004 in.,

Jan 1, 1963

By A. W. Ambrose

The present plans for the Petroleum Division of the American Insti-tute of Mining and Metallurgical Engineers provide for two principal meetings in the year 1928. The first will be at Tulsa, Okla., in September or October, 1928, with the exact date largely dependent upon the date of the .International Petroleum Exposition. The officers wish to hold the meeting at the same time as the Exposition in order that members of the Petroleum Division of the A. I. M. E. may have the advantage of attending both meetings at the same time. It is planned that this meeting will be devoted largely to petroleum production engineering problems. A tentative outline of subjects to be discussed is as follows: 1. Repressuring New Oil Fields, and naturally in conjunction with this falls Repressuring of Old Fields. 2. Air or Gas Lift. 3. Flow Strings in New Wells. 4. Deep Drilling Technique. It is also planned to have at this meeting a general paper relating to Supply and Demand of Petroleum and its Products. The second meeting is planned for February, 1929, in New York at the same time as the annual meeting of the Institute. Special details have not been carried very far on this meeting, although it is expected the program will cover technical problems in relation to production and refining of crude oil, as well as 1928 development in foreign fields and the United States. It is planned during 1928 to cooperate with the Bureau of Mines in an attempt to compile a set of definitions on petroleum engineering. These would be of value to the petroleum engineering profession, in order to better standardize various terms used in discussion of current problems. It has also been suggested that the Petroleum Division study certain problems in which research work is needed by the petroleum industry and outline certain definite programs that could be carried out by the Bureau of Mines and the U. S. Geological Survey, as a follow-up to

Jan 1, 1928

By P. A. Beck, Hsun Hu

As described by means of quantitative pole figures, the annealing texture of highly rolled aluminum consists of the four retained components of the rolling texture near (123) [121], rather more sharply developed, and of a cube texture component. Local reorientation corresponds fairly well to 40 rotation around a [111] axis. In copper strip rolled 96 pct, the annealing texture is mainly the cube texture, with the four twin orientations as minor components. The annealing texture of highly rolled brass strip consists of four components of the (225) [734] type. REVIEWS by Wassermann,&apos; Barrett,&apos; Dunn,3 and Richards&apos; give detailed accounts of the numerous publications dealing with annealing textures in rolled polycrystalline metals. Although a considerable amount of information of an empirical nature has been available for many years, even relatively recently the state of recrystallization-texture theory was considered uncertain. The reviews referred to above deal mainly with the description of experimental results, without developing generally applicable principles, suitable for explaining the observed annealing textures. The investigations of Burgers and Louwerse5 and Barrett6 showed that in deformed single crystals of aluminum the orientation of the recrystallized grains deviates drastically from that of the deformed matrix. According to Barrett and to Beck and Hu,7 the relationship between the two orientations can be best described as a rotation of about 40° around a [111] axis. Recent investigations led to similar orientation relationships for various face-centered cubic metals with a simple texture, regardless of whether the annealing process was recrystallization (strain-free grains growing in a highly deformed large crystal of aluminum&apos; or copper: or in deformed cube texture copper") or coarsening (strain-free grains growing at the expense of an essentially strain-free, fine grained, polycrystalline matrix of single orientation texture copper,&apos;" aluminum,&apos; or nickel-iron). Barrett" pointed out the possibility that this orientation relationship may be a result of the orientation dependence of the rate of grain boundary migration. More recently, considerable evidence became available in favor of this view.12,13 In apparent contradiction to the above results, it has been known for a long time that the recrystallization texture of polycrystalline metals is often similar to the deformation texture. This was found, in particular, for the fiber textures obtained by wire drawing, compression, or compression rolling.&apos; Following a suggestion by Barrett,2 Kronberg and Wilson and Beck and Hu7 described a mechanism by which a [Ill] fiber texture, resulting from plastic deformation, may be retained upon recrystallization, even though the orientation of individual recrystallized grains differs from that of the local area of the matrix in which they grow. This mechanism assumes that the reorientation corresponds to a rotation around the [1ll] axis, which is also the fiber axis. The present investigation was undertaken to examine in detail the orientation relationship between deformation texture and recrystallization texture in rolled face-centered cubic metals, using the quantitative methods of texture determination that have recently become available.", &apos;" Quantitative pole figures for the rolling textures of such metals were reported recently." Quantitative pole figures for annealing textures are given in the present paper. It was planned to investigate whether or not the orientation relationship previously found for the recrystallization of deformed single crystals, and for coarsening of single-orientation texture material, is capable of accounting for the observed, often complex, annealing textures in rolled polycrystalline metals. The question whether local reorientation is predominant, even in the early phases of the annealing process, was to be studied with high purity aluminum. by making use of an oxide film and sensitive tint illum-

