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By G. C. Broadhead

THE lead district of Southeast Missouri covers an area of over 3000 square miles, including Maries County on the west, Jefferson on the east, Franklin on the north, and part of Madison on the south, or parts of ten counties. A general section of the rocks of the southeast part of this region would be about as follows, numbering from the top 1. Sandstone (the second of Missouri geologists), - 20 feet. 2. Cbert beds-beds of passage below, - 125 feet 3. Magnesian limestone, chert, and quartzite, - 100 to 300 feet 4. Lower magnesian limestone, - 100 to 150 feet 5. Gritstone and lingula beds, - 50 feet 6. Ozark marble beds, - 5 to 20 feet 7. Sandstone and conglomerate, - 5 to 90 feet 8. Porphyry, Archaean. 9. Granite, The thickness is approximate, for it is not possible to obtain the correct thickness of the various beds. No. 1 may be seen as de¬tached outliers or loose masses of a hard sandstone or quartzite, and is found on the hilltops in the southern part of Madison County, in like topographical position in Reynolds County and the western part of Washington County. No. 2 consists of alternations of chert, clay, and quartzite. It is the formation which contains most of the limonite deposits of Central and Southern Missouri. In Reynolds County shafts have pene¬trated it 75 feet. Outcrops there and in Madison would indicate it to be at least 125 feet thick. Fossils obtained in various places prove it clearly to be of the age of the calciferous sandrock of the New York system, and Nos. 1 and 2 may also be referred to the age of the second sandstone of Missouri. No. 3 consists chiefly of thick beds of ash, drab and flesh-colored magnesian limestone, both coarse and fine-grained. These beds, where they occur, in Washington, Jefferson, and the southern part of Madison Counties, contain a good deal of quartz in drusy cavities. In Washington County the limestones are beautifully ramified by a system of connected drusy cavities generally lined with minute quartz crystals arranged in botryoidal and mammillary forms, and called u mineral blossom " by the miners. This is the lead-bearing rock of Washington County, but in the southern part of Madison it does not appear to be galeniferous. It is also undoubtedly the equivalent of

Jan 1, 1877

By Wallace Ralston

The East Texas district includes the northeast 38 counties of the State of Texas. It still remains one of the most important oil-and-gas-producing areas of the United States, since it includes within its boundaries the large East Texas field. Other fields of importance are: Van, Rodessa, Talco, Cayuga, Long Lake and Sulphur Bluff. Production is from the Nacatoch, Blossom, and Woodbine of the upper Cretaceous and the Paluxy and Glen Rose of the lower Cretaceous. Of these, the Woodbine is the most important, since it is the producing horizon iri the East Texas field. Fields East Texas Field.—There were 2471 oil wells, 1 gas well and 84 failures completed during the year of 1936 in the East Texas field; that is, 1565 fewer than in the year of 1935. The total number of producing wells is now 22,031, of which 50 are temporarily shut down; 18,435 wells flowing their production; 3150 pumping; 293 on gas-lift, and 82 operated by other methods. This shows an increase of 1642 wells on artificial lift over Jan. 1, 1935. The average daily salt-water production is estimated at 42,700 bbl. from 2327 wells—an increase of 1201 wells over the year of 1935. The field is now drilled to an average density of one well to 5.85 acres. Average bottom-hole pressure has dropped from 1193 Ib. to 1168 lb., approximately 1 lb. drop for each 6,600,000 bbl. of oil produced. During the month of December 1936, the estimated daily average production of illegal oil had dropped from 20,500 bbl. in December 1935 to 7500 bbl. The commercial gas production is of minor importance in the East Texas field, and figures for the amount of gas taken from the field are not available at the present time. Talco Field, Titus and Franklin Counties.—The discovery well was drilled by Housh, Thompson et al. on the C. M. Carr tract and completed in March 1936, as a pumping well making 552 bbl. per day of 24' gravity oil. This well was first completed at a total depth of 4208 ft., the top of the sand being 4190 ft. Later it was deepened to 4260 ft., which increased the production from 552 to 725 bbl. per day. This field is producing

