Search Documents

By V. R. Garfias R. V. Whetsel

Production of crude petroleum in Mexico during 1935 totaled approximately 40,082,000 bbl., an increase of 1,925,000 bbl. over the previous year. Successful development continued in the Poza Rica field during the year, increasing production in that area from 3,708,000 bbl. in 1934 to 9,542,000 in 1935. The output of the South fields (Golden Lane) area decreased by 3,000,000 bbl. during the year, and the heavy-oil district of the Northern fields by 1,500,000 bbl. Production in the Tehuantepec fields showed a slight gain. Production of natural gasoline increased from 430,000 to 600,000 bbl. in 1935. Crude run to stills in local refineries is estimated at 30,000,000 bbl., some 4,000,000 bbl. more than in the previous year. Exports of crude and refined products were approximately 22,000,000 bbl., or 2,000,000 bbl. less than in 1934. Exclusive of ships bunkers, domestic consumption increased about 900,000 bbl. during the year, reaching an estimated total of 14,500,000 barrels. Only 74 wells were completed, as compared to 148 in 1934 and 91 in 1933. In proven areas 58 completions resulted in 33 producers and 25 failures. In northeastern Mexico, near the United States border, six wildcat wells were completed, all of which gave little or no encouraging results, except Rancheria No. 3, near Camargo, which is a fair-sized gas well. Four wildcats were drilled just northeast of the Northern fields (heavy-oil district), all of which were failures. A deep test was completed a short distance southeast of the Golden Lane (South fields) in Palo Blanco, which encountered small production not sufficient to exploit. On the Isthmus of Tehuantepec a wildcat well was completed for an estimated initial production of 2000 bbl. daily, a short distance south of the old Jalapa field, which was perhaps the most important new development of the year. Four other wildcats drilled in the Isthmus district resulted in failures. Fields Northern Fields (Heavy-oil District).—In the Northern fields, 18 producing wells and 20 failures were completed, as compared to 34 producers and 71 failures in 1934. The initial production of the new

Jan 1, 1936

By Joseph Jensen, J. B. Stevens

The history of the normal oil field is supposed to show an oil graph starting high in flush production, descending more or less steeply into the curve of settled production and dropping gradually to the vanishing point of economical operation. Together with this, somewhere in the early history of the field, there appears from a vanishing point a graph showing the production of water. During the period of settled production this graph rises higher and, toward the close, unless extensive work is done in the line of correction, rises far above the oil graph to the point at which the cost of operation terminates profitable pumping. Fields that start out with a high relative content of water are generally very short-lived. Fields that never develop a water problem are exceedingly rare. The McKittrick oil field, Kern County, California, with 840 acres of proved ground, 300 wells and a present recovery per acre of 94,598 bbl. from 1898 to Aug. 1, 1930, presents a study which is an apparent reversal of the outlined normal history. Though the history of the field now covers over 30 years of operation, it is still too early and the conditions too unique to project the graph of production to completion. The present conditions and directions of change are most interesting, in that the curve of oil production is remarkably flat and the curve of water invasion, after reaching an appalling height, has shown a definite reversal and a continued decline for 10 years. Early drilling in the McKittrick field was in or prior to 1898. Development continued steadily to 1918 when the present limitations of the field were determined. Shut-offs, according to accepted practice of the time, were made by driving the shoe into a shale stratum or into a tamped-in bridge of sand, rosin and clay. Records of early days speak of three waters: (1) surface water which was fresh; (2) an intermediate sulfur water, encountered below the top oil or tar sand; (3) bottom salt water. In different portions of the field any one of these waters let into a well by faulty completion might require immediate correction to obtain satisfactory production. In many wells,

Jan 1, 1931

By Wallace Ralston

DuRing the year of 1937, the East Texas district produced 211,194,467 hbl. of oil and marketed more than 22,329 million cu. ft. of gas; 3377 oil and gas wells were completed. During this same period 106 exploratory wells were drilled, discovering three new oil fields and one gas-distillate field. Fields East Texas Field.—The East Texas field again led the district as to production and number of wells completed. During the year, 2420 oil wells were completed, making a total of 24,382 producing wells, which produced 171,336,854 bbl. of oil, for a total of 1,156,352,834 bbl. since the beginning. During the year the average bottom-hole pressure dropped 49 lb., making the average bottom-hole pressure 1119 lb. Approximately 3500 wells are making salt water, 20 per cent of them making over 80 per cent of the water. During the month of December, the daily average production of salt water was 119,000 barrels. Talco Field, Titus and Franklin Counties.—The Talco field produced 9,780,948 bbl. of oil during the year, from 637 wells. During the year 472 wells were completed. All of the wells are pumping and 241 are making salt water. This field has followed a normal development and did not exceed the estimated number of acres reported last year. Rodessa Field, Cuss and Marion Counties.—The Rodessa field was extended about 13 miles southwest into Marion County, which added approximately 4000 acres to the field. During the year 260 wells were completed, making a total of 416 producing wells, which produced 12,646,-970 bbl. of oil. The author was unable to obtain figures for the amount of gas produced. The field has two gasoline plants, which had a daily average of 16,558,000 cu. ft. of gas during December, averaging 0.83 gal. per M cu. ft. As of Jan. 1, 31 wells were making salt water. The bottom-hole pressure varies greatly, depending upon the pay from which the well is producing. The average bottom-hole pressure from the Young

