1665.5 
 
 COLL 
 
 c.3 
 
 RS,TY OF ILLINOIS-URBANA 
 
 3 0112 121926353 
 
 STATE OF ILLINOIS 
 
 ".LINOIS 
 
 FEB 3 1988 
 
 Department of Registration and E|L4>lfl0IS STATE LIBRARY 
 
 A. M. Shelton, Director, Sirinckieijj 
 
 STATE GEOLOGICAL SURVEY DIVISION 
 
 M. M. Leighton, Chief, Urban a 
 
 PRESS BULLETIN 
 
 (For immediate release) 
 
 discarded 
 
 Apk 1986 
 
 May 17, 1924 
 
 19551 L 
 
 EXTENSION OF ALLENDALE OIL FIELD 
 
 By D. M. Collingwood 
 
 The discovery in 1922 of the flowing well on the Della 
 Wright farm in sec. 8, T. 1 N., R. 12 W. initiated an active 
 drilling compaign in the area surrounding the Allendale 
 oil field in Wabash County. In the hope of being able to 
 aid the operators in testing more efficiently the possibili¬ 
 ties of the extension of the Allendale oil field, the Illinois 
 Geological Survey made a study of conditions in the area 
 in 1923. A detailed report embodying the results of the 
 field investigation is being prepared, but in order to hasten 
 the availability of certain outstanding points of informa¬ 
 tion which may prove helpful in furthering exploratory 
 drilling this spring, this press bulletin is issued. Paucity 
 of accurate and detailed logs, and a general neglect on the 
 part of drillers to save cores and samples, which serve as 
 the most reliable source of information, rendered definite 
 correlation difficult. 
 
 STRUCTURAL RELATIONS OF ALLENDALE OIL FIELD 
 
 The Allendale oil field is situated at the southern ex¬ 
 tremity of the southeastern Illinois oil fields, and is struc¬ 
 turally associated with the same major structure—the La¬ 
 Salle anticlinal uplift—that gives rise to the main oil field. 
 Although this anticlinal structure continues with a region¬ 
 al southward pitch in Wabash County, its crest broadens 
 into several radiating folds centering in the neighborhood 
 of Allendale, and includes wide terrace-like areas on its west¬ 
 ward flank (PI. 1). The main production has been found 
 associated with small domings caused by minor folding, 
 on two step-like terraces situated generally just above the 
 abrupt change to a steep north-west flank dip. 
 
2 
 
 It has been recognized, however, that structure is not 
 the sole consideration in locating areas favorable to oil 
 accumulation in this field. Although holes drilled to the 
 east and north of the producing fields are probably not 
 located exactly on the anticlinal crest, they are structurally 
 higher than the terraces, and expectation of production, 
 from a structural viewpoint, would have been justified. 
 However, dry holes and only small showings of oil have 
 been the results to date. 
 
 STRATIGRAPHIC POSITION AND DESCRIPTION OF 
 OIL-BEARING STRATUM 
 
 The sand, locally called the Biehl sand, is found at 
 a depth of 1400 to 1600 feet, and lies about 125 feet below 
 the top of the Chester series of the Mississippian system 
 which is immediately overlain by the basal salt water sand 
 of the Pennsylvanian system. 
 
 Examination of cuttings from the sand stratum of 
 some producing wells revealed the fact that in places the 
 Biehl sand consists of relatively thin beds of fairly well 
 sorted sand, the maximum grains being of medium size. 
 These beds are quite porous and contain the oil pay. They 
 are interbedded with hard sandstone, composed of very 
 poorly sorted sand ranging in sizes of grain from medium 
 to very fine. This rock is practically non-porous. In some 
 places the drill cuttings are broken in the form of chips 
 instead of grains, and the sandstone has been logged 
 erroneously as “lime” by many drillers. Some of the rock 
 contains particles so small that it might easily be called a 
 coarse shale or siltstone. 
 
 LENTICULAR CHARACTER OF OIL SAND 
 
 The abrupt change laterally from well sorted sand¬ 
 stone to hard, non-porous siltstone in some places explains 
 the fact that holes offsetting producing wells in the Biehl 
 sand have proved to be dry. The porous beds or parts of 
 the sand bed are apparently lenticular. The accumulation 
 of oil, therefore, is dependent not only upon favorable 
 structure but also upon the existence of porous lenses. 
 The presence or absence of such lenses can not generally 
 be predicted in advance of drilling, and it is recommended 
 that drilling be extended from a given producing well on 
 favorable structure one location at a time. However, 
 when the general trend .of the zone characterized by len¬ 
 ticular porosity can be determined, recommendations of 
 locations within the defined zones can be made ahead of 
 the drill. 
 
 Continued on page 3 
 
w. 
 
 2Q 
 
 le coal (light dash - and - dot lines) relative to sea level. 
 2 W. will be indicated on Plate II of main report. 
 
