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By Ben Gumpertz

THE important factors in any study of the screening of sand with a gravel enve-lope, as applied to use in oil wells, are: (r) sand size and shape, (2) gravel size and shape, (3) ratio of gravel size to sand size, (4) flow velocity, (5) viscosity of the fluid. Perhaps the first extensive investigation of the function of gravel in screening sand was performed by Coberly and Wagner,1 from which the following conclusion was drawn: "The diameter of the largest grains in a single classified sand suitable for gravel packing is approximately 23 times the grain size at the ten-percentile analysis of the formation sample." This applies to sands classified by Tyler screens and is for gravel grains of the maximum size that could be used to form a stable bridge. Field practice has shown that the screening effect of a given gravel for a given sand apparently varies with the flow velocity.2 Also, it has been assumed by some opera-tors that the thickness of the walls of the gravel envelope surrounding the well has little effect upon the screening process. It is thought by others that a narrow envelope of gravel might form an ineffec-tive screen. Thus the purposes of this work are: I. To investigate the effect of gravel-sand size ratio upon screening action under the condition of varying flow velocities. 2. To investigate the effect upon screen-ing action of varying the thickness of the gravel screen.

Jan 1, 1940

By C. R. Garr, A. R. Troiano

FLAKING or hair-line crack formation has been a major problem confronting the producer of large alloy steel forgings.' Today it is generally conceded that hydrogen in one or more forms in alloy steel sections is a requisite for flaking. Hence an obvious remedy is a thermal cycle that reduces the hydrogen content to some low level. In practice, this generally means holding the material at some subcritical temperature for a period of time depending on the size of the ingot or forging. Another method that will suffice in some cases is to cool large forgings slowly, i.e., bury in ashes. In practice, this hydrogen bake is sometimes accemplished inadvertently by a series

Jan 1, 1958

By T. E. Wayland

The general geology and mineralogy of bentonite, including pertinent technological details of clay minerals in the montmorillonite group, are summarized. Worldwide occurrences of bentonite deposits are reviewed, with emphasis on geologic methods and economic principles of evaluation. Active mining districts are described and areas with potential for current and future development are assessed. The production history of bentonite, principal producers, major consumers, and indicated trends are noted; also attention is directed to the hundreds of minor industrial uses of this versatile material, ranging from the manufacture of (A)cid neutralizers to (Z)eolite water softeners. Recent significant results of both basic and applied research are reported, with suggested lines of investigation for current and near-future consideration.

Jan 1, 1972

By G. Sachs, G. Espey

IT is well known that high residual stresses are created in tubing by the sinking process, in which no internal tool or mandrel is used.1-4 In this process, the wall thickness is usually slightly increased.4,5 In tube drawing with a plug, the residual stresses are gradually reduced with increasing reduction of wall, and, by the conventional approximation methods of stress measurement, no stress is detected in tubing in which the wall reduction is over 50 per cent of the total reduction in cross-sectional area.1-6, It has also been observed that higher stresses are set up by the use of wide-angle dies than by the use of acute dies.2 The actual stress distribution in drawn .tubing has been investigated by a few workers,7-9 but has not been related to the conditions of the drawing process: Some attempts have been made to correlate accelerated cracking tests for stresses in brass products with the magnitude of the circumferential stresses and the condition of the metal.1-10 MATERIALS AND PREPARATION The material used in this experiment was commercial cartridge-brass (70 per cent Cu, 30 per cent Zn) tubing in the straightened and annealed condition.‡ This tubing was of various outside diameters and had a wall thickness of 0.032 in. It was sunk to 1/2-in. outside diameter by means of an experimental 10,000-lb. hydraulic draw-bench, with a maximum drawing speed of 8 ft. per minute. All dies were of 1/2 -in. diameter. Various die materials and contours were used in order to study the effect of die design on residual stresses in the tubing; the specifications for the dies are given in Fig. I. Castor oil was used throughout as lubricant. Chattering occurred in sinking some of the tubing, particularly when dies having the more acute angles were used, but the tubes showing chatter marks did not differ markedly from those with a smooth surface regarding the magnitude of residual stress. The source of the chattering has not yet been revealed. The wall of the tubing becomes thicker during sinking, as previously observed 4,5 The increases in wall thickness were 3, 7 and 9.5 per cent on the average for 6, 20 and 33 per cent reductions in diameter, no effect of the contour being noticeable. The reductions mentioned throughout this investigation do not consider this fact, but are reductions of the outside diameter. For the evaluation of the residual stress two fundamentally different methods were used. The approximation method1,11 of splitting a certain length of tubing was employed to obtain a bird's-eye view of the effect of various drawing conditions on the circumferential stress measured by the diameter change occurring on splitting. For the determination of the complete stress