Jan 1, 1938

The Jeffrey Company Opens Branch in Seattle The Jeffrey Manufacturing Co. of Columbus, Ohio, announces the re-opening of its Northwestern Branch Office at Seattle, Wash., and the appointment of Mr. Percy E. Wright, Consulting Mechanical Engineer, as District Manager for Oregon, Washington, Alaska, British Columbia and Alberta. Mr. Wright, who has been in the Northwest since 1910, and whose connection with the Jeffrey company dates back to 1902, has' had a wide and varied experience and training in the handling of the Jeffrey line which will enable him to be of great assistance to customers in solving their elevating, conveying and transmission problems. Trade Catalogs To a majority of the public, the name 'DuPont suggests military powder-munitions of war. The DuPont Products Book A-430 (April, 1916) lists 251 distinct commodities made. and sold by this company, many of which are far removed from destructive work. Mining men are fully cognizant of the need for explosives in constructive work, but they may be surprised to know that side by side with the powder and dynamite this company manufactures such peaceful articles as substitute leather, combs and collar buttons. The substitute for leather is Fabrikoid, varying in weight from a quality light enough for bookbinding to one heavy enough for trunks and automobiles, and the combs and collar buttons (with scores of other articles) are made from Pyralin. The book also contains a long list of chemicals, and a shorter list of special products and miscellaneous materials such as charcoal, wood flour and saltpeter. The Jeffrey Manufacturing Co. of Columbus, Ohio, making elevating, conveying, crushing, screening and power transmission machinery, has just issued its. latest Bulletin, No. 177, :featuring self-propelling wagon and truck loaders for handling crushed stone, sand, gravel, clinker, coke, etc. These machines are described as having a capacity of 1 to 1 ½ cu. yd. of material per minute, with power to load crushed stone maximum size pieces through 3 ½ -in. ring and to load trucks or wagons in 3 or 4 min. The self-propelling device is designed to enable one man to operate the loader as it is fed into the pile, and to move the machine about under its own power.

Jan 7, 1916

By Julian Glasser, Arthur Fleischer

THIS country was faced with the possible necessity of utilizing nonbauxitic ores for producing aluminum during World War 11. Construction of four experimental plants to treat such ores by four different processes was authorized1-4 including one at Salt Lake City, for the conversion of Marysvale alunite to metal-grade alumina and potassium sulphate by the Kalunite process.' An aluminum reduction plant in Tacoma, Wash., with a capacity of 50 tons of aluminum per day, was constructed to handle the Kalunite alumina produced at the Salt Lake City plant. The alumina and aluminum plants were Defense Plant Corp. projects operated by Kalunite, Inc. and Olin Industries, Inc., respectively. Kalunite alumina differs from Bayer alumina in several respects, particularly in that the former contains potash instead of soda. The presence of potassium in the alumina feed to the cryolite bath was stated by aluminum technologists to be undesirable under the usual operating conditions of aluminum furnaces. In 1940, about 20 tons of Kalunite alumina produced in the Kalunite pilot plant, were reduced electrolytically in a 10,000 amp furnace at Battelle Memorial Institute and at the aluminum reduction plant at Neuhausen, Switzerland. These relatively small scale tests indicated that satisfactory commercial aluminum could be produced in a practical manner. The Tacoma plant reduced about 2,500,000 lb of Kalunite alumina to produce more than 1,200,000 lb of aluminum, in accordance with the accepted gractice for reducing Bayer alumina. It was desired to determine whether commercial aluminum could be produced on a large scale and to establish the technological differences in commercial reduction practice between Kalunite and Bayer alumina. In the course of collecting data, the effects of the abnormal chemical composition and physical properties of Kalunite alumina were observed wherever possible. Tacoma Reduction Plant The reduction plant had two pot lines, each with 120 cells in series, operated at approximately 32,000 amp. Each cell was provided with a single rectangular Soederberg continuous anode, with side-pin electrical contacts. Each cell was hooded and ventilated through a stack connected to 14 other cells, with 25,000 cfm blower. When the plant started operation in 1942, all of the cathode linings were of block construction. Rebuilt cells were of rammed paste construction.