Jan 1, 1937

By R. A. Bergier

The Transactions of the Institute contain nothing, as yet, on the subject of pocket-compasses; and in the belief that American miners, explorers, geologists, and engineers will gladly welcome any infor mation about new forms of apparatus, simple in construction and adapted to rapid use, I offer a short description of an improved French combination pocket-compass, which, if once introduced into use, would seem likely to supersede similar instrumens of older pattern. The instrument in my possession I owe to the kindness of M. G. de.La Bouglise, of Paris. The frame of the compass is a double-bottomed box, 2 1/2 inches square and 9/16 of an inch high, made of white metal, and with its sur faces very carefully planed. The sides of the box make true right angles with each other. Two sides are parallel with, and two are normal to, the north and south line of the principal graduation. The bottom is accurately planed, so that the instrument will lie true on a plane surface. A glass, 2 3/8 inches in diameter, is set in the top plate. The graduation for the needle is engraved on the upper face of a ring, connected with the flat disk, in which the center-pin is in serted. Between this disk and the bottom of the box there is a hollow space a quarter of an inch deep. The needle is 1 7/8 inches in length, and can be balanced by means of a small sliding piece of metal. The graduation extends from 0° to 360°, reading from right to left. The stopping of the needle is effected by a screw, A, on the side of the box near the handle, H (Fig. 1). There is also a clinometer attachment, the graduation for which is engraved on the upper face of the silver-plated disk. The compass has two sights. The north sight, B, is a simple pin, a little more than an inch high, which, when not in use, is kept folded down, and is partially protected by the exterior sliding-plate, C. When raised for use, the sight is stopped in a vertical position by a projecting pin attached to the side of the box.. The south sight, D, is connected with the handle, H, and the sight and handle

Jan 1, 1890

By G. C. Broadhead

The lead district of Southeast Missouri covers an area of over 3000 square miles, including Maries County on the west, Jefferson on the east, Franklin on the north, and part of Madison on the south, or parts of ten counties. A general section of the rocks of the southeast part of this region would be about as follows, numbering from the top: 1. Sandstone (the second of Missouri geologists),.... 20 feet. 2. Chert beds—beds of passage below,...... 126 " 3. Magnesian limestone, chert, and quartzite,. .. 100 to 300 " 4. Lower magnesian limestone,......100 to 150 " 5. Gritstone and lingula beds,....... 50 " 6. Ozark marble beds,........5 to 20 " 7. Sandstone and conglomerate,. .. .. 5 to 90 " 8. Porphyry, Archæan 9. Granite, The thickness is approximate, for it is not possible to obtain the correct thickness of the various beds. No. 1 may be seen as detached outliers or loose masses of a hard sandstone or quartzite, and is found on the hilltops in the southern part of Madison County, in like topographical position in Reynolds County and the western part of Washington County. No. 2 consists of alternations of chert, clay, and quartzite. It is the formation which contains most of the limonite deposits of Central and Southern Missouri. In Reynolds County shafts have penetrated it 75 feet. Outcrops there and in Madison would indicate it to be at least 125 feet thick. Fossils obtained in various places prove it clearly to be of the age of the calciferous saudrock of the New York system, and Nos. 1 and 2 may also be referred to the age of the second sandstone of Missouri. No. 3 consists chiefly of thick beds of ash, drab and flesh-colored magnesian limestone, both coarse and fine-grained. These beds, where they occur, in Washington, Jefferson, and the southern part of Madison Counties, contain a good deal of quartz in drusy cavities. In Washington County the limestones are beautifully ramified by a system of connected drusy cavities generally lined with minute quartz crystals arranged in botryoidal and mammillary forms, and called " mineral blossom " by the miners. This is the lead-bearing rock of Washington County, but in the southern part of Madison it does not appear to be galeniferous. It is also undoubtedly the equivalent of

By Donald B. Gillies

PROBABLY the most critical and difficult period in an engineer's career is that between the completion of his college work and his attainment of professional recognition and accepted status in the industrial world. Upon leaving school the young graduate breaks his immediate ties with his educational institution and in a sense finds himself adrift. At this time in his life a society like our Institute has both the responsibility and the privilege of meeting a vitally important need in his professional life. Some of these young men are Student Associates, in the year after graduation, and some are Junior Members, but all need advice and assistance. In some respects this situation will be accentuated by the war. Not only will thousands of young engineers be mustered out of military service but the process we describe generally as industrial reconversion will make necessary many readjustments in personnel. About two years ago the Institute recognized the opportunity of helping the younger member to help himself by appointing a new standing committee to be known as the Committee on Professional Development of Junior Engineers. Herbert Hoover is Honorary Chairman and it is my privilege to serve as Chairman. The name of the Committee is not entirely satisfactory but it expresses the general objective. The present article is in the nature of a progress report of the work of this Committee.

