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By John Hays Hammond

The following notes are descriptive of a country as yet in its infancy as regards the advancement made in mining operations. Its inaccessibility and other militating circumstances have retarded progress in that direction. With the completion of the railroad, now under construction, having the city of Cali as its objective point, with the concomitant civilizing and developing consequences, it is certain that the slopes of the Cordilleras will prove to be a South American Eldorado. Deposits of coal, copper, and minerals other than those of the precious metals are known to exist in quantities which, under more favorable conditions of accessibility, etc., could be profitably mined. The Government of the United States of Colombia, I think, is disposed to encourage and foster mining enterprises. Articles designed for mining are admitted free of duty; the permanency of the government is, at least, as well assured as that of Mexico (which is not noted for its immutability), and a more sincerely friendly sentitment towards Americans prevails in the United States of Colombia than in Mexico. This paper is confined to a description of the property of the Cauca company's mines, and is intended rather as a preliminary notice than as an exhaustive report. The Cauca mining district is reached by the following route: New York to Aspinwall; to Panama; to Buenaventura, a port on the west coast of the United States of Colombia, distant thirty-six hours from Panama by steamer; to Cali in the State of Cauca. The State of Cauca is bounded on the north by the Atlantic Ocean, on the northwest by the State of Panama, on the northeast by the States of Bolivar and Antioquia, on the east by Brazil and Venzuela, on the south by the Republic of Ecuador, and on the west by the Pacific. Ocean. It has a territory of 41,443 square miles, which is about one-tenth of the entire territory of the United States of Colombia. Its population, including the 50,000 savage Indians of the Caqueta (some of whom are cannibals), is nearly 450,000 souls, or about one-sixth of the population of the Colombian republic. Of these, one-fifth are whites (Spanish' South Amer-

Jan 1, 1885

By I. N. Zavarine

The observations presented in this paper were recorded during a study of the spheroidizing process. Spheroidization of cementite in steel is either brought about to develop a set of desirable mechanical properties or is an incidental result of mechanical and heat-treating manipulations. Physical properties of steel are materially influenced by the state of the cementite. Conversion of cementite from the lamellar to the spheroidal state is usually accompanied by a decrease of hardness and of strength and by an increase in ductility. The spheroidized structure is usually considered as an ultimate step in the process of the softening of steel. The unorthodox hardening of a 3.5 per cent Ni steel (SAE No. 2330) after a heat-treatment that previously proved entirely suitable for a complete spheroidization of cementite in carbon steels led to the observations that constitute the subject of the present paper. Experimental Procedure The steels used for the experiments described were bought on the market. All were in the form of 3/4-in. round bars. Their chemical compositions are given in Table 1. The spheroidization of cementite in steels can be obtained in several ways. The method used in the present work is, perhaps, the least known. It consists of cyclic heating and cooling of steel, the temperature being

Jan 1, 1939

By I. N. Zavarine

The observations presented in this paper were recorded during a study of the spheroidizing process. Spheroidization of cementite in steel is either brought about to develop a set of desirable mechanical properties or is an incidental result of mechanical and heat-treating manipulations. Physical properties of steel are materially influenced by the state of the cementite. Conversion of cementite from the lamellar to the spheroidal state is usually accompanied by a decrease of hardness and of strength and by an increase in ductility. The spheroidized structure is usually considered as an ultimate step in the process of the softening of steel. The unorthodox hardening of a 3.5 per cent Ni steel (SAE No. 2330) after a heat-treatment that previously proved entirely suitable for a complete spheroidization of cementite in carbon steels led to the observations that constitute the subject of the present paper. Experimental Procedure The steels used for the experiments described were bought on the market. All were in the form of 3/4-in. round bars. Their chemical compositions are given in Table 1. The spheroidization of cementite in steels can be obtained in several ways. The method used in the present work is, perhaps, the least known. It consists of cyclic heating and cooling of steel, the temperature being

Jan 1, 1939

By Paul Merica

THOSE of you who, like myself, have had the privilege of hearing previous Howe Memorial Lectures will note, and I hope without too much disaffection, that for the first time in this series of lectures iron has been chosen as the subject. I feel sure that the predominant choice by previous lecturers of subjects relating to steel has been principally in deference to the well-known interest this subject held for Professor Howe, and that their choice has not reflected any lack of respect for the material, iron. Nevertheless, in the face of this record, I feel some diffidence in introducing this "Cinderella" of materials into the circle of distinguished subjects hitherto treated by Howe lecturers, which is relieved only by the fact that I hope to be able to present some evidence that this Cinderella has at last undergone some of those magical trans-formations which render her acceptable even in the society of her dis-tinguished sister, steel. Fortunately I can cite the old master himself in support of my choice of subject and recall to you that Professor Howe by no means overlooked or neglected cast iron in the long course of his metallurgical meditations. Indeed his attention was early arrested by a metallurgical aspect of cast iron which he believed and we still recognize as of the most funda-mental importance-namely, the genesis of graphite in gray iron and the means for the control of its quantity and distribution. He made some comments over 20 years ago regarding the nature of J. E. Johnson's oxygenated iron which indicate that even then his thoughts were taking directions which today we are finding it useful to explore in connection with the theory of high-strength iron. Had we had in the subsequent years the continuing benefit of Professor Howe's illuminating consider-ation of this important subject, our progress in the improvement of cast iron would undoubtedly have been even more rapid.