Jan 1, 1952

By L. W. Kempf, K. R. Van Horn

DURING the recent development of aluminum alloys for free-cutting screw-machine rod, it became desirable to know something of the solubility of lead and bismuth in liquid aluminum and in some aluminum alloys. The literature is not particularly helpful in supplying this information. These portions, therefore, of the constitutional relationships of aluminum-bismuth and aluminum-lead alloys were investigated by thermal analysis and by chemical analysis of samples taken from aluminum-rich melts in equilibrium with precipitated lead or bismuth. The solubility of lead and bismuth in some liquid aluminum-copper alloys was also investigated. Some consideration was also given to the solubility of these elements in solid aluminum. Among the earliest investigators of the aluminum-lead and aluminum-bismuth systems was Wright,1 who reported that melts of aluminum and lead formed two layers indicating limited liquid solubility. Under his conditions, the aluminum-rich layer was reported to contain 1.91 per cent Pb and the lead-rich layer, 0.07 per. cent Al. Subsequently, Pecheau2 found that in aluminum-rich alloy melts with more than 10 per cent Pb three layers were distinguishable. He reported that the middle layer contained from 3 to 10 per cent Pb. He also found that the melting point of aluminum appeared to be lowered slightly by the addition of lead. Gwyer3 investigated these alloys and found evidence of a slight lowering of the freezing point of aluminum by the addition of either lead or bismuth. He found no evidence of solid solubility in either case and made no attempt to determine the liquidus curves. Hansen and Blumenthal4 reported that the addition of lead distinctly lowered the solidification point of aluminum. They also found that bismuth lowered the melting point of aluminum. Guillet5 reported almost complete mutual immiscibility for the aluminum-bismuth alloys in the liquid state. Bohner6 examined the effect of various concentrations of lead and bismuth on the electrical conductivity of aluminum. He found decreases in conductivity on annealing at 500° C. as compared with the conductivity of the same alloys on annealing at 300° C.

Jan 1, 1938

By Daniel N. Beshers, Ralph H. Condit

An expression for the diffusion coefficient of inlerstitial atoms in the bcc lattice is derived which takes account of jumps between tetrahedral and octahedral interstices. The results are applied to the case of carbon diffusion in iron to find values for jump frequencies of the types, octahedral-tetrahedral, tetra-hedral-tetrahedral, and tetrahedral-octahedral. ThERE has been renewed discussion1-5 concerning the mechanism of diffusion of interstitial atoms in the bcc lattice. This lattice has both octahedral and tetrahedral interstices, and it has been pointed out that the interstitial atoms may make jumps of the octahedral-octahedral type, hereafter called o-o, octahedral-tetrahedral, o-t, and tetrahedral-tetrahedral, t-t. Doubt has been cast on the applicability of snoek's8 model for internal friction to some interstitial migrations in bcc lattices wherein he proposed 0-0 jumps as the principal mechanism of migration. Also, the anomalous excess diffusion of carbon in iron at high temperatures4 has been ascribed to t-t jumps,2,3 even though the sites normally occupied are octahedral. In this paper an expression is derived for the diffusion coefficient, taking account of the three types of jump mentioned. The relationship of the coefficient to the corresponding internal friction relaxation time is found for the limiting case corresponding to Snoek's model. These results are applied to the case of carbon in iron. In Fig. 1, the structure is shown with the locations of the interstices. Each o site has four t site neighbors coplanar with it, and each t site lies halfway between two o sites. There are four t site first neighbors of a t site lying at the vertices of a tetrahedron. Let the average fraction of atoms occupying o sites and t sites be No and Nt, respectively. Since there are six o and twelve t interstices per unit cell having a lattice parameter, a, the concentration of interstitial atoms will It will be assumed that three types of jumps may be distinguished, t — t, t — o, o — t,for which the jump

