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By Frank A. Wardlaw

MY subject covers the effect that recent metallurgy has had on operations at the Utah-Delaware mine. This mine is the old Highland Boy mine of Bingham Canyon, Utah, one that has now been in operation for about 30 years. It was first operated by Messrs. Weir and Newhouse as a gold mine, under direction of the Highland Boy Gold Mining Co. The ore was oxidized gold ore and it was treated on the property in a cyanidation plant. During the process of development, sulfide ore was found assaying about 5 per cent copper. It proved to be the discovery of what is yet the largest sulfide copper orebody in the State. The first shipment was made in December, 1896. A smelter was built in Salt Lake Valley to treat this ore and not long after the property was sold to the Utah Consolidated Mining Co. From 1900 to 1924, the mine was a large producer of direct-smelting ore which averaged for many years 4.5 per cent. copper, then later dropped to 2 per cent. copper. During the years 1912 to 1920, direct-smelting lead ore was also mined. In 1918'and 1919 ore developments at depth showed a decided increase in silica content and a porphyry sill so closely associated with the ore that it was impossible to mine the ore clean and it was found necessary to build a copper flotation Eoncentrator at Tooele. The mill had a capacity of 1000 tons a day and made a recovery of 90 per cent., and would have been responsible for a continuance of profitable operations had it not been for a slump in the copper market and the necessary high cost of mining ore on the lower levels. RESULTS OF SELECTIVE FLOTATION In 1924 the mine was on the point of a shutdown which had all the earmarks of being permanent; it was being operated at a heavy loss and preparations were made to pull the pumps and salvage the machinery. The plant at Tooele was remodelled for selective flotation by the Inter- national Smelting Co. in order to treat custom ores, and incidentally to clean up a possible 10,000 tons of lead-zinc ore which it was thought possible to get in the Utah-Delaware before shutting the mine down. Results were so encouraging that an effort was made to develop more lead-

Jan 1, 1928

By Frank A. Wardlaw

My subject covers the effect that recent metallurgy has had on operations at the Utah-Delaware mine. This mine is the old Highland Boy mine of Bingham Canyon, Utah, one that has now been in operation for about 30 years. It was first operated by Messrs. Weir and Newhouse as a gold mine, under direction of the Highland Boy Gold Mining Co. The ore was oxidized gold ore and it was treated on the property in a cyanida-tion plant. During the process of development, sulfide ore was found assaying about 5 per cent. copper. It proved to be the discovery of what is yet the largest sulfide copper orebody in the State. The first shipment was made in December, 1896. A smelter was built in Salt Lake Valley to treat this ore and not long after the property was sold to the Utah Consolidated Mining Co. From 1900 to 1924, the mine was a large producer of direct-smelting ore which averaged for many years 4.5 per cent. copper, then later dropped to 2 per cent. copper. During the years 1912 to 1920, direet-smelting lead ore was also mined. In 1918 and 1919 ore developments at depth showed a decided increase in silica content and a porphyry sill so closely associated with the ore that it was impossible to mine the ore clean and it was found necessary to build a copper flotation concentrator at Tooele. The mill had a capacity of 1000 tons a day and made a recovery of 90 per cent., and would have been responsible for a continuance of profitable operations had it not been for a slump in the copper market and the necessary high cost of mining ore on the lower levels. Results of Selective Flotation In 1924 the mine was on the point of a shutadown which had all the earmarks of being permanent; it was being operated at a heavy loss and preparations were made to pull the pumps and salvage the machinery. The plant at Tooele was remodelled for selective flotation by the International Smelting Co. in order to treat custom ores, and incidentally to clean up a possible 10,000 tons of lead-zinc ore which it was thought possible to get in the Utah-Delaware before shutting the mine down. Results were so encouraging that an effort was made to develop more lead-

