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By W. A. Ver Wiebe

The year 1940 was singularly unmarked by sensational developments in Kansas. Routine operations were carried on in a systematic, orderly fashion and the efforts of oil producers were concentrated on extending known fields. In Kansas an arbitrary yardstick for wildcats has been set up. A well drilled mile or more from a known pool or well is now considered a wildcat. A "rank wildcat" is one that is drilled at least 2 miles from any known producer. During 1940, rank wildcats resulted in the completion of 116 test wells, among which 16 were successful in finding new oil pools and the remaining I00 were dry holes. The ratio of successful wells to dry holes, therefore, was approximately I:6. During the year, 1890 wells were completed in eastern and western Kansas. This figure is somewhat lower than that given in several trade journals, because it does not include wells that were deepened or wells that were recompleted in a different geological horizon. About three fourths of these (1423) were completed as commercial oil wells (I220 in western and 203 in eastern Kansas). The commercial gas wells completed number 58 of which 10 are in eastern Kansas and 48 in western Kansas. Of the remzining completions 147 are dry holes in eastern and 262 are dry holes in western Kansas. Based on daily potential capacity, the new discoveries of the year account for a cumulative initial production of 46,000 bbl. in eastern and 2,128,000 bbl. in western Kansas. The state of Kansas attained a new peak in production, with the total of 66,245,000 bbl. for the year 1940, the number of contributing wells being 20,779. Thus the increase over 1939, when about 58 million barrels was produced, is considerable. The previous peak occurred in 1937, when 70,761,000 bbl. was marketed. In another still earlier peak, in 1917, slightly more than 45,000,000 bbl. was produced and sold. The production of gas probably reached a new peak also during 1940, with its total of 85 1/2 billion cubic feet. Between the peak of the year 1908, when over 80 billion cubic feet was produced, and that of 1940, the production dropped to a low point of 16 billion cubic feet in the year 1921. The number of test wells drilled was larger than in 1939; that is, 1890 compared with 1458. The first peak was reached in 1904, when 2782 wells were drilled. The number dropped off rapidly, to 368 three years later, but rose to the second and highest peak in 1918, when 4671 test wells were completed. In the period between 1904 and 1912 more gas wells were completed than oil wells. Between the high peak of completions in 1918 and somewhat lower peak of 1937, the low point was reached during 1931, with the completion of only 470 test wells. In the number of new pools discovered, Kansas again ranks high among the states. The exact number depends somewhat upon the interpretation of a "new" area— whether it should be called a new pool or a long extension of an old pool. Unfortunately, the matter of securing the right kind of production allowable also enters into this question. Often the decision regarding a new pool cannot be made until other wells

Jan 1, 1941

By Coleman D. Hunter, George M. Straughan

Oil and gas development as well as extensive leasing in Kentucky during 1940 has shown a marked improvement over the past three years.$ The most noticeable improvement is the gas development in eastern Kentucky and the deep tests being drilled by major oil interests. In western Kentucky, 406 wells were drilled, of which 173 were oil producers, 12 were gas wells and 221 were dry or abandoned. The number of dry tests was large, because no important, new oil or gas pool was discovered and many of the dry holes could be considered wildcat tests. However, with either oil or gas possibilities from Pennsylvanian formations on through Mississippian, Silurian, Devonian, and Ordovician, this percentage of dry holes seems rather high. Many of the dry tests possibly should have been tested in deeper horizons before being abandoned: namely, Silurian and Ordovician ages. In eastern Kentucky, 213 wells were drilled, of which 113 were gas producers, 61 were oil wells, and 39 were dry holes. Of these wells, 117 were drilled in the most important Big Sandy gas field, in Floyd, Pike, Knott and Martin Counties, and of this number 103 were gas producers, 5 were oil wells, and 9 were dry holes. In the Big Sinking oil field of Estill, Lee and Powell Counties, 70 of the remaining 96 wells were drilled, j6 being oil producers. During 1940, four deep tests were drilled in eastern Kentucky. One test penetrated the Knox dolomite in Knox County and was dry; no St. Peter sand was encountered. Another test in Lee County had some gas in what might be called St. Peter sand, according to the State Department, and also some gas deeper in the Knox dolomite. In Wolfe County, a small oil well was completed in the Ordovician, which was undoubtedly of Trenton age. ilt the present time, four deep tests are being drilled, all of which will go to the Knox dolomite. In Elliott County, on the Burke dome, the Inland Gas Co, is drilling at 3650 ft. In Magoffin County, on the Paint Creek uplift, the Cumberland Petroleum Co. is drilling at 3800 ft. In Clark County, in the Ruckerville fault area, W. 0. Allen is drilling at 1800 ft. In Laurel County, on the Sinking Creek dome, the Globe Oil and Gas Co. is drilling at I750 ft. If production is encountered in the Trenton, St. Peter, or Knox dolomite in any of these tests, eastern Kentucky will experience a marked increase in deep development.