Jan 1, 1941

A letter from Mr. E. F. Cykler, Secretary-Treasurer, informs us that the Engineering Societies Club of Hawaii has been established, and that a member of any one of the following organizations is eligible for membership in the Hawaiian club: American Society of Civil Engineers, American Society of Mechanical Engineers, American Institute of Mining Engineers, American Institute of Electrical Engineers, American Society of Naval Engineers, American Railway Engineering Association, American Society for Testing Materials. The main purpose of this club is the entertainment of visitors from the various national organizations above mentioned, and the Secretary will be glad to hear from any one who is making a trip to the Hawaiian Islands. Mr. Cykler's address is 2A Pantheon Building, Honolulu, Hawaii.

Jan 12, 1917

* A demonstration pipeline for transporting coal will be constructed by Pittsburgh Consolidation Coal Co, at the Georgetown strip-mining operation near Cadiz, Ohio, The 12-in., 17,000-ft line, special crushing and preparation equipment, and pumps especially designed for the operation will cost about $550,000. A slurry of fine coal and water will be fed into the line and moved through it under pressure. * Sulphur resources in the U.S. are being rapidly exhausted with no new major deposits being found, This common mineral may become one of the most strategic items during the next five years. Recovery of sulphur from pyrites is being considered in case of an emergency. Already the British have adopted stringent measures to conserve sulphur supplies.

Jan 3, 1951

By Alden B. Greninger

THE study of mosaic structure of crystals1 has been confined until recently to the field of theoretical physics Crystallographers, in general, have neglected the subject, although X-ray crystallographers constantly make use of formulas for intensities of X-ray reflection as modified by mosaic structure Work on mosaic structure has centered chiefly on the task of proving or disproving the secondary-structure theory of Zwicky,2 and very little attention has been paid to the visible imperfections of crystals A Goetz has been responsible for most of the supposed experimental confirmations of Zwicky's theory 3 On the other hand, Smekal,4 and Orowan,5 among others, maintain that these is neither theoretical nor experimental evidence to substantiate Zwicky's secondary structure

Jan 1, 1935

By W. Chubb

FOR the past several years there has been considerable interest in the development of zirconium and zirconium alloys for application in nuclear reactors. In a portion of the development work being conducted, attention has been given to the development of high-strength zirconium alloys. One of the most outstanding alloys developed in the course of this work is Zr-4 wt pct Sn-1.6 wt pct Mo.' Fabrication and Test Methods Over 50 ingots of zirconium containing either tin and molybdenum or both have been evaluated in the process of selection of an optimum composition. Most of these were prepared as 20-g are-melted buttons; a few were prepared by induction melting. All ingots were prepared by the me of Foote Mineral

Jan 1, 1958

By P. J. G. duToit

The continually growing shortage of skilled underground miners, the escalating costs of labor, supplies and equipment, and the indisputable example of "what can be done" by our friends in the space-travel field, seem to be catalysts that are accelerating improvements in underground mining technology. The search for an economic, automated continuous excavation method that would produce rock at the mining face in sizes suitable for automated transportation directly into the rod-, ball-, or autogenous grinding mills is continuing. New mining methods and techniques were devised and many improvements on old methods and techniques came forth at an increasing pace that reflected a widely spreading policy among mining men to shun the shackles of conservatism and to forge ahead and venture into newer ideas.

Jan 2, 1967

Seismological Society of America, University of California, Berkeley, Calif. Perry Byerly, Secretary. The Bulletin of the Seismological Society of America is issued quarterly. The four numbers each year are collected in a volume; in 1932 the 22nd annual volume was published. The articles contained in the copies of the Bulletin are not, perhaps, of direct interest to a mining engineer but many of them will interest geologists. To indicate the type of articles contained in the Bulletin, the following titles, taken from the current issue, for June, 1932, are given: The Japanese earthquake of march 28, 1925, and the Problem of depth of focus; the earthquake in Santa Monica Bay, California, on August 30, 1930; a new vertical seismography. For copies of the bulletin or information concerning them, address the above.