Jan 1, 1937

By Ralph H. Sweetser

Carbon in pig iron is not only essential but, ordinarily, it is the most abundant metalloid present; iron without carbon could not be pig iron. Carbon in pig iron has been accepted, but seldom specified. How it gets into the pig iron as it is being smelted in the blast furnace, and why just about so much of it enters into the pig iron in certain blast furnaces, and more of it,; or less of it, enters the pig iron in other blast furnaces, or in the same blast furnace under varying conditions, are problems that have not yet been satisfactorily solved. During my own practical blast-furnace experience, I collected analyses of pig iron, including the graphitic and combined carbon, and recorded them in reference to the percentage of silicon present, having in mind the generally accepted explanation that "silicon drove out the carbon." To this actual experience, I have added some analyses given to me by J. B. Rogers, who was superintendent of the blast furnaces of the Ashland Iron & Mining Co., Ashland, Ky., and was making "silvery iron" at the time. These analyses are shown in Table 1. The analyses do not tell the whole story, but they show that with Pocahontas beehive coke, the total carbon was generally high. The data relating to the composition of the slag are lacking but my own customary practice was to have a rather basic slag. During my experience in making pig iron for the Bessemer and open-hearth departments, there were times when the steel men would complain about some mysterious quality in the pig iron that caused bad steel, in spite of the fact that the percentages of silicon, sulfur, phosphorus and manganese were within the specifications. Many reasons were advanced for this undetermined "poison" in the pig iron, but the favorite one offered by the steel men was that the blast-furnace man had "oxidized" the pig iron at the tuyeres in his eagerness to get big production and low cost. To these complaints of the users of steel-making pig irons were added those of the gray iron-foundry men and the malleable iron men. These groups are unaninlous in their conclusions that the trouble lies with the blast-furnace men; but there is not yet any harmonious conclusion as to the exact cause and remedy.

Jan 1, 1927

By Malcolm Wilson

THE year 1923 was one of great importance in northern Louisiana and southern Arkansas, so far as the' development and expansion of previously discovered oil and gas fields were concerned. However, the search for new fields failed to produce a single discovery that led to important development during the period; in this respect, the year was one of discouragement to the prospector. During the winter and spring months, an especially active "wildcat" campaign was in. progress in southern Arkansas, and a large number of tests were drilled in northern. Louisiana but this activity subsided during the summer and fall. By the close of the year, only routine drilling was in effect in the fields; and only two new areas-Cotton Valley, in Webster Parish, and an area in Union Parish, La.-were showing any important activity because of favorable oil showings. Further drilling is contemplated in both of these areas, and the present feeling is that one or the other may produce the next oilfield in this territory. Briefly, the development of the Smackover field was the overshadowing event of the year. In. southern Arkansas, important development also took place in the East El Dorado, Stephens, and Irma fields; but all of these were relatively small. In northern Louisiana, many new oil wells were drilled in the Bellevue field, and many new gas wells in the Monroe field. In the old Caddo field, a large number of the deep Woodbine wells were plugged back to the "chalk rock," where a high gravity oil is obtained. In the other fields, only a few small wells were drilled. Therefore, Arkansas, furnished the real development of the year in this area. The production for the year showed a material increase over that of 1922, due, chiefly, to Smackover, and practically altogether to the Arkansas fields. In Louisiana, every field, except Caddo, Bellevue, and Elm Grove, showed slight to marked declines; while in Arkansas, El Dorado was the only field that declined throughout the year.

Jan 3, 1924

By H. P. Greenwald

THOSE interested in the early developments and experiments, both in the United States and abroad, that led to modern rock dusting, will find an excellent summary in a paper by George S. Rice,13 published in 1914. The period from 1914 to 1924 was one of intensive experiment on coal-dust explosions in the United States; abroad, war activities and rehabilitation stopped this work over a large part of that decade. Amer-ican findings were published by the Bureau of Mines, particularly in Bulletins 167 and 268. It is convenient to consider that in the United States rock dusting to prevent coal-dust explosions in mines was initiated in 1924 with the publication of tentative specifications.17 This was followed in 1925 by an investigation of methods and costs12 and approval by the American Engineering Standards Committee of a Recommended American Prac-tice.18 Approximately 13 years have elapsed since this approval, and inasmuch as changes in rock-dusting practice in the United States have been evolutionary, it is necessary to consider this entire period as "recent" in some phases of the work. There have been no official changes in the Recommended American Practice since its approval. This paper reviews as briefly as possible knowledge acquired since the issue of the earlier papers mentioned, through experience in mines and experiments conducted by different organizations engaged in the pro-motion of mine safety.

