INDUSTRIAL A N D ENGINEERING CHEMISTRY
August, 1926
789
The Distillation of Lubricating Oils under High Vacuum’ By Benjamin T. Brooks 50
EAST4 1 ~ TST., NEWY O R K , N. Y .
ECENT industrial developments in the art of distilling pump.* * Considering the cost of their installation, the lubricating oils in vucuo have aroused considerable advantages obtained over properly applied steam are doubtinterest both in this country and in Europe. The ful.” Steinschneider, in an article entitled “New Improvements object of this paper is to point out wherein these new developments differ from the much older, well-known vacuum in the Field of Distilling High-Boiling Oils,”6 stated that a distillation processes. vacuum of 690 to 720 mm. of mercury was employed. As The outstanding characteristic of the recently developed late as 1922, Graefe6 described what he termed high-vacuum process is the very high vacuum employed-i. e., an absolute distillation of the oils and tars from the distillation of brown pressure which in actual practice is 3 to 5 mm. of mercury. coal, stating the vacuum to be about 680 mm. of mercury. The old practice of vacuum distillation, which was first carried Kissling’ illustrates the apparatus employed by Steinschneider out on typical light crudes rich in paraffin wax-Pennsyland shows that cooling water is passed through the dephlegvania petroleum-did not employ a high vacuum as we mators and then into the water leg, and points out that if this water is warmed to 45” C. now understand that term. (113” F.) or higher, water Most of the early patents cannot be condensed under did not specify or in any LTHOUGH the distillation of lubricating oils under way definitely characterize a vacuum of 90 per cent of a partial vacuum is an old art, the advantages of the degree of vacuum emthe normal barometric readoperating at very low pressures have only recently been ing. Singer8 gives the conp l o y e d . The advantages realized on a commercial scale. The early practice is ventional rather unfavorgained in the older practice briefly reviewed, followed by a discussion of the work of able opinion of vacuum diswere considered by many to Steinschneider in Europe. tillation and states that if be outweighed by other conSchulze, in this country, has recently shown that by siderations, and fire distilladistillation a t very high vacadapting the welding practice so extensively used in uum were to be carried out tion with steam came to be natural gas gasoline plants, and by the use of the latest the customary procedure, the handling of the enorimproved vacuum pumps, distillation on a commercial though a few of the eastern mous vapor volumes would scale can be carried out under an absolute pressure of refiners have continued the i n v o l v e g r e a t difficulties 3 m m . Under these conditions it is possible t o obtain vacuum process. The genw h i c h would overbalance lubricating distillates of any desired viscosity up to eral opinion of it, however, the gains of such operation. about 175 seconds at 210’ F. The oils so obtained need is reflected in the various These opinions of Singer, as not be acid-treated. descriptive publications and his language indicates, are The properties of these distillates and the general b o o k s describing refinery speculative. The only vacfeatures of the process are discussed. processes. uum specifically mentioned Redwood2 dismisses the by Singer is 680 to 700 mm. subject with the following of mercury. Scheithauers refers to vacuum distillation as being carried-out at 400 to 500 sentences: Continuous as well as intermittent distillation of lubricating mm. and that water jets or vacuum pumps do equally well, for oil base is frequently conducted under high vacuum, a lower producing the vacuum. I n 1924 Gurwitsch’Ogives a table still-temperature being in this way obtained than by the ordinary of boiling points of heavy oils, calculated for vacuum as low steam distillation at atmospheric pressure. The resulting dis- as 5 mm. of mercury, but states that such operation “seems tillates are paler in color and of higher flashing points. Some not to have made its appearance in the petroleum industry.” difference of opinion exists, however, as to the improvement being The foregoing notes are given rather fully to indicate the sufficiently great t o warrant the extra expense. character of the vacuum heretofore employed and the pre,4 small cast-iron still is shown connected to a water-jet air vailing opinions regarding vacuum distillation of lubricating Pump. oil. Bacon and Hamor3 give fifteen lines to the subject and Although the vacuum distillation plants installed in Europe state: by Steinschneider and his associates have apparently not It has long been known t h a t there is an improvement over the employed an absolute pressure lower than about 40 mm. of results of the ordinary methods, both in the quantity and quality mercury, they embody an improvement of importance. I n of the distillation products, when vacuum distillation combined this process” most of the heavy oil distillates are condensed with steam distillation is used. However, many American and run to receivers which are not attached to the vacuum refiners, who are familiar with the results which can be obtained by the vacuum method, state that the difference is not great pump. I n distilling lubricating oils a t very low pressures it enough t o warrant the increased cost of installation and operation. is found that if a small fraction of light oil and the uncon5 8th Intern. Cong. A p p l . Chem., 25, 735 (1912). Day4 states: “A few American refineries operate reducing 6 Brennstoff-Chem., 3, 167 (1922). stills under a partial vacuum obtained by the aid of a vacuum 7 “Chemische Technologie des Erdols,” latest edition.