Jan 1, 1933

By C. Le Neve Foster

The object of this paper is to offer a few suggestions for improving the mining and mineral statistics presented by the governments of various nations on both sides of the Atlantic. At the present time one may fairly complain of' two evils—lack of uniformity in some cases and want of completeness in others. The consequence is that the statistics are either less plain than they might be, or are useless for comparisons, or fail to present a faithful picture of the state of the mining industries of a country. The principal subjects upon which information is desirable are: the amount and value of the mineral products raised and the number of the mining population. With these data it is possible to form an estimate of the importance of the mining industries of any given

Jan 1, 1894

By Dol Duwez, R. H. Willens

A technique is described by which metastable alloy phases can be obtained by very rapid cooling from the liquid state. The results obtained so far have lead to; 1) extension of solubility limits beyond their equilibrium values, 2) new phases not found under equilibrium conditions, and 3) amorphous alloys. MANY new nonequilibrium phases have been found in alloys rapidly cooled from the liquid state. The technique used in these investigations essentially consisted of propelling a small molten globule of an alloy against the inside surface of a rotating copper cylinder. Since these original experiments were performed, the technique has been greatly improved. The purpose of this paper is to describe in detail, for the first time, a simple and efficient apparatus for producing foils of alloys which are rapidly cooled from the melt and to summarize some of the observations made on these alloys. I) FAST COOLING APPARATUS In the original fast cooling apparatus used by Duwez, Willens, and Klement,' the alloy was melted in a graphite container having the shape shown schematically in Fig. 1. A shock tube was attached to one end of the graphite part to supply the pressure for ejecting the molten globule. The globule was received on the inside of a rotating cylinder located about 0.5 in. from the exit of the graphite container. The globule trajectory made an angle of about 15 to 25 deg with the tangent to the cylinder at the point of

