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By C. R. Johnson, R. A. Greenkorn, E. G. Woods

A new method of reservoir evaluation called pulse-testins has been developed for describing formation properties between wells. Pulse-testing utilizes a sensitive differential-pressure gauge at a responding well to measure and record the response generated by a series of flow rate changes (pulses) at an adjacent or pulsing well. Since the pulse-test instruments have a sensitivity of about 0.001 psi, pulses of several hours or less in duration will generate a measurable response in most reservoirs. For this reason, many well pairs can be tested in a short period of time with little interference in field operations. Comparison of pulse-test results to conventional testing methods shows that the pulses obey unsteady-state, compressible-flow theory and thus provide a measure of both transmissibility (kh/µ) and storage (Fch). In additian, the method can be used qualitatively to describe communication across faults and between zones, and direction and tnagnitude of fracture trends. INTRODUCTION To obtain maximum usefulness of new reservoir analysis methods as well as to aid the field engineer in understanding local reservoir anomalies, improved methods are needed to describe heterogeneities in specific reservoirs. Optimum well spacing, equipment specifications, well completion design and especially the economics of pressure maintenance and secondary recovery programs depend on the extent and location of the heterogeneities that affect flow behavior in the field. One method for obtaining a measure of areal reservoir heterogeneity is an interference test. In the simplest interference test. constant-rate production or injection is initiated at one well and the effect of this flow is measured as pressure vs time at another well. Thus, during interference tests the flow characteristics of the formation are determined in situ. Despite their obvious usefulness in reservoir delineation. interference tests have not enjoyed frequent usage. Reasons for this have been the weeks or months required in many fields to obtain a pressure response measurable with conventional gauges, and the interruption of routine field operation during the field-wide shut-in normally required during these long times. Also, only average properties of the relatively large volume of the reservoir disturbed during these long times can normally be obtained — variations in properties between individual wells cannot be delineated. To eliminate these drawbacks of conventional tests, a special reservoir description technique called pulse testing' has been developed. Pulse-testing has several advantages that make it more convenient and practical for field use than interference tests. Valid tests are more certain because use of a series of flow disturbances gives rise to a diagnostic pressure response that can more readily be distinguished from unknown trends in reservoir pressure and other "noise." The time required is only a fraction of that for an interference test because a special, high-sensitivity differential pressure gauge can detect a much smaller pressure change. Variations in properties between individual wells can be delineated because of the relatively small volume of the reservoir disturbed during these short times. Finally, wells other than the pulsing and responding wells do not have to be shut in or carefully regulated.

Jan 1, 1967

By C. D. Michaelson

The memory of D. C. Jackling serves chiefly to remind us how much we owe to the pioneers of our industry. Jackling was one of the giants. Orphaned at the age of two, he made his way through sheer persistence and plain hard work. His brilliance gave rise to a vision, and his tenacity made his vision a reality. Foreseeing that economies of scale would make the handling of low-grade ore profitable, he introduced the revolutionary concept of open-pit copper mining. During World War I, the defense effort of the United States was immeasurably strengthened by the tremendous supplies of copper from the western mines that Jackling had made possible. Again in World War II, the demands for copper were supplied, and the nation once more had profound reason to be grateful to this rugged, stubborn man who had long ago ventured into the mountains and unlocked their wealth. We are now embarked upon another great era of change, and we must devise new concepts to meet it. The task is not only to create new techniques of mining, but to forge better ties between men and institutions which will let us work in harmony with the techniques we have. We might recall that while Jackling was a man of towering pride and formidable will, he was also adept at getting others to share his vision and join his purpose. Today our reach for cooperative endeavor must go far beyond our own shores as we seek to develop the buried riches of distant lands. And we would do well to remember that Jackling's remarkable insight would have come to nothing had not British investors been willing to provide much of the initial capital. As was true of so many early enterprises in America, European capital was absolutely essential.

Jan 4, 1969

For $100 a month plus expenses, Thomas A. Edison in 1879 hired a colorful adventurer named Frank McLaughlin to go west as a prospector. A few months later, McLaughlin triumphantly returned to the inventor's laboratory in Menlo Park, N. J. "On his shirt bosom and fingers sparkled glittering stones," recalled one of Edison's associates. These were only the tangible parts of his new trappings. In addition, McLaughlin "now wore the title of major which he acquired somewhere west of Omaha."