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1 Received March 29, 1926. Presented before the Division of Petroleum Chemistry a t the 71st Meeting of the American Chemical Society, Tulsa, Okla., April 5 to 9, 1926. * “Petroleum,” 2nd ed., 1922, Vol. 11, p. 507. 8 “American Petroleum Industry,” 1916, Vol. 11. p. 458. 4 “Handbook of the Petroleum Industry,’’ 1922, Vol. 11, p. 353.
Pet7Okum Z., 10, 605 (1915). “Die Schwelteere,” Leipzig, 1911, p. 6s; “ D i e Fabrikdtion der Mineralole,” p. 103. 10 “Wissenschaftliche Grundlagen der Erdalverarbeitung.” 2nd ed., 8 @
1924, p. 205. $1
Steinschneider. U. S. Patent 981,958 (1911).
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Vol. 18, No. S
I N D U S T R I A L AAVDE,VGINEERlNG CHEMISTRY
densed vapors and gases are taken off separately and kept out of the heavier distillates, these heavy oils do not darken in color on exposure to air. The lightest condensate is foul smelling and darkens quickly on exposure to air. Steinschneider provides for this operation as shown in Figure 1. Distillation at Very Low Pressures
The advantages and markedly different results obtained by distilling lubricating oils at absolute pressures of 3 to 5 mm. as contrasted with former practice at 40 mm. or higher, appears to have been first shown, and the practicability of so operating industrially first demonstrated, by John E. Schulze.
of the run, the evacuation being back through the condensers and light overhead line to the vacuum pump. The stills and all the lines are welded throughout, with the exception of the manholes on the stills and the large gate valves in the oil lines connecting the various receivers, these valves being scre xed in, not flanged. The process is being operated both by the batch and continuous systems, using 10 X 3O-foot stills suitably braced inside. Schulze has also adopted a type of furnace setting by which the stills are very uniformly heated, largely by radiant heat, as shown in Figure 3. Stills heated in this way which have been in practically continuous operation for about two years show no signs of buckling or having been locally overheated. The vacuum pumps employed have been considerably improved to meet the requirements of this process. The power consumption is very small, two vacuum pumps being mounted on one base and driven by one 40-horsepower motor. Worthington "feather" valves are a noteworthy feature of these pumps, as is the pump design, which practically eliminates dead air space. The total power consumption a t one plant, including lighting and incidental pumping was 1.5 kilowatthours per barrel of crude charged. Method of Operation
High-vacuum distillation is probably most advantageous in the case of wax-free oils, not only on account of the relatively low market value of such crudes, but also because the absence of paraffin Figure 1-Steinschneider's Apparatus wax makes the production of finished lubricating oils in this way an exceedingly direct and simple The effect on the boiling point of lowering the absolute pres- process. Gasoline and kerosene, if present, should be resure is much more pronounced, for a given difference in presi moved in a preliminary topping distillation and, although sure, a t very low pressures than a t moderate vacuum. -4 some gas oil may be taken over in this way, care should black car oil distilled by Schulze illustrates this (Table I). be taken not to crack the oil. Very heavy crudes, such as heavy Smnckover oil, is first dehydrated and charged diTable I-Distillation of Heavy Residuum in Vacuo rectly into a vacuum still, the gas oil distilled under a modInitial b p. erate vacuum and the vacuum is then raised to the usual Absolute pressure Per cent over of fraction Mm. H g a t 572' F. (300' C 1 F. operating pressure. 