Jan 1, 1963

By Hsun Hu, B. B. Ruth

The rates of migration of high-angle boundaries in zone-refined aluminum crystals rolled 20 to 70 pct in the (110)[i12/ orientation were studied. Following a recovery anneal at an appropriate temperature to stabilize the polygonized structure, boundary migration rates of artificially nucleated grains were measwed isothermally at several temperatures. Results indicate that the rate of boundary migration depends strongly on the amount of deformation and on the cell size of the polygonized matrix, and is related to the driving free energy by a power function. The degree of anisotropy in growth 0.f the re crystallized grains nn&apos;th preferred mientation is independent of deformation; the migration rates of the fast-moving and the slow-moping boundary segments of a gowing grain differ by as much as one order of magnitude. The actir\ation energy fm a grain boundary migration, although nearly the same for both the fast-moving and the slow-moving boundaries for a given deformalion, decreases from 45 to 30 kcal per mole with an increase in deformation from 20 to 70 pct reduction. Re crstallization by the growth of the artificially nucleated grains results in preferred orientation. The Percentuge of&apos; grains favorably oriented for growth increases with increasing deformation. None of these grains corresponds to the ideal Kronberg-Wilson orientation relationship. The observed growth aniso-tropy is discussed in terms of boundary structure. The boundary velocity as a function of the cell inter -facial area, or the driving free energy, is discussed in the light of current theories of boundary migration. It is well established that recrystallization with re-orientation occurs by the migration of high-angle boundaries of strain-free grains. The driving force for this process is provided by the free energy stored in the metal during deformation. A quantitative study of the effect of varying driving force on grain boundary migration in deformed metals has not been possible heretofore, primarily because of: 1) concurrent recovery steadily decreasing the available driving free energy for boundary migration, &apos;-3 and 2) in-homogeneity of strain in the deformed metal.4 Aust and Rutter3 studied grain boundary migration in striated single crystals of zone-refined lead. Although the driving free energy in such crystals remains unaltered during annealing, this method does not provide a range of driving free energies over which measurements of grain boundary migration can be made. In the present investigation, the rates of migration of high-angle boundaries in deformed aluminum zone- refined single crystals were studied at various temperatures, after deformation ranging from 20 to 70 pct reduction by rolling at -78°C in the (ll0)[i12] orientation. The boundary migration rates along different crystallographic directions were determined under steady-state conditions, i.e., in the absence of competing recovery processes or impingement of recrystallized grains growing into the deformed single crystal matrix. Simultaneous recovery was eliminated by suitable anneals prior to the boundary migration measurements. The recrystallized grains, which grew a ni so tropically into the homogeneously polygonized matrix, developed flat boundary segments during early stages of growth. These boundary segments subsequently migrated along a direction approximately normal to the boundary plane into the matrix rystal. Increasing deformation over the range employed was estimated to increase the driving free energy for boundary migration by about five times. The kinetics of the boundary migration process, examined under these conditions, indicate that the boundary velocity is greatly affected by a small change of the driving free energy in the matrix crystals. These results were examined in the light of the current theories of grain boundary migration. EXPERIMENTAL PROCEDURES Single crystal strips (9 by 1 by 0.125 in.) of zone-refined aluminum, were seed-grown by the Bridgman method in a high-purity graphite mold (<lo ppm ash) at 1 in. per hr. Precautions were taken to minimize contamination of the metal during crystal preparation and subsequent handling. Spectrographic analysis of the metallic impurities in the grown crystals is Qven in Table I. The crystals were rolled in the (110)[112] orientation at -78°C to various reductions in thickness, ranging from 20 to 70 pct, in 10 pct increments. The desired reduction was achieved by many rolling passes, each being no more than 0.002 in. To minimize surface friction, the crystal was rolled between two thin layers of teflon. For those crystals rolled more than 40 pct, it was necessary to remove the disturbed surface layers by electropolishing at -5" to -10°C at an intermediate stage of rolling. The edges of deformed crystals were removed by a jeweler&apos;s saw while submerged in alcohol at -78° C to obtain samples of about ? by i in. The distorted metal at the cut edges and the surface layers were then removed by electropolishing, with removal of a minimum of 0.004 in. from each surface. The thickness of the crystals prior to rolling was chosen so that the final thickness was 0.025 in. for all samples. These deformed single crystals were each prean-nealed for 1 hr at an appropriate temperature in the range of 130" to 280°C, depending upon the amount of deformation. The purpose of this preannealing was to

Jan 1, 1970

By Daniel R. Hull

IN 1026 Genders&apos; reviewed the existing theories of this subject and stated his views in support of the gas-pressure theory. Again, in 1937, the subject was thoroughly reviewed by N. B. Vaughan,3 and by Phillips and Brick,2 so that no resume is called for here. The purpose of this paper is to describe certain observations made in the course of mill work, and to point out that they mostly tend to confirm the gas theory of Genders. VAPOR SEGREGATION There is, however, one type of inverse segregation that can be accounted for by considering the volatility of one of the constituents of an alloy. The most familiar case is ordinary brass, which is subject to a zinc enrichment of a few tenths of a per cent at the surface of a chill casting. This has been noted in 70-30 brass by Genders, and a typical example of it is given in Table I, which represents a [ ] cylindrical billet 7 in. in diameter by 5; in. long. After lathe-turning 1/32 in. from the surface, the remaining distance to the center was sampled at six equally spaced intervals. The lead, which is essentially the same throughout, will be mentioned later. Consider a brass-mill mold, either round or rectangular in cross section, standing several feet high. It may require a minute or two for pouring. Before it is full, the metal in the lower end has partly solidified and contracted somewhat away from the mold. The initial shell of solidification follows not far behind the top of the column, even if the central portion is liquid for a long way down. There is, then, a space between metal and mold that is filled with zinc vapor. The vapor has no exit, because the liquid at the top of the rising column is not only in contact with the mold but keeps up a fresh supply of zinc vapor, which has, perhaps, already begun to condense in the lower portion. The cycle is short. Within a minute or two after the mold is full the bar has cooled enough to condense all the zinc. Some of it may condense on the mold; it might be expected that most of it would condense there, but the mold at that time is well coated with a velvety carbon residue from the oil dressing, overlain by fluffy zinc oxide that commenced covering the inside of the mold as soon as pouring began. The clean skin of the freshly cast brass offers a preferred surface for condensation. Reabsorption is quick and inevitable. A simple experiment indicates that a surprisingly large quantity of zinc vapor is trapped in the space between mold and

