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By Albert Sauveur

This paper explains the possibility of using advantageously a boiling solution of sodium picrate to reveal dendritic segregation in steel. The mechanism of the action of the reagent is described. The failure of manganese alone to produce persistent dendritic segregation is also considered. IRON, like other metals, solidifies through the formation of dendritic crystals; iron alloys forming solid solutions, like other solid solutions, solidify likewise through the formation of dendritic crystals. The alloying elements or impurities as well as the inclusions segregate generally in the interstices, or "fillings," between the axes and branches of the dendrites; that is, in the portions last to solidify. This results in dendritic segregation or heterogeneity, which is generally persistent and makes possible the revelation of the dendritic crystallization of the metal through the selective action of a suitable etching reagent.1 For this purpose, a cupric solution, such as Le Chatelier's, is generally used, copper being deposited on the pure, or relatively pure, ferrite present in the axes while the fillings remain free, or relatively free., from copper deposition. The dendritic structure, formed on solidification in a steel containing 0.50 per cent. carbon, 0.37 per cent. manganese, 0.12 per cent. silicon, 0.07 per cent. sulfur, and 0.035 per cent. phosphorus is shown, after treatment with Le Chatelier reagent, in Fig. 1 under a magnification of 8 diameters. Commercial steel always contains inclusions of manganese sulfide, which are located in the fillings of the dendrites. Comstock has shown that boiling sodium picrate imparts a dark coloration to these inclusions. We find that this reagent likewise reveals dendritic segregations in commercial steel, as shown in Fig. 2, under a magnification of 8 diameters, which represents the same spot as that shown in Fig. 1. The fillings

Jan 2, 1924

By Alec M. Crowell, C. H. Thigpen

Continuing the increase in production of crude oil and condensate started in 1937, the oil fields of South Arkansas reached a 13-year peak with 26,570,704 bbl. for the year 1942. The stability of the production branch of the industry in the area is demonstrated by Fig. I, which reflects the fact that although the number of producing wells in the state has declined from 3280 in 1931 to 2957 at the end of 1942, total production has continuously increased since the beginning of 1937. This is because all fields discovered since Jan. I, 1937, have observed spacing patterns up to one well to each 160 surface acres, the dual completion of wells where there is more than one producing horizon Eight new pools were brought into production in South Arkansas during 1942 (Fig. 2) They increased the state's crude oil and condensate reserve by 121,000,000 bbl., bringing the total recoverable reserve figure to 450,000,000 bbl. (Table 3) as of Jan. I, 1943. Abandonment of wells in the stripper areas of the state increased by 32 per cent over the preceding year, there having been 142 wells permanently abandoned in 1942. For economic reasons 279 wells were temporarily shut down as of Dec. 31, 1942. A price increase may start these wells to pumping again and also be the incentive toward the commencing of several secondary recovery projects in the fields discovered between 1922 and 1937. There were 149 wells brought into production in 1942 as against 119 for the

Jan 1, 1943

By C. H. Thigpen, Alec M. Crowell

Continuing the increase in production of crude oil and condensate started in 1937, the oil fields of South Arkansas reached a 13-year peak with 26,570,704 bbl. for the year 1942. The stability of the production branch of the industry in the area is demonstrated by Fig. I, which reflects the fact that although the number of producing wells in the state has declined from 3280 in 1931 to 2957 at the end of 1942, total production has continuously increased since the beginning of 1937. This is because all fields discovered since Jan. I, 1937, have observed spacing patterns up to one well to each 160 surface acres, the dual completion of wells where there is more than one producing horizon Eight new pools were brought into production in South Arkansas during 1942 (Fig. 2) They increased the state's crude oil and condensate reserve by 121,000,000 bbl., bringing the total recoverable reserve figure to 450,000,000 bbl. (Table 3) as of Jan. I, 1943. Abandonment of wells in the stripper areas of the state increased by 32 per cent over the preceding year, there having been 142 wells permanently abandoned in 1942. For economic reasons 279 wells were temporarily shut down as of Dec. 31, 1942. A price increase may start these wells to pumping again and also be the incentive toward the commencing of several secondary recovery projects in the fields discovered between 1922 and 1937. There were 149 wells brought into production in 1942 as against 119 for the