 .-1000 
 
 v Structure contours on cop 
 ol Biehl sand 
 
 
 400 
 
 Structure contours on top 
 of Fr toads villc coni 
 
 Iuilex Dumber to wells 
 listed tn Tabic 1 
 
 LEGEND 
 
 Producing wed 
 
 Abandoned veil 
 
 Dry bole 
 
 Show of oil 
 
 / 
 
 l-NDALE 
 
T. 
 
 2 
 
 N. 
 
 T. 
 
 1 
 
 N. 
 
 Typical driller’s log in 
 sec. 5, T. 1 N., R. 12 W. 
 
 Plate 1. Structure map of Allendale oil field, showing contours on Biehl sand (heavy lines) and contours on Friendsville coal (light dash - and - dot lines) relative to sea level. 
 Index numbers refer to wells which will be listed in main report. Wells located in secs. 3, 4, 5, 8, 9, and 10, T. IN., R. 12 W. will be indicated on Plate II of main report. 
 
3 
 
 ORIGIN OF THE SAND LENSES 
 
 It is suggested that the local sorting of the sand may 
 be attributed to the action of waves and shore currents 
 during the time of sand deposition. Although most of the 
 uplift was post-Pennsylvanian, there is evidence that the 
 La Salle anticline had already been slightly uplifted to the 
 north in Chester time. In the shallow waters around the 
 southern nose of the pitching anticlinal axis of the La 
 Salle anticline it is possible that currents paralleling the 
 shores may have had various slight fluctuations in intens¬ 
 ity and direction due to slight changes in the shore line 
 during Chester time. If such fluctuations were responsi¬ 
 ble for the formation of porous lenses, in general they prob¬ 
 ably would occur as concentric zones around the southern 
 nose of the anticlinal structure. These zones would thus 
 tend to parallel the structure contours as can be seen on the 
 accompanying structure map. 
 
 PROMISING AREAS FOR FURTHER DEVELOPMENT 
 
 Several promising anticlinal areas occur outside the 
 present producing areas in secs. 3, 4, 5, 8, 9, and 10, T. 1 N., 
 R. 12 W. There are anticlinal noses in the vicinity of (a) 
 sec. 36, T. 2 N., R. 12 W., and sec. 1, T. 1 N., R. 12 W.; 
 (b) secs. 15, 20, and 21, T. 1 N„ R. 12 W.; (c) secs. 15, 
 22, and W.l/ 2 sec. 27, T. 1 N„ R. 12 W.; (d) common cor¬ 
 ner of secs. 8, 9, 16, and 17, T. 1 S., R. 12 W.; (e) secs. 
 26, 27, 28, and 29, T. 1 N., R. 13 W.; and monoclinal ter¬ 
 races in the vicinity of (a) sec. 18, T. 1 N., R. 11 W.; (b) 
 secs. 25 and 26, T. 1 N., R. 13 W., and secs. 30 and 31, 
 T. 1 N., R. 12 W.; (c) sec. 1, T. 1 S., R. 13 W., and E,f/ 2 
 secs. 6, 7, and 18, T. 1 S., R. 12 W. If complete local clo¬ 
 sures in the Biehl sand occur on the monoclinal terraces, 
 the locations of the crests will probably be found slightly 
 up the regional dip from the crests of the Friendsville coal 
 closures, as shown on the map. This is due to a thickening 
 down dip of the interval between the coal and the Biehl 
 sand. 
 
 In the consideration of all favorable structures, por¬ 
 osity must be taken into account. Some structurally fav¬ 
 orable areas have nearby dry holes in structural depres¬ 
 sions. If these show the existence of porous sand containing 
 salt water a more favorable chance for pi’oduction would be 
 found on nearby anticlinal noses or domings. Areas that 
 have nearby dry holes without salt water or small showings 
 of oil with very hard and non-porous sand, should not be 
 selected until more favorable areas have been drilled. 
 
 4 
 
 ECONOMIC POSSIBILITIES 
 
 In the extension of the field, 26 dry holes and 18 pro¬ 
 ducing wells have been drilled. If the cost of drilling pro¬ 
 ducing wells is distributed conservatively over their life; 
 if most of the drilling cost of the dry holes is charged to 
 the first year’s production with the remainder charged to 
 the following year’s production brought in on proven acre¬ 
 age ; and if the yearly cost of lifting and other appropriate 
 charges are also placed against the first year’s production, 
 it will be seen that the first year’s balance would show 
 hardly any profit. But in the later life of the field, with 
 added production from semi-proven acreage and careful 
 drilling on geologically recommended locations, economic 
 gain to the operator should be expected. With a view to 
 furthering cooperation between the operators and the 
 Illinois Geological Survey, the Biehl sand should be cored 
 in order that its character may be entirely revealed, and 
 in addition, samples and logs should be carefully and ac¬ 
 curately kept. 
 
 DATE DUE 
 
 
 
 
 
 
 MOV 1 3 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 Demco, Inc. 38-293