Jan 1, 1968

No records have been found of coal in the old Spanish documents, although some mention of it probably exists in manuscripts. Coal was found in Mt. Diablo, in Contra Costa County, about five miles south of the San Joaquin River in 1852, but the first mine, the Teutonia, was located in 1858. The deposits are located on both sides of a high ridge, and vessels of 1,000 tons burden could ascend the river to the nearest point to the mines.1 In 1854, coal was found about four miles from Oroville, on the Feather River, in Butte County. Development work was started and in 1856 a mine was opened. From the description the coal was likely a variety of lignite and probably never amounted to anything commercially, as it does not appear again in the records 2 The more valuable mines at Mt. Diablo were opened in 1859 and 1860. By 1867 there had been 11 mines started and at that time five were in operation. The seam conditions were much disturbed and lack of knowledge of them caused much waste of effort and money. All of the coal excepting that used locally and in nearby towns, was shipped to San Francisco, and largely used for steam purposes. The first receipts were in 1861-6,620 tons. A railroad to the river had been constructed and opened in February 1866. The Corral Hollow field in Alameda County was found and prospected to a small extent in 1862. Two mines were opened but little work was done and the field was then abandoned. Good exposures were rare and the cost of underground exploration was then prohibitive. The Commercial mine produced coal in 1869 and 1870, but a fire in the latter year destroyed the tipple and communications to the mine. The Livermore mine was abandoned after 18 months operation in 1875 and 1876 and no other work was done here until the nineties. In 1867 Hyne reported the presence of coal in workable thickness, and of good quality, on the property of the Pacific Coast Petroleum Company,

Jan 1, 1942

By J. Campbell

Long freezing range casting alloys are particularly susceptible to a type of porosity which is observed to form in layers parallel to the supposed position of the isotherms in the solidifying casting. Under favorable conditions (which appear to be typified by low-temperature gradients in the casting giving rise to a wide and more or less uniform pasty zone, and which arise from several factors, particularly: a) wide freezing range alloy, b) high thermal conductivity of metal, c) low thermal conductivity of mold, and d) high mold temperature3) layer porosity has been observed in many different casting alloys: copper,' aluminum, magnesium,' steels, and high-temperature alloys.3 Baker4,5 and later cibula6 argue that layer porosity occurs because of thermal contraction, in a manner analogous to hot tearing. In outline, the theory consists of the establishment of a coherent dendrite network by the impinging of dendrite tips. Subsequent shrinkage imposes tensile stresses on the network which tears perpendicularly to the stress, i.e., parallel to the isotherms. If these tears are not filled by the inflow of residual liquid then layers of porosity result. Baker7 attempted to test whether the porosity was the result of thermal contraction by casting test pieces in a mold designed to accentuate hot tearing. However, no significant increase in porosity was observed. This negative result of Baker's critical experiment appears to be substantiated by numerous observations, particularly the experiments by Lagowski and Meier8 on Mg-Zn alloys covering the range of zinc contents up to 30 pct Zn. These clearly reveal that the maxima for the incidence of hot tearing and layer porosity are well-separated, occurring at 1 and 6 pct Zn, respectively. Furthermore, the thermal contraction maximum occurred at 1 pct Zn, indicating that hot tearing is associated with contraction in the solid state, and not with porosity. These observations are further substantiated by the elementary consideration that the thermal contraction of the casting is likely to produce (if anything, since the temperature difference across casting of high thermal conductivity, such as aluminum and copper, is likely to be negligible) a compressive stress on the

Jan 1, 1969

By E. Keller

Some years ago the writer's attention was called to the fact that rolling-mill scales from auriferous copper do not have the gold content proportional to the gold contained in the copper from which they are derived.' So, later, he made a few simple experiments, which are described herewith. In order to test the gold movement on the changing surface of a copper plate under the influence of oxidation, plates 6 in. by 8 in. by 1 in. (15.2 cm. by 20.3 cm. by 2.5 cm.) of converter copper, refined, of 99.29 per cent. purity, and leaded copper with a content of 95.65 per cent, copper, were obtained. Ten cuts were made through the thickness of the plates along the longitudinal center and the silver and gold content ascertained in each of the 10 samples in both plates, as shown in the accompanying illustration. The assay results, recorded in Tables 1 and 2, show that the gold distribution is relatively uniform in both plates, while silver has greater variations, especially in the leaded plate. The plates subjected to oxidation were placed in a red-hot muffle for about 2 hr., two small scarifiers being used as supports. Arranged alongside each other, they nearly filled the width of the muffle, and so were practically under equal conditions of heat and draft. The accurate observance of the time was not possible, however, because of other work, but the time of the exposure of each plate in a pair was identical. At the end of each period, each plate was plunged into water and completely freed of scale, which was carefully collected, dried, weighed, and analyzed. Samples of the plates had also been taken of the molten metal and duly analyzed. Table 3 contains the analytical data for the two plates and their several sheets, or layers, of oxide scales. These figures show that in the oxidations of the converter copper the silver is fairly uniform, while the gold is highly irregular and especially low in the first layer. In the oxidations of the leaded copper plate, the silver and gold contents are variable; however, this irregularity is due to two different causes. The