Jan 1, 1943

By W. M. Small

Austria.—Austria produced some 430 cisterns of 10,000 kg. each of crude oil of a 0.9428 sp. gr. during 1934. Gosting II well near Zis-tersdorf was placed on the pump in August and at the end of the year was still producing about three cisterns daily. This well is owned by the Erdöl-Produktionsgesellschaft while Gösting I is owned by Raky-Danubia. Only five wells were completed in the republic during the year. These accounted for 1783.5 meters of the 2225 meters drilled. The only producer completed was Gosting 11. At the close of the year, four rigs were in operation and one rigging up. At least 8 or 10 new wells are planned in Lower Austria for 1935. The European Gas & Electric Co. put its 6-km. gas line into operation in May and has sold 12,301,550 cu. m. of gas to the Vienna City Electric Works. A 2-km. pipe line was built from Gösting II to the railway loading rack near Zistersdorf. Hungary.—No oil or gas was produced except a small amount of gas trapped from flowing artesian wells. The Government completed and abandoned a 1500-m. hole at Tisztaberek in northeastern Hungary and is drilling at 967 m. near Bogáes, 120 km. northeast of Budapest. It is unofficially reported it plans to drill two new wells in 1935. The European Gas & Electric Co. has a rig up for a test at Mihalyi in Transdanubia. Czechoslovakia.—In Gbely (Egbell) there were produced 1283 cisterns of 10,000 kg. of 0.935 sp. gr. oil and a small amount of gas used for fuel. This field is operated by the Government; 17 shallow producing wells and three dry holes were drilled, with a total of 3351 m. of hole completed. In Hodonin (Goding) there were produced approximately 1300 cisterns of 10,000 kg. each of 0.91 sp. gr. oil and a small amount of gas used for fuel. The field is operated by the Apollo, which drilled four producing wells averaging 460 m. in depth, one small gas well of 550 m., one small gas well 260, and one dry hole 230 m. Two wells were deepened a total of 80 meters. The Government is drilling below 800 m. in a wildcat test in eastern Czechoslovakia near the Rumanian frontier.

Jan 1, 1935

By G. F. Fix

Oil and gas activity reached a higher peak in Indiana during 1940 than for any like period during the past decade. Major activity, as during 1939, was in the southwestern part of the state, the Indiana portion of the Eastern Interior Coal Basin, where most of the increase was due to field drilling in previously proven areas. The amount of wildcat drilling was about the same as for 1939. No new fields of any apparent consequence were discovered during the year, with the possible exception of the College pool, in southwest Posey County. Only one well had been completed in this area at the end of the year. About 10 ft. of saturated Aux Vases sandstone was drilled in this well and the initial production was I00 bbl. of oil a day. Other discoveries during the year 1940 include: St. Thomas, in southwestern Knox County, where four McClosky wells, ranging from I00 to 300 bbl. a day initially, were com-pleted; Buff kin, in central Posey County, with 11 oil wells and 5 gas wells completed; and new developments in two old areas —Randolph County (part of the old Trenton field) and Gentryville, northwestern Spencer County, where some oil was found many years ago. The St. Thomas field proved disappoint-ing, with very spotty production from the McClosky horizon of the St. Genevieve limestone at a depth of about 1875 ft. The discovery well flowed 362 bbl. a day ini-tially. At the end of the year the field was pretty well outlined by dry holes and some inside locations were dry. The Buffkin pool also proved spotty, with production from shallow Pennsylvanian sands and from the Basal Pennsylvanian Mansfield sandstone, the latter at a depth of approximately I175 ft., with small production from the Cypress sandstone of Chester age. Oil wells in this pool are small, ranging from 25 to 75 bbl. a day. The Randolph County area, on the east side of the Trenton gas field, showed some promise for a commercial gas field, with four completed gas wells having cumulative initial flows of about 1,200,ooo cu. ft. a day. The area appar-ently was not depleted during the Trenton boom at the turn of the century, since casing pressures are about as high as the virgin pressure in the old field. Elsewhere the pressure has dropped as low as 5 pounds. The Griffin field received most of the drilling during 1940, with 163 completed oil wells. This field now covers about 3200 acres on the Indiana side of the Wabash River and is not as yet completely delimited. It produced the major part of Indiana's oil during the year—a total of 3,594,000 bbl. At the end of 1940, there were 253 producing wells in Griffin. New Harmony had five completions for a total of 24. The Rockport field, in Spencer County, continued to be actively developed and had a total of 45 gas wells and 9 oil wells at the end of the year. Oil in commercial quantities had not been found in the field previous to 1940. Total gas production for the year was 394,470,000 cubic feet. In all, 521 wells were drilled in the state during 1940, as compared to 377 for 1939. Of this number 248 were oil wells, 77 were gas wells and 196 were dry. Divided into