Jan 1, 1928

Jan 1, 1935

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

Joseph Hartshorne was born in Philadelphia in 1852. He died Aug. 23, 1918. After graduating from Haverford College, he took a special course in chemistry at the Massachusetts Institute of Technology, and later at the University of Pennsylvania. He started with The Pennsy!vania Steel Co. as an apprentice in 1873, working in the laboratory and mills for two years, and then one year as foreman in the Bessemer Department. Next, he was assistant chemist in the second Geological Survey of Pennsylvania. In 1878, he went to Prance to investigate the Pernot open-hearth furnace for the Cambria Iron Co. Upon his return, he assisted in designing and erecting the plant in Johnstown and was foreman of a turn for one year, and superintendent for the next. In 1881, he became superintendent of the Bessemer and rolling-mill departments. In 1884, he went to Pottstown and also made a trip to Europe to investigate the Bessemer basic process. Upon his return he dcsigned and erected the basic Bessemer plant for the Pottstown Iron Co., and was superintendent there until 1893, when the company failed. Since then he has been a consulting metallurgical engineer, and expert in patent cases. The !most important of the latter was that of Krupp versus Midvsle on the armor-plate patent case, in which he was leading cxpert for Midvale. He was a good linguist, having command of French and German, and a fair knowledge of Italian and Spanish. In all, he made eight professional trips to Europe.

Jan 1, 1920

By T. C. Clarke

The history of iron construction in this country well illustrates the three phases of thought described by Auguste Comte, the French philosopher. The first is the era of faith, when belief in the safety of structures rests on the authority of the designer. The second is the era of criticism, when plans of structures are analyzed with much mathematical skill, but the data upon which the chain of reasoning depends is assumed upon insufficient experiment. The third, upon which we are now entering, is a scientific era, which demands experimental proof. It also demands that this proof shall be derived from experiments made on full-sized specimens, such as are in actual use, and not upon toy models. Until the construction of the United States testing-machine, now at Watertown Arsenal, it was impossible to make such experiments with accuracy. We now have a machine in which we can test full-sized specimens of every part of a bridge or other structure that we want to use, and under the same conditions in which it is actually used. The next thing is to get money to make these experiments available. No private individuals can afford to do it, and even if they could, they might wish to keep the results to themselves. So that the next point is that we want money, and that, I believe, everybodly thinks we should ask Congress for. We want also, as has been said, some one who shall make a business of testing, and who has plenty of time. Persons who are employed in private business are too much in a hurry; they want to do a thing and get done with it, and then do something else; but government officers are entirely free from this feeling; time to them is of no account, and in experimenting that is the very element that is of value; it does not do to be hurried; the great thing is to get it right and to test your results, and go over it, again and again. And the experimenter who operates the machine must be some person educated up to the use of it. We then want a general advisory board who will indicate a plan of experiments, collect the results; and publish them. Some experiments were made the other day at the Watertown Arsenal upon full-sized

Jan 1, 1882

By C. E. Shoenfelt

The discovery of oil in the Powder Wash stricture in northwestern Colorado late in the fall of 1936 is the most important development in Colorado since oil was first discovered in the Moffat dome in the same county in 1923. The Powder Wash structure gives promise of developing into an oil and gas field of major proportions and is of particular interest because the oil was found in Tertiary rocks of Eocene age, which heretofore had been productive in the Rocky Mountain region of gas only, and very few of the many structures of this kind have been tested because it was believed that oil production probably would be confined to rocks of Cretaceous age only, and these were, in most instances, at excessive drilling depths. Powder Wash is one of a series of small domes in the belt of folds and faults on the south side of the large but shallow depression known as

