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By J. Geertsma

In order to obtain a better insight into the pressure-volume relationship of reservoir rocks a theory of pore and rock bulk volume variations is presented. The theory is independent of the shape of the pores but is restricted to isotropic porous media built up of continuous homogeneous matrix material. The main conclusion obtained from this theory is that only three elastic constants and three viscous constants are required for describing pore and rock bulk volume variations if the porosity is explicitly introduced into the treatment. In addition, reasonable approximations are introduced for various types of reservoir rock, e.g., sandstones, limestones, and shales, which lead to further simplifications of the basic formulas. In consequence there is then a further reduction in the number of deformation constants which have to be determined experimentally. It is shown how measurements of these remaining deformation constants can be performed most conveniently. Finally the application of the theory to reservoir studies is discussed and the translation of experimental results obtained in the laboratory into reservoir behavior is considered. INTRODUCTION The decline of fluid pressure in connection with the withdrawal of fluid from an underground reservoir gives rise to a change in volume of both reservoir fluids and reservoir rock. The volume variation of the reservoir rock results in a decrease of both the pore volume and the total volume of the fluid-filled formation. Whereas the variation in volume of the reservoir fluids with pressure is usually known from PVT analysis, that in the volume of the porous medium is rarely measured, as it is considered of minor importance in reservoir engineering. Nevertheless, certain experimental results' suggest that in a number of cases the neglection of the variation in pore volume may introduce errors into material balance calculations of reservoirs producing above the bubble point. Only a few experimental results on the compressibility of porous rocks have been published. The compressibility of pure quartz and of calcite can be found in a paper by Adams and Williamson'. Botset and Reed' carried out some experiments on the compressibility of loose sands, while Carpenter and Spencer' measured the compressibility of a number of consolidated sandstones, which data were supplemented by Hughes and Cooke5. Hall' finally reported a number of experiments designed to study the influence of the porosity on the compressibility of oil-bearing formations, from which it appeared that, particularly in the low porosity range, the compressibility of the pore volume is important enough to be taken into account. Difficulties, however, arise in applying these experimental results to field cases. This is partly due to the fragmentary nature of the published data. Yet even if more complete data were available, the need for a theoretical background would be strongly felt. Such a background can be partially found in studies carried out by Biot,6,7 who published a theory of elastic deformations of porous materials and their influence on fluid displacement within the pores, by Lubinski8, who studied the stress distribution in an elastic porous medium neglecting pore compressibility, and by Gass-mann" who mathematically analysed the elasticity of packings of spheres. The contributions of Biot intro-duce a number of deformation constants which are impractical for reservoir rocks from an aspect of experi-mental determination. The theory developed by dass-mann is correct but difficult to read. It appeared, how-

Jan 1, 1958

By G. F. Tagg

In an earlier paper1, the author described a method of interpreting earth-resistivity curves, based on the theoretical investigation of a single horizontal underlying stratum. If the four-electrode system of Wenner is employed, the resistivity in a homogeneous soil is given by the formula p = 2paR [1] where a is the electrode separation and R is the resistance of the earth between the two inner electrodes. If the earth is not perfectly homo¬geneous, the application of this formula gives an apparent specific resistance varying with the electrode separation. In the special case of the single horizontal underlying stratum, there is a surface layer of thickness h and resistivity pi and a lower layer, extend-ing to infinity, of resistivity p2. It has been shown by Lancaster-Jones2 that the apparent resistivity, obtained by an application of equation 1 is related to the true resistivities, the depth h and the electrode separation a by an expression of the form pa/p1 = 1 + 4F [2] where Pa is the apparent resistivity and F is a function (actually an infinite series), of the ratio h/a, and a reflection coefficient k = (p2 - p1)/(p2 + p1). For given values of h/a and k, the right-hand side of equation 2 can be calculated, and curves drawn showing the relationship between Pa/P1, h/a and k. Such a set of curves for the case when pi > P2 is given in Fig. 1.