Jan 1, 1941

By G. F. Fix

Oil and gas activity reached a higher peak in Indiana during 1940 than for any like period during the past decade. Major activity, as during 1939, was in the southwestern part of the state, the Indiana portion of the Eastern Interior Coal Basin, where most of the increase was due to field drilling in previously proven areas. The amount of wildcat drilling was about the same as for 1939. No new fields of any apparent consequence were discovered during the year, with the possible exception of the College pool, in southwest Posey County. Only one well had been completed in this area at the end of the year. About 10 ft. of saturated Aux Vases sandstone was drilled in this well and the initial production was I00 bbl. of oil a day. Other discoveries during the year 1940 include: St. Thomas, in southwestern Knox County, where four McClosky wells, ranging from I00 to 300 bbl. a day initially, were com-pleted; Buff kin, in central Posey County, with 11 oil wells and 5 gas wells completed; and new developments in two old areas —Randolph County (part of the old Trenton field) and Gentryville, northwestern Spencer County, where some oil was found many years ago. The St. Thomas field proved disappoint-ing, with very spotty production from the McClosky horizon of the St. Genevieve limestone at a depth of about 1875 ft. The discovery well flowed 362 bbl. a day ini-tially. At the end of the year the field was pretty well outlined by dry holes and some inside locations were dry. The Buffkin pool also proved spotty, with production from shallow Pennsylvanian sands and from the Basal Pennsylvanian Mansfield sandstone, the latter at a depth of approximately I175 ft., with small production from the Cypress sandstone of Chester age. Oil wells in this pool are small, ranging from 25 to 75 bbl. a day. The Randolph County area, on the east side of the Trenton gas field, showed some promise for a commercial gas field, with four completed gas wells having cumulative initial flows of about 1,200,ooo cu. ft. a day. The area appar-ently was not depleted during the Trenton boom at the turn of the century, since casing pressures are about as high as the virgin pressure in the old field. Elsewhere the pressure has dropped as low as 5 pounds. The Griffin field received most of the drilling during 1940, with 163 completed oil wells. This field now covers about 3200 acres on the Indiana side of the Wabash River and is not as yet completely delimited. It produced the major part of Indiana's oil during the year—a total of 3,594,000 bbl. At the end of 1940, there were 253 producing wells in Griffin. New Harmony had five completions for a total of 24. The Rockport field, in Spencer County, continued to be actively developed and had a total of 45 gas wells and 9 oil wells at the end of the year. Oil in commercial quantities had not been found in the field previous to 1940. Total gas production for the year was 394,470,000 cubic feet. In all, 521 wells were drilled in the state during 1940, as compared to 377 for 1939. Of this number 248 were oil wells, 77 were gas wells and 196 were dry. Divided into

Jan 1, 1941

By Verne E. Hooker, Robert M. Becker

The evaluation of in-situ rock stresses from measurements of the change in diameter of a borehole that is stress-relieved by overcoring has become a common practice. Generally the stress evaluation has been based on isotropic relations whereas rock in varying degrees is aniso tropic. A plane elasticity solution fora circular hole along one axis of an orthotropic medium has been adapted to evaluation of in situ stress. The necessary elastic parameters for this evaluation may conveniently be obtained from static tests on the overcore in conjunction with a consistent orthotropic thick-wall cylinder solution. The method and equations for the laboratory and field evaluations are summarized and illustrated. The determination of in-situ rock stresses from boreholc deformation measurements has gained widespread acceptance. Hastl measured the change in diameter of a borehole that was stress-relieved by drilling a larger concentric core; this overcoring method has produced a major portion of the field data for recent stress evaluations in rock. These evaluations are based on the elastic properties of the rock, which are conveniently determined by testing the overcore.6-8 The stress evaluation and the overcore testing procedures generally assume isotropic relations whereas rock is anisotropic in varying degrees. Recently, an anisotropic plane stress solution was adapted for evaluation of in-situ stress9 and a related plane strain solution was developed for the testing of stress-relief core. 10 The present paper unifies the stress evaluation and overcore testing procedures for a general class of anisotropic rock. Equations are presented for calculating the state of stress in a plane normal to the borehole, and a consistent thick-wall cylinder solution is given for determining the necessary elastic properties. In addition, a complete example of stress evaluation from laboratory and field data is presented, and the order of error in computing the state of stress from isotropic relations is illustrated. Several limitations of the results should be emphasized. All results assume small linearly elastic deformations of a homogeneous medium. Rock characterized by orthotropic, transversely isotropic, and isotropic elasticity is considered; however, the anisotropic results assume a special relation among certain elastic constants in addition to geometric orientation with respect to a plane of elastic symmetry. For some stress determinations in rock, these may be severe limitations. On the other hand, the anisotropic evaluation procedure involves little additional effort and is much more flexible than the corresponding isotropic evaluation procedure. The collection of field data is identical. The laboratory determination of elastic parameters is no more difficult and time-consuming for the anisotropic than for the isotropic model. Only the calculations require some additional effort for the anisotropic evaluation, and this additional effort is eliminated by use of a small computer. The flexibility of the anisotropic procedure is greater because more than two independent elastic constants are available in fitting rock data. For the special relationship assumed among orthotropic constants, five independent elastic constants are available for the determination of in-situ secondary principal stresses as compared with two independent elastic constants for the isotropic model. Much of the material presented is either directly from the literature or adapted from the literature through superposition or the usual transformations. Consequently, only enough detail for clarity of presentation is included. RELATIONS FROM ANISOTROPIC ELASTICITY Materials that have three mutually orthogonal planes of elastic symmetry are called orthotropic. By directing the axes of the coordinates perpendicular to these planes, Hooke's law for an orthotropic solid 11 is