Jan 1, 1919

By K. G. Davis, P. Fryzuk

VALUES for the equilibrium distribution coefficient, ko, are required for solidification studies. The procedure generally adopted1-3 is to progressively solidify alloy rods over a range of growth rates, under conditions where a high degree of convective mixing is present in the melt. The measured effective distribution coefficients are plotted as a function of growth rate, and the extrapolated value at zero growth rate is taken to be the equilibrium ko. The method is limited by the experimental difficulty in obtaining steady growth rates less than approximately 10-4 cm per sec. Extrapolation from rates greater than this can lead to inaccuracy. In the present investigation, an alternative method for determining ko, previously used by the authors for the Ag-Sn system,' was applied to alloy of thallium in tin. Specimens were grown under conditions where convective mixing was absent, and experimental concentration-distance curves in the region of the initial transient were compared with curves calculated for trial values of ko. The ko which gave the best fit was taken as the correct value. To obtain the calculated curves, a value for the diffusion constant in the liquid near to the melting point was needed. This was determined by the capillary-reservoir method. Diffusion Constants. Details of the experimental procedure used by the authors in the capillary-reservoir technique have been described in previous papers,5'6 the only variation being in the use of Tl204, a ß emitter, as tracer, in contrast to previous work where ? emitters were used. The activity of a ß-emitting sample, as measured in a Geiger counter, is proportional to the surface area. To measure the concentration of thallium along the capillary after diffusion had taken place, the solidified capillary (1 mm diam) was cut into 2.5-mm lengths and each length compressed between parallel steel plates to form a disc approximately 5 mm in diam. The discs were placed in a flat-bottomed dish, covered by a thin lead shield with a central aperture, and counted in a 0 counter with fixed geometry. Each disc was etched lightly in a dilute solution of nitric and hydrochloric acids a short time before counting, to eliminate sur-

Jan 1, 1968

By R. W. Hertzberg, R. W. Kraft

A study of the fracture behavior of unidirectwn-ally solidified Cu-Cr eutectic alloy was performed. Fractured whiskers, grain boundaries, and the interface between proeutectic Cr dendrites and the Cu matrix were the predominant failure initiation sites where grain size was larger. Strain induced void formation was restricted at lower solidification rates. This was attributed to a lack of adequate plastic constraint and a probable preferred orientation. A modification of the Crussard et al. model is presented to explain the appearance of "elongated dimples" on the shear fracture surface. A Cu-Cr alloy containing about 1.8 at. pct Cr solidifies by a eutectic reaction forming filamentary crystals of chromium within a continuous copper solid solution matrix.' Webb and Forgeng2 have shown by bend tests that the extracted chromium filaments, which are ordinarily curved and branched (due to random solidification), have the high strengths associated with whiskers. If an ingot of the eutectic alloy is unidirectionally solidified and appropriate control exercised over the thermal gradient, growth rate, and impurity level, the chromium fibers can be forced to solidify as fibers which are substantially parallel to the growth direction, Fig. 1. Uniaxial tensile tests on these straight chromium fibers extracted from controlled ingots3 have confirmed the earlier bend test results on curved fibers. Combining the facts that the strength and modulus of the chromium filaments are higher than the more ductile copper matrix and assuming that a "good bond" exists between the two phases, the Cu-Cr controlled eutectic system fulfills the requirements for effective fiber reinforcement of ductile matrices as established by studies on fiber glass reinforced plastics and other two-phase systems.4 Therefore, it was decided to study the fracture characteristics of morphologically simple specimens of chromium fiber reinforced copper (i.e., specimens of the controlled eutectic with substantially parallel reinforcing fibers) with the objective of establishing the dominant aspects of fracture. PREVIOUS WORK Comparatively little work has been done to understand the manner in which ductile alloys fail be- cause of the limited demand for this kind of information. Ordinarily ductility is specified for safety or similar reasons and when a part deforms plastically its useful life is terminated. In recent years, however, a number of investigators have begun to