Jan 1, 1937

By N. M. Levine, W. M. Fassell

In this laboratory study the problem of aerative conditioning to separate chalcopyrite and pyrite from cobaltite was simply effected with a sulfy-drate collector and pH by proper choice of mixing variables. It was shown that for a given impeller type and geometry, selectivity is governed by a relation between the Froude number and a modified power number multiplied by impeller tank-diameter ratio wherein the power factor is expressed as power intensity or horsepower per unit volume of contained pulp. In applying this approach to other systems, other criteria would be used in place of selectivity. The purpose of this paper is to show how solutions to problems of aerative conditioning of pulps may be enhanced by development of mixing parameters in a given system through application of a fundamental approach to agitation. The term aerative conditioning refers to a combination of processes which include mechanical gas dispersion, gas solution in the liquid phase, transport of dissolved gases and other reactants to the reaction zone, physico-chemico interaction within the liquid phase and/or at the solid surface, and, finally transport of products away from the reaction zone. Important elements of these processes are: 1) Air-Liquid Contact Area: This area limits the rate at which a given gas may dissolve in a given liquid. Thus, an aerative conditioning system should be designed for optimum gas dispersion. 2) Diffusional Factors: Such factors as concentration gradient, diffusion film thickness, and diffusivity may govern the rate at which dissolved constituents are transferred to the zone of interaction at a particle surface and the rate at which reaction products are transported therefrom. Thus, such systems would be designed for maximum turbulence to effect good mixing and to minimize diffusion film thickness. 3) Solids-Turbulent Liquid Contact Time: Sufficient time should be provided for interactions to take place at solid-liquid interfaces. The region of maximum turbulence for mechanical systems being in the impeller zone, it is important that the number of passes through this zone be optimized. This means that a proper balance should be struck be- tween flow and turbulent power to achieve optimum conditioning time. Too high a flow rate and insufficient turbulence may be improper if the reactions are diffusion limited. On the other hand, too much turbulent power and too little time in the reaction zone due to insufficient flow power may also be limiting. 4) Geometry and Impeller Design: The design of the conditioning vessel and the type of impeller employed are important factors in determining the relative distribution between flow and turbulent power and the degree of gas dispersion. Maximization of power input would be to no avail if the distribution between flow and turbulent power were improper or gas dispersion insufficient. 5. Physical Chemistry: The reactions between dissolved gases and solid surfaces may be limiting if gas solubility, activation energies and/or free energies are not favorable. J. H. Rushton, E. W. Costich, and H. J. Everett' have summarized the mechanical elements of the combination of processes listed in a fundamental mixing equation. This equation was derived by dimensional analysis and relates the physical variables for a single impeller, centered in a cylindrical, vertical axis, flat-bottomed tank. It is, where T is tank diameter in feet; H is liquid depth in feet; C is height of impeller off tank bottom in feet; S is pitch of impeller; L is length of impeller blades; W is width of impeller blades; R is number of baffles; D is impeller diameter in feet; Np is the power number, pg/dN3D5; P is power in foot-pounds per second; g is the gravitational constant, feet per second; J is width of baffles; B is number of im-

Jan 1, 1961

By J. B. Austin

IN considering so complex a process as the smelting of iron in the blast furnace, there is obviously no single method of calculating efficiency that gives a complete appraisal of the performance of the furnace in all its several functions; such a comprehensive view as is required to evaluate producing ability and manufacturing costs for a given furnace is obtained only by considering a group of efficiencies, each of which measures the performance of the furnace from a specific point of view. For instance, there is the rate of consumption of coke per ton of iron produced, which is probably the most frequently considered, and is certainly one of the most important of the group; there is the efficiency of recovery of iron charged; and there is the efficiency of utilization of energy, both chemical and thermal, in some respects related to the former two yet in other ways independent of either. In each of these cases, the calculation can be made on the basis of the actual input of material or energy, or it may be based . upon a comparison with the minimum amount of material or energy that would be required by a "perfect" furnace; that is, an imaginary ideal furnace analogous to the perfect steam engine used in thermodynamic calculations, when this furnace is operating under optimum conditions. Moreover, the furnace itself can be considered either as an apparatus for smelting iron or, taking a somewhat less common point of view, as a gas producer yielding iron and slag as by-products. Some of these effi-ciencies are more useful than others, yet all are instructive; for a knowl-edge of them not only leads to good engineering practice from the standpoint of control but also discloses limits to possible improvement in performance and indicates the lines along which improvement is most likely to be profitable. Estimates of some of these efficiencies have appeared from time to time in the literature, but many of them are open to objection because they are based on data of uncertain accuracy or because they have been calculated without due regard to the thermo-dynamic principles involved. Moreover, so far as the author is aware, no general survey of the blast furnace comparing its performance in all the aspects mentioned has been made.

Jan 1, 1938

By J. B. Austin

In considering so complex a process as the smelting of iron in the blast furnace, there is obviously no single method of calculating efficiency that gives a complete appraisal of the performance of the furnace in all its several functions; such a comprehensive view as is required to evaluate producing ability and manufacturing costs for a given furnace is obtained only by considering a group of efficiencies, each of which measures the performance of the furnace from a specific point of view. For instance, there is the rate of consumption of coke per ton of iron produced, which is probably the most frequently considered, and is certainly one of the most important of the group; there is the efficiency of recovery of iron charged; and there is the efficiency of utilization of energy, both chemical and thermal, in some respects related to the former two yet in other ways independent of either. In each of these cases, the calculation can be made on the basis of the actual input of material or energy, or it may be based upon a comparison with the minimum amount of material or energy that would be required by a "perfect" furnace; that is, an imaginary ideal furnace analogous to the perfect steam engine used in thermodynamic calculations, when this furnace is operating under optimum conditions. Moreover, the furnace itself can be considered either as an apparatus for smelting iron or, taking a somewhat less common point of view, as a gas producer yielding iron and slag as by-products. Some of these efficiencies are more useful than others, yet all are instructive; for a knowledge of them not only leads to good engineering practice from the standpoint of control but also discloses limits to possible improvement in performance and indicates the lines along which improvement is most likely to be profitable. Estimates of some of these efficiencies have appeared from time to time in the literature, but many of them are open to objection because they are based on data of uncertain accuracy or because they have been calculated without due regard to the thermodynamic principles involved. Moreover, so far as the author is aware, no general survey of the blast furnace comparing its performance in all the aspects mentioned has been made.