Jan 1, 1970

By Frank C. Greene

Drilling in Missouri in 1939 was marked by wildcatting in the northern half of the state. The total completions numbered 82, exactly half the 164 of 1938. There were 15 gas wells with an initial open flow of 6,383,150 cu. ft., 4 oil wells with about 40 bbl. initial production, and 63 dry holes. The wildcatting followed the widely publicized leasing activity in the Forrest City Basin in northwestern Missouri, northeastern Kansas, southeastern Nebraska and southwestern Iowa. It is worth noting that

Jan 1, 1940

By Frank C. Greene

Drilling in Missouri in 1939 was marked by wildcatting in the northern half of the state. The total completions numbered 82, exactly half the 164 of 1938. There were 15 gas wells with an initial open flow of 6,383,150 cu. ft., 4 oil wells with about 40 bbl. initial production, and 63 dry holes. The wildcatting followed the widely publicized leasing activity in the Forrest City Basin in northwestern Missouri, northeastern Kansas, southeastern Nebraska and southwestern Iowa. It is worth noting that

Jan 1, 1940

By Alfred H. Bell

Drilling activity increased in Illinois in 1935. There were 34 com-pletions as compared with 26 in 1934 and 18 wells were drilling at the end of 1935. Some large blocks of acreage were leased in Marion and Clay counties near the central part of the Illinois structural basin. Production of oil in the state totaled 4,305,000 bbl., a decrease of 4 per cent from that of 1934 There was some curtailment of production in the early part of 1935 but none after April 30 as shown in the following table. Percentage Pro-duced of Potential ProductioN (USING September 1934 Period as BaSis) Jan. .l-Feb. 20............................................ 79 Feb. 21-Feb. 25............................................ 85 Feb. 26-Feb. 38............................................ 79 Mar. 1-Mar. 11............................................ 85 Mar. 12-Mar. 31............................................ 100 Apr. 1-Apr. 9.......................................... 80 Apr. 10-Apr. 30............................................ 86 May 1-Dec. 31........................................... 100 This is equivalent to an average curtailment throughout the year of 5 per cent. The price of Illinois crude oil at the wells remained constant during 1935 at $1.13 per barrel. A small amount of oil was sold at a 1ower price, notably from the Dupo field, but to arrive at a value for the state's production there would be little error in assuming an average price of 81.13, giving a total value of $4,864,465. The following table shows production in Illinois by moths in 1935, according to the U.S. Bureau of Mines. Jan............. 332,000 May.......... 382,000 Sept ,............. 370,000 Feb............. 295,000 June. ........... 858,000 Oct.............. 391,000 Mar............ 370,000 July............ 377,000 Nov............. 369,000 April............ 338,000 Aug............. 379,000 Dec............ 344,000