Jan 1, 1945

By L. H. de Wald, J. Walter Scott

The removal of lead by fire refining methods from copper of electrolytic quality is growing in importance. Particularly is this true of the refining of secondary copper and copper cathodes obtained from electrolytic cells where lead is used as the anode material, as in the electrolysis of ore-leaching solutions and foul electrolyte. When investigating the removal of small amounts of lead from molten copper in a reverberatory furnace during the refining of secondary copper of otherwise electrolytic copper quality,' it was found necessary first to know something about the distribution of the lead throughout the bath. The authors believe that it is not generally known how small amounts of lead as an impurity are distributed in a molten copper bath; that is, whether the lead is concentrated at the bottom or at the top, or whether it occurs more or less uniformly throughout the bath. The data contained in this report may help, therefore, in the development of a satisfactory fire refining method for the removal of this obstinate element from a molten copper bath. The first step was the development of a method for taking samples from various locations in the bath, at the surface and at various depths. The sampling device used, shown in Fig. 1, consisted of a 10-gram fireclay assay crucible fitted into a ring on the end of a steel rod handle of suitable length. A fireclay scorifier, 2 in. dia., with a ½-in. hole bored in the

Jan 1, 1930

[†Aaronson, Alfred E., Oil Producer, Pres., Tuloma Oil Cc Tulsa, Okla. '18 ¦Abad, Leopoldo F., College of Min., Univ. of California Berkeley, Cal. '23 ¦Abadilla, Quirico A., Geol. Dept., Cia. Mexicans de Petroleo "EI Aguila," S. A., Edifico "El Aguila," Esq., Calles Aurora y Comercio, Tampico, Tamps., Mexico. '20 ¦Abbey, Robert Graham, Student, Case School of Applied Science Cleveland, 0. '21 Abbott, Clarence E., Gen'l Supt., Iron Mines Div., Tenn. Coal, Iron & R. R. Co., 1405 Minnesota Ave., Bessemer, Ala. '04] [ ]