Jan 1, 1941

By H. K. Shearer

North Louisiana (including all townships north of the Louisiana base line) had a year of normal development in 1940, marked by the discovery of two shallow oil fields producing from the Wilcox formation in La Salle Parish and a large increase in drilling in the old Caddo shallow field. This renewal of shallow drilling activity led to a somewhat unexpected increase in the number of wells drilled, although the total footage and average depth continued to decline, as in several preceding years. Well completions and depth statistics for 1940, with previous years for coinparison, are as follows: Wildcat producers in 1940 include the discovery oil wells in the Olla and Nebo fields; also three gas wells in the vicinity oi the Olla field and a shallow gas well, which opened a new field or extension in the Greenwood area of Caddo Parish. This table illustrates the lack of important deep discoveries since 1937, in which year the Rodessa, Lisbon and Cotton Valley fields were being actively developed. Operators have been forced to return to the old type of shallow drilling, which necessarily means smaller producing wells. Oil production in 1940 was 24,381,760 bbl., a decrease of 867,880 bbl. from 1939, or 3.44 per cent. The newly discovered fields of La Salle Parish produced over a million barrels, and other increases worthy of note were at Cotton Valley, Caddo, Sligo and Sugar Creek. The greatest decrease was again at Rodessa, although this remains the principal producing field. Geological Names Revised Deep drilling during 1940 did not provide a great deal of new geological information. However, by agreement of a majority of the members of the Shreveport Geolog- ical Society, the names of some of the Lower Cretaceous formations have been revised in the interest of greater clarity and in order to make the descriptions agree better with the facts discovered in recent years. The geological section is discussed in detail and reasons for changes in nomenclature are stated in a recent publication by Ralph W. Imlay. Although not yet in universal use among field men, the new names are employed in this report and accompanying tables, as