Jan 1, 1953

By David A. Sterling, Roger C. Malan

The Atomic Energy Commission is investigating the distribution of uranium and thorium in the Precambrian of the western United States and the relationship of time-space-facies patterns of uranium and thorium enrichment in the Precambrian, to the major resources of umanium in Mesozoic and Cenozoic continental clastic sediments. The results of preliminary studies in the southwestern. United States are summarized. Approximately 50% of the uranium resource of the Free World is in deposits of Precambrian age, principally in lower Proterozoic conglomerates in Canada and South Africa (Uranium Resources, Joint Report, ENEA and IAEA, 1967). Most of the uranium resource of the United States is in Mesozoic and Cenozoic continental clastic sedimentary rocks that fill intracratonic basins. The Atomic Energy Commission (AEC) is investigating the distribution of uranium and thorium in the Precambrian of the western United States and the relationship of time-space-facies patterns of uranium and thorium enrichment in the Precambrian to the major resources of uranium in the Mesozoic and Ce-nozoic host sedimentary rocks. This paper summarizes the results of preliminary studies of the Precambrian in the southwestern United States including New Mexico, Arizona, southern Nevada, and southern California (Fig. 1). The host rock provenances for the major uranium resources in epigenetic deposits of Mesozoic and Ce-nozoic age in the western United States were in areas of extensive Precambrian exposure along the eastern margin of the Phanerozoic geosynclinal belt (Fig. 2). Mesozoic continental clastic sediments in the Colorado Plateau contain about two-thirds of the uranium resource of the United States. These sediments formed from detritus derived from the Mogollon highland in the southwestern United States where the Precambrian was extensively exposed1-1 (Fig. 2). A genetic relationship may exist between this provenance and the major uranium deposits of the Colorado Plateau. The Pre- cambrian might be equally important in the genesis of uranium deposits whether the most important process in the formation of these deposits was the leaching of low-order intrinsic amounts of uranium from Precam-brian granite or from Mesozoic pyroclastics derived from syntexis of the Precambrian basement rocks.&apos; Precambrian Geochronology of the Southwestern United States The Precambrian geochronology of the southwestern United States is in an early stage of systematic study. Until recently, the only basis of correlation was through inconclusive field relationships. However, with the increased use of isotopic age dating, new data are becoming available for correlating regional and local events. As yet, there is no undisputed evidence of ages greater than 1.8 billion years (by) old in the southwestern United States. However, most geologists who have studied the region agree that volcanism and marine sedimentation of predominately eugeosynclinal facies took place in a northeasterly trending geosyn-cline prior to 1.7 by."&apos; Because of insufficient evidence for a pregeosynclinal continental crust, some researchers believe the geosyncline may have developed on oceanic crust.&apos; However, sediments metamorphosed to 1.7 by-old felsic paragneisses in the Panamint Range, California," and southeastward into southern Nevada are believed to have had a nearby continental provenance. The three Precambrian disturbances that are recognized in the southwestern United States are 1.6 to 1.8 by, about 1.4 by, and about 1.1 by-old (Fig. 3). In addition to plutonism, these disturbances are characterized by predominately lower-grade metamorphism. In this report, lower-grade metamorphic rocks include argillite, phyllite, slate, mica schist, and gneiss with relic sedimentary textures. Higher-grade metamorphic rocks, in this report, are recrystallized beyond megascopic recognition of the original rock type. Principal