Jan 1, 1938

By J. B. Austin

In considering so complex a process as the smelting of iron in the blast furnace, there is obviously no single method of calculating efficiency that gives a complete appraisal of the performance of the furnace in all its several functions; such a comprehensive view as is required to evaluate producing ability and manufacturing costs for a given furnace is obtained only by considering a group of efficiencies, each of which measures the performance of the furnace from a specific point of view. For instance, there is the rate of consumption of coke per ton of iron produced, which is probably the most frequently considered, and is certainly one of the most important of the group; there is the efficiency of recovery of iron charged; and there is the efficiency of utilization of energy, both chemical and thermal, in some respects related to the former two yet in other ways independent of either. In each of these cases, the calculation can be made on the basis of the actual input of material or energy, or it may be based upon a comparison with the minimum amount of material or energy that would be required by a "perfect" furnace; that is, an imaginary ideal furnace analogous to the perfect steam engine used in thermodynamic calculations, when this furnace is operating under optimum conditions. Moreover, the furnace itself can be considered either as an apparatus for smelting iron or, taking a somewhat less common point of view, as a gas producer yielding iron and slag as by-products. Some of these efficiencies are more useful than others, yet all are instructive; for a knowledge of them not only leads to good engineering practice from the standpoint of control but also discloses limits to possible improvement in performance and indicates the lines along which improvement is most likely to be profitable. Estimates of some of these efficiencies have appeared from time to time in the literature, but many of them are open to objection because they are based on data of uncertain accuracy or because they have been caleulated without due regard to the thermodynamic principles involved. Moreover, so far as the author is aware. no general survey of the blast furnace comparing its performance in all the aspects mentioned has been made.

Jan 1, 1938

By J. B. Austin

In considering so complex a process as the smelting of iron in the blast furnace, there is obviously no single method of calculating efficiency that gives a complete appraisal of the performance of the furnace in all its several functions; such a comprehensive view as is required to evaluate producing ability and manufacturing costs for a given furnace is obtained only by considering a group of efficiencies, each of which measures the performance of the furnace from a specific point of view. For instance, there is the rate of consumption of coke per ton of iron produced, which is probably the most frequently considered, and is certainly one of the most important of the group; there is the efficiency of recovery of iron charged; and there is the efficiency of utilization of energy, both chemical and thermal, in some respects related to the former two yet in other ways independent of either. In each of these cases, the calculation can be made on the basis of the actual input of material or energy, or it may be based upon a comparison with the minimum amount of material or energy that would be required by a "perfect" furnace; that is, an imaginary ideal furnace analogous to the perfect steam engine used in thermodynamic calculations, when this furnace is operating under optimum conditions. Moreover, the furnace itself can be considered either as an apparatus for smelting iron or, taking a somewhat less common point of view, as a gas producer yielding iron and slag as by-products. Some of these efficiencies are more useful than others, yet all are instructive; for a knowledge of them not only leads to good engineering practice from the standpoint of control but also discloses limits to possible improvement in performance and indicates the lines along which improvement is most likely to be profitable. Estimates of some of these efficiencies have appeared from time to time in the literature, but many of them are open to objection because they are based on data of uncertain accuracy or because they have been caleulated without due regard to the thermodynamic principles involved. Moreover, so far as the author is aware. no general survey of the blast furnace comparing its performance in all the aspects mentioned has been made.

Jan 1, 1938

By Arthur Taggart

Recent jig practice has shown such marked departures from the pronouncements of the textbooks, particularly as to particle size recovered and size range of feed, as to make it desirable to reexamine the mechanism of jig action. This paper presents the results of such a study. The general conclusions of the Paper are: I. A jig bed is a bi-functioned as well as bi-parted body. The upper layer comprises a plastic stream moving slowly in a substantially horizontal direction from feed lip to tail board. It serves to rough out tailing and light middling and to pick up heavy middling and lift it out 01 the jig box. The lower layer acts as the ultimate separating means by absorbing concentrate and rejecting heavy middling. 2. The separating function of the lower layer is performed in three definitely diflerent ways, depending upon the relative sizes of the grains presented to it and those composing it. Experimental The experimental work consisted of close and long-continued visual observations of operating beds in a plunger jig, eccentric driven, and in determinations of the settling rates of various metal spheres through a quartz bed under various conditions of operation. Falling velocities were measured by an ingenious method devised by A. 6. Dorenfeld, a student in the Mining Department at Colum- bia. Spheres of different metallic alloys, 3/8-in. diameter, were cast with a short piece of fine copper wire frozen in to Serve for suspension-A short piece of black cotton thread was looped to the top of the wire to serve as an indicator. The set-up for a test is shown in Fig. I. The thread should be boiled, if necessary, to make it freely water absorbent. The piece of clean plate glass D is supported rigidly at the proper height in a vertical position. The white scale E is similarly supported behind the glass. At the beginning of a test, D is filmed with water by holding it (best with clean rubber finger cots) under running tap water. It is then clamped in approximate position and C, already wet, is laid across it and drawn straight and vertical with the upper end at or near the top of D, and the ball A slightly above the top of the expanded bed. The water film holds the string to the glass. For a test the string is released, its upper end position noted just after the top of the ball becomes submerged, when the corresponding time is read, and thereafter simultaneous readings of position and time are taken as desired. Results of the visual studies of the bed are given at the pertinent places in the following discussion. Results of the settling tests are summarized in Figs- 2 and 3. Definitions The name bed as used herein refers to the entire mixture of solids and water filling the jig box. A layer is a stratum of a bed composed of particles of substantially the same specific gravities. A granular product is long-range when it approximates a crushed or ground product limited as to upper size only; a short-rafzge product is one closely sized. A bed is loaded when operating with continuous feed and discharge of products; it is unloaded when pulsating norma11y but neither being fed nor