Jan 1, 1941

By J. Brian Eby

The Gulf Coast of southern Louisiana during the year of 1940 was subjected to an extensive exploration and development campaign, as a result of which 16 oil fields and about 38 new producing sands were found. Although this record of discovery appears in keeping with the rate of 1939 actually in amount of new proven reserves, it may fall short of that of the previous year. Only five or six of the discoveries rated as first-class or important fields at the close of the year. The most prominent new fields opened during the year were Neale field in Beaure-gard Parish, the West Cote Blanche field in St. Mary Parish, the Stella field and the West Bay field in Plaquemines Parish, and the Lake Salvador field in St. Charles Parish. There were many important oil-sand discoveries in proven fields, such as in the Bayou Perot field, the Golden Meadows field, the Iowa field, West Lake Verrett field, and the Venice field. During the year, 1047 weUs were drilled in southern Louisiana, of which 768 were completed as oil-producing wells, 17 as gas wells and 262 as dry holes. The Neale field in northwest Beauregard Parish is considered one of the most important discoveries of the year. The f~eld centers around the north half of sec. 26, 'Y.3 S., R.I I W., just north of the town of Neale. It was discovered by the Atlantic Refining Co., using reflection seismograph to locate the structure. Production was found in the second well drilled in the Wilcox sand on the downthrown side of a fault. The structure is known as the "Tepetate" type, being similar to that of the well-known Tepetate field. There were 12 oil wells and 3 dry holes drilled during the year. The Wilcox sand in this field occurs between 8350 and 8400 ft. and averages 30 ft. in thickness. The West Cote Blanche Bay field, in West Cote Blanche Bay, St. Mary Parish, is a 1940 discovery by the Texas Company, credited to reflection seismograph exploration. The oil is from two sands occurring at 3110 to 3140 ft. and from 4950 to 5020 it. Four wells were drilled during the year, three oil wells and one dry hole. The deepest hole drilled reached 9491 ft. without encountering salt or dome material. In Plaquemines Parish, south of New Orleans, the California company has a new field known as the Stella field. The sand was found at a depth of 7485 ft., and 5 ft. of perforations made a well capable of producing 486 bbl. of oil in 24 hr. through a 9.is-in. choke. The oil is 42" gravity. The discovery well was drilled to a total depth of 10,258 ft. and other producing sands were indicated. A good field appears assured, although only one well was completed within the year. The Lake Salvador field, in the center of Lake Salvador, St. Charles Parish, gives promise of being one of the most important discoveries of the year. The discovery well was perforated at 9775 to 9800 ft. making 850 bbl. of 33.7° gravity oil daily through a 1/4-in. choke. Three wells were completed in 1940 but few details have as yet been made available.he Gulf Oil Corporation apparently has a good field in its wildcat discovery in West Bay, Plaquemines Parish. This well found

Jan 1, 1941

By Theron Wasson

No major oil-field discoveries were made County; the second in Marion township, in Michigan during the year 1940. Produc- Osceola County. Both are producing from tion for the year was maintained by the Stray sand at about 1350 ft. These discoveries made in 1938 and, as a result, is fields are on structures founci by core test-below the total for 1939. Several extensions ing through the glacial drift. The Six Lakes to old fields have been made, which have field, Montcalm County, discovered in helped to maintain production in the face 1934, is Michigan's largest gas-producing of rather rapid decline in the fields of the field. it has 195 wells producing from the southwestern part of the state. Important Michigan Stray sandstone and the Upper extensions were made in Overisel, Porter, Marshall sandstone. This field was devel-Sherman, and Adams fields. Important oil oped on a 40-acre spacing plan, and gas fields of the state are shown on the -map, Fig. I. WiI~dcat Drilling Michigan's production of 19,700,000 bbl. A test in sec. 29, Winterfield township, during 1940 was 3,800,000 bbl. less than Clare County, which is producing oil from the total for 1939, but about one million the Monroe of Devonian age at a depth of greater than 1938. This brings the total 3760 ft., and a well in sec. 31, Lincoln accumulated production for the state to a township, Osceola County, producing from little over 145,000,000 bbl. the Monroe at 3625 it., should be classed as wildcats that are sure to lead to further Active Oil Fields development in I94L The leading producer for the year was the At the end of the year the Gulf Refining Temple field, Clare County, where 29 new Company's deep test on the Kawkawlin wells were drilled. The Walker field, Kent structure in Monitor township, Bay County, was second, but drilled 183 new County, was preparing to drill deeper after wells in order to gain that position. In the having had a gas blowout from a depth of extension of the Overisel field in Allegan 7775 ft. This test is the most important one County, 115 new producers were drilled. drilling at the end of the year in Michigan, The Adams field, Arenac County, was for should it develop commercial produc- revived by several wells with initial production from deeper beds it will lead to deeper tions of over 1000 bbl. per day from the drilling on many well-known structures Dundee of Devonian age. that have been producing from shallower sands. Active Gas Fields Two important gas fields were discovered Exploration by Taggart Brothers during the year. The A small amount of reflection seismograph first was in Riverside township, Missaukee work was done in Clare, Osceola, and Glad-Win Counties during the year. Exploration Manuscript received at the office of the Institute March 28 1941 by shallow drilling for structural informa- tion on beds below the glacial drift con- 347