Jan 1, 1925

By R. W. Kewish

The preparation of massive uranium metal containing very low concentrations of a number of light elements by bomb reduction of UF4, with calcium is described. Details of procedures are given for preparing high-purity ingredients for the bomb reduction. The as-reduced uranium metal contained, on the average, less than the following amounts of light element impurities, in ppm: Li, 0.1; Be, 0.1; B, 0.1; C, 25; 0, 70; Na, 1; Mg, 3; Al, 2; and Si, 7. Other impurities for which the metal was examined averaged, in ppm: Ca, < 10; V, < 10; Cr, 2; Mn, 6; Fe, 50; Co, < 5; Ni, 8; and Cu, 1. THE preparation of very high-purity uranium metal in massive form for research purposes is of great importance. Recently the kilogram-scale preparation of uranium metal containing less than 70 ppm of detected impurities was accomplished by Blumen-thal and coworkers by vacuum remelting of high-purity crystals of uranium obtained by fused salt electrolysis.1"3 Albert and coworkers4 have reported successful experiments in lowering the concentrations of certain impurity elements in uranium, notably iron, to a few ppm by the zone-melting method. The present paper describes the preparation of high-purity massive uranium metal by the bomb reduction of UF4, with calcium. Early in 1951 a program was undertaken at the Los Alamos Scientific Laboratory to prepare uranium metal of very high purity with respect to a number of the light elements. The methods considered for this purpose were 1) bomb reduction of a uranium halide with calcium, 2) electrolysis of fused salts, and 3) hot wire decomposition of UI4, The first of these processes had been used extensively at Los Alamos since 1943 (and still is used) for the production of uranium metal.5 In considering the three processes it was evident that either of the last two would require an extensive development program with no certainty of success. On the other hand, a study of available data showed that uranium metal of very high purity with respect to some light elements had occasionally been made in routine processing by the first method. It was therefore decided that an intensive study of the bomb-reduction process would be made to see if it could be improved to yield uranium metal with very low concentrations of light elements. DEVELOPMENT OF PROCEDURES The bomb-reduction process used at Los Alamos consists of reducing UF4 with calcium, using iodine as a booster. The reaction is carried out in a magnesium-oxide crucible enclosed in a steel bomb. Argon is used in the bomb to avoid objectionable side reactions which would occur in the presence of air. All ingredients for this bomb-reduction process were examined as possible sources of light elements. It was known that high-purity UF4 was required. The calcium used in the reductions was a source of carbon and magnesium. The magnesium-oxide crucibles were sources of boron, silicon, and magnesium. The iodine did not appear to be a source of any impurities. Pure UF4- The UF4 for bomb reduction is prepared from U3O3 , by successive reduction to UO2, with hydrogen and hydrofluorination of the UO2, with anhydrous HF. Since it was known that no impurities were normally introduced during the gas-solid reactions, effort was directed toward the preparation of high-purity U3O3. Of the many possible procedures for the purification of uranium solutions the following were investigated: 1) Precipitation of uranium peroxide. (Two procedures were tried. The first consisted of simultaneously adding hydrogen-peroxide and ammonium-hydroxide solutions to a uranyl-nitrate solution, containing citric and malonic acids, at such relative rates that precipitation was carried out at a constant pH of 1.5 The second consisted of simultaneously adding uranyl-nitrate, ammonium-hydroxide, and hydrogen-peroxide solutions to an aqueous solution

Jan 1, 1960

By COURTNEY DE KALB

IRON ore is the cause of the present trouble in Morocco. At least three nations are interested in the outcome and private syndicates have been active. The iron deposits are found in that mountainous northern coast line known as the Rif. This is an uplift that has been cut through, by the northward drainage, representing an ancient land surface. Erosion has produced .a fiordlike coast, which circum- stance has aided contraband&apos; traffic to the tribes dominated by Abd-el-Krim, the chief of the clan of the Beni Urriaguel, near the center of &apos;the north coast, opposite Alhucemas. The iron deposits are extensive in the territory of the Beni Urriaguel. They were "located," if such a term is permissible, many years ago. The first arrangements, through direct contracts with the tribal chieftains, have been reinforced by compliance with the subsequent code under the Spanish protectorate in 1914. Under those terms, the location had to be made through the Arbitral Commission sitting in Paris. These locations, or "denouncements," were made by the I-louse of Mannesmann, of Hamburg.

Jan 1, 1925

By E. J. Kenaedy, E. H. Robie

THOUGH the fall meeting of the Coal Division was held in the heart of the anthracite section, at Hazleton, Pa., the bituminous industry was well represented also, and the two groups found much common ground for discussion. The&apos; technical part of the program was confined to two sessions in the morning and afternoon of the first day, Friday, Oct. 14, the evening and the following day being reserved for field trips and social functions. The attendance more than met the expectations of those in charge of the arrangements; there seemed no hint of depression here.

Jan 1, 1932

By John V. Beall

Let&apos;s start at the beginning, Mr. Turner. Where and when were you born? In Lansing, Mich., on July 31, 1880. And what was your education? I went to the University of Michigan, where I got an A.B. degree in 1902; then to the Michigan College of Mines at Houghton, graduating from there in 1904 with a B.S. and an E.M. What was your first job in the mining industry, Mr. Turner, and what were you paid? In the summer of 1902, 1 was a field assistant for the U. S. Geological Survey in southwestern Idaho and southeastern Oregon, working under Israel C. Russell, professor of geology at the University of Michigan, who incidentally, had just returned from an expedition to study the effects of the eruption of Mt. Pelee, on Martinique. I was paid $60 a month and found; in addition to doing geologic and hydrographic work, I cooked many of the meals for a party of four, and wrangled four horses. I slept for four months under the stars, without a tent.