Jan 10, 1961

By Lester C. Uren

Tars paper reviews the industrial trends and changes in educational concepts that have led to the development of the modern petroleum engineering curriculum. A trend toward emphasis on engineering fundamentals is noted. While most universities are committed to the traditional four-year engineering program, it is agreed that more than four years is necessary for academic preparation of the petroleum engineer in all phases of his profession. The author proposes a coordinated program of undergraduate and graduate training that will permit of adherence to the general pattern of the present four-year engineering course, with provision for extension of the program into specialized graduate courses of professional character. In the latter, emphasis may vary with the interests and objectives of the individual student. A specific undergraduate curriculum is proposed in which upward of 80 per cent of the available time is devoted to engineering fundamentals. A broad survey of the professional field is afforded in courses grouped in the third and fourth undergraduate years, but detailed treatment of the professional aspects of petroleum engineering is reserved for the graduate program. INTRODUCTION Of necessity, engineering curricula must ever be changing to reflect the new techniques, the changing concepts that are presented as the engineering industries develop and unfold. Particularly is this true of the younger engineering curricula representing comparatively new and rapidly changing industries such as the petroleum industry. Institutions that planned their petroleum engineering curricula a decade or two ago now find that the petroleum industry has become vastly more technical in its requirements. En¬tirely new methods and techniques have come into vogue and must be given place in the curriculum, and some of these are of a character that demands changing emphasis in the fundamental preparatory subjects. College and university faculties cannot complacently assume that curricula in this field that were considered appropriate 10 or 20 years ago still reflect the needs of the industry that they are designed to serve. If they do, their graduates will be poorly equipped to meet the requirements imposed upon them by a rapidly changing industry. Perhaps it is not too much to expect academic authorities to anticipate the trends of industry and equip their graduates with what they will need to attain leadership 10 or 20 years after graduation. Whether or not this desirable objective is possible, there is no excuse for allowing curricula to fall behind the current needs of industry. DURATION OF CURRICULUM The majority of our engineering schools and colleges still adhere to the four-year curricula and there appears to be a definite sentiment among many engineers engaged in industry that work should be so planned that the engineering student may secure the essential academic preparation for his profession in a terminal four-year program. Yet, in recent years, it has become increasingly apparent that four years of

Jan 1, 1941

By Charles M. Cooley

DURING the last week in April, cards were sent out from New York to Institute members affiliated with the Mining, Geology, and Geophysics Div. The cards requested recipients to indicate their main technical interest, within the division, i.e., mining, or geology, or geophysics. The reason for the cards is simple. Within the Institute more than 8000 have expressed either primary or secondary interest in this division. However, there is no way to determine the technical association stimulating this interest.

Jan 6, 1953

By John W. Vanderwilt

The fluorescence of scheelite has been an important aid in recent years in the discovery and development of scheelite deposits. The use of fluorescence of synthetic compounds in industry, particularly in advertising, also has expanded greatly during the past decade. As a result, a number of new and convenient units for producing ultraviolet energy have become available, which have led to a greater application of fluorescence in the study of minerals. Studies have shown that the fluorescent color of a mineral may vary: (I) with the kind and quantity of trace elements, and (2) with the particular wave length of ultraviolet energy used. The wave length is dependent first on the type of generating equipment used, and finally on the filter employed to remove the visible light that may be present. A number of so-called ultraviolet lamps are listed and described, together with suitable filters known to be available. Scheelite fluoresces brilliantly with wave lengths of 2200 to about 3000Å., but not with longer wave lengths. The most convenient and efficient sources of ultraviolet for scheelite fluorescence are portable and laboratory units designed particularly for use with scheelite. So-called ultraviolet light globes of the photo-flood type emit wave lengths too long to cause scheelite to fluoresce. Attention is called to the minerals that fluoresce in a manner similar to scheelite, which necessitates a check test by means of characteristic physical properties. Chemical tests are the final authority both for identity and content of tungsten in scheelite ore. Introduction Recent development and extensive use of fluorescent lighting make it unnecessary to explain what fluorescence looks like. The fluorescent light tube is in reality a mercury vapor arc, which generates ultraviolet energy. Coating the inside walls of the tube is a substance, called a phosphor, that converts the ultraviolet rays to visible rays of light. In a like manner, certain minerals will transform ultraviolet energy to visible rays of various colors. The phenomenon of brilliant fluorescent colors cannot be satisfactorily described or reproduced photographically; a display must be seen to be appreciated. Only a few years ago fluorescence was regarded primarily as a source of entertainment, chiefly in spectacular displays of specimens in museums. The brilliant fluorescence of willemite, a zinc ore mineral, at Franklin, New Jersey, was utilized quite early in checking the efficiency of certain milling operations. Fluorescence has been used extensively in exploring for scheelite, as well as in mining this ore, during the past 10 years. The use of fluorescence in detecting scheelite, an important tungsten ore mineral, is well established, and much success has attended this new method; scheelite is a very inconspicuous white to gray mineral in ordinary light, but it