Jan 1, 1936

By Alfred H. Bell

Drilling activity increased in Illinois in 1935. There were 34 com-pletions as compared with 26 in 1934 and 18 wells were drilling at the end of 1935. Some large blocks of acreage were leased in Marion and Clay counties near the central part of the Illinois structural basin. Production of oil in the state totaled 4,305,000 bbl., a decrease of 4 per cent from that of 1934 There was some curtailment of production in the early part of 1935 but none after April 30 as shown in the following table. Percentage Pro-duced of Potential ProductioN (USING September 1934 Period as BaSis) Jan. .l-Feb. 20............................................ 79 Feb. 21-Feb. 25............................................ 85 Feb. 26-Feb. 38............................................ 79 Mar. 1-Mar. 11............................................ 85 Mar. 12-Mar. 31............................................ 100 Apr. 1-Apr. 9.......................................... 80 Apr. 10-Apr. 30............................................ 86 May 1-Dec. 31........................................... 100 This is equivalent to an average curtailment throughout the year of 5 per cent. The price of Illinois crude oil at the wells remained constant during 1935 at $1.13 per barrel. A small amount of oil was sold at a 1ower price, notably from the Dupo field, but to arrive at a value for the state's production there would be little error in assuming an average price of 81.13, giving a total value of $4,864,465. The following table shows production in Illinois by moths in 1935, according to the U.S. Bureau of Mines. Jan............. 332,000 May.......... 382,000 Sept ,............. 370,000 Feb............. 295,000 June. ........... 858,000 Oct.............. 391,000 Mar............ 370,000 July............ 377,000 Nov............. 369,000 April............ 338,000 Aug............. 379,000 Dec............ 344,000

Jan 1, 1936

By L. P. Teas

ALTHOUGH 1927 in the Arkansas-Louisiana territory will probably pass into history as a year of small profits and little new production, nevertheless during this period two large gas fields were developed; two new oil fields were discovered, and two new oil horizons, hitherto of minor Annual Production in Millions of Barrels FIG. 1.-PRODUCTION OF NORTH LOUISIANA AND ARKANSAS BY FIELDS FOR 1926 AND 1927. importance, were developed; In spite of the "hard times" some of the leading, supply houses did more business this year in this. district than in any year since 1920.

Jan 1, 1928

By C. A. Hartnagel, D. H. Newland

Detailed production statistics listing the operations according to producing sands, districts, etc., are not available for New York State and are scarcely obtainable without extraordinary effort and expense, hardly warranted by the current rate of developments. The oil industry is practically stabilized, so far as exploration for new sources of supply are concerned; no new pools have been tapped in the last 25 or 30 years. There is little prospect of extending the boundary of the oil fields beyond their present limits, though possibly some additional reserves may be found below the present productive sands. Natural gas, on the other hand, is not restricted to such confined areas. Drilling for gas has been fairly active, under the stimulation of some important finds in formations that previously were overlooked. The year's field operations will be covered somewhat fully. Oil production, which has been steadily advancing for a number of years, showed a further moderate gain in 1936. The output for 11 months (figures for December are not yet available) was 4,217,000 bbl., indicating a total for the year of around 4,600,000 bbl. The increase was about 10 per cent, a rate maintained for some time. Prices were more satisfactory than in the preceding five years, with an advance to $2.57 a barrel before the year's close. New York State yield is all paraffin-base, in the same class with high-grade Pennsylvania oil. Most of the output is now obtained by the water drive, which has given a new lease of life to the fields and promises to bring the total to about 200,000,000 bbl. before the known acreage has been exhausted by this method. Before its introduction the annual production was under 1,000,000 bbl. a year. The fields cover an aggrcgate area of 55,000 acres, with some 17,000 wells in operation. Development Exploring for natural gas in New York in 1936 outside of the old established pools continued actively, as in the previous year. There was an increase in total initial production. Operations were conducted in nine counties of the central and western parts of the state, and 43 wells

Jan 1, 1937

By Warren B. Weeks

The development of the relatively deeper fields discovered during 1937 helped build the 1938 production to 18,456,760 bbl., an increase of 6,295,910 bbl., or 51.6 per cent over 1937, and the largest production for south Arkansas since 1930. Schuler and Rodessa accounted for the increased production as well as for over half of the wells drilled in the state. There were 243 holes drilled during 1938, of which 200 were completed as oil or gas wells. Of the 29 wildcat wells completed, 25 were dry, 3 found oil in the Smack-over limestone, while 1 made a small oil well in the Nacatoch sand. This was less than half the number of wildcats drilled the previous year, but nearly twice as many field wells were drilled. The old depth record of 7973 ft. was exceeded twice during the year, with the present record of 8332 feet. Trend of Prospecting The porous "Reynolds" oolite of the Smackover limestone1 has been the object of most of the wildcat prospecting during the past two years. Seismograph work, which brought 22 crews into this area during 1938, was largely pointed toward a study of the structure of this limestone formation. Thirteen dry wildcats have been drilled to this formation and five pools have been opened in it since it was first found to be productive at Snow Hill in the spring of 1936. With the failure of "updip" prospects to produce, activity moved southward and basinward. Success in five instances in Columbia and south Union Counties has spurred activity in this area. Much of the acreage is under lease and half a dozen deep limestone tests are assured for the current year. Fig. 1 shows the location of the principal oil fields in south Arkansas, as well as one or two minor producing areas. The fields are numbered in the order of their discovery. It is shown that most of the recent discoveries are from the deeper formations. Dry wildcats that penetrated