Jan 1, 1971

By E. T. Turkdogan, L. S. Darken

Using the quadratic formalism, thermodynamic equations are derived for the composition dependence of the heat and entropy of mixing. The applicability of these equations is confirmed by available experimental data on the activities and heats of mixing for binary metallic systems of Group ZZB elements. In a recent paper arkeen&apos; introduced a quadratic formalism describing the composition dependence of the activity coefficient in the terminal regions of binary metallic solutions. That is, in the terminal region, which may extend to as much as 60 at. pct, the logarithm of the activity coefficient, log y,, of component 2 is a linear function of (1 - N,)&apos; where N2 is the atom fraction of component 2. Similarly, for the other component, log yl is a linear function of (1 - N,)&apos;. A number of iron-base binary liquid alloys were shown to obey this quadratic formalism. arkeen&apos; extended this formalism also to any corner of a ternary system and showed that the activity coefficients of the components 1, 2 and 3 (1 is taken as the solvent) can be represented by quadratic terms involving five parameters, four of the binaries and one for the ternary system. Numerous examples given by arkeen&apos; demonstrated the general applicability of the quadratic formalism to iron-base systems over a wide composition range. In this paper further examples are given of binary liquid systems (Group IIB elements, Zn, Cd, and Hg) and of several solid solutions, again demonstrating the appropriateness of this concept. A further purpose of this paper is to extend the quadratic formalism to the enthalpy and excess entropy of binary metallic solutions and to test the equations so found using available experimental data. QUADRATIC FORMALISM FOR HEATS AND ENTROPIES OF MIXING OF BINARY METALLIC SOLUTIONS The following equations, reproduced from Darken&apos;s paper, are for the two terminal regions of binary systems. at infinite dilution and a&apos;s are temperature dependent parameters to be determined from the experimental data. Although the quadratic formalism is an assumed representation of the data, Eqs. [I] to [4] are thermo-dynamically consistent with the Gibbs-Duhem relation and satisfy Raoult&apos;s and Henry&apos;s laws as limiting cases. As pointed out previously,&apos; the following form of the Gibbs-Duhem equation facilitates the integration in general but particularly in regions I and 11, where each of the derivatives is constant. The partial molar enthalpy of solution i, (and i; the value of i, at infinite dilution) are related to the activity coefficients y, and y," by the thermodynamic relation Differentiating Eq. [l ] with respect to 1/T and substituting the above thermodynamic relation gives for region (I) It is reasonable to assume that over a temperature range of experimental interest, the enthalpy of mixing is essentially independent of temperature, implying from Eq. [7] that the derivative da,,/d(l/) is also independent of temperature. On the basis of this argument, the temperature dependence of a has the form where £ and S have the units of enthalpy and entropy respectively; they are characteristic parameters for a terminal region of a binary system, e.g. for region (I), C12, S12 and for region (II), d:,,, S2,. Using this equation gives for dff ,/ d(l/), From Eqs. [7] and [9] an expre_ssion is obtained for the composition dependence of L,. Similar calculations are made for El and the results are summarized below for the two terminal regions. For region (I), The corresponding expressions for the molar heat of solution, AHM, are readily obtained from the above equations for the two terminal regions: For region (I),

Jan 1, 1969

By I. W. Alcorn

THE cost of drilling in the past few years of proration and ever decreasing allowables has received increasing thought and study. It seems to parallel the strides made with respect to pumping problems in 1932 and 1933. Low profit margins stimulate the search for economies. Any discussion of slim-hole drilling involves a multitude of abstract values, and the problem can be attacked only by a study of records and rational thinking. In a measure, traditional methods must be studied with a questioning attitude. The words "slim hole" may be somewhat misleading, as the term is entirely relative. For that reason I wish to define it as used in this discussion. On the Gulf Coast, I would define a normal hole as one in which 10 3/4-in. surface casing has been set and below which a 9 7/8-in. hole is dug. With this as a datum, holes of larger diameter below surface would be called "large holes," with 12 1/4 in. as the "extra large" class and holes of smaller diameter classed in the slim-hole range, 6 1/4 in. representing about the minimum size. The optimum size has not been definitely determined, but the preference is for a program that would call for setting 8 5/8-in. surface casing and digging a 7 3/4-in. hole. Different sections of the country might very properly deviate from this practice because of differences in depth, formations, regulations, or other factors. This paper will be confined to a discussion of the drilling of exploratory wells, as the drilling of this class of wells is quite a different problem from that of drilling a proven field, although many of the same considerations apply in both cases, as will be apparent. Although for many years shallow slim-hole and core-test holes of small diameter had been dug, it was not, I believe, until the fall of 1937 that serious consideration was given to its application in drilling wells 7000 ft., 8000 ft. and 9000 ft. deep on the Gulf Coast. This does not mean that nearly all such wells drilled on the Gulf Coast now are of the slim-hole variety, but only that efforts have been aimed in that direction with very encouraging results and there has been a very definite trend to reduce the size of holes, a trend that probably will continue. As to exploration policy, there appear to be two distinct and opposite views. The one usually followed in the past was more or less designed to "shoot the works" on one well. Generally on the Gulf Coast, the depth at which production might be obtained is limited by the drilling equipment and economics. With this thought in mind, wildcat wells are often planned with the idea of carrying the depth to 10,000 ft., or even 15,000 ft. All of the possible hazards are anticipated and the general drilling and casing programs are so predicated. Such wells contemplate the drilling of large-diameter holes; the setting of at least one protective string of casing and an extensive coring policy, all of which finally adds up to an expensive well. As opposed to this general policy is the slim hole. This, on the Gulf Coast, recognizes that new discoveries represent gam-