Jan 1, 1949

By Will H. Coghill

WITH gold at $35 for the last four years, almost double the old figure, and &apos;an unlimited market, there is perhaps more activity in the mining and milling of that metal than in that of any other of the widely distributed ores. Despite threats from Russia, the Rand district is still dominant. In South Africa in 1936, 48,200,000 tons of gold ore was crushed after sorting out about 10 per cent of that mined. The pounding of 5914 trusty stamps on the 60 mi. of Rand reefs is noteworthy. At the end of 1935, 466 tube mills were operating on the Rand, the popular size being 6 1/2 by 20 ft. The grinding medium normally consists of ore pebbles picked from the ore but recently a composite load of 3-in. steel balls and pebbles has found favor for added capacity, a ratio of 2.5 tons of pebbles to one ton of halls being maintained. The total ore fed to the mills is only about 0.14 ton per hp.-hr. Such a slow rate &apos;of feed cannot help but result in overgrinding. Ball mills, 9 by 8 ft., some of which have come from Canada, are now being tried. Stamps have been ousted from all new flow sheets, but the old stamp mills are continually renovated and kept on duty as they are at the Homestake in the United States. Half of the world&apos;s gold and silver ores is still crushed by stamps, a few of which are single, dropping in individual mortars.&apos;

Jan 1, 1938

By Shiou-Chuan Sun

THE fact that coals of different ranks and even of the same rank differ greatly in their amenability to froth flotation is well known. In recognition of the need for an explanation of this phenomenon, two hypotheses have been suggested. Wilkins1 reported that the floatability of coals increased with an increase of the carbon content or rank. This postulate is handicapped by the fact that bituminous coals that possess moderate carbon contents are actually more floatable than anthracite coals that have high carbon contents, as shown in columns 6 and 9 of Table I. Taggart and his associates&apos; implied that the difference of floatability between bituminous and anthracite coal was caused by the variation of carbon-hydrogen ratio. This is not applicable to the relative floatability of other coals and carbons. For example, column 11 of Table I shows that the carbon-hydrogen ratios of low-floating lignitic coal and non-floating animal charcoal are not only smaller than the moderate-floating anthracite coal, but are also similar to the high-floating bituminous coal. Furthermore, according to this hypothesis, high temperature coke-A (464), Ceylon graphite (1238), and lamp-black (357), all possessing extremely high carbon-hydrogen ratios, should be less floatable than other substances having much lower carbon- hydrogen ratios such as high volatile-B bituminous coal (11.9 to 22), anthracite coal (35.7 to 60.5), lignitic coal (15.6 to 33.6), and charcoal (13 to 26.2). However the former group is actually more floatable than the latter group.

Jan 1, 1954

L50 Adirondack L1 Alaska L2 Arizona L58 Arkansas L66 Billings Petroleum L3 Black Hills L4 Boston L5 Carlsbad Potash L6 Central Appalachian L60 Central New Mexico L7 Chicago L8 Cleveland L9 Colorado L57 Colorado Plateau L10 Columbia LII Connecticut L55 Dallas L12 Delta L65 Denver Petroleum L13 Detroit L14 East Texas L15 El Paso Metals L71 Evangeline L45 Florida L54 Fort Worth L16 Gulf Coast L61 Hobbs L62 Hugoton L68 Illinois Pet Basin L17 Kansas L18 Lehigh Valley L52 Lou-Ark L47 Mexico L19 Mid-Continent L20 Minnesota L56 Mississippi L21 Montana L22 Nevada L64 Niagara Frontier L23 New York L67 New York Petroleum L25 North Pacific L24 North Texas L26 Ohio Valley L27 Oklahoma City L28 Oregon L63 Panhandle L29 Penn -Anthracite L30 Permian Basin L51 Peru L31 Philadelphia L32 Pittsburgh L33 St Louis L34 San Francisco L59 San Joaquin L35 Southeast L36 Southern Calif L69 Southern Calif Pet L53 South Plains L37 Southwest Texas L48 Southwest Alaska L38 Southwest N Mex L44 Spindletop L39 Tri-State L40 Upper Peninsula L41 Utah L70 Venezuela L42 Washington, D C L43 Wyoming L49 West Central Texas L46 Philippine