Jan 1, 1941

By Daniel R. Hull

In 1926 Gendersl reviewed the existing theories of this subject and stated his views in support of the gas-pressure theory. Again, in 1937, the subject was thoroughly reviewed by N. B. Vaughan3 and by Phillips and Brick,2 so that no résumé is called for here. The purpose of this paper is to describe certain observations made in the course of mill work, and to point out that they mostly tend to confirm the gas theory of Genders. Vapor Segregation There is, however, one type of inverse segregation that can be accounted for by considering the volatility of one of the constituents of an alloy. The most familiar case is ordinary brass, which is subject to a zinc enrichment of a few tenths of a per cent at the surface of a chill casting. This has been noted in 70-30 brass by Genders, and a typical example of it is given in Table 1, which represents a cylindrical billet 7 in. in diameter by 55 in. long. After lathe-turning 1/32 in. from the surface, the remaining distance to the center was sampled at six equally spaced intervals. the lead, which is essentially the same throughout, will be mentioned later. Consider a brass-mill mold, either round or rectangular in cross section, standing several feet high. It may require a minute or two for pouring. Before it is full, the metal in the lower end has partly solidified and contracted somewhat away from the mold. The initial shell of solidification follows not far behind the top of the column, even if the central portion is liquid for a long way down. There is, then, a space between metal and mold that is filled with zinc vapor. The vapor has no exit, because the liquid at the top of the rising column is not only in contact with the mold but keeps UP a fresh supply of zinc vapor, which has, perhaps, already begun to condense in the lower portion. The cycle is short. Within a minute or two after the mold is full the bar has cooled enough to condense all the zinc. Some of it may condense on the mold; it might be expected that most of it would condense there, but the mold at that time is well coated with a velvety carbon residue from the oil dressing, overlain by fluffy zinc oxide that commenced covering the inside of the mold as soon as pouring began. The clean skin of the freshly cast brass offers a preferred surface for condensation. Reabsorption is quick and inevitable. A simple experiment indicates that a surprisingly large quantity of zinc vapor is trapped in the space between mold and

Jan 1, 1941

By Daniel R. Hull

In 1926 Gendersl reviewed the existing theories of this subject and stated his views in support of the gas-pressure theory. Again, in 1937, the subject was thoroughly reviewed by N. B. Vaughan3 and by Phillips and Brick,2 so that no résumé is called for here. The purpose of this paper is to describe certain observations made in the course of mill work, and to point out that they mostly tend to confirm the gas theory of Genders. Vapor Segregation There is, however, one type of inverse segregation that can be accounted for by considering the volatility of one of the constituents of an alloy. The most familiar case is ordinary brass, which is subject to a zinc enrichment of a few tenths of a per cent at the surface of a chill casting. This has been noted in 70-30 brass by Genders, and a typical example of it is given in Table 1, which represents a cylindrical billet 7 in. in diameter by 55 in. long. After lathe-turning 1/32 in. from the surface, the remaining distance to the center was sampled at six equally spaced intervals. the lead, which is essentially the same throughout, will be mentioned later. Consider a brass-mill mold, either round or rectangular in cross section, standing several feet high. It may require a minute or two for pouring. Before it is full, the metal in the lower end has partly solidified and contracted somewhat away from the mold. The initial shell of solidification follows not far behind the top of the column, even if the central portion is liquid for a long way down. There is, then, a space between metal and mold that is filled with zinc vapor. The vapor has no exit, because the liquid at the top of the rising column is not only in contact with the mold but keeps UP a fresh supply of zinc vapor, which has, perhaps, already begun to condense in the lower portion. The cycle is short. Within a minute or two after the mold is full the bar has cooled enough to condense all the zinc. Some of it may condense on the mold; it might be expected that most of it would condense there, but the mold at that time is well coated with a velvety carbon residue from the oil dressing, overlain by fluffy zinc oxide that commenced covering the inside of the mold as soon as pouring began. The clean skin of the freshly cast brass offers a preferred surface for condensation. Reabsorption is quick and inevitable. A simple experiment indicates that a surprisingly large quantity of zinc vapor is trapped in the space between mold and