Jan 1, 1941

By C. H. Samans, G. F. Tisinai

HARDENING and embrittlement of the ferritic chromium stainless steels at temperatures near 885 °F have been known for a long time.&apos; However, no satisfactory explanation has been given. Both ordering and precipitation hardening have been suggested. Fisher, Dulis, and Carroll2 discovered a chromium-rich body-centered-cubic precipitate in embrittled alloys. Subsequently, Williams&apos; and Wright4 also have found evidence of this body-centered-cubic constituent. William&apos;s hardness, electrical resistance, and magnetic studies led to his proposal of a new constitutional diagram for the Fe-Cr alloys. The new feature of this diagram is the eutec-toidal decomposition, below about 970°F, of the s phase into two stable body-centered-cubic solid solutions, one rich in iron and the other rich in chromium. An observation of Heger5 that the amount of s phase has increased and the amount of chromium-rich body-centered-cubic phase decreased in the interval 5000 to 32,600 hr at 900°F, even though the alloy increased in hardness, casts some doubt on this diagram. If precipitation hardening causes the embrittlement, the precipitate probably is always coherent with the matrix, since no evidence of overaging has been reported. It cannot be stated positively, however, that Fisher&apos;s body-centered-cubic constituent is the embrittling phase. According to Preston&apos;s data,6 such a chromium-rich phase should have a parameter less than about 0.5 pct larger than that of the iron-rich matrix lattice. Moreover, the constitutional relationships whereby Fisher&apos;s constituent forms, and whether it is stable, metastable, or a transition phase, are not yet completely clear. The recent studies of Wright4 and of Lommel,7 as well as the earlier studies of Becket8 and of Hochmann,9 have shown that 885°F hardening occurs in relatively pure Fe-Cr alloys. No evidence of its occurrence or absence in chromium itself has been reported. The rate of hardening in high purity alloys seems appreciably slower than that in alloys containing larger amounts of impurities (chiefly carbon and nitrogen). This may be due merely to the absence of hardening and straining effects from precipitated carbides and/or nitrides. These observations on high purity alloys make it seem unlikely that 885 °F hardening is caused by a constituent containing other than iron and chromium atoms, e.g., carbides and/or nitrides. Wright,4 Lommel,7 and Lena and Hawkes10 emonstrated the accelerating effects of a finely dispersed precipitate of (probably) chromium nitride on the hardening reaction. This appears to be evidence that lattice straining increases the rate of nucleation of the hardening constituent. Some new observations on 885°F hardening are reported here. They show an effect of preheat treatment that should contribute to a better understanding of the 885°F hardening phenomenon. They also clarify a discrepancy which exists in the literature. Some investigators have reported most rapid hardening at 885", whereas others have reported it at 930°F. The present work also shows that 885°F hardening does not occur in electrolytic chromium, and that any long range ordering type of reaction affecting any sizeable part of the volume is unlikely. Materials Studied Table I shows the currlposition of the alloys used in this investigation. In these alloys carbon and nitrogen are present in roughly similar amounts. Presumably both elements precipitate, as carbides and/or nitrides, during the heat treatments given.

Jan 1, 1958