Jan 1, 1956

United Engineering Trustees, Inc. WILLIAM H. BASSETT H. G. MOULTON R. M. ROOSEVELT The Engineering Foundation GEORGE D. BARRON E. DEGOLYER R. M. ROOSEVELT Engineering Societies Library Board ROBERT PEELE H. K MASTERS A. B. PARSONS, Ex-officio F. F. SHARPLESS R. H. SWEETEST

Jan 1, 1934

By W. L. Freyberger

In a study of the kinetics of flotation of coal, employing a single-cell continuous flotation system, Jowett and Safvi1 pointed out that it was experimentally impossible to float all of the coal which could be floated in a batch tests. On the other hand, deBruyn and Modi, in a discussion of their paper, suggested that under certain conditions the recovery of floatable material from a similar one-cell continuous system would have been 100%.2 Both of these pairs of authors make the assumption that a state of perfect mixing exist in the flotation cell. This assumption, usually made by investigators studying flotation kinetics in a continuous system, has been confirmed experimentally on several occasions. The work is summarized by Arbiter and Harris.3 It is the purpose of this note to demonstrate that, for conditions of perfect mixing, one of two conditions exist: 1) the recovery of floatable material is 100%, and the flotation is infinitely fast, or 2) the recovery of floatable material must be less than 100%. This theorem can be proved simply in the following manner: 1) If recovery, R, of the floatable material is 100%, the concentration in the tailing must be zero. This follows from the definition of recovery as

Jan 1, 1964

By John A. Baker

S EVERAL FACTORS have brought about a vastly greater interest in the gold-mining industry in the last two or three years. Outstanding is the fact that there is an open market at a fixed price for all that can be produced. a condition that holds for no other commodity. Costs of production have decreased greatly, owing to lower prices of supplies and equipment and lower wages. Improved metallurgical processes and equipment are also available. To big new gold district is being opened up but virgin ground is being prospected with some success in many of the more remote parts of the world and right here in the United States many old properties are being reopened 111 the light of present condition<, tailing dumps are being re- worked, and profitable leases taken on abandoned property. Many of the men who are becoming interested in gold are mining engineers whose experience has all been with base metals heretofore: some are engineers with no mining experience; some are not engineers at all but men who cannot find profitable employment in their usual field of activity and are attracted by the age-old lore of the yellow metal. Some are business men with a little money and an idea that under present conditions gold mining offers a safer investment for it than most other kinds of business. It is to those more or less inexperienced new- comers in the gold-mining industry that this article i4 ad dressed. Those who are connected with the large gold mines or who have had rears of experience with the small ones will find in the following pages little or nothing of interest but it is hoped that the newer generation of small mine operators, on whom the healthy growth of the industry depends so much, may find here some helpful hints.

Jan 1, 1932

By M. H. Richman, W. D. Sproul

THE indexing of a field-ion micrograph is in many cases similar to the indexing of the poles of a stereo-graphic projection.* If one has a standard projection as a guide, the task of indexing is relatively simple. In this way, field-ion micrographs of bcc and fcc wires have been oriented from projections available in most any text on X-ray diffraction. These books always illustrate the projections for the bcc and fcc structures and even for a particular hcp structure. There is no "standard" hcp projection because the angles between planes depend on the c/o ratio of the unit cell. In order to index field-ion micrographs of hcp metals, one must compute the angles between various planes—a rather laborious task. In recent work,, we have had to identify the structure and index the orientation of field-ion micrographs of the compounds WC and W,C. To overcome the problem of computing angles by hand or calculator, a program was written in Fortran lV for use on the IBM 360, Model 50 which will compute all angles between planeswith indices (hlklll) and (17,k,l2) in the range from (447) to (444) for any given c/o ratio. The program, which is more specific than that of Camp and clum, was so written as to take advantage of the multiplicity of the hexagonal system, and, for the limits defined above, only 26,649 values out of a possible 265,721 values had to be computed. This is a 90 pct saving in time (and cost) and was accomplished in the following way. Because the lattice parameters of the hexagonal crystal system are defined such that: a = b * c [1] the I index does not enter into the multiplicity (i.e., it cannot be transposed with the h or k indices), and all possible values of h and I, from 4 to 4 must be used—a total of eighty-one combinations. The index h2 varies the most—it must assume values from - Ill,: to 3Ihl. The indices kl and k2 are always equal and vary