Jan 1, 1949

By John W. Vanderwilt

The fluorescence of scheelite has been an important aid in recent years in the discovery and development of scheelite deposits. The use of fluorescence of synthetic compounds in industry, particularly in advertising, also has expanded greatly during the past decade. As a result, a number of new and convenient units for producing ultraviolet energy have become available, which have led to a greater application of fluorescence in the study of minerals. Studies have shown that the fluorescent color of a mineral may vary: (I) with the kind and quantity of trace elements, and (2) with the particular wave length of ultraviolet energy used. The wave length is dependent first on the type of generating equipment used, and finally on the filter employed to remove the visible light that may be present. A number of so-called ultraviolet lamps are listed and described, together with suitable filters known to be available. Scheelite fluoresces brilliantly with wave lengths of 2200 to about 3000Å., but not with longer wave lengths. The most convenient and efficient sources of ultraviolet for scheelite fluorescence are portable and laboratory units designed particularly for use with scheelite. So-called ultraviolet light globes of the photo-flood type emit wave lengths too long to cause scheelite to fluoresce. Attention is called to the minerals that fluoresce in a manner similar to scheelite, which necessitates a check test by means of characteristic physical properties. Chemical tests are the final authority both for identity and content of tungsten in scheelite ore. Introduction Recent development and extensive use of fluorescent lighting make it unnecessary to explain what fluorescence looks like. The fluorescent light tube is in reality a mercury vapor arc, which generates ultraviolet energy. Coating the inside walls of the tube is a substance, called a phosphor, that converts the ultraviolet rays to visible rays of light. In a like manner, certain minerals will transform ultraviolet energy to visible rays of various colors. The phenomenon of brilliant fluorescent colors cannot be satisfactorily described or reproduced photographically; a display must be seen to be appreciated. Only a few years ago fluorescence was regarded primarily as a source of entertainment, chiefly in spectacular displays of specimens in museums. The brilliant fluorescence of willemite, a zinc ore mineral, at Franklin, New Jersey, was utilized quite early in checking the efficiency of certain milling operations. Fluorescence has been used extensively in exploring for scheelite, as well as in mining this ore, during the past 10 years. The use of fluorescence in detecting scheelite, an important tungsten ore mineral, is well established, and much success has attended this new method; scheelite is a very inconspicuous white to gray mineral in ordinary light, but it

Jan 1, 1949

By Ta M. Li

Expanded mine-mill capacity and greater operating flexibility are part of the dramatic changes taking place in the Tennessee mining operations of Asarco, Inc. Climaxed by the recent start-up of the $6.3 million Young mill in September 1975, Asarco has pushed Tennessee back into number one position as the leading zinc mining state. Furthermore, start-up of the Young mill is expected to insure a much-needed and continuing domestic zinc supply, at a time when US mines can only supply one-half of 1975 domestic consumption.

Jan 5, 1976

By J. D. Wood, J. T. Smith

ALLOYS with a dispersed second phase in a metallic matrix are generally much stronger than the matrix itself. Plastic deformation in dispersion-strengthened alloys is usually confined to the matrix phase when recovery processes are active, while in the absence of recovery both phases may yield.' The alloy system studied in the present research was WC-12 wt pct Co and consisted of noncoherent WC particles dispersed in the cobalt matrix. Some particle-to-particle contact existed but not enough to produce a continuous WC skeleton. The microstruc-ture of the WC particles was characterized by very straight edges, forming a trapezoidal shape in any plane of polish. Previous investigations with WC-Co alloys at room temperature have shown that fracture of the WC particles occurs in transverse rupture testing.' Room-temperature slip was reported for WC particles after indentation for hardness measurements.3 Elevated-temperature deformation of WC particles in a WC-12 pct Co alloy was suggested by recent electron microscope studies of specimens deformed at 900' to 1000°C.4 In highly deformed alloys, the WC edges were serrated in contrast to the usual straight or smooth appearance. WC-12 pct Co and WC-15 pct Co alloys have been previously studied under elevated-temperature com-pressive-creep conditions by the present authors. Electron microscope studies of two-stage replicas from deformed specimens showed no evidence of slip or fracture of the WC particles. These specimens were brought to temperature and allowed to equilibrate prior to the application of the creep load. It was believed that the load-application rate, a crosshead speed of 0.005 in. per min on an Instron universal testing machine, was sufficiently low that recovery within the cobalt matrix was sufficient to limit the deformation to this matrix. A series of experiments was performed to evaluate the influence of loading rate on the deformation of WC-Co alloys. A WC-12 pct Co alloy was selected for these determinations. The average WC particle size was 4.45 p with an average linear separation between particles of 0.59 p. The selected temperature was 800°C and was monitored with a Chromel-Alumel thermocouple attached to the specimen. Testing was conducted in an argon-atmosphere chamber to prevent oxidation of the WC-Co specimens. This chamber was mounted on an Instron universal testing machine equipped to apply the load at a fixed rate. Each specimen was loaded to 110,000 psi compression stress at 0.05 and 0.5 in. per min. The loading rate was monitored prior to insertion of the test chamber and was found to be almost precisely the nominal rate selected. The specimens were raised to temperature and held to equilibrate with the surroundings, and then the load was applied and held for 4 hr to duplicate the exposure time utilized for the creep specimens. The time to reach full load at a crosshead speed of 0.005 in. per min was some 500 sec and was reduced to 50 and 5 sec as the loading rate was increased to 0.05 and 0.5 in, per min, respectively. The model developed by Ansell,' when recovery processes do not occur, considers that fracture or deformation of the dispersed particles is necessary to relieve back stresses on dislocation sources and allow dislocations piled up against particles to sweep out in the matrix to cause plastic deformation; he further states that, even at elevated temperatures, the dispersed-particle deformation is necessary for yielding in the absence of recovery. For the case of straight dislocation segments piled up against a straight barrier, such as the straight-sided WC particles, the shear stress, 7 exerted on a particle is: where h is the spacing between particles (0.59 p), a is the applied stress (110,000 psi), p, is the shear modulus of the matrix (6.7 X lo6 psi at 80O°C), and b is the Burgers vector of the matrix dislocation. From Eq. [I], the shear stress, 7, exerted on the WC particles when no recovery occurs is of the order of 6 X lo6 psi at 800°C. The limiting stress, F, that will