Jan 1, 1943

By Arthur Taggart

Recent jig practice has shown such marked departures from the pronouncements of the textbooks, particularly as to particle size recovered and size range of feed, as to make it desirable to reexamine the mechanism of jig action. This paper presents the results of such a study. The general conclusions of the Paper are: I. A jig bed is a bi-functioned as well as bi-parted body. The upper layer comprises a plastic stream moving slowly in a substantially horizontal direction from feed lip to tail board. It serves to rough out tailing and light middling and to pick up heavy middling and lift it out 01 the jig box. The lower layer acts as the ultimate separating means by absorbing concentrate and rejecting heavy middling. 2. The separating function of the lower layer is performed in three definitely diflerent ways, depending upon the relative sizes of the grains presented to it and those composing it. Experimental The experimental work consisted of close and long-continued visual observations of operating beds in a plunger jig, eccentric driven, and in determinations of the settling rates of various metal spheres through a quartz bed under various conditions of operation. Falling velocities were measured by an ingenious method devised by A. 6. Dorenfeld, a student in the Mining Department at Colum- bia. Spheres of different metallic alloys, 3/8-in. diameter, were cast with a short piece of fine copper wire frozen in to Serve for suspension-A short piece of black cotton thread was looped to the top of the wire to serve as an indicator. The set-up for a test is shown in Fig. I. The thread should be boiled, if necessary, to make it freely water absorbent. The piece of clean plate glass D is supported rigidly at the proper height in a vertical position. The white scale E is similarly supported behind the glass. At the beginning of a test, D is filmed with water by holding it (best with clean rubber finger cots) under running tap water. It is then clamped in approximate position and C, already wet, is laid across it and drawn straight and vertical with the upper end at or near the top of D, and the ball A slightly above the top of the expanded bed. The water film holds the string to the glass. For a test the string is released, its upper end position noted just after the top of the ball becomes submerged, when the corresponding time is read, and thereafter simultaneous readings of position and time are taken as desired. Results of the visual studies of the bed are given at the pertinent places in the following discussion. Results of the settling tests are summarized in Figs- 2 and 3. Definitions The name bed as used herein refers to the entire mixture of solids and water filling the jig box. A layer is a stratum of a bed composed of particles of substantially the same specific gravities. A granular product is long-range when it approximates a crushed or ground product limited as to upper size only; a short-rafzge product is one closely sized. A bed is loaded when operating with continuous feed and discharge of products; it is unloaded when pulsating norma11y but neither being fed nor

Jan 1, 1943

By N. K. Chen, R. Maddin, R. B. Pond

A METHOD has been described by Andrade' for obtaining very rapid grain growth so that single crystals of high melting point metals could be made with comparative ease. The furnace construction was essentially a very thin wire through which was passed an electrical current so that "a high uniform temperature" was maintained. The wire was surrounded by a fused quartz tube from which the air had been evacuated. Andrade applied this method to the growth of single-crystal wires of alpha iron, and Tsien and Chow2 prepared single crystals of molybdenum 0.25 mm diam in this way. In the present report a method is described in which the basic idea of the Andrade furnace is utilized. However, modifications are employed so that large single crystals of molybdenum or of any refractory metals can be grown. Furnace The modified Andrade furnace is shown in Fig. 1, and the detailed drawing of its construction can be seen in Fig. 2. The furnace proper consists of a 2'/2-in. diam fused silica tube, 20 in. long, which is evacuated continuously at the bottom. Two water-cooled copper electrodes hold the specimen by means of collets held in place in the electrodes by set screws. These electrodes serve also to transmit power to the specimen. The lower electrodes can be clamped to the stand, while the upper electrode is fastened in place to the bellows which in turn is further connected to one side of the lever arm, flexibly supported at the top. After the specimen is mo;nted- and the vacuum is secured, the lever arm is adjusted by means of the counter weight so

Jan 1, 1952

By V. Patarini, M. Salkind

BECAUSE of its high strength and stiffness coupled with low density, continuous boron filament is showing great promise as a potential reinforcement for both metals and nonmetals. Of primary consideration for structural applications is the fatigue behavior of boron fiber composites. Composite fatigue behavior is dependent upon three factors: 1) fiber fatigue behavior, 2) matrix fatigue behavior, and 3) the effect of the interface and fiber ends. The purpose of this note is to describe the behavior of boron filament in rotating beam fatigue. The filament, described by Talley' and Galasso, Salkind, Kuehl, and Patarini,' was made by the hydrogen reduction of boron trichloride on a hot tungsten filament. Testing was performed using a commercial rotating beam wire fatigue tester* described by Votta.~ One end of the test sample is held in a chuck in a synchronous motor. The sample is bent around in a "U" shape, and the other end inserted into a carbide bushing. The maximum strain occurs at the bottom of the "U" where the radius of curvature is a minimum. The strain is adjusted by adjusting the length of the specimen and the location of the bushing. Samples were rotated at 3600 rpm and an automatic shutoff device used to determine the number of cycles to failure. The measurements were accurate to the nearest 360 cycles. The fatigue behavior is summarized in Fig. 1 for fifty-one samples of 4.8 x 10"3 in. diam fibers and ten samples of 3.2 X 10"3 in. diam fiber. The two sample groups represent two different filament production runs and two different nominal size groups. Both groups exhibited nominal tensile strengths of 400,000 psi. No significant difference in the fatigue behavior of the two sample groups is apparent. The scatter in the data is not unexpected for a brittle filament which exhibits a tensile strength distribution with a standard deviation of 10 to 15 pct. Because the test procedure provides a known outer fiber strain in the sample, the maximum stress was calculated assuming a Young's modulus of 58 x 10' psi. This value was selected as being representative of several nominal fiber sizes.2 All of the samples which failed exhibited sudden, catastrophic fracture, and no permanent deformation. One sample was stopped after 1.66 x lo8 cycles at *200,000 psi. The fiber exhibited no apparent damage or deformation. It is apparent that the fatigue resistance of boron filament is quite good. It can therefore be speculated that the fatigue behavior of boron fiber composites would be controlled by the "weaker links", namely matrix fatigue resistance and interface behavior. In fact, preliminary investigations have revealed that this is true for boron-reinforced aluminum? It should be noted that the data presented herein may not necessarily reflect the tensile fatigue behavior of boron filament. It is well-known that boron filament has a radial residual stress pattern with the outer surface in ~om~ression.~ Because of this fact, tensile failure is normally nucleated in the interior of the filament.5 Since the data presented herein is for a rotating beam test in which only the outer surface of the fiber is stressed to the maximum value, it would be incorrect to assume that the failure mechanism and fatigue behavior would be the same if the fiber were tested in tensile fatigue. The fact that many of the data are well above the nominal 400,000 psi tensile strength would tend to support this argument. The authors would like to express their appreciation to the United Aircraft Research Laboratories for supporting this investigation and for permission to publish the results. A portion of this effort was supported by the Air Force Materials Laboratory under contract AF33(615)-2125.