Jan 1, 1963

By Robert H. Richards

THE Institute of Mining Engineers has shown so much interest in the educational problem of profitably combining theory and practice, that it seems especially appropriate to lay before its members the methods and aims of the mining laboratory of which I have charge, and in which one form of combination of hand with head work is now being tried. If anything may be contributed toward the solution of this problem by the discussion which follows, my purpose mill be attained. Whether it was wise or not to establish a mining school so far from the principal mining centres, does not now enter into the question. Given, a mining school already begun, how shall it be made most efficient in developing engineers who are trained to think for themselves as well as versed in the works of others ? This is the question with which we have had to deal. In considering the bearing of this laboratory work upon the students' preparation, it will be convenient to take it up under five different heads: 1. The methods and aims of the laboratory. 2. The advantage to students of having a part, at least, of their practical work in the curriculum of their school. 3. The advantage to be derived by mine; and works. 4. Degree of accuracy which may be attained in working ores on a small scale. 5. Reslts of work in the laboratory. 1. The Methods and Aims of the Laboratory.—During the May meeting of 1873, held in Boston, I had the privilege of reading before you a paper stating the plan; and aims of this laboratory. Since that time me have been constantly following out those plans, and are more than ever convineed that me are working in the right direction. We do not feel that the time we have spent has been in any sense thrown away. Perhaps the aims of the laboratory can be most clearly shown by illustration. Many young engineers have school thinking that they know everything. They go to the works, and expect to teach the superintendent something and the men a good deal, regardless of the fact that it is this spirit that has prejudiced workmen against schoolmen. They are often more trouble than they

Jan 1, 1879

By W. D. Bennett

AN interesting effect has been observed in the vacuum etching of titanium in the high temperature ß phase. Using a high vacuum annealing furnace, operating at less than 2x10-6 mm with a tubular titanium liner, it has been found possible to etch polished metallographic specimens at different temperatures between room temperature and 1000°C without contamination or increase in hardness.' Heat etching of titanium has been reported by other workers,' but the following example is of interest as an experiment under high vacuum in the absence of any contamination. Two polished specimens of iodide-processed titanium are placed at different positions along the axis of the furnace corresponding to temperatures of 900" and 800°C above and below the a-ß transus. The specimens are then raised to these temperatures and annealed simultaneously for 3 hr under the same high vacuum conditions. After cooling and withdrawing the specimens, their surfaces are photographed without further treatment. Figs. 1 and 2 show the results for the 800" and 900°C specimens, respectively. Fig. 1, corresponding to a vacuum etch in the a region, shows a typical equiaxed structure with what appears to be a slight shift of grain boundaries. Fig. 2, corresponding to a vacuum etch in the ß region, shows an equiaxed type of structure with the growth of striations in certain grains. The striations are only superficial, as a light polish and chemical etch restores the clean equiaxed structure. The vacuum etch, occurring as it does above the a-ß transus, records the state of the metal in the ß phase by means of the surface relief produced by the selective evaporation of metal from different grains; the metal itself reverts to the equiaxed a on cooling. The nature of the ß etch" (Fig. 2) suggests that, in transforming from the close-packed-hexagonal a to the body-centered-cubic ß lenticular-shaped laminae are formed parallel to common planes of the two structures. This would explain why some grains appear to be unaffected by the etch. The technique has interesting possibilities in the investigation of the mechanics of high temperature transformation. Acknowledgment This note is published by permission of the Deputy Minister, Dept. of Mines and Technical Surveys, Ottawa, Ont., Canada.

Jan 1, 1956

By W. T. Turrall, D. Porter

The paper describes a machine developed for the purpose of concentrating clear optical grade fluorspar crystal from a feed material containing less than 1 pct impurities. The principle of concentration is based on the fact that in a liquid having an index of refraction equal to that of fluorite (n — 1.434) clear crystals are invisible, whereas crystals containing occluded impurities absorb a part of the light. As the crystals pass through a light beam, undesired crystals give themselves away by creating a shadow on a photoelectric receiver. .The shadow is converted by the photoelectric cell into an electric pulse. An electronic circuit amplifies this pulse and commands the operation of a mechanical concentrator. Hp HE crystal laboratory, Dept. of Physics, Massa--*- chusetts lnstitute of Technology, was confronted with the problem of obtaining a supply of optical grade calcium fluoride (CaF,) for use in growing synthetic CaF, crystals. A search of the known fluorspar deposits did not indicate that any quantity of optical spar could be obtained. Even the best material had to be sorted by hand to remove impurities. The process for growing CaF, crystals developed by Professor D. C. Stockbarger of the Dept. of Physics, M.I.T., necessitates very pure feed materials. Exclusion of impurities is required, even in amounts detectable only spectrographically. The impurities occurred as minute inclusions of SiO,, BaSO,, CaCO,, FeS2, water or air. Crystals up to 4 in. in diam and weighing several pounds are made by the Harshaw Chemical Co. in Cleveland. Since the time required to grow a 4-in. crystal is about one week, and since the cost of manufacture is high, removal of impurities by any concentration method appeared practical. The mineral engineering section of the Dept. of Metallurgy undertook to investigate the possibility of concentrating clear optical fluorspar, —4 mesh + 10 mesh, from a feed containing over 99 pct CaF,. Various innovations of the known methods of concentration were considered, but in each case the minute amount of impurities associated with the crystal produced such extremely small differences