Jan 1, 1969

By Lester C. Uren

THIS paper reviews the industrial trends and changes in educational concepts that have led to the development of the modern petroleum engineering curriculum. A trend toward emphasis on engineering fundamentals is noted. While most universities are committed to the traditional four-year engineering program, it is agreed that more than four years is necessary for academic preparation of the petroleum engineer in all phases of his profession. The author proposes a coordinated program of undergraduate and graduate training that will permit of adherence to the general pattern of the present four-year engineering course, with provision for extension of the program into specialized graduate courses of professional character. In the latter, emphasis may vary with the interests and objectives of the individual student. A specific undergraduate curriculum is proposed in which upward of 80 per cent of the available time is devoted to engineering fundamentals. A broad survey of the professional field is afforded in courses grouped in the third and fourth undergraduate years, but detailed treatment of the professional aspects of petroleum engineering is reserved for the graduate program. INTRODUCTION Of necessity, engineering curricula must ever be changing to reflect the new techniques, the changing concepts that are presented as the engineering industries develop and unfold. Particularly is this true of the younger engineering curricula representing comparatively new and rapidly changing industries such as the petroleum industry. Institutions that planned their petroleum engineering curricula a decade or two ago now find that the petroleum industry has become vastly more technical in its requirements. Entirely new methods and techniques have come into vogue and must be given place in the curriculum, and some of these are of a character that demands changing emphasis in the fundamental preparatory subjects. College and university faculties cannot complacently assume that curricula in this field that were considered appropriate 10 or 20 years ago still reflect the needs of the industry that they are designed to serve. If they do, their graduates will be poorly equipped to meet the requirements imposed upon them by a rapidly changing industry. Perhaps it is not too much to expect academic authorities to anticipate the trends of industry and equip their graduates with what they will need to attain leadership 10 or 20 years after graduation. Whether or not this desirable objective is possible, there is no excuse for allowing curricula to fall behind the current needs of industry. DURATION OF CURRICULUM The majority of our engineering schools and colleges still adhere to the four-year curricula and there appears to be a definite - sentiment among many engineers engaged in industry that work should be so planned that the engineering student may secure the essential academic preparation for his profession in a terminal four-year program. Yet, in recent years, it has become increasingly apparent that four years of

Jan 1, 1941

(Members are urged to send in for this column any notes of interest concerning themselves or their fellow-members.) Members and guests who registered at Institute headquarters during January: A. Neustaedter, Jersey City, N. J. William Jones, Kent, England. A. J. Sweetser, Boston, Mass. Percy E. Barbour, Candor, N. C. Algernon Del Mar, Los Angeles, Cal. Herbert S. Kohlberg, El Paso, Texas. W. B. Cogswell, Syracuse, N. Y. I. N. Knapp, Ardmore, Pa. R. E. Chambers, New Glasgow, N. S.

Jan 2, 1914

By C. Laird, C. E. Feltner

An investigation into the effect of a material's slip character on its high strain fatigue properties has been carried out using copper and Cu-7.5 wt pct A1 as representative wavy and planar slip mode materials, respectively. In copper, the constant term and exponent in the Coffin-Manson equation, ?EpNf1/2 = const, are unaffected by the temperature of testing or the history of the metal. On the other hand, in Cu-7.5 wl pcl Al, while the exponent is invariant, the constant is increased with respect to copper and increased further with decrease in temperature. The life in Cu-7.5 wt pct A1 is double that of copper at room temperature and about four times at 78°K. Fractoflaphic studies indicate that these diffevences in life are associated with the early stages of cracking. In copper, severe surface rumpling provides crack nuclei at pain boundaries independent of' testing temperature or the history of the metal. In Cu-7.5 wt pct Al, the planar slip mode of deformation prevents grain boundary folding; crack nucleation is therefore mainly transgranular and the increase in life with respect to copper is associated with a prolonged linking-up stage of such transgranulay cracks. At the lower temperature the increased difficulty of cross slip inhibits multiplication of trans-granular cracks and retards the linking-up process, giving a further enhaancement in life. It is expected that such behavior will be found general in materials of wavy and planar slip mode, respectively. STAGE II crack propagation in high strain fatigue takes place by a repetitive process of crack tip blunting in the tension part of a fatigue cycle followed by resharpening of the crack in the compression part.1-3 This mechanism has come to be called the "plastic relaxation process".3 At very high strains (lives to failure less than 103 cycles), most of the life of a specimen is spent in crack propagation by the plastic relaxation process.4,5 Since the differences in the cyclic strain hardening behavior of metals and alloys are comparatively small in this strain range,6,7 the amount of blunting at a crack tip depends primarily on the applied strain amplitude. The rate of crack propagation in this life range is therefore nearly constant with respect to material and temperature of testing. In the longer life portion of the high strain fatigue range (l03 to 103 cycles to failure), a considerable fraction of the lives is spent in crack initiation and Stage I growth. Grain boundaries have frequently4,5,8 been found to be the sites for this growth which is also associated with a surface folding process.4'5 Such folding behavior may also be general in any material having a grain structure and capable of plastic deformation. It has therefore been suggested475 that the universality of the Coff in-Manson law,9'10 constant,* where ?Ep is the plastic strain range and Nf the number of cycles to failure, is reflected in the approximate invariance of both the crack initiation and propagation behavior. It happens that, in most investigations of the phenomena associated with failure,4,5,8 materials with a wavy slip mode have been used as vehicles for the studies, or else "normally" planar slip mode materials have been tested under conditions giving rise to wavy glide deformation, e.g., stainless steels cycled at high temperature.'' The purpose of the present investigation was to determine whether or not different cracking phenomena would occur when the slip mode of a material is planar and if the associated life to failure would be different than that of a wavy slip