Jan 1, 1968

By H. Y. Bassett

THIS paper attempts to show the various major operations used in nonferrous tube mills and does not necessarily represent the current practices at the two plants of the Wolverine Tube Div., of Calumet and Hecla Consolidated Copper Co. Inc. The operations now utilized in the production of tubing are quite varied and show the continual interest and advance metallurgically and mechanically to produce the best quality at the lowest cost. Naturally, any advance or lowering of cost is dependent on large production runs, which mean longer machine running time with maximum worker productivity. Standardization of tube sizes and elimination of unnecessary alloys are therefore very necessary, otherwise the development of costly new production machines would be of little benefit to the consumer as a whole. It should be noted that in such a short presentation it is impossible to describe in any detail the major operations. The short descriptions, it is hoped, will enable all who are interested to obtain a general idea of present, day practices in the copper tube producing field. Fig. I is a flowchart or sequence of operations showing the steps usually employed in tube production. RAW MATERIALS Quality starts with the raw material, and it is absolutely necessary that raw material be controlled and held to rigid specifications. Little need be said, however, regarding the raw materials for the casting of bars or billets, as the material always is purchased and checked against the various governing A.S.T.M. specifications. CASTING Casting, as is indicated in Fig. I, is quite varied and for convenience can be classified into two groups: The casting of solid billets, and the casting of hollow tubes, each of which is the base for subsequent operations. In the melting of the raw materials various types of furnaces are used, and the selection of any one is dependent on many factors outside the scope of this paper. However, as of general interest, a short description will be made of each. Induction Furnace (Low Frequency) This is popular in the melting of copper-base alloys, Fig. 2. In the induction furnace the principle of an inefficient transformer is used for the production of the necessary melting heat. The primary coil is.arranged around a transformer core made of high permeability silicon steel sheet. The secondary circuit is through a melting channel around the primary coil and opens into a hearth which contains the main charge. The heat is generated only in the melting channel, but because of the stirring action there is a constant flow of metal around the channel, which when mixing with the charge causes very rapid melting. The volatilization losses are very low as the furnace atmosphere above the charge is heated only by the heat from the melting metal. The stirring action, however, makes the use of any slag cover difficult. Such furnaces- must be started with molten

Jan 1, 1951

By Morgan Walker

ONE of the most serious problems in the produc- tion of natural gas is the removal of water from the wells. As a gas well approaches its period of exhaustion, the removal of water by properly de-signed devices becomes increasingly important. Sev-eral methods are used for dewatering gas wells. If the .gas velocity and pressure are high enough, the water in the well will be carried out by the gas on opening the well to atmospheric pressure and allowing the gas to flow unrestricted except for the resistance of the casing. This method of dewatering a gas well is detri-mental to the producing sand, and very wasteful if used frequently. When the well has declined in production a string of tubing is often run in the well, with a packer set at the top or bottom of the well. If the top of the tubing is opened to atmospheric pressure and the gas is allowed to flow unrestricted as in the above method, the water can be discharged at the top of the well, provided the velocity of the gas is high enough. However, if the water has accumulated in the well until the water pres-sure is equal to or greater than the gas pressure, the ,water cannot be brought to the surface. In dewatering :a gas well by this method the operator sometimes finds -that if the packer is set near the top of the well and -the casing is tight, the water can be blown out when .it is impossible to blow it out with the packer set at the top of the sand. This is largely due to some gas leaking into the tubing through the collars. This method of dewatering gas wells is also wasteful. Water can be pumped out of a gas well with virtually the same equipment, as used for pumping oil, but the method involves installing a separate pump for each well, and difficulties are encountered in attempting to pump water under high gas pressure.