Jan 1, 1937

By James A. Barr

The writer's first experience with flotation was during World War I, in the bene-ficiation of Alabama graphite schist ores. One plant used a cone with a peripheral overflow; dried ore was distributed by a rotating disk onto the surface of the water. No reagents were added' The flake-graphite film floated along with some fine silica. Dewatering screens separated the flake. Naturally unit capacities were low but results were satisfactory. Minerals separation mechanical flotation machines were used in another graphite mill. pine oil was added directly to the head cells, with very good results. All the graphite concentrates from both types of flotation were carefully refined after drying by passing through burr mills, followed by very close sizing on sifters. In March 1927, the writer ran a very successful flotation test on minus 28-mesh, deslimed, Tennessee brown phosphate "sand,"† using a mechanical laboratory machine built in the shops of the Anaconda Copper Mining Co., through the courtesy of Ernest Klepetko. The machine was soon converted to a subaeration type, with improved results. This phosphate research program was greatly enlarged and led to the formation of the phosphate Recovery corporation. The development of nonmetallic flotation followed rapidly. The first flotation machine for bene- ficiation of phosphate was installed in January 1928, in a pilot mill, by International Minerals and Chemical Corporation, at Mulberry, Florida. These machines were Minerals Separation, 24-in., sub-,,,tion types, with weir control of pulp between cells. The sand bleeders were very small—about 1¼-in. diameter. As the feed flake. Is to 25 per cent plus 28-mesh material, the cells choked up frequently. This was corrected by cutting a 2 by 6-in. bleeder opening above the impellers, at grid level, which short-circuited the coarse fractions directly into the feed of the next cell. The matter of size classification and grinding was a considerable problem, which does not come within the scope of this article. Because of the troubles noted above, cascade-type roughers were installed in the second flotation plant, built about 1930. Experimental cells had been tried in 1928. General plant layout is shown in Fig. 1 and details of the cascade construction in Fig. 2. The cascade installation in plant NO. 2 gave good results and eliminated troubles due to choke-ups and coarse feed. The capacities and metallurgical results equaled those of the modified 24-in. Minerals Separation flotation machines in plant No. I The objections to the cascade installation are the floor space and mill height required. In 1939 an improved Minerals Separation machine was tested in parallel with the cascades. Extensive tests indicated

Jan 1, 1947

By James A. Barr

The writer's first experience with flotation was during World War I, in the bene-ficiation of Alabama graphite schist ores. One plant used a cone with a peripheral overflow; dried ore was distributed by a rotating disk onto the surface of the water. No reagents were added' The flake-graphite film floated along with some fine silica. Dewatering screens separated the flake. Naturally unit capacities were low but results were satisfactory. Minerals separation mechanical flotation machines were used in another graphite mill. pine oil was added directly to the head cells, with very good results. All the graphite concentrates from both types of flotation were carefully refined after drying by passing through burr mills, followed by very close sizing on sifters. In March 1927, the writer ran a very successful flotation test on minus 28-mesh, deslimed, Tennessee brown phosphate "sand,"† using a mechanical laboratory machine built in the shops of the Anaconda Copper Mining Co., through the courtesy of Ernest Klepetko. The machine was soon converted to a subaeration type, with improved results. This phosphate research program was greatly enlarged and led to the formation of the phosphate Recovery corporation. The development of nonmetallic flotation followed rapidly. The first flotation machine for bene- ficiation of phosphate was installed in January 1928, in a pilot mill, by International Minerals and Chemical Corporation, at Mulberry, Florida. These machines were Minerals Separation, 24-in., sub-,,,tion types, with weir control of pulp between cells. The sand bleeders were very small—about 1¼-in. diameter. As the feed flake. Is to 25 per cent plus 28-mesh material, the cells choked up frequently. This was corrected by cutting a 2 by 6-in. bleeder opening above the impellers, at grid level, which short-circuited the coarse fractions directly into the feed of the next cell. The matter of size classification and grinding was a considerable problem, which does not come within the scope of this article. Because of the troubles noted above, cascade-type roughers were installed in the second flotation plant, built about 1930. Experimental cells had been tried in 1928. General plant layout is shown in Fig. 1 and details of the cascade construction in Fig. 2. The cascade installation in plant NO. 2 gave good results and eliminated troubles due to choke-ups and coarse feed. The capacities and metallurgical results equaled those of the modified 24-in. Minerals Separation flotation machines in plant No. I The objections to the cascade installation are the floor space and mill height required. In 1939 an improved Minerals Separation machine was tested in parallel with the cascades. Extensive tests indicated

Jan 1, 1947

Jan 1, 1930

By A. B. Parsons

When the Seeley W. Mudd Memorial Fund was established in. 1929 the donors mentioned certain types of projects to which preference might be given in selecting those to he financed by the income from the Fund. One suggestion. was that the projects "be of particular benefit to young engineers." This modest little book meets this specification most aptly. It seeks to guide the engineer-particularly the young one-with the least loss of time and effort to the most convenient source of authentic information regarding any topic in which he may at the moment be interested. Knowing the best place to find the literature on a subject is almost as valuable-and far more practicable-than maintaining a library of one's own large enough to provide the information.