Jan 1, 1968

By Morris Cohen, Robert C. Ruhl

Fe-Ni-B alloys were inresligated by X-ray diffraclion after splat quenching. Although this rapid cooling did not produce a measurable supersaturation of dissol1ed boron in either binary Fe-B or Ni-B alloys, a marked increase in dissolved boron was achieved by the splal quenching of lernary Fe-Ni-B alloys. Boron additions up to 2.0 wl pcl to Fe-13Ni and Fe-24Ni alloys cause an increase in retained austenite from 0 to 59 pet and to 92 pet, respectively. The martensitic phase in the Fe-13Ni-9 at. pct B alloy is .found to conlain about 0.6 at. pet interstitial boron, as evidenced by the tetragonality of this phase, and about 3.6 at. pct substilutional boron, us deduced from the lattice paratrieler decrease, the balance of the boron being precipitated as (Fe,Ni)aR. The austenitic Fe-Ni-B plznses also contain both interstitial and substitutional boron. Iron-Boron System. The phase diagram and related information about the solid solutions and intermediate phases in the Fe-B system are given by ansen,' Elliott.2 and Pearson.1 The equilibrium solid solubility of boron in both ferrite and austenite is quite small: the maximum solid solubility of 0.02 wt pct B (0.11 at. pct B) occurs in iron at the eutectic temperature of 1150°C. while the maximum solubility in a iron is less than 0.01 wt pct.l There is disagreement in the literature as to whether these solid solutions are substitutional or interstitial. Based on the measured activation energy of boron diffusion in iron, it appears likely that boron moves interstitially in austenite. 4 However, this observation does not rule out the possibility that some of the dissolved boron may also occupy substitutional sites in this phase. Investigations of internal friction of boron in iron have suggested that boron is interstitial there.' Shevelev, 5 on the other hand, reports a decrease in the ferrite lattice parameter with dissolved boron content, thus indicating a substitutional solution. Unfortunately. Shevelev's methods and analysis are unclear. Goldhoff and spretnak6 have measured the lattice parameters of pure iron and an Fe-0.005 wt pct B (0.027 at. pct) alloy at both room temperature (ferrite) and from 920° to 1200°C (austenite). They reporte: a lattice contraction in the ferrite of 0.0003 ± 0.0002 due to boron, thus indicating a predominately substitutional solution. Appreciable (0.0010 to 0.0060) lattice contractions were found in boron-containing austenites, but these effects were much larger than could be accounted for by the substitutional solution of all the boron present. Nickel-Boron System. Elliott 2 gives a summary of thephase diagram and recent work on this system. The solubility of boron in nickel reaches a maximum of 0.03 wt pct at the eutectic temperature of 1080°C. Iron-Nickel System. ansen' presents the equilibrium diagram for this system and also discusses the metastable austenitic and martensitic phases along with the a=? transformations. The lattice parameters of Fe-Ni ferrites have been recently redetermined by Abrahamson and Lopata.7 Their data, Fig. 1, show an unusual change in slope at about 1.7 at. pct Ni. Very few measurements of the lattice parameters of Fe-Ni martensites are available in the literature. The values of Roberts and Owen8 are considerably higher than those measured in the course of the present work: they find that a, is constant at 2.874? from 8 to 30 at. pct Ni. Both the slope change in the ferrite parameters and the occurrence of a maximum plateau in the marten-sitic lattice parameters vs composition denote the

