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By R. L. Boyer, F. Morgan, M. Muskat

In the last several years a type of application of the fundamental permeability-saturation relationships has been developed which offers great promise in the interpretation of general reservoir performance.l-' In these developments no attempt is made to solve the detailed flow dynamics in actual oil and gas-producing systems. That problem still remains unsolved. But the permeability-saturation phenomena are incorporated in the analysis of oil-producing reservoirs in a manner such as to reflect the true role they play in controlling the gross reservoir behavior. In particular, they are introduced in such a manner as to determine the gas-oil ratio of the production at any stage of depletion, and, when combined explicitly with the so-called material-balance principles in differential form, one can obtain a differential equation describing completely the average pressure and gas-oil-ratio history of oil-producing reservoirs. While thus far they have been applied directly only to gas-drive reservoirs, they are susceptible of extension to partial water-drive systems, and qualitatively the same principles are of value in the study Of complete water-drive reservoirs. Moreover, in addition to giving a means for computing the variation of the reservoir pressure and gas-oil ratios vs. the cumulative production, they automatically lead to predictions of the gross ultimate recovery under natural depletion—and when properly extended they provide means for predicting the ultimate recovery under gas or water injection. The data required for such applications are the initial fluid distribution in the producing section, the pressure-volume-temperature data on the gas and liquid phases, and the permeability-saturation relationship for the oil-satuiated zone. The former can be obtained with reasonable accuracy by methods that are well established and available throughout the industry. The permeability-saturation data, however, involve techniques that are not at all standardized. In fact, only

Jan 1, 1947

By M. Muskat, R. L. Boyer, F. Morgan

In the last several years a type of application of the fundamental permeability-saturation relationships has been developed which offers great promise in the interpretation of general reservoir performance.l-' In these developments no attempt is made to solve the detailed flow dynamics in actual oil and gas-producing systems. That problem still remains unsolved. But the permeability-saturation phenomena are incorporated in the analysis of oil-producing reservoirs in a manner such as to reflect the true role they play in controlling the gross reservoir behavior. In particular, they are introduced in such a manner as to determine the gas-oil ratio of the production at any stage of depletion, and, when combined explicitly with the so-called material-balance principles in differential form, one can obtain a differential equation describing completely the average pressure and gas-oil-ratio history of oil-producing reservoirs. While thus far they have been applied directly only to gas-drive reservoirs, they are susceptible of extension to partial water-drive systems, and qualitatively the same principles are of value in the study Of complete water-drive reservoirs. Moreover, in addition to giving a means for computing the variation of the reservoir pressure and gas-oil ratios vs. the cumulative production, they automatically lead to predictions of the gross ultimate recovery under natural depletion—and when properly extended they provide means for predicting the ultimate recovery under gas or water injection. The data required for such applications are the initial fluid distribution in the producing section, the pressure-volume-temperature data on the gas and liquid phases, and the permeability-saturation relationship for the oil-satuiated zone. The former can be obtained with reasonable accuracy by methods that are well established and available throughout the industry. The permeability-saturation data, however, involve techniques that are not at all standardized. In fact, only

Jan 1, 1947

By H. H. Campbell

Many attempts have been made to write a formula by which to calculate the strength of steel from its chemical composition, but most of these endeavors have failed because there were too many disturbing conditions. It is idle to collect from the pages of trade-papers, books, or the proceedings of scientific societies, a multitude of observations. The combination of such results will simply show that steel of the same composition will vary in tensile strength through wide limits—a fact that has been known for generations. That cold-working, overheating, and many another form of heat-treatment alter fundamentally the strength of steel, is ancient history, although it is only recently that the microscope has pointed out the road to an explanation of the phenomena. It mag be urged that the microscopic structure must betaken into consideration in any formula giving the ultimate strength, but from the standpoint of the present investigation this is unnecessary. We are trying to determine primarily, not what changes in ultimate strength may be made by variations in the condition of carbon, but what effect is produced by changes in the amount of carbon, when its condition remains constant. For such an inquiry, in order that the condition of the carbon should remain as nearly uniform as possible, it is essential that all testrpieces be made under the same conditions; and it is believed that the tests described in this paper satisfy that requirement. The investigations were made at the works of the Pennsylvania Steel Company, Steelton, Pa.; the ingots from which the tests were made were 6 in. square in every case; they were heated in the same furnace and forged at the same ham-

Jan 1, 1905

By John M. Loveioy

EVERY producer of crude oil knows what is meant by the Rule or Law of Capture. It means that the ultimate ownership of a migratory substance such as oil is not determined until that substance is reduced to physical possession. Unless, therefore, the producer moves quickly to capture his share from the common pool, he may lose to any neighbor who is drilling and producing more rapidly than he a portion of the oil originally underlying his property. And there is no recourse open to him if his property is so drained. Under this rule it is obvious that the owner of an oil property, if he is to protect his' ownership, must be governed in his development and production policies by the activities of his neighbor rather than by his own business requirements. He must drill as densely and as fast as the other operators in the field or lose part of the oil to which he should be entitled.