Jan 1, 1933

Jan 1, 1911

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Jan 1, 1907

Jan 1, 1880

By Arthur S. Dwight

The profeseional career of Thomas Septimus Austin, who died at El Paso, Tex., Aug. 23, 1906, was contemporaneous with the growth of the silver-lead smelting-industry of the Far West, to which his talents and zeal contributed in no small degree. Born at Stratford, Conn., Dec. 7, 1853, he was the seventh son in a family of thirteen. His parents were well-to-do; and he received a thorough preliminary training at the Hopkins Grammar School, New Haven, Colin., passing thence to the Columbia School of Mines, in New York, where he was graduated in 1876. His first professional work was that of analytical chemist with a Cuban sugar company. In this position he spent a year, and, whatever else of benefit he may have acquired during that year in Cuba, he gained a facility of speech in the Spanish language which was of inestimable value in his subsequent work in Mexico and the southwestern United States. In 1877, he went to the Rocky Mountains, and, under the firm name of Murphy & Austin, opened an assay-ofice in Lead-ville, Colo., which was just then coming into public notice as a rich silver-lead camp. The next year, however, he entered the service of the Germania Smelting & Refining Co. at Salt Lake City, Utah, where he remained until 1882, first as assayer and chemist, and later as Assistant Superintendent. The Germa-nia bears the honorable distinction of being one of the first of the large " custom" lead-smelters erected in the West. Its founders may be called the pioneers of the modern lead-smeltr ing practice, and the Germania served, to a large extent, as a model for the many plants that sprang into existence during the next few years in Utah, southern Idaho, Colorado and other lead-producing districts. The formulation, for the first