Jan 1, 1970

By H. G. Doll

A new electrical logging method called Laterolog is described which provides for better recording of formation resistivity. In this method a current, preferably of constant intensity, is forced into the formation perpendicularly to the wall of the hole as a sheet of predetermined thickness by means of a special electrode arrangement and of an autonlatic control system. The essential advantages of the Laterolog over the regular resistivity logs are explained. With the Laterolog, the mud column has much less influence than with conventional methods. The Laterolog is, therefore. particularly useful in wells drilled with highly conductive mud. Moreover. when the electrode system is located opposite a bed of moderate or small thickness, the disturbing effect of the adjacent formations becomes practically eliminated, provided the bed is thicker than the sheet of current. which itself is usually a few inches to a few feet thick. The sequences of beds are. therefore, much more sharply differentiated, and, in many cases, it is possible to read directly from the logs values close to the true resistivities of the formations without further corrections. Field examples are shown to illustrate the results of the method in various types of formations. INTRODUCTION As soon as it was introduced into the petroleum industry, electrical logging roved to be a powerful instrument for the delineation of the strata traversed by bore holes and for correlation of such strata." Research and engineering efforts were mostly devoted at this early time to the design of the techniqurs which could provide the best data for these purpoes. Later, attention was directed toward the quantitative analy5i.s of electrical logs, in order to obtain information on. reservoir characteristics, and, in particular, on oil and water saturation.3,4 Efforts have been made, accordingly, with a view to improving the already existing methods, or to finding new methods which could satisfy these new requirements." Quantitative analysis implies a determination as accurate as possible of the true resistivity of the formations. In fact, however; the "apparent resistivity" recorded in front of a given bed by a conventional electrical logging method is frequently quite different from the true resistivity of this bed. This is due to the combined influence of the mud column, of the adjacent formations both above and below the bed, and of the invaded zone, in which the original fluid has been more or less replaced by mud filtrate. When the beds are thick enough, and, as is frequently the case in sand and shale formations, when their resistivity is not much greater than that of the mud, it is generally possible to obtain their true resistivity directly on the electric log, or at least to obtain an approximate value which can be corrected without undue difficulty by means of recently published charts known as "departure curves."" When the beds are thin, and particularly when, in addition. their resistivity is substantially greater than that of the mud column, the apparent resistivities recorded on conventional logs are seriously affected, and it is generally very difficult, if at all possible, to estimate their true resistivity with a good enough accuracy. In the most severe cases, such as are encountered in holes drilled through hard formations with muds of high salinity, the conventional logs are so distorted and rounded that they do not even show clearly the houndaries of the different beds. In order to overcome the effect of the mud column and of the adjacent formations, it is possible to make use of appro. priate systems whereby the measurements involve a comp3ratjvelv thin slice of space at the level of the measuring device. A mention is due, in this respect, to a measuring system. called the "guarded electrode;" invented by C. Schlumberger over 20 years ago. The system, schematically represented in

Jan 1, 1951

By H. G. Doll

A new electrical logging method called Laterolog is described which provides for better recording of formation resistivity. In this method a current, preferably of constant intensity, is forced into the formation perpendicularly to the wall of the hole as a sheet of predetermined thickness by means of a special electrode arrangement and of an autonlatic control system. The essential advantages of the Laterolog over the regular resistivity logs are explained. With the Laterolog, the mud column has much less influence than with conventional methods. The Laterolog is, therefore. particularly useful in wells drilled with highly conductive mud. Moreover. when the electrode system is located opposite a bed of moderate or small thickness, the disturbing effect of the adjacent formations becomes practically eliminated, provided the bed is thicker than the sheet of current. which itself is usually a few inches to a few feet thick. The sequences of beds are. therefore, much more sharply differentiated, and, in many cases, it is possible to read directly from the logs values close to the true resistivities of the formations without further corrections. Field examples are shown to illustrate the results of the method in various types of formations. INTRODUCTION As soon as it was introduced into the petroleum industry, electrical logging roved to be a powerful instrument for the delineation of the strata traversed by bore holes and for correlation of such strata." Research and engineering efforts were mostly devoted at this early time to the design of the techniqurs which could provide the best data for these purpoes. Later, attention was directed toward the quantitative analy5i.s of electrical logs, in order to obtain information on. reservoir characteristics, and, in particular, on oil and water saturation.3,4 Efforts have been made, accordingly, with a view to improving the already existing methods, or to finding new methods which could satisfy these new requirements." Quantitative analysis implies a determination as accurate as possible of the true resistivity of the formations. In fact, however; the "apparent resistivity" recorded in front of a given bed by a conventional electrical logging method is frequently quite different from the true resistivity of this bed. This is due to the combined influence of the mud column, of the adjacent formations both above and below the bed, and of the invaded zone, in which the original fluid has been more or less replaced by mud filtrate. When the beds are thick enough, and, as is frequently the case in sand and shale formations, when their resistivity is not much greater than that of the mud, it is generally possible to obtain their true resistivity directly on the electric log, or at least to obtain an approximate value which can be corrected without undue difficulty by means of recently published charts known as "departure curves."" When the beds are thin, and particularly when, in addition. their resistivity is substantially greater than that of the mud column, the apparent resistivities recorded on conventional logs are seriously affected, and it is generally very difficult, if at all possible, to estimate their true resistivity with a good enough accuracy. In the most severe cases, such as are encountered in holes drilled through hard formations with muds of high salinity, the conventional logs are so distorted and rounded that they do not even show clearly the houndaries of the different beds. In order to overcome the effect of the mud column and of the adjacent formations, it is possible to make use of appro. priate systems whereby the measurements involve a comp3ratjvelv thin slice of space at the level of the measuring device. A mention is due, in this respect, to a measuring system. called the "guarded electrode;" invented by C. Schlumberger over 20 years ago. The system, schematically represented in