Jan 3, 1927

By D. Muraoka

Introduction Soda ash, anhydrous sodium carbonate, is produced from underground trona deposits occurring in the Green River Basin of southwestern Wyoming. Stauffer Chemical Co. of Wyoming, a jointly owned subsidiary of Stauffer Chemical Co. and Rocky Mountain Energy Co., mines the trona and processes it into high-purity soda ash. Stauffer Wyoming has been in operation since 1962 with a current production capacity of about 1.8 Mt (2 million st) per year of soda ash. The refinery has five parallel operating trains using the monohydrate process which is a series of chemical processing unit operations described below. Screening and Crushing The mined trona is brought to the surface in two counterbalancing ore skips. The ore is initially screened with refinery feed (less than peagravel size material) entering the process. Oversize is conveyed to an outdoor stockpile. Ore is recycled from under the stockpile via cone feeders as the refinery needs require. The ore is conveyed to hammer type crushers and screened. The refinery feed enters the process and the oversize is recycled to the crushers. Calcining The first step in refining trona to soda ash is calcining the trona ore. This is accomplished in concurrent flow, rotary kilns that are direct fired with natural gas. [2 (Na CO NaHCO 2H O) Heat 3Na CO + 5H20 + CO 2 3~3~ 2 ~~2 32] The trona ore is fed to the kiln at the burner end and is intimately mixed with the hot exhaust gases from the burner. Direct contact with the flame is avoided. The ore moves down the kiln by gravity and rotation aided by the kiln's internal lifters. The exhaust gases are cleaned to 99 + % particulate removal and discharged to the atmosphere. Dissolving the Calcined Trona The calcined trona is conveyed from the kiln discharge to a rotary drum dissolver where it is mixed with water and weak solution (unsaturated solution of calcined trona in water). The calcined trona is soluble whereas the impurities, primarily shale, are insoluble. The discharge from the dissolver is a slurry containing saturated solution (about 30% dissolved calcined trona in water), some undissolved calcined trona, insoluble impurities, and organic impurities. The dissolver discharge enters a rake classifier that makes the first solid/liquid separation in the process by removing the heavy undissolved material from the saturated solution. This undissolved material is conveyed to a second rotary drum dissolver and mixed with water to dissolve any remaining calcined trona. The secondary dissolver discharges to a second rake classifier that separates the solids from the liquid. The solids are now primarily insoluble impurities with very little unrecovered calcined trona. These wastes are conveyed to evaporation ponds for disposal. The liquid from the secondary rake is recycled to the primary dissolvers' weak solution system. Returning to the primary rake classifier, the saturated solution which contains suspended insoluble muds is pumped to a thickener. Flocculant is added to aid settling of the suspended muds. The flocculated muds are collected at the bottom of the thickener and pumped to vacuum cloth filters. The adhering saturated solution is separated from the muds that remain on the filter cloth. The recovered solution is returned to the dissolvers' weak solution system. The muds are reslurried and pumped to the evaporation ponds for disposal. Saturated solution, containing some suspended insoluble muds along with the organic impurities, overflows the thickener. Filtering the Saturated Solution The saturated solution overflowing the thickener enters a holding tank where it is pumped to a bank of pressure leaf filters. The suspended muds are captured on the filter leaves while the cleaned saturated solution is pumped to polishing filters. The polishing filters are also leaf pressure type, intended to remove any suspended solids that may pass the primary filters. Organic impurities are removed with activated carbon. The purified solution is now free of insoluble muds and has most of the organic impurities removed. Crystallizing and Drying the Monohydrate The purified saturated solution is pumped to evaporative crystallizers. The solution is circulated from the crystallizer vessel through a heat exchanger. Indirect contact with steam in the heat exchanger causes the saturated solution to boil, thus crystallizing the soda ash in its monohydrate form. Slurry crystal density is maintained in the crystallizer by simulta¬neous feed of fresh saturated solution and drawoff of the slurry.

Jan 1, 1986

By Hermsdorf, Richard P. E.

AMONG the newer lead smelting and refining plants of the country is that of the United States Metals Refining Co., at Carteret, N. J. Not only is the technical practice here modern and efficient, but exceptional care is taken to assure healthful operating conditions for the employees. One large building houses the entire department, which includes, as its chief units, one reverberatory smelting furnace, one blast furnace, two softening furnaces, one utility reverberatory furnace, two Faber du Faur retorts, five 120-ton kettles, three 60-ton antimouial lead kettles, and one 5-ton kettle for experimental purposes. There is a 10-ton overhead crane in the kettle aisle, which is also used for shipping lead. Other auxiliary equipment is referred to in the outline of operations. A general plan of the plant is shown in Fig. 2, and a general view in Fig. 1. Primary smelting operations are conducted in a 30 by 11-ft. reverberatory furnace with bottom, roof, and upper walls of clay brick, magnesite

Jan 1, 1934

By E. Robert Ruhlman

The term potash refers to potassium oxide (K2O), a compound not found in nature or produced by man but used as a basis for comparison of all potassium compounds and now is applied generally to various compounds of potassium used by agriculture and industry. Potassium, the last of the three major plant foods to be used in appreciable quantities by agriculture, was originally produced only from organic materials for chemical uses. The first recorded identification of a mineral source of potassium was in 1797; but, until the discovery in 1839 of the large deposits of soluble potassium salts in Germany and their development in 1860-61, nearly all potassium compounds continued to come from organic sources. With the importance of potash to plant life discovered in 1840 by von Liebig and the production of potash in Germany after 1861, agriculture soon became the major consumer of potash. In 1958 agriculture accounted for about 95 pct of the total potash consumption; the chemical industry used the remaining 5 pct. Mineralogy and Geology Potassium, an important constituent of the earth's crust, occurs in many forms in numerous rocks and minerals, including water solutions, but is not found in its native state. Twenty-five of the more important potash minerals are listed in Table 1. The properties of the five potash minerals most common in Permian salt formations follow: Sylvite is isometric; has a hardness of 2, a specific gravity of 1.98, vitreous luster, and cubic cleavage; and ranges in color from clear to brick red. In taste it is similar to halite but has a sharper taste and a cooling effect on the tongue. It is very plastic under pressure. Langbeinite is isometric; has a hardness of 4, a specific gravity of 2.82, vitreous luster, conchoidal fracture, and no cleavage; and ranges in color from clear to gray. It is taste- [ ] less, somewhat granular, and slowly soluble in water. Polyhalite is triclinic; has a hardness of 3, a specific gravity of 2.77, and dull luster; and