Jan 1, 1941

By H. M. Morse

During the year of 1940, wildcat wells were drilled in 32 counties of Mississippi; 85 wells in all. These were scattered over the state from the most northern county to the southern counties and from the Mississippi River on the west to the Alabama line on the east. Yazoo County, with 19, received the largest number. The average depth of all the wells was 5333 ft. The shallowest well completed as a dry hole was in Yalobusha County, aban-doned at 1392 ft. in the Selma. The deepest well drilled was in Scott County, abandoned at 10,365 ft. in the Lower Cretaceous Paluxy. G. C. Grasty drilled the Kentucky Lumber Company No. I well, sec. 7, T. 10 S., R. 10 E., Itawamba County, to a depth of 3530 ft. and bottomed his hole in the Ordivician. Tinsley Oil Field.—In the Tinsley oil field 104 wells were completed as producers during 1940. Five producing sands have been logged with a total average thickness of I57 ft. of oil sand. One of these sands is in the Selma, three in the Eutaw, and one in the Tuscaloosa. Vaughan-Pickens Field.—The Vaughan-

Jan 1, 1941

By Frank C. Greene

The wildcatting in northern and northwestern Missouri, which started in 1939, was continued in 1940. Two new gas fields were found and one discovered in 1939 was further extended. The total number of completions was 94, of which 5 were oil wells with about 48 bbl. initial production, 30 were gas wells with an initial open-flow capacity of 37,655,000 cu. ft., and 59 were dry holes. The outstanding discovery was the Polo gas field, T. 55 N., R. 28 and 29 W., in Caldwell County. A sand now believed to be a lens in the Bandera shale at a depth of 400 ft. yielded flows of more than 12,000,-000 cu. ft. In all, I0 wells with 31,490,000 cu. ft. of gas, were drilled. The rock pres-sure is 80 lb. At present no arrangements for an outlet have been made. In Platte County, the Prairie Point gas pool in sec. 7, T. 51 N., R. 33 W., and sec. 12, T. 51 N., R. 34 W., and the Lake-side pool in sees. 5 and 6, T. 50 N., R. 33 W., were further developed, and in the latter both oil and gas have been found, but data are not available for publication at this time. Drilling for gas continued in proven areas in Clay County, and for both oil and gas in proven areas in Jackson and Cass Counties. Table 1 summarizes the results of drilling in Missouri in 1940.

Jan 1, 1941

By E. C. Reed

Oil was discovered in Nebraska on Nov. I, 1939, when the Pawnee Royalty Company's Boice No. I well, about 3 miles west of Falls City (NE 1/4 NE 1/4, sec. 18, T.r N., R.16 E., Richardson County) was drilled into the Hunton formation but the develop-ment of the area took place during 1940. After a pumping test lasting 18 days, the Boice well stopped producing and failed to qualify for the State bonus of $ 15,000 offered for the first oil well to produce go bbl. per day for 60 consecutive days. On May 9, 1940, the Pawnee Royalty Company's Bucholz No. I well was completed about M mile southeast of the discovery well and flowed at the rate of about 330 bbl. per day, easily meeting the State bonus requirements. In addition to the discovery well, which later was reconditioned, and the bonus well, 28 producers were drilled in the Falls City field during 1940. Of these wells, 23 are in sec. 20, two are in the northern part 'of sec. 29, two in the southwestern part of sec. 17 and three in the eastern part of sec.