Jan 1, 1908

By T. R. A. Davey

IN 1947 the author became interested in the fundamental aspects of the desilverizing of lead by zinc, conducted some experimental work, and searched the technical literature for all available fundamental data. Since then a revival of interest in the subject in Europe resulted in the appearance of quite a number of papers. It became evident that it would be more profitable to collect together and examine thoroughly the results of various workers, than to attempt to duplicate the experimental determinations. There are many inconsistencies in the various publications, and it is opportune to review at this time the present status of knowledge on the Ag-Pb-Zn system. There is also a need for a clear description, in fundamental terms, of the various desilverizing procedures. This paper is presented in four sections: 1—There is an historical review of the origins of the Parkes process, of the results of many attempts to find a satisfactory fundamental explanation for the phenomena, and of the modifications proposed to date. 2—A diagram of the Ag-Pb-Zn system is presented. This is believed to be free of obvious inconsistencies or theoretical impossibilities, although thermodynamic analysis subsequently may reveal errors. 3—The fundamental bases of the various desilverizing procedures, which have been used up to the present day, are described; and a new method is suggested for desilverizing a continuous flow of softened bullion in which the bullion is stirred at a low temperature in two stages producing desilverized lead at least as low in silver as that from the Williams continuous process and a crust which, on liquation, yields a very high-silver Ag-Zn alloy. 4—A suggestion is made for the revival of de-golding practice, following a recently published account which does not seem to have attracted the attention it deserves. The terms "eutectic trough" and "peritectic fold" as used in this paper are synonymous with "line of binary eutectic crystallization" and "line of binary peritectic crystallization" as used by Masing.' The German literature on ternary and higher systems is rather extensive and a fairly general system of nomenclature has arisen, whereas in English usage the corresponding terms are not as well established. For this reason the meanings of terms used in this paper, together with the equivalent German terms, are given as follows: 1—Eutectic trough—eutektische rinne: line at which a liquid precipitates two solids S1 and S2 simultaneously. If the composition of a liquid which is cooling reaches this line, it then follows the course of this line until a eutectic point is reached, or until all the liquid is exhausted. The tangent to the eutec-tic trough cuts the line joining S1S2. 2—Peritectic fold—peritektische rinne: line at which a solid S1 and a liquid L transform into another solid S2. If the composition of a liquid which is precipitating S1 reaches the line, on further cooling only S2 is precipitated. The liquid composition moves from one phase region (L + S1) into the other (L + S2), and does not follow the course of the boundary. The tangent to the peritectic fold cuts the line S1S2 produced nearer S,. 3—Liquid miscibility gap, or conjugate solution region—mischungslucke: the region within which two liquid phases coexist in equilibrium over a certain range of temperature. A system whose composition is represented by a point in this region comprises one liquid at high temperature; then as the temperature is progressively reduced, two liquids, one liquid and one solid, one liquid and two solids, and finally three solids. 4—Liquid miscibility gap boundary—begrenzung der flussigen mischungsliicke: the line along which the surface of the miscibility gap dome, considered as a solid model, intersects the surrounding liquidus surfaces. 5—Tie lines—konoden: lines joining points representing the compositions of two liquids, a liquid and a solid, or two solids, in equilibrium. In binary systems the only tie lines customarily drawn are those through invariant points, e.g., through the eutectics of the Pb-Zn and Ag-Pb systems, or the various peritectics of the Ag-Zn system, as in Figs. 1 to 3. In ternary systems it is desirable to draw sufficient tie lines to indicate the slopes of all possible tie lines. 6—Ternary eutectic point—ternares eutektikum: point at which liquid transforms isothermally to three solids, S1, S2, and S Such a point can lie only within the triangle 7—Invariant peritectic (transformation) point— nonvariante peritektische umsetzungspunkt: (a) — On the miscibility gap boundary, the point at which two liquids and two solids react isothermally so that L, + S, + L, + S2. (b)—On the eutectic trough, the point at which a liquid and three solids react iso-thermally so that L + S, + S2 + S3. Such a point must lie on that side of the line joining S,S which is further from S,. (c)—A further possibility, not found in this ternary system, is that the point is at the intersection of two peritectic folds when the reaction concerned is L + S, + S, + S Historical Introduction Karsten discovered in 1842 that silver and gold may be separated from lead by the addition of zinc.2 Ten years later Parkes used this fact to develop the well known desilverizing process which bears his

Jan 1, 1955

By J. G. Richardson, F. M. Perkins

Results and procedures are pre-cented covering a laboratory investigation of the effect of rate of water advance on the displacement of oil from clean water-wet sands. The experiments included water floods at atmospheric pressure with and without gas present over a range of flow rates from reservoir rates to rates ten thousand-fold higher. Water floods were also conducted at various rates at elevated pressure with no gas present. Other tests were made at elevated pressures by forming a free gas saturation by evolution of gas from solution in the oil before water flooding. Recovery of oil was found to be independent of the rate of water advance with or without gas present and independent of the pressure level of the water flood. A dimensionally-scaled model of a reservoir composed of a thick uniform sand was used to study the effect of rate on the tendency of water to underrun the oil because of the greater density of the water. Another model was used to study the effect of rate on the tendency of water to channel down the more permeable sand in a stratified reservoir composed of sands of diffierent per-meability in intimate contact. The effect of the presence of gas on the flooding conformance was studied with both models. The results obtained using these simple models provide a basis for predicting behavior in more complicated systems. INTRODUCTION In spite of the great amount of research on the flow of fluids in porous rocks, there still exists some disagreement as to the influence of the rate of water advance on the displacement of oil by water flooding. Various investigators have found that increasing the rate of water injection would decrease, increase, or have no effect on recovery of oil. One reason for this disagreement has been a lack of understanding of the effects of the capillary forces which influence the results obtained in the laboratory at low rates with short columns. Other causes of the disagreement have undoubtedly been inconstancy and uncertainty of the wetting properties of the porous media studied, inaccurate saturation determinations, and in some instances conclusions based on insufficient data. Capillary forces are involved in the displacement of oil by water in two ways. On the microscopic scale, the capillary forces control the dis- tribution of oil and water in the pore spaces of the sand. The magnitude of these forces is governed by the preference of the sand to be wet by water, the pore sizes and geometrical shapes, and the interfacial tension between the water and oil. On the macroscopic scale, differences in saturation at the flooding "front" when water displaces oil result in capillary pressure gradients. These gradients cause water to flow preferentially ahead of the front. In short laboratory columns at low rates, the front can span the entire column length. Also, at the outflow boundary the preference of sand to be wetted by water results in retention of water and a high water saturation in the region of the outflow face. This effect is commonly called the boundary effect.' The capillary pressure gradients which complicate the interpretation of flooding performance of short laboratory columns at low rates of water advance become negligibly small under certain conditions. The conditions where capillary pressure gradients are negligible are in long, homogeneous reservoir sands,' at high rates of water advance in short laboratory columns,3 and at any rate in laboratory columns as the residual oil saturation is approached. Thus, laboratory water floods, conducted