Jan 1, 1941

By M. T. Halbouty

The Laredo oil district, South Texas, includes an area of approximately 200 miles long north and south and 75 miles wide, embracing the following counties: Starr, Zapata, Jim Hogg, Webb, Duval and McMullen. The area is relatively old in respect to the production of oil, as the first oil was discovered and produced in the Piedra Pintas field in Duval County on Sept. 10, 1905. Since that date, continuous new discoveries have contributed to the development of this district until, at the present time, it is one of the important oil-producing and gas-producing areas in the world. The year 1937 also had its share of new discoveries in the district, including not only new oil fields but also new sands in already producing pools and important extensions to existing sands and fields. Among the most important field discoveries, by counties, are: Duval County..... Benavides, Sweden, Thomas-Lockhart, Labbe and Lundell fields Jim Hogg County.. Las Animas field McMullen County. Ezzell field Starr County...... El Tanque field Webb County..... Killam and Oilton fields Of these, Benavides, Oilton, Killam and Ezzell have so far proved themselves most important; the Benavides field, Duval County, showing by far the most activity. For the year 1937, therc were 283 wildcat tests drilled in this district, of which 35 were oil producers, 20 completed as gas wells and 228 abandoned as dry holes. Duval County, as usual, received the greatest amount of wildcat drilling, having 21 oil wells, 5 gas wells and 63 dry holes completed during the year for a total of 89 tests. Next came Webb County with 4 oil wells, 4 gas wells and 53 dry holes for a total of 61 tests.The Laredo oil district, South Texas, includes an area of approximately 200 miles long north and south and 75 miles wide, embracing the following counties: Starr, Zapata, Jim Hogg, Webb, Duval and McMullen. The area is relatively old in respect to the production of oil, as the first oil was discovered and produced in the Piedra Pintas field in Duval County on Sept. 10, 1905. Since that date, continuous new discoveries have contributed to the development of this district until, at the present time, it is one of the important oil-producing and gas-producing areas in the world. The year 1937 also had its share of new discoveries in the district, including not only new oil fields but also new sands in already producing pools and important extensions to existing sands and fields. Among the most important field discoveries, by counties, are: Duval County..... Benavides, Sweden, Thomas-Lockhart, Labbe and Lundell fields Jim Hogg County.. Las Animas field McMullen County. Ezzell field Starr County...... El Tanque field Webb County..... Killam and Oilton fields Of these, Benavides, Oilton, Killam and Ezzell have so far proved themselves most important; the Benavides field, Duval County, showing by far the most activity. For the year 1937, therc were 283 wildcat tests drilled in this district, of which 35 were oil producers, 20 completed as gas wells and 228 abandoned as dry holes. Duval County, as usual, received the greatest amount of wildcat drilling, having 21 oil wells, 5 gas wells and 63 dry holes completed during the year for a total of 89 tests. Next came Webb County with 4 oil wells, 4 gas wells and 53 dry holes for a total of 61 tests.

Jan 1, 1938

By Rodney L. Stone

In past attempts to characterize green and dry iron ore pellets, the authors have found large variations in the results of strength tests performed on closely sized pellets from the same batch. Where bentonite was the binder, such variations in the pellet quality were attributed to the presence of internal flaws and the nonuniform distribution of the binder. Studies have shown that pellet strength is strongly dependent on the degree of "mixedness" of the iron ore concentrate and the bentonite binder. However, before such a relationship can serve as a guide for the development of better mixing techniques and the associated economy of bentonite consumption, more precise knowledge of the bentonite-concentrate mixtures is needed. For example, what is the bentonitc distribution from pellet to pellet and within pellets?