Jan 1, 1953

By W. T. Turrall, D. Porter

The paper describes a machine developed for the purpose of concentrating clear optical grade fluorspar crystal from a feed material containing less than 1 pct impurities. The principle of concentration is based on the fact that in a liquid having an index of refraction equal to that of fluorite (n — 1.434) clear crystals are invisible, whereas crystals containing occluded impurities absorb a part of the light. As the crystals pass through a light beam, undesired crystals give themselves away by creating a shadow on a photoelectric receiver. .The shadow is converted by the photoelectric cell into an electric pulse. An electronic circuit amplifies this pulse and commands the operation of a mechanical concentrator. Hp HE crystal laboratory, Dept. of Physics, Massa--*- chusetts lnstitute of Technology, was confronted with the problem of obtaining a supply of optical grade calcium fluoride (CaF,) for use in growing synthetic CaF, crystals. A search of the known fluorspar deposits did not indicate that any quantity of optical spar could be obtained. Even the best material had to be sorted by hand to remove impurities. The process for growing CaF, crystals developed by Professor D. C. Stockbarger of the Dept. of Physics, M.I.T., necessitates very pure feed materials. Exclusion of impurities is required, even in amounts detectable only spectrographically. The impurities occurred as minute inclusions of SiO,, BaSO,, CaCO,, FeS2, water or air. Crystals up to 4 in. in diam and weighing several pounds are made by the Harshaw Chemical Co. in Cleveland. Since the time required to grow a 4-in. crystal is about one week, and since the cost of manufacture is high, removal of impurities by any concentration method appeared practical. The mineral engineering section of the Dept. of Metallurgy undertook to investigate the possibility of concentrating clear optical fluorspar, —4 mesh + 10 mesh, from a feed containing over 99 pct CaF,. Various innovations of the known methods of concentration were considered, but in each case the minute amount of impurities associated with the crystal produced such extremely small differences

Jan 1, 1953

By Jack Washburn

The c axis indentations in zinc crystals were shown to undergo 100 pct strain recovery on heating. The mode of deformation and the details of the polygonization and collapse of indentations were found to be consistent with a number of predictions of dislocation theory. IT has been observed that indentations of the type made by Jillson in zinc crystals can, under certain conditions, be macle to shrink in size and even completely disappear on heating the crystal, Fig. 1. The details of the process are interesting in that they afford a simple experimental illustration of several predictions of dislocation theory. The indentations were made as shown in Fig. 2 by dropping a 0.2 g indenter with a hemispherical point on a cleavage face of a. zinc crystal. Such indentations can be made through relatively great thicknesses in the c-axis direction. The material close to the struck surface, where mechanical twinning and complex distortion occurred, was removed by cleavage. The remaining crystal, which was about 1 cm thick, contained a dent that was accurately round and almost the same size on both top and bottom surfaces. The indentation had the form of a flat cone of half angle approximately 89°, having a rounded apex and a rounded intersection with the unde-formed part of the crystal. The mode of deformation was primarily slip on the three equivalent systems in the basal plane. Six types of dislocation loop (plus and minus in each of the three directions) as shown in Fig. 3 are required by the geometry of the indentation. The maximum shear strain in the radial direction amounted to approximately 2.5 pct. Slip was distributed in the usual, microscopically nonuniform, manner among the possible parallel slip planes. When an indentation was made close to a (2110) surface, three separate sets of interpenetrating slip bands appeared as shown schematically in Fig. 3. A small biaxial tension strain in the plane of (0001) is also a geometrical necessity for the formation of an indentation. If the sides of the dent are tilted l° with respect to the undeformed surrounding crystal, and the surround-