Jan 1, 1938

By Lewis Reeve

As. part of a program of investigation of the properties of electric arc welds carried out in the laboratories of the A. 0. Smith Corporation, considerable work has been done on the determination of the oxygen, nitrogen and hydrogen content of different types of weld metal, employing for this purpose the so-called "vacuum fusion method." It is the purpose of this paper to describe certain improvements that have been introduced in this method of determining the gas content of metals, with particular references to the steel specimens examined in this investigation. The method and apparatus used at the beginning of the investigation were essentially those of the Bureau of Standards as described by Vacher and Jordan.1 Later a number of changes were introduced which resulted in. more rapid evacuation of the graphite crucibles employed and which enabled larger volumes of gas to be dealt with than could be handled conveniently in the Bureau of Standards equipment. In addition, the analyzing of the gases evolved from a melt in the same apparatus as collected was abandoned in favor of analysis outside the equipment using standard methods of gas analysis. The time required for gas analysis in the apparatus itself, as described by the Bureau of Standards, was found to be considerable, and during this time the rest of the equip-ment was tied up, preventing its use for the analysis of further steel sam-ples. As a result of the modifications introduced, the time required for the analysis of a steel sample for gas content was reduced from about 8 hours to less than 3 hours. Subsequently, the whole procedure of melting the sample and collect-ing the gases evolved was modified so as to enable a distinction to be drawn between the easily reducible oxides such as iron oxide and the more stable oxides such as silica and alumina. At the same time evidence was obtained indicating the probable existence in the steels of other nitrides than those of iron alone and making possible their quantitative determination.

Jan 1, 1933

By Harry H. Nowlan

A heavy development campaign progressed during the year 1936 in South Texas1, following up important discoveries made in 1935. Oil and gas wells completed during the year were 1473 against 704 in 1935. The drilling program reached its peak of operations in June in consequence of offset requirements made necessary principally in Duval County in the Seven Sisters, Loma Novio, Lopez and Cole fields. There were six new fields discovered during 1936 as follows: Rhode in McMullen County; Peters, El Mesquite and North Kohler in Duval County; Wood in Starr County and Colorado in Jim Hogg County. No discovery of unusual consequence was made during the year. The pools mentioned above are simply in the primary stages of development. The most intensive exploratory work during the year was in Duval, Webb and Zapata Counties. Considerable activity also prevailed in Starr and Brooks Counties. Much significance is attached to the California Company's discovery in the Alta Mesa field in Brooks County, which is considered to be a deep-seated salt dome. The Comitas field, in Zapata County, developed some surprisingly good production in a shallow sand at 900 ft. and is being followed by a heavy wildcat campaign throughout that area in search of like production. In Starr County an active wildcat campaign is in progress in a continued effort to find new fields northwest of the Sam Fordyce field, in Hidalgo County. This play continues in a northerly direction through Starr and Jim Hogg Counties. New Fields Rhode.—The Rhode field, in southeastern McMullen County, was opened in May by the Magnolia Petroleum Co. with a gas well in the Whitsett (Upper Jackson) sand at a depth of 1810 to 1822 ft., this test is located in the southeast corner of sec. 86 on the Rhode ranch. Four gas wells have been completed, proving up a gas area of 1000 acres, more or less. Development will be slow because of lack of market for the gas.

Jan 1, 1937

By I. N. Zavarine

THE observations presented in this paper were recorded during a study of the spheroidizing process. Spheroidization of cementite in steel is either brought about to develop a set of desirable mechanical properties or is an incidental result of mechanical and heat-treating manipulations. Physical properties of steel are materially influenced by the state of the cementite. Conversion of cementite from the lamellar to the spheroidal state is usually accom-panied by a decrease of hardness and of strength and by an increase in ductility. The spheroidized structure is usually considered as an ultimate step in the process of the softening of steel. The unorthodox hardening of a 3.5 per cent Ni steel (SAE No. 2330) after a heat-treatment that previously proved entirely suitable for a complete spheroidization of cementite in carbon steels led to the observa-tions that constitute the subject of the present paper.