Jan 1, 1939

By Warren B. Weeks

The development of the relatively deeper fields discovered during 1937 helped build the 1938 production to 18,456,760 bbl., an increase of 6,295,910 bbl., or 51.6 per cent over 1937, and the largest production for south Arkansas since 1930. Schuler and Rodessa accounted for the increased production as well as for over half of the wells drilled in the state. There were 243 holes drilled during 1938, of which 200 were completed as oil or gas wells. Of the 29 wildcat wells completed, 25 were dry, 3 found oil in the Smack-over limestone, while 1 made a small oil well in the Nacatoch sand. This was less than half the number of wildcats drilled the previous year, but nearly twice as many field wells were drilled. The old depth record of 7973 ft. was exceeded twice during the year, with the present record of 8332 feet. Trend of Prospecting The porous "Reynolds" oolite of the Smackover limestone1 has been the object of most of the wildcat prospecting during the past two years. Seismograph work, which brought 22 crews into this area during 1938, was largely pointed toward a study of the structure of this limestone formation. Thirteen dry wildcats have been drilled to this formation and five pools have been opened in it since it was first found to be productive at Snow Hill in the spring of 1936. With the failure of "updip" prospects to produce, activity moved southward and basinward. Success in five instances in Columbia and south Union Counties has spurred activity in this area. Much of the acreage is under lease and half a dozen deep limestone tests are assured for the current year. Fig. 1 shows the location of the principal oil fields in south Arkansas, as well as one or two minor producing areas. The fields are numbered in the order of their discovery. It is shown that most of the recent discoveries are from the deeper formations. Dry wildcats that penetrated

Jan 1, 1939

By H. K. Shearer

Drilling for oil and gas in Arkansas in 1934 showed more activity than in any year since 1929; with a total of 96 completions, including 36 oil wells, 1 gas well and 59 dry holes. Of the producers, the lone gas well and 35 oil wells were in old fields, and one wildcat producer opened a new pool. Of the dry holes, 16 were in or near fields and 43 were wildcats. The total reported initial daily production of the oil wells was 9013 bbl., averaging 252 bbl. per well. Active drilling operations numbered 65 at the close of the year, compared with 26 at the beginning.

