G)tb[ ^XK(VOtU 
 
 Press Bulletin Series Issued Twice Quarterly 
 
 STATE OF ILLINOIS 
 DEPARTMENT OF REGISTRATION AND EDUCATION 
 
 A. M. SHELTON, Director 
 
 e olog\cal 
 
 No.10 LLINOIS PETROLEUM July 23, 1927 
 
 DIVISION OF THE fiJLlNOl 3 0/ oV 
 
 STATE GEOLOGICAL SURVEY* 1 " cU o\/tV l lv3R ^ 
 
 M. M. LEIGHTON. Chief, Urbana © r\P T %»•*" 
 
 CONTENTS 
 
 PAGE 
 
 Structure of Centralia and Sandoval oil fields, Illinois 1 
 
 New producing horizon in Wabash County 12 
 
 STRUCTURE OF CENTRALIA AND SANDOVAL OIL FIELDS, 
 
 ILLINOIS : 
 
 By A. H. Bell 
 
 Introduction 
 
 Ranking next after the eastern Illinois fields (situated chiefly in Clark, 
 Crawford, and Lawrence counties) in total oil production for the State are 
 the Carlyle field, Clinton County, and the Sandoval field, Marion County. 
 The former has produced approximately 3,500,000 barrels of oil and the 
 latter 2,500,000 barrels. 
 
 A detailed description of the Carlyle field was published" as a result of 
 a study made after the greater part of the drilling had been done. For the 
 Sandoval field, on the other hand, the only published information 3 was the 
 result of a study made when only two of the producing wells had been drilled, 
 and hence little could be included in that report about the details of the 
 structure. Since that time oil has been produced from about 100 wells in 
 the Sandoval pool and the results of a study of all of the available data are 
 embodied in the present paper. 
 
 The report deals with an area about 100 square miles in extent, situated 
 in the southeast part of Marion County and adjacent part of Clinton County. 
 This area includes the Sandoval pool, and a number of smaller productive 
 pools which in order of importance are (1) Wamac, (2) Junction City, 
 
 1 This paper was planned as a contribution to the symposium recently organized 
 by the American Association of Petroleum Geologists on the subject of "Relation of 
 structure to petroleum accumulation in oil fields", the results of which, gathered from 
 the oil fields of the entire country, will ultimately be published in one volume by the 
 Association. As the present paper contains some structural data hitherto unpublished, 
 gathered under the auspices of the Illinois State Geologieal Survey, it is desirable that 
 such data be first published by the Survey. 
 
 2 Shaw, E. W., The Carlyle oil field and surrounding territory: Illinois State Geol. 
 Survey Eull. 20, pp. 45-80, 1915. 
 
 • Blatchley, U. S., Illinois oil resources: Illinois State Geol. Survey Bull, l(i, pp. 
 130-146, 1910. 
 
2 ILLINOIS PETROLEtTM 
 
 (3) Langewisch-Kuester, (4) Brown. Brief preliminary reports on all 
 except the Sandoval pools have heen published. 4 
 
 Acknowledgments 
 
 The writer is under obligation to the oil and coal operators of the dis- 
 trict for placing at his disposal the information that rendered the work pos- 
 sible. Joseph H. Markley, Jr., acted as field assistant. Former publications 
 of the Illinois Geological Survey have been freely drawn upon, chiefly for 
 information about the history of development. 
 
 Physiography 
 
 The physiography of the region is not described in this report because 
 it is controlled by Pleistocene glacial deposits and the thickness of these 
 deposits obscures the structure of the Paleozoic rocks. 
 
 History 5 
 
 "The discovery and use of oil from a seep in the mine of the Marion 
 County Coal Company, sec. 30, T. 2 N., R. 1 E., attracted oil operators to 
 this section of the State. The see]) in the mine came through a fault " 
 
 The Marion County Oil and Gas Company drilled a well on the Sher- 
 man farm in sec. 29, T. 2 N., R. 1 E., half a mile east of the shaft of the 
 mine. The well was completed byNovember 1, L908, with only a showing 
 of oil in a sand immediately below No. (i coal (now known as the Dykstra 
 sand). Three other wells were drilled just southwest of the Sherman well 
 on the Dykstra farm in sec. 32. These had an initial production of 18 barrels 
 a day each after shot and by the end of 1908 their production had declined 
 to 3 barrels a day each. 
 