Jan 1, 1939

By W. O. Philbrook, L. D. Kirkbride

IN the normal operation of the iron blast furnace, reduction of the iron oxides is accomplished almost entirely above the tuyeres.' Blast furnace slags usually contain less than 0.5 pct FeO, although higher values may occur with abnormal operation. There is reason to conjecture, however, that incompletely reduced ore may sometimes reach the hearth and enter the slag as a result of heavy slips or, perhaps, even from cores of excessively large lumps of a charge material of poor reducibility. The possibility of reoxidation of iron droplets falling in front of the tuyeres has been considered by several writers. It would be of interest, to know how rapidly iron oxides reaching the slag for any of these reasons could be reduced by reaction with coke or with the high carbon liquid iron in the hearth. In comparison with the hundreds of papers that have appeared on various aspects of the reduction of solid iron oxides by gases and in the presence of several forms of carbon, little work has been published on the reductioin of liquid oxides or slags. Dancey measured rates of reaction of the pure liquid oxides, both FeO and Fe,O,, with molten iron containing about 4.3 pct C. The oxide was dropped into the cup formed in the upper surface of the iron by rotating the crucible and melt. Under these conditions, reduction of either FeO or Fe,O., was completed in less than 10 sec. The present study was concerned with the reduction of FeO from blast furnace-type slags containing less than 5 pct FeO and melted over carbon-saturated iron in stationary graphite crucibles. The results were considerably different from those found by Dancey, as will be discussed later. Although this work is of interest in relation to hearth reactions in the blast furnace, interpretations must be made with caution because the experimental conditions do not duplicate those within a furnace and may not even lead to the same reaction mechanism. The authors were motivated in undertaking this work by an additional interest—the part played by FeO reduction in the mechanism of de-sulphurization of iron by slags under similar experimental conditions. Derge, Philbrook, and Goldman eveloped detailed experimental evidence to support a three-step mechanism for desulphurization like that originally proposed by Holbrook and Joseph' (These reactions are written in molecular form for convenience, but this is not intended to imply the existence of molecules of FeS in the bulk metal phase nor to deny the likelihood of ionic reactions in the slag.) Earlier work by Chang and Goldman" had shown that the overall reaction follows first-order kinetics with respect to sulphur and that the rate of reaction is proportional to the slag-metal interface area, which observations have been confirmed by subsequent work. Later studiese,' have established the influence of al.loying elements on the first and last steps of the reaction. This paper reports a study of step 3 alone, uncomplicated by the simultaneous process of sulphur transfer. Apparatus and Procedure The experiments were made in a conventional high frequency induction furnace powered by a 35 kva Hg spark gap converter. The graphite crucibles used for most of the runs were 14 cm (5.5 in.) deep and 4.8 cm (1.9 in.) ID with 0.75 cm (0.3 in.) wall. An insulating cover with a small opening for withdrawing samples was used to minimize heat loss and infiltration of air into the furnace. The crucible was charged with 300 g of carbon-saturated iron and either 65 or 100 g of prefused slag analyzing 38.0 pct SiO,, 15.4 pct A10 and 47.1 pct CaO. To obtain the cleanest possible interface at the start of the reaction, the metal and slag were brought to temperature together to prevent the rejection of kish graphite that would have been caused by the chilling effect of a large addition of cold slag to carbon-saturated iron. After temperature control had been established, the desired amount of iron oxide was added in the form of a prefused slag of composition 73.6 pct FeO, 7.7 pct AWX and 19.0 pct SiOl. This slag addition was observed to be molten in somewhat less than 1 min, and a very vigorous reaction proceeded for 1 to 2 min after its introduction. Zero time was taken as 2 min after the ferrous silicate slag addition. Slag samples weighing about 0.5 g each were taken periodically by a copper chill sampler." The weight of the initial slag was large relative to the weight of samples removed, so that the slag weight never varied by more than 5 pct during any run. Temperature was measured by a calibrated W/Mo thermocouple immersed in the metal, with a graphite tip cemented over the fused silica protection tube to prevent attack by slag and metal. After some difficulties with uncertain temperatures during the first two runs, the practice adopted to position the thermocouple for reproducible results was to lower the protection tube to touch the bottom of the crucible and then raise it 0.5 cm. The apparent temperature gradient between the bottom of the crucible and the top of the slag was found to be 15°C (27°F). but much of this spread was probably the result of inadequate immersion of the protection tube to off-set conduction losses along the graphite tip when the thermocouple was inserted only into the slag. The temperature of the bath was controlled within 25°C (9°F) during a run.