30 455 40 In this method of 25 50 437 1; 68 419 94 364 J batch operation the s t ill temperatures The rapid lowering of boiling points with decrease of ab- may reach 575' to '@ solute pressure, particularly at low pressures, below 40 mm., 625' F., depending is shown by Figure 2, recently given by Steinschneider. upon the character 3 0 It is, of course, true that a t absolute pressures as low as of the oil and its re3 mm., the oil vapors occupy a large volume, approximately sistance to cracking. 0' 250 times the volume at atmospheric pressure, though this The lubricating oil 3w volume ratio is slightly reduced by the lower distillation tem- d i s t i l l a t e thus ob- % peratures resulting from the low pressure. I n order to pro- tained is emulsified 2 vide for this large vapor volume and prevent the choking with just sufficient ,&oo effect which would result from the usual still construction, concentrated caus- 3 Schulze provides as many as ten vapor outlets, 10 inches tic soda to combine diameter each, on each 10 x 3O-foot vacuum still. With with thenaphthenic this multiplicity of vapor outlets the still shows practically a c i d s , and without 1w the same absolute pressure, within 1 mm. as shown by the s e p a r a t i n g t h e s e manometers on the receivers and on the lines adjacent to soaps the oil is rethe vacuum pumps. These outlets dip slightly away from the distilled a t 3 to 5 still, considerable condensation being effected by air cooling m m . , c u t t i n g the oO1 30 so *m before passing to the water-cooled condenser, which functions fractions according Absolute Pressure-Mm. of Mercury as much as a cooler as a condenser. Somewhat less than 1 t o the viscosity de- Figure 2--Relation between Point and Absolute Pressure per cent of light, volatile, malodorous oil is taken off in a sired. These distilseparate overhead line, leading to a separate condenser; lates are color stable this overhead vapor and gas line is directly connected to the and substantially odorless and tasteless as produced, without vacuum pump. The bulk of the distillate flows by gravity acid or any other treatment. I n order to remove moisture to a series of receivers which are evacuated at the beginning and brighten these distillates, the receivers are provided with 4'0
4,
,jg
1
L
1"
20
7-
August, 1026 liy which IIIOL~IILthe oil is ireaied to about 5" E'. aud blown with air inrtil bright. Nu other refining trentment is necessary if the charging stock tias not been previously d a m a g d by cracking arid the distillation has heen properly carried out. i n pipes
Yields from Various Heavy Crudes
posite lubricating oii showed a vi&osity of 552 at 100' F. and 18.4' A. .'1 1. On redistillation of this composite lubricating oil, the following yields were obtained:
Owing to the high vacuum and the correspondingly low still ti:niperat,urcs employed, no loss by cracking or decomposit,ioii occurs, and tlie yields are appreoial)ly greater than are obt:iinahle by other refinery practice. I'roBabIy the maxininin loss by cracking occurs in the prevailing method of dis-
Heavy Viilton crude, 18.8'A. P. I., yielded 42.4 per cent of unfinished lubricating oil distillate which on redistilling gave the following cuts: ViSCOSitY
1B)
100" 1:.
060 94 146
i 210'l*.