Jan 1, 1935

By T. Y. Yan

SUMMARY Laboratory high pressure column tests have shown that the presence of 1-20 ppm of aluminum ion effectively prevents permeability loss during uranium leaching with leachates containing sodium carbonate. If added after permeability loss has occurred, aluminum ion can restore the permeability to nearly its original value. No deleterious effect was observed on uranium leaching performance and the technique should be quite compatible with all field operations. INTRODUCTION The recovery of uranium values from underground deposits by in situ leaching or solution mining has become economically viable and competitive with conventional open pit or underground mining/milling systems (Merrit, 1971). In situ leaching processes are particularly suitable for small, low-grade deposits located in deep formations and dispersed in many thin layers. Many such ore bodies occur along a broad band of the Gulf Coastal Plain (Eargle et. al., 1971). The advantages of the in situ leaching processes have been reviewed (Anderson and Ritchi, 1968). In the in situ leaching process, a lixiviant containing the leaching chemicals is injected into the subterranean deposit and solubilizes uranium as it traverses the ore body. The pregnant lixiviant or leachate is produced from the production well and is then treated to recover the uranium. The resulting barren solution is made up with the leaching chemical to form lixiviant for re-injection. Upon completion of the leaching operation, the formation is contaminated with leaching chemicals and other species made soluble in the leaching operation and has to be treated to reduce the concentration of these contaminants in the ground water to levels acceptable to the regulatory agencies (Witlington and Taylor, 1978). Restoration is accomplished by injecting a restoration fluid, which could be the fresh water or water containing chemicals, into the formation. As it traverses the leached formation, the restoration fluid picks up the contaminants and is then produced at the production well. This produced water is either disposed or purified for recycle. In both phases of operation, formation permeability or well injectivity is one of the most important parameters which determines the viability of the in situ leaching process. Low formation permeability limits production rates, leading to uneconomical operations. The formation is said to be sensitive if there is a sharp loss of permeability on contact with water and other fluids. Many uranium bearing formations, for example, the Catahoula formation of the Texas Coastal Plain, contain significant amounts of clay minerals which are water sensitive. Serious permeability losses can occur when the pH and chemical composition of the lixiviant is significantly different from that of the formation water. Jones has investigated the influence of chemical composition of water on clay blocking of permeability (Jones, 1964) and Mungan studied permeability reduction through changes in pH and salinity of the water (Mungan, 1965). Various mechanisms of permeability damage have been proposed and reviewed (Jones, 1964; Mungan, 1965; Gray and Rex, 1966; and Veley, 1969). When large amounts of swelling clays are present, a significant fraction of the flow channels in the formation can be reduced due to swelling. However, in most cases, swelling need not be the main cause of permeability losses. Particle dispersion and migration or clay sliming can be more important causes for formation damage. Clay particles entrained in the moving fluids are carried downstream until they lodge in pore constrictions. As a result, microscopic filter cakes are formed by these obstructions, plugging the pores, effectively restricting fluid flow and reducing the formation permeability. Moore found that as little as 1-4 percent clays present in a fine grained sandstone could completely plug the formation if they are contacted by incompatible injected fluids (Moore, 1960). It has been found that injection of NaHC03/Na2CO3 lixiviant into formations with significant clay content often leads to loss of formation permeability and well injectivity. To alleviate this problem a change of the lixiviant composition to KHC03/K2CO3 has been proposed. At present, however, many in situ leaching operations employ NH4HC03/(NH4)2C03 mixtures as a source of carbonates. This approach has been successfully used in South Texas by Mobil, Intercontinental Energy, Wyoming Minerals and U.S. Steel, etc. The use of ammonium carbonates solutions, however, contaminates the formation and requires a time-consuming restoration operation. The other approach to reduce the permeability loss is to pretreat the sensitive formation with chemicals which prevent clay dispersion and migration. Such chemicals include hydroxy-aluminum (Reed, 1972 and Coppel et. al., 1973), hydrolyzable zirconium salts (Peters and Stout, 1977), hydrolyzable metal ions in general (Veley, 1969) and polyelectrolyte polymers (Anonymous). Still another approach, is to minimize the "shock" caused by sudden injection by gradually changing the chemical composition of the injected fluids from that of the formation water. THE APPROACH Since permeability loss can be an important factor limiting the efficiency and economic viability of the in situ leaching process, a study was initiated on

Jan 1, 1982

By W. N. Logan

THE petroleum industry of Indiana made somewhat notable progress during the year 1923, considering the number of handicaps it encountered. The price of labor and materials continued to have an upward slant while the price of crude oil took a decidedly downward course. In spite of these adverse conditions, the quantity production will closely approximate that of 1922, when it passed the million-barrel mark. The progress of the industry in Indiana should be considered fairly satisfactory as long as the present production is maintained. In other words, if the loss of production from the waning old wells can be offset by the production from the new for a period of 10 or 15 years longer, the industry may have cause for congratulation. SUB-TRENTON INVESTIGATIONS In recent years a number of tests of strata lying below the Trenton limestone have been made in Indiana. Several of these tests were completed in 1923. Indications of oil were reported by drillers from several horizons below the Trenton. The most satisfactory of these came from the St. Peter sandstone lying immediately below the Trenton limestone, but no production has yet been obtained from any of the Sub-Trenton horizons. Glen Valley Wells.-Two wells in Marion County were drilled into the St. Peter sandstone, 1 mi. north of Glen Valley and 9 mi. south of Indianapolis. About 30 ft. of sand saturated with a dense asphaltic oil was found in the upper part of the St. Peter sandstone in one of the wells, which contained about 10 per cent. of the light oils, or more easily volatile constituents, and about 90 per cent. of a dark, dense, asphaltic residue. The oil resembled the residue of an asphaltic petroleum from which the more volatile oils had disappeared.