Jan 1, 1951

By Dorsey Hager

North Central Texas has recently become a center of interest for the oil men of America. The bringing in of the McClosky well at Ranger, Eastland County, and the shallow pool at Brownwood, Brown County, in 1917, has stimulated interest in this area to fever pitch. Oil men from all over the United States are now investing there. The area of present interest is shown by the accompanying map (Fig. 1). The money spent in leases runs into millions of dollars. It is no exaggeration to say that a strip of country 200 miles (321 km.) long and 125 miles (201 km.) wide, comprising some 15,000,000 acres (6,070,310 ha.), has been leased practically solid at a cost for rentals and bonuses of at least $1 per acre. The test holes contracted for will certainly number 400, at a cost of at least $5,000,000. From what has been done in the past six months, $20,000,000 at least will be spent. To pay returns on this amount of money, new production to the extent of at least 12,000,000 bbl. must be obtained. At present, the production from new fields will not average over 5000 bbl. per day; three wells at Ranger are producing 3000 bbl.; 250 wells at Brownwood produce 1000 bbl.; and the Gray well, Coleman County, is as yet an unknown factor. However, at Ranger there is every indication of developing a good pool covering from 1500 to 2000 acres (607 to 809 ha.), more or less, but the wells are deep, 3400 to 3800 ft. (1036 to 1158 m.), and cost $35,000 to $40,000 to drill. Large wells are necessary to pay for such expensive holes. As new wells are drilled, the gas pressure will be lowered rapidly, and large production need not be expected. For those oil men who expect a second Cushing or an Eldorado, Ranger holds little of promise. At Brownwood, Brown County, there are some 250 shallow wells (depths from 200 to 350 ft.) averaging 4 to 7 bbl. per day. There is a chance of an extensive producing area for these shallow sands to the southwest, and the opening of several thousand acres of shallow oil territory, and also some promise of deeper oil horizons in the Ranger horizon, but probably all under 2500 ft. At present, the lease brokers and speculators, and only a handful of oil men, have made any money. More fields must be developed, and it is more particularly with these possibilities that this paper deals. Lack of water for drilling purposes has undoubtedly held back development so far this year; this part of Texas has had a drouth for two years and there is an actual scarcity of water. Geological investigations so far undertaken cover nearly all the area outlined, and while pakt of the

Jan 1, 1920

By F. W. Jessen, N. Lamont

The effect of an existing fracture or joint plane, which may exist in a rock, on the extension of a hydraulically induced fracture through the rock has been investigated in the laboratory. By use of a series of models made from various outcrop rocks, the width and orientation of existing fractures do not alter the extension or direction of the hydraulic fracture. The results, which conform quite well with the Grifith theory of failure, are illustrated by a series of photographs of the various models. INTRODUCTION The process of hydraulic fracturing has been widely used in the oil industry since its introduction in 1948 and has made possible the production of many reservoirs which would have been uneconomical prior to this process. Numerous studies of the mechanics of the process2-h nd of the effects of oriented fractures on recovery'.' have appeared in the literature. The increased recoveries led to attempts to predict the orientation of hydraulic fractures at the wellbore and to the development of methods to control this orientation. Field tests have been devised"." which indicate the validity of theoretical predictions of fracture orientation at the borehole. The direction of extension of hydraulic fractures from the borehole has not received much attention since most studies have predicted, at least implicitly, that a fracture will continue in the same plane unless a change of state of stress in the rock occurs. Since such predictions are based on the assumption of rock homogeneity, the effects of rock heterogeneities are left unknown. Most sedimentary rocks are composed of layers which reflect the changing depositional conditions of geological time. In addition, the more competent rocks frequently are fractured and jointed as the result of structural deformations or tectonic movements. Evidence of such joint systems exists in many surface outcrops, and it can be assumed that similar systems occur in many subsurface rocks, although the individual joints may be rather tightly closed due to overburden forces. This paper investigates the effect that an existing fracture in a rock would have on the direction or orientation of an extending or advancing hydraulic fracture when it intersects the existing fracture. The study was conducted on small rock models under triaxial stress conditions. The results indicate that an existing fracture will have little effect on the hydraulic fracture. THE MODEL STUDY The rock model represents an elemental portion of the earth containing an existing fracture which is located at some distance from a borehole from which hydraulic fracture is being extended. A generalized view of a model is presented in Fig. 1. The models were constructed from cement blocks and natural rocks. The various materials tested and some of the physical properties are listed in Table 1. The rocks were cut into rectangular blocks with dimensions of 11/2 X3Y2 X4 to 8 in. An initial slot was cut into the end face of each block along the longitudinal axis normal to the top face. The slot was filled with plastic aluminum along its outer edge to a depth of 1/16 in. A hole of 3/8-in. diameter was drilled into the sealed slot at the center of the end face to serve as an entry port for the fracturing fluid. Existing fractures of various types were simulated in the models. A "hairline" fracture with essentially zero width was created by cutting the model into two parts with a diamond saw and replacing the two parts together along the cut. A finite-width fracture was created by placing a layer of sand grains between the two faces of the cut just described (see Fig. 12). A large open fracture (similar, perhaps, to a vug) was created by cutting the model in two parts and removing a portion of the downstream block to a depth of % in. See Fig. 13. For a fourth