Jan 1, 1969

JOINT convention week has become a feature of the year with western mining men. The first was held at Denver in 1926, the second at Salt Lake City in 1927, and the third is about to take place at Los Angeles. Holding in the same city in one week the meetings of a number of related organizations has been .found to permit the development of a well-rounded program at the same time that it economizes time and money for the members, many of whom belong to several of the participating organizations. For the third time, the American Mining Congress, represented by its Western Division, of which Philip Wiseman is chairman, is taking the lead and assuming the main responsibility. The A.I.M.E. is furnishing the papers for two sessions and the California Development Association for one. The Southern California Section, Robert R. Boyd, chairman, is host for the Institute, but the Northern California, Nevada and Arizona sections have each contributed papers to the program, and will be represented at the meeting. It will be a real reunion of the mining men of the Southwest.

Sep 1, 1928

By Forrest F. Craig

Both early and more recent1 laboratory measurements of gas-oil relative permeabilities were made by subjecting oil-saturated cores to external gas drives. In these runs it was generally assumed that the flowing gas/oil ratio was constant at every point throughout the core. Using this assumption, the resulting equation for the gas-oil relative permeability ratio becomes A where Q is the flow rate at the producing end of the system. This relative permeability was then specified for the average saturation of the core. The assumption and resulting equation fail to recognize that in an external drive, the oil flow rate varies from zero at the injection end to a maximum at the producing end. The assumption also fails to consider the existence of a saturation gradient during an external drive. This saturation gradient is due solely to non-steady-state flow. Some authors2,3,4 have used this erroneous method of calculating relative permeability ratios from external drives. Other authors5,6,7 have used relative permeability ratios in calculating expected field performance by external drive, using Equation (1) and making the incorrect assumption that the saturation is uniform within the driven portion of the reservoir. To find the correct relation between the relative permeability. ratio at the average saturation and the produced gas/oil ratio, the insertion in Equation (1) of a factor, F, to adjust it for oil velocity gradient has been considered. The equation then takes the form Assuming that the oil velocity is directly proportional to the distance from the injection point leads to the conclusion that, for a linear system, the average oil velocity is one-half that at the producing end. Thus, the average gas/oil ratio is twice the produced gas/oil ratio, and Equation (2) is transformed into However, here again the existence of a saturation gradient is not recognized. The produced gas/oil ratio is related to the relative permeability ratio at the saturation of the outlet end of the system. It can be shown quite readily that, if the true log k,/k, saturation relationship is linear over small ranges of saturation, then d log kjko Where aaxv and u2 are the average and outlet saturations, respectively. Examination of Equation (3) shows that the factor F cannot have a single value over the whole saturation range. Another method of dealing with external drives is that of Buckley and Leverett.&apos; Their method, which assumes no gas expansion and outlet end effects, considers fully the saturation gradient present due solely to the displacement mechanism during an external drive, and applies Equation (1) to each point along this gradient. The calculation of production history using relative permeability ratio is straightforward. However, the calculation of relative permeability ratios from production history by this method is impractical. In a recent paper, Welge,1 using an approach similar to that of Buckley and Leverett, presents a simplified method for determining the saturation at the producing end of the system. At thi; saturation, the relative permeability ratio calculated by Equation (1) applies exactly, after breakthrough of the stabilizej front. By this method, relative permeability ratios or production history may be calculated with equal ease. Use of this method as a laboratory tool in determination of relative permeability ratios by external drive requires the knowledge of the total injected fluid volume; in addition to the average saturation and producing ratio. As a preliminary test of this method of calculation, laborntory external gas drives were run on a 3% in. diameter, 11 in. long sample of Nellie Bly consolidated sandstone. This core sample had a permeability of 824 md and a porosity of 28.1 per cent. The driving fluid was air. Three different oils were used, having viscosities of 1.4, 9.8, and 125 cp, respectively. The runs were made under identical pressure differentials,

Jan 1, 1952