Jan 1, 1936

By R. D. Carnahan

The authors are to be complimented on their timely study of solution-hardening effects in a bcc metal. Unfortunately there are some misleading aspects of the paper that should be discussed and clarified which is the purpose of this letter. In particular the writer is concerned about the allusions to rate theory of deformation that are inferred by the authors. This position is taken on the basis first of the "weaker" temperature dependence of the yield and flow stresses of the alloy relative to pure niobium and second of the strong temperature dependence of the Young's modulus of elasticity. It is by now well-recognized that any collection of data points used to determine a flow-stress temperature-dependence relationship must be established under isostructural conditions, i.e., similar or identical sessile and mobile dislocation densities and arrangements. Admittedly this is a formidable experimental undertaking and not what would be expected in an exploratory investigation of the present kind. As an alternative to the former one can consider, however, the temperature dependence of flow stresses at comparable strains. In the present study the authors have elected to use the lower yield stress and ultimate strengths to exhibit the temperature dependence of their alloys except for the data points taken at liquid nitrogen temperature. Here they have used the proportional limit for the yield stress and the fracture stress for the ultimate strength. This seems to be an unrealistic choice particularly in view of the fact that this temperature is below the duc tile-brittle transition region for the alloy and no supporting data points were obtained between -55" and -196°C. If the authors' data in Fig. 2 are extrapolated and data points selected at a constant strain, for example a strain of 0.01, the reader can quickly verify that a temperature dependence exactly paralleling that of pure niobium is obtained.

Jan 1, 1967

By James F. Kemp

Jan 1, 1914

By G. S. Rice

IT is evident from Professor Louis' remarks that he holds a different opinion on certain phenomena connected with a specific type of surface subsidence from mining than is held by many engineers in the United States. The question which appears to be at issue is whether or not the line or plane of "draw" produced in ground movement resulting from extraction of pillars may, under certain conditions, be vertical or even inclined toward the workings rather than inclined for- ward over the unworked mineral, as it is universally agreed occurs in mining by the longwall advancing method. In discussing this case it is well to take the simplest condition, such as specified by Professor Louis, of a flat bed, whether it be coal, iron or other mineral, where the overburden is stratified rock and where there is no overlying quicksand. Professor Louis says in effect that his experience is that the ultimate angle of draw is always positive and inclined 5" to 15" from the perpendicular over the unwrought mineral. My experience under Illinois coal-mining conditions is that .'where longwall advancing is used the draw is always positive as Professor Louis describes it, but that in extracting of panels by withdrawal of pillars, the ground movement is manifested, after the first roof' beam break, by the forming of an unstable dome over the goave. Then subsequently, by the falling of individual slabs from the under side, the dome gets larger and higher until it breaks through to the surface of the rock., Up to this time, arch stresses buttress the rocks above the solid coal or mineral. When, however, after. the dome breaks through and the central hole - #enlarges so the arch is no longer sufficiently supported -the stratified rocks cantilever out .from over the solid unworked mineral and tend to break off in masses triangular in vertical cross-section, until the broken loose material, sliding down against the solid rock, .has such a thrust that it balances the tendency ,for the solid stratified rock to break away and slide toward the excavation.

Jan 1, 1929

By J. R. McWilliams

Several of the current concepts of brittle fracture involve consideration of the existence of defects or flaws. Griffith 1 observed that the tensile strength of brittle materials was several orders of magnitude less than might be expected from the calculated strength of the molecular bonds. He was able to show that the stress concentration at the tip of an elliptical crack is sufficient to raise the local stress level many fold. He therefore proposed that real materials do contain such stress risers in the form of minute cracks and that this accounts for the rather large difference between theoretical and actual strengths of brittle materials. The degree of stress magnification depends to a great extent upon the orientation of the crack with respect to the general stress system, and to the general geometry of the crack.

Jan 1, 1967

The volumes of Transactions, which are published annually, contain the list of officers, rules, etc., the Proceedings, and the papers revised for final publication. (In this revision, after the preliminary publication, authors are permitted to use the largest liberty; and the changes and additions made in papers are sometimes important. It should be borne in mind by those who study or quote a paper in the preliminary edition, that they may not have in that form the ultimate and deliberate expression of the author's views. It should be added, however, that in the majority of cases there are no important changes.) These volumes are for sale as follows, in paper covers:

Jan 1, 1910

The volumes of Transactions, which are published annually, contain the list of officers, rules, etc., the Proceedings, and the papers revised for final publication. (In this revision, after the preliminary publication, authors are permitted to use the largest liberty; and the changes and additions made in papers are sometimes important. It should be borne in mind by those who study or quote a paper in the preliminary edition, that they may not have in that form the ultimate and deliberate expression of the author's views. It should be added, however, that in the majority of cases there are no important changes.) These volumes are for sale as follows, in paper covers:

Jan 1, 1917

The volumes of Transactions, which are published annually, contain the list of officers, rules, etc., the Proceedings, and the papers revised for final publication. (In this revision, after the preliminary publication, authors are permitted to use the largest liberty; and the changes and additions made in papers are sometimes important. It should be borne in mind by those who study or quote a paper in the preliminary edition, that they may not have in that form the ultimate and deliberate expression of the author's views. It should be added, however, that in the majority of cases there are no important changes.) These volumes are for sale as follows, in paper covers:

Jan 1, 1910

The volumes of Transactions, which are published annually, contain the list of officers, rules, etc., the Proceedings, and the papers revised for final publication. (In this revision, after the preliminary publication, authors are permitted to use the largest liberty; and the changes and additions made in papers are sometimes important. It should be borne in mind by those who study or quote a paper in the preliminary edition, that they may not have in that form the ultimate and deliberate expression of the author's views. It should be added, however, that in the majority of cases there are no important changes.) These volumes are for sale as follows, in paper covers:

Jan 1, 1910

The volumes of Transactions, which are published annually, contain the list of officers, rules, etc., the Proceedings, and the papers revised for final publication. (In this revision, after the preliminary publication, authors are permitted to use the largest liberty; and the changes and additions made in papers are sometimes important. It should be borne in mind by those who study or quote a paper in the preliminary edition, that they may not have in that form the ultimate and deliberate expression of the author's views. It should be added, however, that in the majority of cases there are no important changes.) These volumes are for sale as follows, in paper covers:

Jan 1, 1917

The volumes of Transactions, which are published annually, contain the list of officers, rules, etc., the Proceedings, and the papers revised for final publication. (In this revision, after the preliminary publication, authors are permitted to use the largest liberty; and the changes and additions made in papers are sometimes important. It should be borne in mind by those who study or quote a paper in the preliminary edition, that they may not have in that form the ultimate and deliberate expression of the author's views. It should be added, however, that in the majority of cases there are no important changes.) These volumes are for sale as follows, in paper covers:

Jan 1, 1910

The volumes of Transactions, which are published annually, contain the list of officers, rules, etc., the Proceedings, and the papers revised for final publication. (In this revision, after the preliminary publication, authors are permitted to use the largest liberty; and the changes and additions made in papers are sometimes important. It should be borne in mind by those who study or quote a paper in the preliminary edition, that they may not have in that form the ultimate and deliberate expression of the author's views. It should be added, however, that in the majority of cases there are no important changes.) These volumes are for sale as follows, in paper covers:

Jan 1, 1917

The volumes of Transactions, which are published annually, contain the list of officers, rules, etc., the Proceedings, and the papers revised for final publication. (In this revision, after the preliminary publication, authors are permitted to use the largest liberty; and the changes and additions made in papers are sometimes important. It should be borne in mind by those who study or quote a paper in the preliminary edition, that they may not have in that form the ultimate and deliberate expression of the author's views. It should be added, however, that in the majority of cases there are no important changes.) These volumes are for sale as follows, in paper covers:

Jan 1, 1917

By J. E. Lawver, W. D. Carrier

During the past 20 years, millions of dollars in research effort have been spent to improve methods of phosphate clay dewatering and disposal. Although to date no proven large-scale system has been developed that will result in ultimate below ground storage without the use of at least temporary dams, considerable progress has been made and a variety of techniques are being tested, some on a large scale. This paper summarizes the use of mathematical and centrifuge (physical) models that can analyze and evaluate various systems for the consolidation of phosphatic clays. These provide a powerful tool for engineers responsible for land management and mining waste disposal.

Jan 1, 1985

By R. B. Tippin

Laboratory and pilot plant studies showed that supergrade iron ore concentrates (containing less than 2% SiO2) can be made from standard grade magnetic iron ore products by cationic silica flotation. Continuous tests were run using various flowsheet arrangements. whereby (1) super and standard grade products were made simultaneously or (2) only a superconcentrate was produced. After a caustic scrub and desliming pretreatment, the silica in a magnetic taconite concentrate was reduced to 1.8% SiO2 by amine flotation. Approximately 75% of the iron was recovered in the single flotation stage, and by additional beneficiation 95% of the total iron was ultimately recovered,

Jan 1, 1973

By A. P. Young, L. I. Marsh

HE relationship between microstructure and *- fracture is of interest in many metals and alloys. This relationship is sometimes established by examining the fracture surfaces and the flat surfaces near the fracture path in tensile samples. However, it is often difficult to tell from examining the fractured sample whether the fracture is intergranular, intra-granular, or a mixture of both. Also, it is often of interest to follow the progress of slip, twinning, or crack formation along the fracture path before fracture occurs. The ambiguity concerning the type of fracture generally can be resolved if the area along the path of ultimate fracture can be photographed at inter-

Jan 1, 1959

By M. S. Enders, L. M. Rogers

The Little Rocky Mountains host epithermal gold-silver bearing vein and stockwork deposits in a syenite intrusive complex. Pegasus Gold Ltd. is currently mining these oxidized deposits by open-pit methods and recovering gold and silver by heap-leach processes. A geologic program has been designed to effectively determine the basic ore characteristics; 1) mineralization; 2) oxidation; 3) structural setting; 4) lithology; 5) alteration; and ultimately, 6) the leachability of the ore. Geologic mapping, sampling, drilling, assaying, and testing are routinely used in exploration, development, production control, mine planning, and ore reserve estimations. Timely and accurate assay results are essential for the program's success.

Jan 1, 1984