186 1
Per cent Of crude a.31 4.59 7.88 8.28 8.48 4.77 1.84 (overherd,
Other Tests
F l u r e 3-Schuiee High-Vacuum Stills. Showing hrran%ement fer Separating Low-Boiline Portion of Distillate
billing crudes of high was conbent by fire alone. While this has the merit of cracking most of the amorphous wax and thus facilitating the usual dewaxing operations, this crscking of lubricating oil and the resulting necessary acid refining probably averages more than 2 gallons per barrel of crude. However, there seems to be some question &s to whether lubricating oils of satisfactory cold test can be made by the direct high-vacuum distillation of wax-bearing crude oils; no plants are operating in this way on such oils, so far as the miter is aware. An alternative method is to redistil the dewaxed unfinished lubricating oils, as ordinarily produced, by the high-vaeiium met.hod. If such oils are not too highly c:racked, finished lubricating oils, not requiring acid treatment., can thus be made. While the maximum advantage of the high-vacuum disdillation method i s not realized in this combined operation7 there i s an added advantage in the iiualit,v . " of the lubricatina~.oils so produced. The question of quality is discussed later. Some of the results obtained by Schulze on coinmercial operation follow:
Mexican crude from the Cacalilao field IZ" A. P. I. gravity xiid 3.8 per cent sulfur yielded 28 per cent unfinished composite lubricating oil and M).05 per cent asphaltic residuum. Crude oil from the Coalinga, Calif., field yielded $2 per cent ai finishedlubricating oil. Quality of High-Vacuum 011 Distillates
Many aspects of the question of quality of lubricating oils are warmly debated, and while coininercial bias undoubtedly enters into such discussions, there are a number of generally recognized tests which, taken collectively, are believed to be qualitatively, if not quantitatively, indicative of the quality
Smackover Crude. from Nevada County, Ark. 'A. P. I. Piash. O'P. Fire " F. visrbriir at loo' F. Sulfur, per cent Gravity
Cas oil, 29.6-A. P. I. Finished lubtic%tingoil Asphaii bottoms Fuel d l
18.6 116 190 445
3.3
Per cent vield 28.9
32.15
Figure 4 - V ~ c u u m Pumps and Receivers, Showinzt Welded Consfm~fim of Receivers and Pipe Line8
Y7.6
0.81
.
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of luhricating oils
Moreover, lubricants arc pnt to such a variptv of uses that the intornrrtatlon of tho reqults of tests
INDUSTRIAL A N D ENGINEERING CHEMISTRY
792
such vaguely defined properties as "oiliness" and selective adsorption, which so far have eluded all attempts a t accurate definition and measurement. I n this paper the usual commercial tests are given for a number of oils distilled under high vacuum and without chemical refining and the results of the same tests given for a number of the best known commercial oils now on the market. The tests given in Table I1 were made in the laboratory of one of the largest refining companies, and are believed to be correct within the pardonable experimental error of the methods employed. o n C o m m e r c i a l 011s Distilled u n d e r High V a c u u m ,--OPEN cupCarbon Gravity Viscosity FJash Fire Color ConR. E. No. Test Be. a t 1 O O ' F . N. P . A. radson Minutesb F. O F . Light Oils 1 23.8 204 360 420 0.03 6 3 f 2 6: 197 340 20.3 390 0.03 1'/2 3 0.12 3 25.0 235 380 450 gl/z 0.23 20.2 215 335 385 5 3 ' / 2 4 0.14 22.4 250 370 415 5 3 6 25.5 200 395 470 0.05 4'/a 21/2 7a 2 20.7 200 370 440 0.02 < 1 Medium Oils 8 485 0.50 26.4 285 415 5 J 9 2 21.0 240 340 400 0.07 395 23.8 330 470 10 0.50 14 4 435 2 21.7 340 370 11 0.13 3l/2 20.5 425 12 583 7 0.20 17 360 24-26 480 415 4 0.10 300 13l/z 13 6 25 280-290 415+ 480 24-26 0.22 14" 300 20.2 . 380 450 2'/4 0.03 < 1 360 150 420 642 0.05 17.4 < 1 13/a Heavv Oils 5 3 26.4 480 0.60 405 420 16 415 0.05 2 19.0 470 360 17 495 5 515 425 23.8 18 0.31 >20 9 430 0.17 4 510 360 19.8 19 555 98 460 8 11 26.0 0.64 20 (210" F.) 26 22-24 449 420f 480 0.22 21 6+ 505+ e + 23-25 460-470 440f 0.28 22 35 19.9 500 415 0 . 0 5 < 1 500 2'/r3 23a 19.3 750 435 530 3'/r3/4 0.07 < 1 245 18 9 1000 460 565 4 009 < 1 25" .. 175 450 510 Z1/a 0.10 < 1 26O (210" F.) D 2 10 High 27 22-24 150-160 520 600 > 30 (Bright stock) (210° F.) a High vacuum. b Minutes for emulsion to break.