 The latter part of 1908 was a time of considerable leasing activity in 
 the region. A north and south direction of leasing was maintained upon 
 the supposition that an oil field in this locality would naturally parallel the 
 La Salle anticline. In the early spring of 1909 the L. Stein No. 1 well was 
 drilled in sec. 5, T. 2 N., R. 1 E. The shallow sand found in the Dykstra 
 wells was not reported in this well but a sand producing oil was found at 
 1404 feet and was named the "Stein" sand. A thickness of 22 feet was 
 reported and the yield was 50 barrels per day. Meantime, the Benoist No. 1 
 well of the Southwestern Oil and Gas Company was being drilled in the 
 NE. cor. sec. 8, T. 2 N., R. 1 E. This well was located 1200 feet southeast 
 of Stein No. 1. It found only a show of oil in the Stein sand, and drilling 
 
 4 Bell, A. H., Oil investigations in the Centralia area — preliminary report: Illinois 
 State Geol. Survey, Illinois Petroleum No. 4, pp. 6-12, Aug. 28, 1926. 
 
 Oil investigations in the Centralia area — preliminary report concluded: Illinois 
 State Geol. Survey, Illinois Petroleum No. 5, pp. 1-10, Oct. 16, 1926. 
 
 5 Blatchley, R. S., Illinois oil resources: Illinois State Geol. Survey Bull. 16, pp. 
 130-132, 1910. 
 
 ILLINOIS STATE GEOLOGICAL SURVEY 
 
 3 3051 00005 1403 
 
STRUCTURE OF CENTRALIA AND SANDOVAL OIL FIELDS 6 
 
 was continued. At 1528 feet it struck what is known as the Benoist sand 
 which gave gas and oil. The upper 12 feet of the sand contained gas having 
 a pressure of 370 pounds per square inch. The lower portion of the sand 
 from 1540 to 1546 yielded 200 barrels of oil per day. 
 
 In the succeeding years about 150 wells were drilled in an area of 6 
 square miles around the discovery well, and a boundary of production was 
 found on all sides. 
 
 Structure 
 
 regional folding 
 The Centralia-Sandoval area is situated a little west of the center of 
 the Illinois structural basin, and, accordingly, the regional dip is to the east. 
 To the south and southwest is the Ozark highland, a geanticline of major 
 importance and extent. About 70 miles to the northeast, is the La Salle 
 anticline. In many localities throughout southern Illinois the rock strata 
 have been affected by gentle folding and in some places by faulting. One 
 of the most pronounced of these gentle folds is the Duquoin anticline, or, 
 more accurately, monocline. 11 It is known to extend for a distance of 20 
 miles north from Elkville to a point 2 miles east of Dubois closely parallel 
 to the Illinois Central Railroad. Certain well-defined structural features of 
 the Centralia-Sandoval area are approximately in line with the axis of the 
 Duquoin anticline, though it is not known whether the latter fold is con- 
 tinuous across the intervening gap of 48 miles. 
 
 DETAILED FOLDING 
 
 Detailed subsurface structure of the Pennsylvania:: strata in the Cen- 
 tralia-Sandoval area is shown in figure 1 by means of contours representing 
 the elevations of Herrin (No. 6) coal with reference to sea level. The 
 depth of the coal was obtained from well logs and mine surveys at as many 
 points as possible. Elevations were determined by plane table survey. 
 
 The boundaries of mine workings have been indicated on the map by 
 shaded lines. Elevations had been determined by the mine engineers in only 
 one of the five mined areas, namely the Centralia Coal Company's mines 
 Nos. 2 and 5 south of Centralia. For the Marion County Coal Company's 
 Glen Ridge mine at Junction City, elevations were determined by an under- 
 ground plane table survey by the writer's party. For the other three mined 
 areas, namely at Odin, Sandoval, and the Centralia Coal Company's mines 
 Nos. 3 and 4, underground elevations had not been determined and since 
 none of these mines had been in operation for a number of years it was not 
 possible to enter them. The best available information was that given from 
 memory by former engineers and superintendents of the mines. It con- 
 
 8 Fisher, D. J., Structure of Herrin (No. 6) coal seam near Duquoin: Illinois State 
 Geol. Survey Report of Investigations No. 5, p. 24, 1925. 
 
4 ILLINOIS! PETROLEUM 
 
 sisted of estimates of per cent grades in various parts of the mines and 
 these formed the basis for determining the position of some of the contours 
 in figure 1. 
 
 The regional dip of the Paleozoic strata in the Centralia-Sandoval area 
 is to the east. For Herrin (No. 6) coal it varies from 35 feet per mile across 
 the southern part of the area to 20 feet per mile across the northern part. 
 The maximum dip for the area (in Centralia Coal Company's mine No. 5) 
 is 140 feet in half a mile (5.3 per cent or 3°). 
 