Jan 1, 1957

By V. C. Perini

The North Central Texas district as herein defined includes the counties of Brown, Callahan, Coleman, Comanche, Coryell, Eastland, Erath, Fisher, Hamilton, Haskell, Hood, Jones, Lampasas, Mills, Nolan, Palo Pinto, Parker, San Saba, Shackelford, Stephens, Stonewall, Summer-ville, Taylor, Throckmorton and Wise. These counties as listed are the counties of District 7B, State Railroad Commission. In the new designation of districts for the Transactions, the North Central Texas district includes most, but not all, of the counties of the previously classified West Central Texas district. This district covers the south central crest and the west flank of the Bend flexure north of the Llano uplift. The west flank of the Bend flexure is on the east boundary of the Permian Basin of West Texas. The greater part of the oil and gas produced in this district has been from Pennsylvanian strata. Some oil and gas has been produced from the lower Permian (by the latest, selection of the Pennsyl-vanian-Permian boundary) and minor amounts from the Mississippian and Ordovician sediments. Increasingly important quantities of oil and gas are to be expected from the older sediments by deeper development in proven fields and by new discoveries. Most of the oil and gas in the district has accumulated in localized, well-defined structural traps in limestone and sandstone reservoirs and in traps due to stratigraphic changes in sedimentation, mainly porosity traps in limestone and sandstone lenses, both usually associated with some structural feature. These features are found by surface and subsurface geological structural mapping, by core drilling and by geophysical surveying. Geochemical methods are also the basis for some wildcatting. The demand for sweet crude oil from this district is firm for local and national consumption, but the market price for the oil remains practically the same as in 1941. The price is not adequate to meet the requirements of the average independent operator with the continued advance in production, tievelopment and wildcatting costs. Stripper wells are being plugged daily and should be jealously saved for the future local and national reserves, especially in view of the fact that new discoveries of commercially important oil and gas reserves are not keeping pace with consumption. An expected economic disruption attendant upon the national war effort has arisen and continues in the future outlook for this district. The lack and delay of securing replacement parts for almost all oil-field equipment has handicapped and delayed operations and has decreased efficiency in wildcatting, development and production. Sufficient experienced drilling, scientific and office personnel is lacking because of inductions in the armed forces and migration to war industries during the period before manpower conservation became effective. The office personnel of the average oil and gas producer continues to be swamped by the increasing demands for reports by state and federal bureaus. An average of IQ days

Jan 1, 1944

By V. C. Perini

The North Central Texas district as herein defined includes the counties of Brown, Callahan, Coleman, Comanche, Coryell, Eastland, Erath, Fisher, Hamilton, Haskell, Hood, Jones, Lampasas, Mills, Nolan, Palo Pinto, Parker, San Saba, Shackelford, Stephens, Stonewall, Summer-ville, Taylor, Throckmorton and Wise. These counties as listed are the counties of District 7B, State Railroad Commission. In the new designation of districts for the Transactions, the North Central Texas district includes most, but not all, of the counties of the previously classified West Central Texas district. This district covers the south central crest and the west flank of the Bend flexure north of the Llano uplift. The west flank of the Bend flexure is on the east boundary of the Permian Basin of West Texas. The greater part of the oil and gas produced in this district has been from Pennsylvanian strata. Some oil and gas has been produced from the lower Permian (by the latest, selection of the Pennsyl-vanian-Permian boundary) and minor amounts from the Mississippian and Ordovician sediments. Increasingly important quantities of oil and gas are to be expected from the older sediments by deeper development in proven fields and by new discoveries. Most of the oil and gas in the district has accumulated in localized, well-defined structural traps in limestone and sandstone reservoirs and in traps due to stratigraphic changes in sedimentation, mainly porosity traps in limestone and sandstone lenses, both usually associated with some structural feature. These features are found by surface and subsurface geological structural mapping, by core drilling and by geophysical surveying. Geochemical methods are also the basis for some wildcatting. The demand for sweet crude oil from this district is firm for local and national consumption, but the market price for the oil remains practically the same as in 1941. The price is not adequate to meet the requirements of the average independent operator with the continued advance in production, tievelopment and wildcatting costs. Stripper wells are being plugged daily and should be jealously saved for the future local and national reserves, especially in view of the fact that new discoveries of commercially important oil and gas reserves are not keeping pace with consumption. An expected economic disruption attendant upon the national war effort has arisen and continues in the future outlook for this district. The lack and delay of securing replacement parts for almost all oil-field equipment has handicapped and delayed operations and has decreased efficiency in wildcatting, development and production. Sufficient experienced drilling, scientific and office personnel is lacking because of inductions in the armed forces and migration to war industries during the period before manpower conservation became effective. The office personnel of the average oil and gas producer continues to be swamped by the increasing demands for reports by state and federal bureaus. An average of IQ days