Table 11-Tests
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Vcl. 18, No. 8
troubles incident to the refining of lubricating oils with acid, alkali, etc., are too well known to warrant comment. That the color stability and other properties of the distillates produced by the Schulze process are such that no acid is required to refine them has already been noted. This color stability is also indicated by the fact that the final distillates can be heated to 250" F. and blown with air until bright without darkening in color. The values reported for Conradson carbon and de-emulsification are also noteworthy. T a b l e 111-Vacuum D i s t i l l a t i o n Analyses of C o m m e r c i a l Oils Original oil -Vacuum distillate10% 20% 30% 90-95% Medium Gravity, ' A. P. I. 20.7 22.8 21.5 19.7 Flash, F. 340 265 310 475 Fire O F 415 320 370 566 Viscbsityat 100° F. 341 64 111 2140 Color, N. P. A. 3 1.0 1.0 3 500 Red. 10% 20% so-90% 90-95% 22.5 Gravity, OA. P. I. 19.3 20.5 17.8 17.8 Flash, O F. 355 280 320 440 475 Fire O F. ' 420 315 375 540 565 503 65 123 Viscbsity at 100' F. 2106 2793 ll/z 4 5 6+ 1'/2 Color. N. P. A. Heavy 1st 30% Next 65% Gravity A. P. I. 20.9 22 20.3 Flash, O ' F . 365 320 420 Fire O F 430 370 500 Viscbsity'at 100' F. 519 130 1001 Color, N. P. A. 4 1 Z1/a
.. .. ..
Schulze12has pointed out that i t is commercially feasible to obtain distilled oils having viscosities as high as 170 to 180 seconds a t 210" F. and that unblended distillates even approaching this viscosity have not been known in the industry heretofore. The still bottoms from naphthenic crudes,-left behind after the usual distillation, yield large percentages of heavy lubricating oil distillates when distilled a t 3 to 5 mm., this percentage being as high as 90 per cent in many cases. When the still bottoms or cylinder stock is derived from a paraffin-base oil, free from asphalt, Schulze has shown that about 60 per cent of such a product can be distilled to obtain distillates ranging from 400 to 900 seconds viscosity a t 100" F., color 2 to 5 N. P. A., and leaving a very novel, undamaged cylinder stock, an extremely viscous heavy oil, having a viscosity as h'gh as 250 seconds a t 212" F., 630" F. flash test, and about 700" F. fire test. The oils described in Table IV were obtained by Schulze by high-vacuum distillation, 1.5 mm. absolute pressure, from a quantity of ordinary still bottoms from naphthenic oils.