Jan 1, 1941

By A. Andreas

New Mexico established an annual record by producing 38,897,741 bbl. of oil during 1940. This was approximately 6 per cent greater than the 1939 production of 36,746,840 bbl. The daily average produc-tion was 106,569 bbl. New Mexico retained its position as the seventh oil-producing state. The recommendations of the United States Bureau of Mines were followed by the Oil Conservation Commission in setting the monthly state allowable. At the beginning of the year the average top allowable for each qc-acre unit was 40 bbl. and at the close of the year it was 36 bbl. Remedial work by the operators has been extremely beneficial and satisfactory in reducing the gas-oil ratios in various fields. Gas formerly blown into the air is now being processed by numerous casinghead plants. The Oil Conservation Commission, with the full cooperation of the Proration Office and operators, has taken bottom-hole pressure surveys and has done considerable remedial work in various fields. Two new oil fields and one gas field were discovered in New Mexico during 1940. Numerous extensions to the existing fields were made. Some of these were definitely wildcats in the same townships designated as fields and some, although called extensions, were more than 3 miles from production. Lea County continued to be the largest oil-producing county in the state, with a production of 33,976,394 bbl. It had the largest number of completions during 1940, with 303 oil wells, 9 gas wells and 13 dry holes—a total of 325 wells. Eddy County was the next most active county, with 239 completions, of which 163 were oil wells, 8 gas wells and 68 dry holes. It produced 4,405,158 bbl. of oil during the year. The increased activity in Eddy County and the completion of a large number of producing oil wells have created a transportation problem that can be solved only by additional pipe-line facilities. During the year Eddy County was unable to produce 1,500,000 bbl. of its allowable oil, because there was no pipe-line outlet. There were 601 wells completed in New Mexico in 1940, of which 478 were oil wells, 22 gas wells and IOI dry holes. This was a decline of approximately 9.5 per cent in the number of completions compared with 1939, when 659 wells were drilled. Southeastern New Mexico Lea County.—The largest producing field in Lea County was the Monument field, with 6,894,475 bbl.; followed by Eunice with 6,559,348 bbl. and Vacuum with 4,743,065 bbl. The Hobbs pool, which for years was the largest producing field in the state of New Mexico, was fourth with 3,790,477 bbl. The Vacuum pool was the most active area, having 68 completions, of which 67 were oil wells and one was a dry hole. Only one new field was discovered in Lea County during 1940; the discovery well was in the Caprock area, the Livermore State No. I, in the SE. 1/4 SE. 1/4 sec. 30, T. 12 S, R. 32 E. This well was drilled to a

Jan 1, 1941

By C. A. Hartnagel

The production of petroleum in New York in 1940, totaling 4,999,000 bbl., was only slightly under the amount produced in each of the previous three years. The year 1940 started auspiciously with a posted price on Jan. I of $2.75 a barrel. Four price reductions, beginning in May, resulted in August in a low of $1.85 a barrel, after which two increases brought the year's closing price to $2.15 a barrel. The favorable crude price at the beginning of the year stimulated an increased drilling program, especially in the water-flooding districts. In the Allegany County region, which accounts for about two-thirds of the state's oil production, 886 wells, including water-intake wells, were drilled; 200 more than in the preceding Year. During the closing months of the Year there was a marked decline in the number of wells drilled. The unfavorable position in which the industry found itself before midsummer was due largely to the loss of export markets for its high-grade lubricants, constituting approximately 25 per cent of its business. As a result of this situation, runs to refineries were curtailed as much as 30 Per cent at the middle of the Year. Improvement in market conditions toward the end of the Year found the stocks of available crude at an almost record low. Deep DRILLING with the gradual exhaustion of some of the important natural and flood-oil-produc-ing areas of the Allegany and Bradford pools, overproduction will not be a serious problem in the future. The possibility of finding new territory or deeper producing sands has been further lessened by the drilling of additional deep wells for gas in and about the present oil fields. Many of these wells drilled to the Oriskany sand-stone were over 4000 ft. deep and have tested the entire thickness of the Devonian formation, the upper 2000 ft. of which contain all the important oil-producing strata in the state. Water-flooding It is thus evident that the problem of the New york oil producers is not one of find-ing new supplies but of obtaining as much 6 oil as possible from the old developed fields that during the 60 years of their life have 1 produced I 3o,ooo,ooo bbl. of oil. Although a few floods were in operation before I9I9, when the production of oil by flooding was 1 made legal, the output for that year amounted to only 85I,000 bbl. From 1919 I on there has been an almost constant increase, which during the past four years has averaged well above 5,000,000 bbl. annually. During the last 22 years, which constitutes the period of important flooding operations, 651337,000 bbl. of oil have been produced in the state. Careful estimates indicate that between one-third and one-half of the oil fields are being flooded or are already watered out. Some of the flooded and watered-out areas include territory with unusually thick sands, which were highly productive during the early history of the fields. From a recent study of operations in the New York oil fields, it is estimated that about 65,ooo,oo bbl. of oil