Jan 1, 1970

By J. M. De La Garza Cárdenas

The total production of oil in Mexico in 1942 was 34,715,547 bbl.; that is, 8,179,254 bbl. less than the amount produced in 1941. The daily average for 1942 was 95,111 bbl., while that for 1941 was I17,520 barrels. The reduction of 22,409 bbl. per day in production was due to a decrease in exports because of the scarcity of tankers. This reduction has affected principally the Northern and Southern districts of the Tampico area; in December the Northern district (Panuco) was producing less than zoo0 bbl. per day with 445 wells shut down and the Southern district (GolJen Lane) less than $000 bbl. per day with 140 wells shut down. Drilling.—During the year 14 wells were drilled in Mexico, of which five were productive. Seven dry holes were drilled in Ebano, Tampico Northern district, in search for new producing fractures; plans are being made to explore this area by means of resistivity measurements. Three producing wells were completed in Poza Rica. Drilling in this important field will continue during 1943 to determine its extension to the west. In the Isthmus of Tehuantepec no wells were completed. Two gas wells were completed in northeastern Mexico. Wildcats.-—Two wildcat wells were completed during the year, to test the extension of the Golden Lane to the south; both were unproductive. In the Isthmus a deeper sand was found in the El Plan field* This discovery has made an important increase in the reserves in this field and will allow an increase in the production of the area during 1943. In December, three exploration wells were being drilled, two in the Tampico area and one in the Isthmus. Operating Technology.— Satisfactory progress has been made in Mexico in the application of petroleum engineering to the development and operation of the oil fields. Mud control is now an established practice and has lessened the number of fishing jobs and has allowed more open hole to be carried than formerly was possible. During 1942 the first effective use was made of determinations of bottom-hole pressure, and other modern production practices such as gun-perforating and squeeze-cementing are being introduced. Plans for 1943 The oil production during 1943 is expected to be slightly larger than that of 1942, especially if tankers are available for exporting crude and refined products. The Government proposes to increase exploration and drilling activities to increase the reserves and potential production of the country; about 50 wells will be drilled during the year, including wildcat wells in northeastern Mexico, Tampico and Isthmus areas and exploitation wells in the Ebano-Panuco, Poza Rica, El Plan and Cuichapa fields. Acknowledgment Mr. A. Barnetche, of the Production Department, "Petr6leos Mexicanos," assisted the writer in the preparation of the statistical data.

Jan 1, 1943

By J. M. De La Garza Cárdenas

The total production of oil in Mexico in 1942 was 34,715,547 bbl.; that is, 8,179,254 bbl. less than the amount produced in 1941. The daily average for 1942 was 95,111 bbl., while that for 1941 was I17,520 barrels. The reduction of 22,409 bbl. per day in production was due to a decrease in exports because of the scarcity of tankers. This reduction has affected principally the Northern and Southern districts of the Tampico area; in December the Northern district (Panuco) was producing less than zoo0 bbl. per day with 445 wells shut down and the Southern district (GolJen Lane) less than $000 bbl. per day with 140 wells shut down. Drilling.—During the year 14 wells were drilled in Mexico, of which five were productive. Seven dry holes were drilled in Ebano, Tampico Northern district, in search for new producing fractures; plans are being made to explore this area by means of resistivity measurements. Three producing wells were completed in Poza Rica. Drilling in this important field will continue during 1943 to determine its extension to the west. In the Isthmus of Tehuantepec no wells were completed. Two gas wells were completed in northeastern Mexico. Wildcats.-—Two wildcat wells were completed during the year, to test the extension of the Golden Lane to the south; both were unproductive. In the Isthmus a deeper sand was found in the El Plan field* This discovery has made an important increase in the reserves in this field and will allow an increase in the production of the area during 1943. In December, three exploration wells were being drilled, two in the Tampico area and one in the Isthmus. Operating Technology.— Satisfactory progress has been made in Mexico in the application of petroleum engineering to the development and operation of the oil fields. Mud control is now an established practice and has lessened the number of fishing jobs and has allowed more open hole to be carried than formerly was possible. During 1942 the first effective use was made of determinations of bottom-hole pressure, and other modern production practices such as gun-perforating and squeeze-cementing are being introduced. Plans for 1943 The oil production during 1943 is expected to be slightly larger than that of 1942, especially if tankers are available for exporting crude and refined products. The Government proposes to increase exploration and drilling activities to increase the reserves and potential production of the country; about 50 wells will be drilled during the year, including wildcat wells in northeastern Mexico, Tampico and Isthmus areas and exploitation wells in the Ebano-Panuco, Poza Rica, El Plan and Cuichapa fields. Acknowledgment Mr. A. Barnetche, of the Production Department, "Petr6leos Mexicanos," assisted the writer in the preparation of the statistical data.

Jan 1, 1943