Lubricating oils distilled by fire, or fire and steam, seldom have viscosities exceeding 350 seconds a t 100" F. On redistilling such oils under a very high vacuum, to prevent decomposition, the resulting fractions show a very wide spread in viscosity and the first fractions, amounting to a t least 10 per cent and frequently more than 20 per cent, show characteristics which class these light fractions with heavy gas oil. I n order to obtain oils of relatively high viscosity as ordinarily manufactured, it is necessary to blend the distilled oils with residual oils such as refined bright stocks. The subTable IV-Vacuum Distillates f r o m Ordinary S t i l l B o t t o m stantial amount of gas oil generally present in the distilled Fraction oils results in a very considerable sacrifice of viscosity, reProperties (1) (2) (3) (4) (5, 1 8 . 5 18.2 18.0 17.5 17.0 Gravitx, A. P. I. quiring much more bright stock to obtain blends of a given Flash, F. 455 440 470 490 520 440 460 480 500 viscosity than would otherwise be necessary. The results of Flash range, F. 480 500 540 470 high-vacuum distillation analyses made by Mr. Schulze of Fire, ' F. 545 560 575 600 530 seconds Saybolt a t three commercial oils which are fairly typical are shown in Viscosity, io 85 100 125 150 212' F. 90 80 110 140 Table 111. It will be noted that a commercial oil having a Viscosity range a t 212' F. 110 90 140 170 ?3: viscosity of 519 seconds contained 30 per cent of oil having a Color N. P. A. 5 5l/z 6 6'/2 +1/2 F. J 5 5 10 15 Pour ;est A. S. T. M. viscosity of 130 seconds and that the remainder had a vis- Initial b o h g point, ' F. 475 490 520 550 575 490 520 550 576 590 All distilled over, F. cosity of more than 1000. One of the characteristics of the lubricating distillates proA further comparison of typical light, medium, and heavy duced by high-vacuum distillation is that the cuts can be made quite narrow, corresponding t o a narrow range of boiling point commercial lubricating oils and high-vacuum distillates of' and viscosity. I n the usual practice gas oil is produced by about the same viscosity brings out certain differences and cracking of the more valuable lubricating oils throughout the these differences were in part used by Schulze12in substandistillation period. It is the presence of these light decompo- tiating his claims as to the novel character of the distillates sition products in very substantial proportions which gives obtainable by distillation in a high vacuum (Table V). Considerable interest has been shown in a recent paper on such distillates their pronounced odor and taste, makes them discolor on exposure to air, and necessitates the use of sulfuric high-vacuum distillation by Stein~chneider.'~The work of acid, alkali, and usually fuller's earth to put them in a mar12 U. S. Patent 1,448,709. 18 J. Ins;. Pelroleurn Tech., 11, 514 (1925). ketable condition of refinement, as is well known. The r
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August, 1926
INDUSTRIAL A N D ENGINEERING CHEMISTRY
Steinschneider and his associates, Singer and Porges, has already been referred I n this recent paper Steinschneider referred to plants operating in America, employing 5 to 25 mm. absolute pressure, but did not state what plants or particular processes he had in mind. I n the published discussion of the paper Dvorkovitz stated that while partial vacuum had long been used a t Baku the high vacuum referred to by Steinschneider had not been used; Jenkin also stated that, while operation at 20 to 45 mm. absolute pressure seemed possible, 'hone of the five or six benches of Bruenn-Koenigsfelder stills with which I am acquainted normally operate a t anything like this v:icuum. The usual pressure varies between say 75 mm. and 110 mm., and if for some special reason they manage to reach 50 mm. it is considered something of an achievement." This important technical advance-i. e., large-scale oil distillation a t absolute pressures of less than 5 mm.-has required the painstaking development of a new distillation technic. The procesv has definitely established itself in the petroleum industry and, although it seems that all important technical advances must suffer a certain amount of litigation, it appears to the writer from the publication, prior patent art, and other available information that the credit for this commercial development falls to John E. Schulze.