Jan 1, 1944

By William F. Brace, Howard R. Pratt, Wayne S. Brown

In many engineering structures, the mechanical properties of large volumes of rock must be considered. Typically, such properties are assumed to be the same as those of small laboratory samples, although it is clear that the laboratory samples do not contain the joints, faults, and other natural planes of weakness of the rock mass. A cheap, convenient testing procedure is needed with which the engineer can more accurately assess the strength and elastic properties of natural jointed rock. As a first step in this direction, a test has been developed capable of determining mechanical properties of large samples in their natural undisturbed state. In the present paper, some preliminary experiments on relatively unjointed material are described. Numerous attempts have been made to measure the deformation modulus of rock masses with varying degrees of success. Rocha (1), Grimm (2), and Alexander (3) have placed flat jacks in a slot in the rock and measured the pressure required to deform the slot. Bonnechere (4) has grouted large flat jacks in granite masses and performed similar experiments using a variety of strain measuring techniques. The U. S. Bureau of Mines has conducted radial jacking tests in which a uniform radial stress is applied to the inside of a tunnel of circular cross section and radial deformation is measured by extensometers located at various depths in the tunnel fall. Plate jack tests (Rocha (5), Shannon and Wilson (6)), pressure chamber tests, and cable jacking tests (Zienkiewicz and Stagg (7)) have all been used to determine in-situ deformation modulus. Several bore hole techniques have also been used to measure rock deformation. These include bore hole jacks (Goodman (8)), bore hole dilatometers using expandable membranes (Menard (9)) and bore hole penetrometers. Most of the above tests except the radial jacking test have an unknown stress distribution and require considerable approximation to calculate a deformation modulus. These approximations include the use of elastic theory for solutions of rigid plates, thick-walled cylinders, etc., and determination of values for Poissons

Jan 1, 1971

By H. K. Shearer

Oil production in north Louisiana in 1937 was 28,668,070 bbl., an increase of 1,896,925 bbl., or 7.1 per cent over 1936, as against an increase of 178 per cent from 1935 to 1936. Gas production of 301,148 million cu. ft. from gas wells and 17,330 million cu. ft. of casinghead gas, a total of 318,483 million, was an increase of 33,483 million cu. ft., or 11.7 per cent over 1936. Well completions numbered 716, with 411 oil wells, 175 gas wells and 130 dry holes; compared with 346, 109 and 78, respectively, in 1936. There were 58 wildcat dry holes. In addition to the wildcat producers described and tabulated with the fields, there were two small, shallow gas wells in Sabine and Tensas Parishes, which did not open fields of any present importance. At the close of 1937 there were only five wildcat tests actually drilling, with nine others shut down or temporarily abandoned. Chief interest during 1937 was in development rather than discoveries. The only real discoveries were two deep gas and distillate fields, Bear Creek and Ruston. There were also three completions of gas-distillate producers from deeper formations in old fields, of which the most important was at Cotton Valley, one discovery of oil in a previously known gas sand and five or six extensions of some importance. Geological Section The columnar section in south Arkansas (Fig. 1, p. 317) also applies in north Louisiana, with a few changes noted below. The oldest known formation in north Louisiana is a bed of rock salt. Except on salt domes, only one well at Rodessa has been drilled into this salt, but it has been penetrated by a number of wells in south Arkansas. Salt domes have been discovered near Vicksburg and Hattiesburg, Miss., and a deep well in Limestone County, Texas, has drilled into rock salt. In Louisiana the distance between the "interior salt-dome basin" and a salt dome of the "Gulf Coast salt basin" is hardly 60 miles. In short, evidence is accumulating to indicate that all of Louisiana, with the possible

Jan 1, 1938

By H. K. Shearer

There were no important developments in the oil and gas industry in South Arkansas during 1935. Oil production, totaling 11,138,340 bbl., continued the decline that has been normal since 1925, but the decline from 1934 was only 278,600 bbl., or 2.5 per cent. The principal decline was in the Smackover field, while only the Champagnolle and Garland City fields showed notable increases. More wells were drilled than in any recent year, with a total of 123 completions. There were 44 oil wells, with a total reported initial daily production of 10,013 bbl., or an average of 227 bbl. per well. Two small gas wells were completed in Union County, where the gas is used locally for pumping and field operations. There were 77 dry holes, of which 28 were in or near oil fields and 49 were wildcats. Active drilling oper-at'ions declined from 65 at the beginning of 1935 to 41 at the end. Most of the drilling was done during the first part of the year, espr-chially (luring the flurry caused by the discovery late in 1934 of the "Taylor" sand production in the Champagnolle field, but the producing area was soon outlined. In November, 1935, the J. E. Crosbie, Inc., NO. 1 Sullivant in sec. 12, 17s. 14W., producing 560 bbl. per day at 3175 ft., opened a new sand lens in the eastern part of the field. The Camden "oil field," discovered in the last week of 1934, remained a one-well field, although four offset tests were drilled, besides a number of others in the immediate vicinity. Several interesting deep tests were drilled during the year, which added a great deal to the general knowledge of the subsurface formations and the structure of south Arkansas, but were not particularly encouraging as to prospects for the very deep production. First, the H. L. Hunt, No. 15 E. F. Gregory well in sec. 10, 17S., 14\W., in the Champagnolle field, was drilled to a depth of 6911 ft. It pene-trated red beds for 2982 ft., from 2943 to 5925 ft., mostly if riot entirely of Lower Cretaceous age. There was some anhydrite in the last 135 ft. of red beds. This was followed by 890 ft. of limestone, probahly Permian, and the rock salt was struck at 6815 ft. The salt is now generally conceded to be of Permian age. Finding salt in this well strongly indicates