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Jan 1, 1941

By C. V. Millikan

Temperature measurement in wells is an old practice and geothermal gradients have been of interest to geologists for many years.le2 Their application to the operation of oil wells is a more recent practice. It has long been recognized that temperature anomalies occur in drilling and producing wells but thermometers that could obtain a satisfactory record of the anomalies were not available. The normal geothermal gradient is con-sidered as being about one degree Fahren-heit for each 60 ft. of depth.4 This "nor-mal " gradient varies in different areas, but whatever it may be in an area there is little variation from the surface to as deep as the : drill penetrates. The normal gradient is appreciably changed by gas expanding ; from the reservoir into the borehole or by the movement of fluid through a borehole : while drilling, producing, or circulating. It is the resulting anomalies and abnormal gradients from which conditions in wells can be interpreted. Some of the applications of such interpretations are locating the position of oil or gas sands, permeable strata in a reservoir zone, gas-oil contact, source of water, casing leaks, and the top of cement behind casing. Thermometers A thermometer for use in wells must be sensitive and have a low thermal lag. The sensitivity should permit recording 0.2OF. or less for differential temperatures although the actual temperature need not be more accurate than 1°F. The thermal lag should be as low as rugged construction will permit in order to allow surveys to be made in a minimum of time. Of the several kinds of thermometers, these requirements are most easily obtained with the vapor-pressure, expansion, and electric-resistance types. Thermometers for use in wells may be self-contained—that is, the complete instrument is lowered into the well and a record made of the temperature—or the thermal element only may be lowered into the well and the temperature recorded at the surface. The vapor-pressure and expansion types are more adaptable for a self-contained instrument while the electric-resistance thermometer is more suitable for surface recording of temperatures. The self-contained instrument can be run against high pressure on a single wire line with only one operator required. The instrument and its hoisting equipment is easily portable and can be mounted on a small car. The disadvantages are a somewhat greater thermal lag and the necessity of completing a run before any temperature or temperature anomaly is known. A surface-recording thermometer has the advantage of being somewhat more sensitive and of having a lower thermal lag. The Operator can see what anomalies are encountered and can immediately change the running conditions of the instrument or the well conditions in order to obtain the most