793
T e s t s of Typical Light, M e d i u m , a n d Heavy Oils By highORDINARYDISTILLATION vacuum Paraffin Naphthene distillation, base base narrow c u t L i g h t Oils Gravity A. P. I. 30 21 21 Flash, "F. 405 320 360 290 250 340 Flash range, O F. 550 460 380 Viscosity a t 100' F . , sec. Saybolt 190 200 200 60 100 Viscosity range, 100" F., sec. Saybolt 6% 2000 300 . ~. Color N. P. A. 21/2 2 1/a 1] / a Pour test, A. s T. M.. F. 30 Below zero Below zero 374 320 400 Initial boiling point a t 1.5 mm., F. Per cent distilled up t o 450' F., 1 . 5 mm. 10 60 98 M e d i u m Oils Gravity, O A. P. I. 29 20.5 20.5 Flash, O F. 425 330 380 300 255 370 Flash range, F. 550 480 430 I'iscosity a t 100' F . , sec. Saybolt 260 300 300 60 200 Viscosity range a t 100' F., sec. Say14% 2200 450 bolt Color N. P. A. 3'/z 3 2 Pour iest A. S. T. hi., F. 35 Below zero Below'zero Initial boiiing point a t 1.5 mm., ' F. 410 350 435 Per cent distilled up to 475O F., 1.5 mm. 22 46 9s H e a v y Oils Gravity, A. P. I. 28.5 19.5 19.5 Flash, F. 438 360 400 260 385 Flash range, a F. 510 430 Viscosity a t 100' F., sec. Saybolt 365 500 500 70 400 Viscosity range, 100' F., sec. Say16;; 2400 700 bolt Color N. P. A . 5 3l/z 21/2 Pour Iest A. S. T. M., F. 35 Below zern B;iorv zero Initial boiling point a t 1.5 mm 'F. 437 ago 440 Per cent distilled U D to 500' F.', 1.5 mm. 35 56 98 T a b l e V-Comparative
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Acknowledgment
The writer wishes to express his indebtedness to RIr. Schulze for permission to publish much of the data in the present paper. 18 See also Porges, U. S . Patent 1,011,079 (1911); Steinschneider, U. S. Patent 981,953 (1911) and 1,162,729 (1915).
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Oil-Bearing Shales in North Carolina' By Frank C. Vilbrandt US:V&RSITY
OF N O R T H
CAROLINA, CHAPELHILL,N. C.
A suroey of the Deep River Valley oil-bearing shales together with their retort assays, shale analyses, tonnage yields, and the arialytical distillation data of the oils.
A
PREVIOUS investigation of one of the shales in the Deep River Valley coal fields of Kort,h Carolina2 disclosed the presence of a large deposit of an oilbearing shale with a low shale oil and ammonium sulfate content. A systematic study of all the possible oil-bearing shales of this field was undertaken to ascertain whether more extensive and richer deposits were available.
1 2 4 5 6 7 8 9
__
Shales Investigated
in
The oil-bearing shales that were studied are found in the carboniferous formation, overlying and underlying the coal measures in the Deep River Valley coal field of Moore, Lee, and Chatham Counties in North Carolina. The particular samples investigated were taken from the holdings of the Erskine-Ramsay Coal Company a t Cumnock, from as many different locations on the face of the mine and in the different formations as were thought necessary to include all of the shales of the field. Since the field shows little variation in thickness of the various strata of rock and coal, the accompanying log table from a diamond drill hole, located approximately one-half mile southwest of the Cumnock shaft on the banks of the Deep River, gives a representative analysis of the locations and thickness of the vwious formations in this field.
11 12 13
1 0
Received March 3, 1926. Vilbrandt, J . Elisho Mifchell Sci. SOC.,41, 108 (1925).
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15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37
T a b l e I-Record of D i a m o n d Drill Hole -From-TO-Ft. In. Ft. In. Materials 0 7 Sand 7 14 Clay 14 Sand 30 30 Red shale 32 32 Gray shale 40 40 Red shale 60 Gray shale 60 86 86 91 Black slate 91 Gray slate 96 96 Hard gray sandstone (dark) 173 173 Gray shale 178 178 Black slate 186 186 Gray slate 238 238 244 Black slate 244 Gray slate 268 275 268 Black shale 275 Gray shale 297 297 Black slate 330 Gray slate 330 355 355 Black shale (oil-bearing) 387 387 Hard gray Black slatesandstone 564 564 564 4 564 4 602 4 Black slate and shale (oil-beark g ) 602 4 604 3 Gray sandstone 604 3 Black slate 604 5 604 5 Coal (high-grade) 608 3 608 3 Black band (oil-bearing) 609 9 Coal (low- rade) 609 9 611 7 611 7 Black b a n 3 (oil-bearing) 612 6 612 6 Black slate 613 6 613 6 Slate Fire clay 615 615 627 627 643 Fire Blackclay band (oil-bearing) 642 645 645 647 10 Coal (fair) 647 Black band (oil-bearing) 10 649 Sandstone 649 650