 Two conspicuous structural features are shown in figure 1. One. the 
 Centralia monocline, is a north-south belt of relatively strong east dip which 
 is associated with a fault zone of similar trend. The most continuous fault 
 is about 6 miles long. The upthrow is to the east ; the maximum displace- 
 ment of 110 feet occurs in sec. ?, T. 1 N., R. 1 E., east of the shaft of the 
 Centralia Coal Company's mine No. 4. The displacement decreases north- 
 ward and southward from this point. The other conspicuous feature is a 
 series of anticlines and synclines with an east-west alignment which are in- 
 terrupted by the Centralia monocline. The best example is the Sandoval 
 anticline which seems to be a feature of an east-west trending fold rather 
 than of the north-south Duquoin fold. 
 
 Two cross-sections in an east-west direction (fig. "2) show the attitude 
 of No. 6 coal and illustrate the fault with the downthrow on the west. 
 
 Elevation 
 in feet 
 
 -100. 
 
 Fig. 2. A — B, cross-section through Glen Ridge anticline and Junction City 
 
 dome. 
 C — D, cross-section through Hanseman well and Langewisch-Kuester 
 
 pool. 
 C — D', same cross-section as C — D with vertical and horizontal 
 
 scales equal. (See fig. 1 for lines of cross-sections.) 
 
STRUCTVBK OF CENTRALIA AM) SANDOVAL OIL FIELDS 
 
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STRUCTURE OF CI-NTKALIA AM) SANDOVAL OH. FIELDS 
 
 
 
 
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ILLINOIS PETROLEUM 
 
 PENNSYLVANIAN 
 
 MISSISSIPPIAN 
 
 
STTUI'TIKK. OK ( KNTUAI.1A AM) SANDOVAL Oil. F1KI.DS 
 
 Two structure maps were drawn for the Sandoval area, one with No. 6 
 coal as the key horizon and the other on the Benoist sand which is here 930 
 to 980 feet below No. 6 coal stratigraphically (figs. 3 and 4). These two 
 maps show closed anticlines of essentially similar outline and trend. The 
 chief difference between them is that the dips are in most directions more 
 pronounced on the sand than on the coal. 
 
 The logs for the wells drilled by the Southwestern Oil and Gas Com- 
 pany, which owns nearly two-thirds of the productive acreage in the 
 
 Elevation 
 in feet 
 
 Sea level 
 
 -100 
 
 -1000 
 
 Top of 
 Benoist sand 
 
 -1100 . 
 
 Sea level 
 
 -100 
 
 -1000 
 
 -1100 
 
 2000 
 
 4000 
 
 Scale 
 
 1 
 
 6000 
 
 8000 
 
 10000 
 
 12000 feet 
 
 Pig. 5. Cross-sections through the Sandoval pool, comparing the attitude of 
 Herrin (No. 6) coal with that of the top of the Benoist sand. (See fig. 3 
 for lines of cross-sections.) 
 
 Sandoval held, are "skeleton'" lugs and most of them give the depth of only 
 a coal and the Benoist sand. The coal recorded in some of them is probably 
 Merrin ( No. *i ) coal. In determining the structure of the Benoist sand the 
 skeleton logs could he used with very few exceptions, but many of them 
 could not he used in constructing the structure map of the coal bed because 
 of difficulty in correlating the coals. Accordingly the structure of the coal 
 was determined from a smaller number of datum points than that of the 
 sand. 
 
10 hxinois pp:troleum 
 
 Two cross-sections through the Sandoval pool (fig. 5) compare the 
 attitude of No. G coal with that of the top of the Benoist sand. They show 
 an increase o! interval of 30 feet to the west and north. 
 
 Producing Horizons 
 
 In order to consider the relation of production to structure a brief 
 resume of the producing sands is here given, and for the purpose of show- 
 ing their relative importance some production figures are included. Oil has 
 been produced from five sands in the Centralia- Sandoval area, three of which 
 are in the Pennsylvanian and two in the Chester. Named in order from the 
 top downward these are the (1) Dykstra, (2) Wilson, (3) Petro, (4) Stein, 
 and (5) Benoist sands. Although no locality is known in which they are 
 all present, their approximate stratigraphic positions are illustrated in one 
 generalized section (fig. 6). 
 
 Pennsylvanian sands: The Dykstra sand, lying closely below Herrin 
 (No. 6) coal, is the sand in which oil was first discovered in the area. The 
 total production obtained from it has been insignificant. It is one of the two 
 producing sands in the Junction City pool ; the other one is the Wilson sand 
 which is situated about 100 feet lower in the section. In the summer of 
 1926, 6.6 barrels per day were being produced by nine pumping wells fron 
 the Wilson sand and 2.5 barrels per day by two pumping wells from the 
 Dykstra sand. 
 