Jan 1, 1941

By Kenneth M. Bravinder, Jonathan E. Koogle, Dean H. Sheldon

The solution of subsurface geological problems requires an analysis of vertical and horizontal dimensional relationships. For many, the ability to visualize structures in three dimensions is not easily acquired, and for areas where the structural conditions are complicated by faulting the need arises for illustrative models. This has led to the many forms of peg models, in which the usual course of construction includes a peg for the well bore, and the suspension of strings from peg to peg to illustrate the formation correlation between wells, thus developing the usual folds and flexures. Such models proved unsatisfactory for the analysis of fault problems. Consideration was then given to the use of transparent materials. A model of the Dominguez oil field was constructed in 1935, which consisted of a series of glass panels irom well to well on which the formations were shown in color. This model, though serving its purpose at the time, proved to be impractical from the standpoints of cost, breakage hazard, and extreme difficulty in maintenance. The cost of materials was estimated to be approxi-mately $300, and the construction required the services of one man for a period of from 10 to 12 months. Maintenance after actual construction was an additional expense. Consideration was then given to the use of celluloid, and aiter some experimental work it was found that the advantages in its use were: (I) a short construction time, (2) ease of handling the material, (3) sec-tions are easily reworked, (4) low cost. Construction It would be of little value to recount here the difficulties encountered in the building of the first celluloid model. The conclusions drawn, however, suggest the following pro-cedure for those who contemplate the construction of such a model: 1. Determilzatiolz of the Scale.—Accurate geological interpretation requires the use of the same scale horizontally and vertically. It should be emphasized that the limited size of the celluloid sheets (20 by 48 in. maximum dimensions), the area to be studied, the maximum depths to be plotted, and area of possible future development are the controlling factors in adopting a scale to he used. 2. Construction of the Base.—A satisfac-tory base may be constructed by using two pieces of three-ply wood separated by strips of I by 2-in. material. This type of construction prevents warping of the base. The size of the base is determined by the dimensions of the area to be studied plus 5 in. on all sides. A map of the same scale as that adopted for the model, indicating the lines of section to be used, should be fastened to the base. 3. Constructiolt of the Frame (Fig. I).—In the construction of the frame the use of %-in. 0.d. pipe welded in a box shape is suggested, with two horizontal rods on each of the four sides, top and bottom. The top rod should be at least r in. higher than the

Jan 1, 1941

By Tracy L. Atherton

The mapping of slant-hole oil fields is complicated by the fact that relationships between wells are subject to variations in three dimensions and are not readily adaptable to representation on a plane surface. Formalized perspectives usually expand into an undecipherable maze of lines and peg models with the necessary supporting dividers serve only to awe the beholder with their perplexity. The usual compromise arrived at is a plotting of the projection of the courses of all of the wells in the field onto a horizontal plane (Fig. I). These complicated plots, when used in conjunction with the individual vertical projections of the wells, heretofore have been the most practical foundation for the study of general field problems. This method has many shortcomings, however, which arc not found in the recently developed straight-hole equivalent projec-tion method. The new method supplies a series of maps similar to the type now in common use in straight-hole fields. It is remarkably simple to use and supplies a ready check on clearances between wells. Perhaps the method can best be understood if the steps that led to its development are described. Common practice of oil-well surveyors is to supply the owner with a tabling of the survey and a plan view plotted against the true meridian. If a vertical projection is plotted, it is usually plotted separately and shows vertical depths against the projection of the stations along a section line joining the top and bottom of the hole on the plan view. A more practical method would be to plot the section line of the plan parallel to the abscissa of the vertical projection (Fig. 2). If this is done, any line parallel to the "base line1' will pass through the points on each projection that represent a single point in the hole. Another very useful graph, which the well surveyor could provide, would be plotting of vertical depths against measured depths. Fig. 3 illustrates the next step facilitated by this form of plotting. The lines designated "well A" represent the proposed course of a hole to be drilled. Superimposed on the drawing, in its proper relative position, is the plan view and a portion of the vertical projection of a present producer, well B." From an inspection of the plan view we arrive at the correct conclusion that the only indicated possibility of collision is at the point of crossing of the wells on the plan view. Referring to the vertical projection, note that the vertical depths of stations on B, in the vicinity of the crossing, are plotted on the same plane of projection as A. The clearance is the indicated distance between the two vertical sections measured along the parallel to the "base line," which passes through the point of intersection of the plan view. Repeat this process for the other wells crossing the proposed course of A on the plan view and you have a preliminary check of clearance for the proposed course. A similar comparison of crossings on the vertical projections of all >

Jan 1, 1941