By Anson Hayes

FOR the purpose of the following discussion the word "research" is interpreted as including all phases of development work on methods of manufacture, metallurgical characteristics, and uses of iron and steel. Research in the iron and steel industry then includes both plant re- search and laboratory research. Since iron and steel came into being, the steel consumer's plant and the steel producer's plant have been important factors in the development of the steel industry. Good minds have always been associated with both consumer and producer plants, so marked progress was made in the industry even when these were the only types of research and development groups in action.

Jan 1, 1937

By William R. Hart

I was this morning an interested listener to the remarks of Mr. Ashbel Welch in regard to his designing a new section for steel rails, in 1866; and for the salze of the truth of history, and in order t:, give the credit to an American (and where it rightfully belongs) of higning the first section for steel rails, which was intelligently adapted to that material; I beg to state the following facts: On the 14th of August, 1866, Mr. Ashbel Welch gave me an order for 200 tons of steel rails, to be made bbr the Camden and Amboy Railroad, from a section designed by him. A copy of this section 1 append herewith.

Jan 1, 1881

By Rex B. McLellan, W. A. Oates, William W. Dunn

Vapor transport experiments have been carried out in order to determine the saturation solubility of carbon in cobalt and nickel with respect to graphite over a large temperature range. Some of the uncertainty existing in the thermodynamics of these systems has been removed and accurate estimates of the heat and entropy of solution of carbon in nickel and cobalt have been deduced. The relatitle partial entropies of carbon are considered to be predominantly vibrational in origin. ALTHOUGH the thermodynamic properties of solid solutions of carbon in cobalt and in nickel have been investigated previously, the results of these investigations show a marked lack of agreement amongst themselves. In this investigation simple vapor transport experiments have been undertaken in order to measure the temperature variation of the saturation solubility of carbon in nickel and cobalt with the object of removing to some degree the uncertainties in the thermodynamics of these systems. In the case of the C-Co system, early measurements of the saturation solubility of graphite in Co show results at the same temperature differing by almost an order of magnitude.1-5 Recently Schenck, Frohberg, and Jaspert6 measured the equilibrium between CH4-H2 mixtures and C-Co solid solutions at five temperatures ranging from 850° to 1050°C. Their values of the activity of carbon in the solid solution, deduced from a knowledge of the chemical potential of carbon atoms in the gas, varies linearly with composition at each temperature and the authors concluded that the solutions were Henryan. The saturation solubilities deduced from Schenck, Frohberg, and Jaspert's measurements are in good agreement with the solubility determined at 1000°C by Rao and Nicholson7 and the value at 1000°C deduced from the measurements of smith8 on the equilibrium between CO/CO2 mixtures and C-Co solutions. The object of this investigation was to check the results of Schenck, Frohberg, and Jaspert and also to extend the range of solubility data to higher temperatures. In the case of the C-Ni system, there is fairly good agreement between the values given by schaefer9 for the saturation solubility of carbon C, in nickel, the value given at 1000°C by Rao and Nicholson,7 and that deduced from Smith's8 measurements of the equilibrium between C-Ni solutions and CO/CO2 mixtures at 1000°C. The values of C, deduced from Schenck, Frohberg, and Jaspert's6 measurements of the carbon activity in nickel are also in fairly good agreement. However, there is a large discrepancy between the above set of measurements and those of Lander, Kern, and Beach," who measured the carbon solubility of nickel in equilibrium with graphite by depositing an excess of graphite on the surface of Ni-foils from a gaseous mixture and subsequently diffusing in the carbon. These results are considerably higher than those mentioned above. The determinations6 of carbon activity a, in nickel from the CH4-H2 equilibrium showed that at all the temperatures investigated, the ac-values varied linearly with concentration up to about a, = 0.6 and then began to increase with concentration much more rapidly. On the basis of auxiliary experiments in which C-Ni solutions were equilibrated with graphite, Schenck, Frohberg, and Jaspert concluded that their CH4-H2 solid equilibrations at high values of a, were spurious and a, behaved linearly with composition up to the saturation limit (a, = 1). The short linear extrapolations of Schenck, Frohberg, and Jaspert's a, data yield values of C, in good agreement with those of Lander, Kern, and Beach." The solubility data for nickel discussed here is presented in Fig. 1 in the form of plots of ln[Cc/(l - 2cc)] vs 1/T. The discrepancies mentioned are clearly seen. In this investigation a vapor transport method is used to measure C, over as wide a temperature range

Jan 1, 1969