 The most important Pennsylvanian production in the area is that of 
 the Waraac pool and here the oil comes from the Petro sand which has been 
 placed tentatively in the Pottsville, although it may possibly belong in the 
 lower part of the Carbondale. This field was opened early in 1922. Dur- 
 ing the period of five years from the beginning of 1922 to the end of 1926, 
 a total of approximately 200,000 barrels of oil was produced. 
 
 Chester sands: The Benoist sand has produced nearly all of the two 
 and one-half million barrels of oil obtained from the Sandoval pool. It lies 
 from 930 to 980 feet below Herrin (No. 6) coal. About 100 feet above 
 the Benoist sand in the section is the Stein sand from which the first oil at 
 Sandoval was produced. The Stein sand production was relatively small 
 and short-lived as compared with that from the Benoist sand and all the oil 
 now produced in the field is from the Benoist sand. The producing sand 
 in the Langewisch-Kuester and Brown pools is in the lower Chester and it 
 has been tentatively correlated with the Stein sand of the Sandoval pool. 
 This production, although small, has proved to be long-lived. 
 
 The Relation of Production to Structure 
 
 The productive areas are so situated with respect to the structural 
 features of No. 6 coal as to suggest the probability of the accumulation of 
 
STRUCTURE OF CENTRALIS AND SANDOVAL Oil. FIELDS 
 
 11 
 
 Depth 
 in feet 
 
 100-: 
 
 200- 
 
 300- 
 
 400- 
 
 500 
 
 600 
 
 700- 
 
 800- 
 
 900- 
 
 1000- 
 
 1100 
 
 1200- 
 
 1300 
 
 1400 
 
 1500- 
 
 
 Pleistocene System 
 
 
 Henin (No. 6) coal ; 
 Dvkstra sand 
 
 Wilson ^>;i if I 
 
 Petro sand 
 
 i! 
 
 J". 
 
 ISenoist sand 
 
 *9 
 
 F\a. 6. Generalized columnar section of 
 Centralia-Sandoval area 
 
12 ILLINOIS PETROLEUM 
 
 the oil into pools under two sets of geological conditions. In the Sandoval 
 and Wamac pools, production extends over the tops of domes, and the 
 boundaries of production tend to be parallel to the structure contours. The 
 location of =these pools seems to have been determined by the folding of 
 porous sand strata of relatively wide lateral extent. On the other hand, the 
 minor pools, Junction City, Langewisch-Kuester, and Brown, are situated 
 on the flanks of anticlines, and the determining condition in their location 
 appears to have been the occurrence of localized bodies of porous sand 
 which were features of original deposition. 
 
 NEW PRODUCING HORIZON IN WABASH COUNTY 
 
 By Gail F. Moulton 
 
 The Eastern Gulf Company have been successful in their attempt to dis- 
 cover a deeper producing horizon in Wabash County in their test on the 
 Jesse Cisel farm in the SE. y 4 SE. y A sec. 2, T. 1 N., R. 12 W. The early 
 reports are that this well is obtaining its production from the McClosky 
 sand which was found at a depth of about 2200 feet. At the present time 
 no information is available regarding the size of this well, but it is believed 
 that it will make a commercial producer. 
 
 The fact that production has been found in the McClosky sand is oi 
 considerable importance to Wabash County, for new work of prospecting 
 deeper sands in localities where earlier drilling had failed to find the Biehl 
 and the 1500-foot sands on favorable parts of the structure is encouraged. 
 The McClosky sand production in the Murphy pool in Lawrence County 
 only seven miles northeast of the new well has been very satisfactory. Some 
 of the wells produced more than 3000 barrels per day, and were the largest 
 in the State. 
 
 In the Murphy pool and adjacent territory, the McClosky sand is not- 
 ably irregular in productivity, and occurs in several lenses. No statement 
 can be made regarding its character in Wabash County until further drilling 
 has been done, but it is believed that similar conditions will be found. 
 
 From the point of view of the Illinois operators, it will be of great 
 assistance to have a map giving a revised interpretation of the structural 
 conditions in the area north of Allendale, so that those desirous of making- 
 tests of the new producing horizon will be able to choose locations on the 
 higher parts of the structure. A map and a brief statement in regard to 
 prospecting for this new deeper producing horizon will be included in an 
 early number of Illinois Petroleum. 
 
 11 (71558 — 1500)