Jan 1, 1958

By M. Paulus

It is known that multicomponent powders are mostly nonhomogeneous. This paper investigates the effects of nonhomogeneity of composition and grain size on the melting point and the sinterability of compact taking into account homogenization mass transport and the length of the diffusion path in solid state sintering, and the kinetics of liquid phase formation in liquid phase sintering. After a discussion on the ideal characteristics of a powder for sintering and low temperature reaction, the main conventional processes are compared. Finally we develop the freeze-drying technique and demonstrate the capabilities and the limits of the process by some examples, mainly in the ceramics field.

Jan 1, 1980

By C. R. Holmgren

A large consolidated sand core was used in this investigation. Four groups of experiments including gas drives, water drives, and water drives combined with gas injection, were made. The results of the gas-drive experiments indicate that greater ultimate recovery may be obtained by higher pressure gradients. However, other considerations challenge the absolute veracity of this conclusion. Results indicate that with connate water present and a low pressure gradient during a gas drive, less gas is required to produce a given amount of oil. The saturation gradient determined during a gas drive is presented. Results of the water-drive experiments indicate that the recovery of oil is not a function of either gradient Or input rate. The presence of initial gas saturation resulted in a slightly lower final oil saturation. Injection of sufficient gas to maintain the initial gas saturation during a water drive resulted in lower final oil saturation. Introduction With the demand for petroleum products reaching an all-time record high and the location and exploitation of new reserves becoming more difficult and expensive, the oil industry must look to more thorough and efficient methods of producing the petroleum already located. Much of the previous work along these lines is exploratory and suggests a more complete investigation. For example, a great amount of laboratory work has been done on flooding sands initially saturated roo pct with oil. Since sands saturated roo pct with oil rarely, if ever, exist in nature, and because the water content is a vital factor in the ultimate recovery from the sand, laboratory investigations on cores without water must be supplemented by comparable work on cores with water present.1'2 Other investigators have done a considerable amount of laboratory work using gas and water drives.3 Krutter and Day4 have reported results of investigations using cores saturated IOO pct with oil and have concluded that " the ultimate recovery obtained, using air drive, from a completely oil-saturated core depends on the pressure gradients used. The higher the pressure gradient, the greater will be the recovery until a certain Pressure range is reached above which the reward of increased recovery is much smaller for similar increments in pressure." Yuster and Day6 conclude that less gas and less time are required to produce a given quantity of oil at high pressure gradients than at low pressure gradients; they also conclude that an increase in the viscosity of the oil requires a proportionate increase in the gas needed for recovery. Their results indicate that the gas required to produce a given quantity of oil is greatly reduced by the presence of connate water. R. C. Earlougher2 concluded, based on results of water-flooding a large number of

Jan 1, 1949