Jan 1, 1936

By H. K. Shearer

There were no important developments in the oil and gas industry in South Arkansas during 1935. Oil production, totaling 11,138,340 bbl., continued the decline that has been normal since 1925, but the decline from 1934 was only 278,600 bbl., or 2.5 per cent. The principal decline was in the Smackover field, while only the Champagnolle and Garland City fields showed notable increases. More wells were drilled than in any recent year, with a total of 123 completions. There were 44 oil wells, with a total reported initial daily production of 10,013 bbl., or an average of 227 bbl. per well. Two small gas wells were completed in Union County, where the gas is used locally for pumping and field operations. There were 77 dry holes, of which 28 were in or near oil fields and 49 were wildcats. Active drilling oper-at'ions declined from 65 at the beginning of 1935 to 41 at the end. Most of the drilling was done during the first part of the year, espr-chially (luring the flurry caused by the discovery late in 1934 of the "Taylor" sand production in the Champagnolle field, but the producing area was soon outlined. In November, 1935, the J. E. Crosbie, Inc., NO. 1 Sullivant in sec. 12, 17s. 14W., producing 560 bbl. per day at 3175 ft., opened a new sand lens in the eastern part of the field. The Camden "oil field," discovered in the last week of 1934, remained a one-well field, although four offset tests were drilled, besides a number of others in the immediate vicinity. Several interesting deep tests were drilled during the year, which added a great deal to the general knowledge of the subsurface formations and the structure of south Arkansas, but were not particularly encouraging as to prospects for the very deep production. First, the H. L. Hunt, No. 15 E. F. Gregory well in sec. 10, 17S., 14\W., in the Champagnolle field, was drilled to a depth of 6911 ft. It pene-trated red beds for 2982 ft., from 2943 to 5925 ft., mostly if riot entirely of Lower Cretaceous age. There was some anhydrite in the last 135 ft. of red beds. This was followed by 890 ft. of limestone, probahly Permian, and the rock salt was struck at 6815 ft. The salt is now generally conceded to be of Permian age. Finding salt in this well strongly indicates

Jan 1, 1936

By John McGhee, Jack Newcombe, M. J. Rzasa

A series of water floods was made on laboratory prepared unconsoli-dated sand columns to study the effects on oil recovery of the solid-water-oil contact angle, the oil-water interfacial tension, flood rate, and oil viscosity. A procedure was developed for treating silica sand with silicone polymer to produce surfaces of varying degrees of wettability as evaluated by measuring the contact angle on a flat silica plate that had been simultaneously treated with the sand. Fluid interfacial tensions were changed by the use of surface active agents in the flood water. Water-wet, oil-wet, and intermediate wettability systems were studied at high and at low values of interfacial tension, at several flood rates, and with oils of different viscosities. For both oil-wet and water-wet systems and a low viscosity oil, recoveries were functions of the oil-water interfacial tension; also, increase in flood rate resulted in increased oil recoveries. High interfacial tension floods were more efi- cient than low interfacial tension floods on water-wet systems, while low interfacial tension floods were more eficient on oil-wet systems. Intermediate or neutral wettability systems were less sensitive to rate of flood advance and interfacial tension than either oil-wet or water-wet systems. The eflects of surface forces on oil recovery for high viscosity oils were not so well defined as for low viscosity oils. INTRODUCTION Reservoir rock surfaces vary in their wettability1, some being water-wet while others are apparently oil-wet. The factor of wettability enters into reservoir performance in both primary and secondary recovery, and into laboratory measurements of capillary pressure, connate water saturation, and relative permeabilities.' In theory, the degree of wettability is measured by the contact angle for the system solid-water-oil. A water-wet system is defined as one in which the advancing water contact angle is less than 90". An oil-wet system is one in which the advancing water contact angle is greater than 90°.3 The surface forces in a solid-water-oil system are related by the Young-Dupree equation as follows4: These surface forces are commonly expressed as the difference in adhesion tension, or the product of the water-oil interfacial tension and the contact angle. If the contact angle is less than 90°, the adhesion tension difference is positive and oil displacement by water from a solid surface will be spontaneous and favored by a high oil-water interfacial tension. If the angle is greater than 90" the displacement will not be spontaneous but will require less energy the lower the oil-water interfacial tension. The contact angle and interfacial tension also appear in the capillary pressure equation5: PC = 2ocosejr .... (2) The quantity cos was used by Rapoport and Leas6 s a factor in the generalized form of their "sealing coefficient." Warren and Cal-houn' presented the results of cos on oil recovery in oil-wet systems and correlated their data using a "scaling coefficient" suggested by Jones-Parra and Calhoun.8 The "sealing coefficients" were advanced to help correlate the effects of the variables influencing oil recovery by