Jan 1, 1960

By Charles Mabery

So FAR as the elementary composition of petroleum is -known, it may be briefly stated. Petroleum consists principally of a few series of hydrocarbons, with admixtures of sulfur, nitrogen, and oxygen derivatives in comparatively minute proportions, which may be regarded as impurities to be removed in the preparation Of commercial products. But as each series is represented by many homologs, in the aggregate, crude petroleum is an extremely complex mixture of hydrocarbons and their derivatives. In part, these hydrocarbons individually conform in structure to the system of synthetic hydrocarbons whose structure is well defined and -represented by the typical series CnH2n+2, CnH2n, the series CnH2n-2, CnH2n-4, the members of which have not been sufficiently studied to establish their structure, and the series CnH2n-6 composed of the aromatic group, benzene and its homologs. Hydrocarbons of greater density contained in the portions of petroleum that cannot be distilled without decomposition doubtless have less hydrogen than is represented by these formulas. Since to every hydrocarbon there is a definite temperature, even in vacuum, at which its constituent carbon and hydrogen atoms fall apart, and since for the heavier bodies this temperature is not much above 360° C. in vacuum, it is evident that some other method than distillation must be devised for their separation if anything further is to be learned concerning their individual constitution. CLASSIFICATION OF PETROLEUMS There is such a wide variation in the composition of petroleum from different fields, it would seem possible to make a classification on this basis were it not that no single variety is entirely free from hydrocarbons contained in others. Such a classification has been suggested of the exceptionally pure Pennsylvania petroleum, the sulfur oil from Trenton

Jan 2, 1920

By Charles E. Johnston

By substituting photoelectric automatic car loading for mechanically induced hydraulic automatic loading and by protecting the process against operational failures, the engineering staff at International Minerals & Chemical Corp.'s Carlsbad potash mine has developed a reliable loading process that operates without an attendant. The photoelectric control, developed primarily because of frequent failures in the hydraulic control system, has not changed the basic loading operation and physical layout. Mine-run ore ranging in size from minus 200 mesh to 30-in. lumps is dumped onto a conveyor belt which discharges into a so-called "flop gate chute" which in turn, feeds the ore into six-ton capacity mine cars. Each car is filled progressively by moving the entire trip forward. When a car is filled 12 in. above its rim, the direction of flow into the car is reversed 180º and filling of the next car back is begun while the entire trip is moved forward again. Once the next car is properly spotted under the front chute, the flow is again directed to the forward position.