Jan 1, 1957

By H. P. Bucker, M. Felsenthal, F. R. Conley

INTRODUCTION In the intensive analysis of core samples from oil raservoirs, there is a recognized need for pore sizc distribution data. Such data, if collected with adequate precision and in sufficient quantity, should contribute to a better interpretation of fluid flow phenomena than is now possible from a knowledge of permeability and porosity data alone. It is hoped, for instance, that pore size distribution data may eventually provide a useful aid for predicting whether a water flood, or other secondary recovery methods. will he successful in a given reservoir.' Apparatus tor measurlng pore size distribution by mercury injection at pressures ranging from 0 to 2,000 psi have been described in the literature.2,3,4 All of these apparatus are somewhat complex and fairly expensive. Furthermore, the callbration of some of the apparatus is not always easy. Great difficulty, for instance, was experienced in obtaining reproducible pressure-volume correction data for the mercury pump shown in one of the references. An apparatus was therefore developed which was less complicated and less expensive than those of previously described designs. This apparatus is, in some respects, an improved version of a previously described low pressure apparatus' (maximum pressure 150 psi) which did not cmploy a mercury pump but instead used a precision bore glass tube for measuring the injected volumes. Tests were performed with the apparatus from vacuum to 2,000 psi and it was observed that the apparatus furnished reproducible pressure-volume correction data. In addition. it was noted that the maximum correction was small. precision of measurement was high. and operation of the entirc apparatus was relatively easy. Although the apparatus was designed exclusively for samples of 1 in. diameter and 1 in, length or smaller, it could be modified without much difficulty for larger samples, if desired. APPARATUS Arrangement of the pore six distribution apparatus is shown schematically in Fig. I. The heart of the apparatus is a steel sample chamber surmounted by a precision bore capillary glass tube. A mercury reservoir is connected to the lower half of the sample chamber. The top of the glass tube is in communication with a

Jan 1, 1957

By Ralph Arnold

The lure of possible new oil fields shut off development of the older Montana fields during the year 1928, cutting down the total production to less than the 1927 mark. However, with the production of oil worth approximately $7,000,000 during the past 12 months, Montana oil producers pushed their total up to $44,000,000 taken from two principal fields during the past 8 years. The highest prices in the United States for oil of similar gravity gave northern Montana producers a decided advantage and brought up the value of the oil to about the same value as the 1927 production, although the oil runs were 1,000,000 bbl. less. Production by Fields The discovery of two new oil fields in the Sweetgrass Arch, in north central Montana, in 1927, diverted attention from the Kevin-Sunburst field. Many operators turned their attention to wildcats and practically all of the drilling contractors were called into the new Pondera and Bannatyne fields. Although discovered in 1927, the Pondera field developed its first commercial production in March of 1928. Mild interest was followed four months later by a rush of operators, and by August practically every string of tools had been moved from the Kevin-Sunburst field to Pondera. The fall months found 40 wells drilling in this field and as the year closed there were 100 producers. Pondera field is remarkable in that every well thus far drilled within the structure proper has been a producer. Dry holes have been drilled around the field, but none within an area of four sections. Experts estimate that Pondera will produce 5000 bbl, of oil to the acre. The producing area now outlined by wells drilled is expected to produce around 15,000,000 bbl. of oil. Pondera crude brings $1.75. This field has one pipe line and a second line is being laid. Lack of a pipe line delayed development of the new Bannatyne field, south of Pondera, and also in the Sweetgrass Arch. Bannatyne has 11 producing wells scattered over an area of approximately three sections. Bannatyne is a sand field with a 70-ft. sand in the lower Jurassic, which core-drill tests show to be 60 per cent. saturated. With the completion

Jan 1, 1929

By Joseph Jensen

Recent developments related to petroleum engineering discussed in this paper are: 1. Drilling wells in with oil or the use of chemical compounds or (Imud solvents" for removing rotary mud from wells in order to increase or make possible oil production. 2. Comparison of results of electrical logging methods in locating water, as shown in a recent test on a well in the Los Angeles Basin. 3. A new method for logging formations through casing, known as the Stratagraph. Drilling Wells in with Oil or the Use of Chemical Compounds or Mud Solvents During the time that the California fields showed high gas pressures, the pressure of the gas within the formation was sufficiently great to break down the mud wall or cake formed while the well was drilling. That this did not always occur was demonstrated by the fact that in some of the older fields new wells sometimes had substantially higher initial productions than other wells near by. The explanation seemed to be that some sands were mudded off in the original drilling. Their pressure was then not great enough to break down the mud wall in competition with the higher pressure of the sands, but the situation reversed itself so that a later well benefited by the pressure in these originally weaker sands. As time passed, in wells deeper than 5000 ft. the difficulty of bringing wells on production became more pronounced. This led to a hunt for substitutes, of which a number have been tried. The one that has proved most successful in our experience at Ventura is known as the Nobs solvent. At well No. 1 of the Associated-Ventura Land & Water Co. when it was recompleted in February 1936, about 10 days were spent in trying to bring the well in in the regular manner, but only about 113 bbl. of water could be swabbed from the well, and even this quantity decreased as time passed. The Nobs solvent was spotted in the bottom of the hole opposite the perforations, inverted Guiberson swab rubbers were used on the drillpipe and the hole was down-swabbed in stages, beginning

Jan 1, 1937