Jan 1, 1956

By M. G. Cheney

Careful estimates indicate that during 1942 new discoveries and extensions in West Central Texas added oil reserves slightly in excess of the eight million barrels produced. Drilling activity fell 40 per cent below 1941 and 82 per cent below the normal drilling activity of the late 1920's. Total production for the district continued its downward trend, now being less than % of the 42.7 million barrels peak in 1921. Rapid revival of activity is not probable under existing conditions, as costs of discovery, development and operations on the average probably now exceed current market price for the oil, the latter having remained constant since the spring of I941. Costs have advanced materially since the third quarter of 1941, when reports to the Tariff Commission indicated a margin of profit of 13.3 per barrel. Physical as well as economic conditions are holding back the amount of drilling in this district. The lenticular sands are not suited to 40-acre spacing regulations. There is no surplus of experienced oil-field labor. To reduce costs, much second-hand material is used for all except the deeper wells.. Price controls have retarded movement of used equipment by prescribing maximum prices that arc too low for the better grade materizl, thus making , owners reluctant to sell. On the other hand, buyers are unwilling to pay ceiling prices asked by sellers for poor material. Seventeen new oil fields and five new gas fields were found during 1942. Extensions and deeper 'drilling brought favorable results in eight older fields. The most significant new developments appear to have been in Coleman, Jones, Shackelford and Taylor Counties. A 5800-ft. completion in Wise County brought this county into the producing column for the first time. None of these new discoveries can he rated above one million barrel reserve on the basis of present development. Probably the most important development was discovery of a deeper pay (Gunsight lime) in the Wimberly field of Jones County, which shows promise of producing over an area of about 1000 acres. Jones and Shackelford Counties still lead the district in total annual production. Discovery of the Reddin pool, north central Taylor County, is credited to geochemical methods, making one success out of five or more wildcats based on such methods. Geophysical surveying increased decidedly during 1942 and returns from these studies are expected during coming years. Most of the wildcatting in the district is still based on surface and subsurface geological structural mapping, study of log data as to distribution of prospective producing reservoirs, and drilling in proximity to previous showings of oil and gas. Geological debate continues as to the proper correlation of the 100 to 300 ft. of gray lime that has produced more than 100 million barrels in the Parks, Brecken-ridge, Curry, Eliasville, Ibex, Pioneer and other important fields of this district. Fossils indicate that this limestone is younger than the Atoka beds of Oklahoma. On a structural basis most geologists include this formation with the Bend but a number of paleontologists believe it is more properly classified with the Strawn.

Jan 1, 1943

By M. G. Cheney

Careful estimates indicate that during 1942 new discoveries and extensions in West Central Texas added oil reserves slightly in excess of the eight million barrels produced. Drilling activity fell 40 per cent below 1941 and 82 per cent below the normal drilling activity of the late 1920's. Total production for the district continued its downward trend, now being less than % of the 42.7 million barrels peak in 1921. Rapid revival of activity is not probable under existing conditions, as costs of discovery, development and operations on the average probably now exceed current market price for the oil, the latter having remained constant since the spring of I941. Costs have advanced materially since the third quarter of 1941, when reports to the Tariff Commission indicated a margin of profit of 13.3 per barrel. Physical as well as economic conditions are holding back the amount of drilling in this district. The lenticular sands are not suited to 40-acre spacing regulations. There is no surplus of experienced oil-field labor. To reduce costs, much second-hand material is used for all except the deeper wells.. Price controls have retarded movement of used equipment by prescribing maximum prices that arc too low for the better grade materizl, thus making , owners reluctant to sell. On the other hand, buyers are unwilling to pay ceiling prices asked by sellers for poor material. Seventeen new oil fields and five new gas fields were found during 1942. Extensions and deeper 'drilling brought favorable results in eight older fields. The most significant new developments appear to have been in Coleman, Jones, Shackelford and Taylor Counties. A 5800-ft. completion in Wise County brought this county into the producing column for the first time. None of these new discoveries can he rated above one million barrel reserve on the basis of present development. Probably the most important development was discovery of a deeper pay (Gunsight lime) in the Wimberly field of Jones County, which shows promise of producing over an area of about 1000 acres. Jones and Shackelford Counties still lead the district in total annual production. Discovery of the Reddin pool, north central Taylor County, is credited to geochemical methods, making one success out of five or more wildcats based on such methods. Geophysical surveying increased decidedly during 1942 and returns from these studies are expected during coming years. Most of the wildcatting in the district is still based on surface and subsurface geological structural mapping, study of log data as to distribution of prospective producing reservoirs, and drilling in proximity to previous showings of oil and gas. Geological debate continues as to the proper correlation of the 100 to 300 ft. of gray lime that has produced more than 100 million barrels in the Parks, Brecken-ridge, Curry, Eliasville, Ibex, Pioneer and other important fields of this district. Fossils indicate that this limestone is younger than the Atoka beds of Oklahoma. On a structural basis most geologists include this formation with the Bend but a number of paleontologists believe it is more properly classified with the Strawn.

Jan 1, 1943