Jan 9, 1962

By R. G. Davies, P. Beardmore, T. L. Johnston

The flow stress of a series of Ni-Cr-A1 alloys consisting of a dispersion of y' (based on Ni3Al) in a rnatrix of nickel-base solid solution y has been measured at temperatures up to 950°C as a fwzction of the volume fraction of y'. At high temperatures the flow stress is controlled by the amount of Y' in the alloy, i.e., the higher the volume fraction of y', the greater is the flow stress. This simple relationship is not obeyed at low temperatures in so far as a peak in the flow stress-volume fraction relation occurs at about 25 pct y'. The variation in the mechanical properlies of these alloys as a function of both temperature and volume fraction of y' has been correlated with changes in distribution of both the dislocations and y'. The results are interpreted on the basis that at low temperatures the y matrix is strengthened significantly bv the presence of a hyperfine y' precipitate due to decomposition on cooling; at high temperatures the y matrix is a single phase of low strength. It is clearly recognized that the high temperature strength of most nickel-base superalloys depends upon a dispersion of the ordered fcc phase y', based on Ni3A1, in a fcc solid solution matrix y based on nickel. Although the volume fraction of y' varies widely from about 0.2 in Nimonic 80A to about 0.6 in Mar-M200, all such nickel-base alloys manifest an unusual insensi-tivity of the flow stress with respect to temperature. In Mar-M200 for example, the 0.2 pct flow stress remains essentially constant from room temperature to 750°C. The conclusion has been drawn1 that the characteristically low temperature dependence of the flow stress of y-y' nickel-base alloys is obtained when the state of dispersion of y' is such that dislocations are forced to cut through the y' particles at the onset of yielding. When the spacing between the y' particles is so large that the flow stress is controlled by dislocation bowing between particles, then the initial flow stress decreases progressively with an increase in temperature at a rate determined by changes in elastic properties. The same conclusion is inherent in the detailed, mechanistic model of the deformation process in commercial superalloys which has been developed by Copley and ear' in which the temperature independent flow stress is attributed primarily to the contribution of the antiphase boundary energy created in the y' particles during deformation. In this theory the temperature insensitivity of the flow stress is a reflection of the constant antiphase boundary energy as a function of temperature. An important microstructural parameter that is relevant to the explanations that have been suggested' to account for the temperature insensitivity of the flow stress is the volume fraction of y'. To vary the latter to any significant extent in a given commercial alloy is clearly difficult. However, it is possible in a relatively simple Ni-Al-Cr ternary system which manifests analogous microstructures in terms of the distribution of y' in y and contains specific alloys which have flow properties that depend on temperature in a manner quite similar to their more complex commercial counterparts. Hornbogen et . have studied precipitation phenomena and deformation mechanisms in such alloys but only where the y' volume fraction was small (less than 0.2) and the y' particle size varied from less than 100A up to a maximum of -1000A. In the present study, a series of alloys was prepared in which the volume percent of y' at 900°C was varied from 0 to 100 pct with the y' particle size (of the order 0.5 p) comparable to the sizes obtained in commercial superalloys. Particular attention has been given to the relationship between variations in the volume fraction and distribution of y' and the temperature dependence of the flow stress EXPERIMENTAL TECHNIQUES The Ni-Cr-Al system was selected because it is well characterized, bears a close relationship to commercial alloys, and offers the advantage of an extra degree of freedom over a binary system. In the present investigation, a series of alloys across the tie line between NisA1 and Ni3Cr (Ni3Cr is not an in-termetallic compound, the nomenclature is only used to designate the composition) were vacuum cast. The pseudobinary6 and the composition of the alloys used are shown in Fig. 1. It is important to note that the compositions of the y phase and the y' phase in the two-phase alloys was always the same. Alloy compositions were selected from the binary diagram, Fig. 1, in order that aging at 900°C would produce from 0 (100 pct y) to 100 pct y' by volume percent. (The size of the y' particles produced during the equilibrium aging treatment increased as the volume fraction of y' increased, ranging from about 0.2 p at low volume fractions up to about 0.8 p at the highest volume fraction.) The y' phase is based on the inter-metallic compound Ni,A1 which has the fcc LIZ type superlattice structure, and chromium substitutes for aluminum in the structure. The y phase is a disordered fcc solid solution. The alloys were heat treated at 1150°C for 2 hr, air cooled to room temperature, and finally annealed for 16 hr at 900°C. The rods were then centerless ground to 0.25 in. diam and cut into compression samples 0.5 in. long. The compression tests were made on an In-stron machine at a strain rate of 7 x 10"4 sec-'. A rapid heating radiant heat furnace was used which minimized the heating and temperature stabilization time to 10 min for the highest testing temperature. All the tests were stopped after 5 pct plastic strain.

Jan 1, 1970

By B. H. Caudle, L. H. Silberberg

Reservoir depletion by natural water drive is typified by the movement of water from an aquifer into the adjacent oil-bearing formation. Prior studies of this type 01 water movement have generally neglected the resistance to flow in the aquifer and its effect on the movement of water into the oil bearing zone. A method for designing and operating scaled models of such reservoir systems is presented. Experimental data on a model of an edge-water-drive reservoir are shown and discussed. INTRODUCTION Most petroleum reservoirs derive at least a part of their productive capacity from water influx. This water may be injected from the surface or it may come from an aquifer adjacent to the oil zone. In either case, the reservoir engineer must be able to estimate the advance of the water as a function of either the elapsed time or the fluid produced. This paper describes a type of fluid flow model which includes the effect of viscous and gravitational forces in the reservoir and the surrounding aquifer. Natural water influx can be divided into three general (but widely overlapping) categories according to the direction of flow in the aquifer. These are shown schematically in Fig. 1. Fig. l(a) illustrates an edge-water-drive mechanism. In this case, water advances updip along the stratum but the movement of water is essentially horizontal and very little of the oil is actually underlain by water. The bottom-water drive (Fig. l(b)) is characterized by a thick aquifer underlying the oil zone. The water movement is generally vertical in the aquifer. The third category is illustrated in l(c). Referred to as the "thin oil column", this type of oil accumulation consists of oil over water in a relatively thin stratum. Fluid movement is horizontal in both the oil and water zones, except close to the producing well. One characteristic which all three of these types have in common is that part of the water flow takes place in the water invaded region of the oil reservoir while the remainder of the water flow occurs in the aquifer. The resistance to the flow of water usually will not be the same in these two regions. This occurs because the porous rock normally contains only water in the aquifer, while the water-invaded region always contains microscopic globules of bypassed oil (residual oil) which interfere with the flow of water through the rock. The production history of any type of a water-drive system is a function of two phenomena — where the water goes, and how it displaces the oil in the area invaded by the water. It is usually impractical to study these two phenomena at the same time. In most cases one type of analysis is used to predict the gross movement of water in the reservoir, while a different type of analysis is employed to determine the amount of oil to be recovered from the gross volume contacted by the water. The portion of the oil reservoir which is invaded by water is mainly a function of the resistances to fluid flow in the several parts of the flow system. This gross water influx in the three types of natural water drive typically results in water cusping to the production wells either from the side or from below (water coning). In 1747, Muskat described a greatly simplified mathematical model for predicting the area invaded by water in a bottom-water-drive reservoir.1 This model used the Laplace equation and suitable boundary conditions to describe the isopotentials and streamlines in the flow system. The use of this model assumes that (1) the reservoir rock is homogeneous in nature, (2) the oil and water mobilities are equal, (3) there is no oil flowing in the water invaded region, and (4) external forces — such as gravity — do not affect the flow. This method has been used for both natural water drives and water injection projects. In this, as in most models, the method of images is used to reduce the size of the model necessary to describe the reservoir. The assumption of equal viscosities and permea-

Jan 1, 1966