Jan 3, 1924

By Thomas Brownfield

Development and production activity in Oklahoma during the year 1940 was of routine nature. Production, according to the Corporation Commission's figures, averaged 409,100 bbl. daily as compared with 421,000 bbl. for the year 1939. Discoveries were of minor importance except for the Cumberland pool in Marshall and Bryan Counties, in the southern part of the state. Maintenance of a relatively stable producing rate is attributable to the drilling of new wells and the recompletion of many old wells in the previously established producing areas. During the year 1785 new wells were drilled, a decline of approximately 10 per cent as compared with the previous year. Of the wells drilled, 962 were oil wells with a combined initial production of 241,000 bbl. daily, 172 were gas wells having aggregate capacities of 1205 million cu. ft., and 651 were dry holes. Wildcat activity increased 20 per cent over 1939 and 227 such wells were completed during the year; that isl 43 oil wells, 16 gas wells, and 168 dry holes. In addition to the new work completed, 603 wells were recorded as having been drilled deeper or plugged back to test new horizons; included were 334 producing wells with total initial production of 65,000 bbl. daily, 37 gas wells with initial aggregating 305 million cu. ft., and 232 abandonments. Footage drilled amounted to 4,730,000 ft., an average of 2650 ft. per well as com-pared with an average depth of 2600 ft. recorded the previous year. The principal new pools discovered as a result of the exploratory drilling were Cumberland; East Cromwell, in Okfuskee County, and Prague, in Lincoln County. At the end of the year Cumberland had 13 completed wells, which averaged 700 bbl. initial through tubing from the Simpson Bromide formation (Ordovician) at 4750 ft. East Cromwell had 10 wells with average initial of 435 bbl. in the Cromwell sand (Pennsylvanian) at 3460 ft. Prague had II wells with an initial average of 220 bbl. from the Senora sand (Pennsylvanian) at 3260 ft. There were notable extensions to the Dill pool, Okfuskee County, and to the Hewitt pool, Carter County. At the end of the year, 19 producing wells had been drilled in the former, with initials averaging 1000 bbl., and 63 wells averaging 150 bbl. daily in the latter. There were no notable changes in the policy of State conservation authorities with respect to proration. The Bureau of Mines recommendations for the year averaged 413,000 bbl. daily; the State author-ities fixed allowables at an average of 406,000 bbl. daily, while, as noted above, production averaged 409,100 barrels. The most important development in the older areas occurred in the following pools: Billings.—Seven oil wells with an average initial production of 2500 bbl. and two dry holes were completed during the year. Production from the Simpson horizon averaged 6025 bbl. daily as compared with 5950 the previous year. Production from this field has been almost steady since reaching its peak early in 1937. The major portion of the pool is efficiently operated as

Jan 1, 1941

By Thomas Brownfield

Development and production activity in Oklahoma during the year 1940 was of routine nature. Production, according to the Corporation Commission's figures, averaged 409,100 bbl. daily as compared with 421,000 bbl. for the year 1939. Discoveries were of minor importance except for the Cumberland pool in Marshall and Bryan Counties, in the southern part of the state. Maintenance of a relatively stable producing rate is attributable to the drilling of new wells and the recompletion of many old wells in the previously established producing areas. During the year 1785 new wells were drilled, a decline of approximately 10 per cent as compared with the previous year. Of the wells drilled, 962 were oil wells with a combined initial production of 241,000 bbl. daily, 172 were gas wells having aggregate capacities of 1205 million cu. ft., and 651 were dry holes. Wildcat activity increased 20 per cent over 1939 and 227 such wells were completed during the year; that isl 43 oil wells, 16 gas wells, and 168 dry holes. In addition to the new work completed, 603 wells were recorded as having been drilled deeper or plugged back to test new horizons; included were 334 producing wells with total initial production of 65,000 bbl. daily, 37 gas wells with initial aggregating 305 million cu. ft., and 232 abandonments. Footage drilled amounted to 4,730,000 ft., an average of 2650 ft. per well as com-pared with an average depth of 2600 ft. recorded the previous year. The principal new pools discovered as a result of the exploratory drilling were Cumberland; East Cromwell, in Okfuskee County, and Prague, in Lincoln County. At the end of the year Cumberland had 13 completed wells, which averaged 700 bbl. initial through tubing from the Simpson Bromide formation (Ordovician) at 4750 ft. East Cromwell had 10 wells with average initial of 435 bbl. in the Cromwell sand (Pennsylvanian) at 3460 ft. Prague had II wells with an initial average of 220 bbl. from the Senora sand (Pennsylvanian) at 3260 ft. There were notable extensions to the Dill pool, Okfuskee County, and to the Hewitt pool, Carter County. At the end of the year, 19 producing wells had been drilled in the former, with initials averaging 1000 bbl., and 63 wells averaging 150 bbl. daily in the latter. There were no notable changes in the policy of State conservation authorities with respect to proration. The Bureau of Mines recommendations for the year averaged 413,000 bbl. daily; the State author-ities fixed allowables at an average of 406,000 bbl. daily, while, as noted above, production averaged 409,100 barrels. The most important development in the older areas occurred in the following pools: Billings.—Seven oil wells with an average initial production of 2500 bbl. and two dry holes were completed during the year. Production from the Simpson horizon averaged 6025 bbl. daily as compared with 5950 the previous year. Production from this field has been almost steady since reaching its peak early in 1937. The major portion of the pool is efficiently operated as

Jan 1, 1941