14.GS: CIR272 c. 1 STATE OF ILLINOIS WILLIAM G. STRATTON, Governor DEPARTMENT OF REGISTRATION AND EDUCATION VERA M. BINKS, Director FREEBURG GAS POOL ST. CLAIR COUNTY, ILLINOIS Wayne F. Meents DIVISION OF THE ILLINOIS STATE GEOLOGICAL SURVEY JOHN C. FRYE, Chief URBANA CIRCULAR 272 1959 Digitized by the Internet Archive in 2012 with funding from University of Illinois Urbana-Champaign http://archive.org/details/freeburggaspools272meen FREEBURG GAS POOL St. Clair County, Illinois Wayne F. Meents ABSTRACT The Freeburg gas pool, discovered in 1956, is near the western border of southern Illinois and at the west edge of the main oil and gas producing region. Twenty-nine gas wells in the pool in an area of 2400 acres had initial open-flow capacities ranging from 139,000 to nearly 4 million cubic feet per day from Cypress Sandstone. Average depth to the top of the gas pay is 335 feet. At present the wells are shut in, but the contract for a pipeline has been let and gas should be marketed in the East St. Louis area by the winter of 1959. The Freeburg gas reservoir and its underlying formations may be important for the underground storage of natural gas brought from other areas. Because of the economic importance of the gas reservoir, the geology and production history of the area are sum- marized here. INTRODUCTION The Freeburg gas pool in St. Clair County is in the south part of T. 1 S., R. 7W., and the north part of T. 2S., R. 7W., about eight miles southeast of Belleville, the county seat, and at the south edge of the city of Freeburg. It is about 20 miles from the industrial gas market of East St. Louis. The pool is on the western boundary of the principal oil and gas producing area of Illinois (fig. 1). The producing zone consists of two lenses of sandstone in the Cypress Formation. The Illinois Power Company of Decatur, Illinois, has option to buy the gas (in place) from the operator, McCandlish and Gwaltney Drilling Company of Vin- cennes and Washington, Indiana, and expects to have the gas for sale within several months from the date of publication of this Circular. The Freeburg gas reservoir and its underlying formations may also be impor- tant for the underground storage of natural gas brought in from other areas. Because of the reservoir's economic importance, therefore, the geology and production his- tory of the area are summarized here. DEVELOPMENT The discovery well, the No. 1 Behrens in the SW} SW} NW| sec. 33, T. 1 S., R. 7 W., was drilled by E . E. Rehn in 1955 to the Kimmswick (Trenton) Lime- stone at a total depth of 2000 feet. Rehn plugged the well but in 1956 Leo Dare drilled it out and completed it in the Cypress Sandstone at a depth of 389 feet. The well had an open-flow gauge of 206, 000 cubic feet of gas per day. It also produced much water with a slight show of crude oil when the casing head valve was open to a greater degree in a gas test on October 24, 1956. Since then 28 gas wells have [1] ILLINOIS STATE GEOLOGICAL SURVEY been completed. The gas-producing area is somewhat rectangular in shape, about 2\ miles long and l\ miles wide, and in- cludes about 2400 acres. Open-flow capacities of the gas wells range from 139,000 cubic feet per day up to 3, 780, 000 cubic feet per day . The average open-flow gauge is 1,713- 000 cubic feet per day. Two of the wells penetrated the water table, and in several other wells the sandstone became shaly, thus lowering the open- flow average. The shut-in pressures on the better wells range from 163 pounds per square inch dead weight (psid) to 164 psid. In three wells in a separate sandstone reservoir on the west side of the pool, shut-in pres- sures range from 152 psid to 154 psid. The average depth to the top of the gas pay is 335 feet. Gas gravities measured 0.57 and 0.56 (air is 1.00), indicating a dry gas. This also is verified by Orsat gas analyses (table 1). The Illinois Power Company has calculated the gas reserves down to zero pressure for the field to be 5,400 MMcf. Table 1. - Analyses of Gas from Two Wells in the Freeburg Gas Pool H. Reinheimer Well No. 1 SW| SW± SE± sec. 32, T. 1 S., R. 7 W. St. Clair County Absorption method (Orsat) Fig. 1. - Index map showing location of the Freeburg Gas pool with respect to nearby oil and gas pools, the main oil- producing area, and the major gas pipelines. W. Baltz Well No. 1 SE} SW{ NW{ sec. 32, T. 1 S., R. 7 W., St. Clair County Absorption method (Orsat) percent percent Carbon dioxid e 2.2 Carbon dioxide 2.1 Illuminants 0.4 Illuminants 0.6 Oxygen 0.3 Oxygen 0.1 Carbon monoxide 0.3 Carbon monoxide 0.4 Hydrogen 0.2 Hydrogen 0.2 Methane 96.2 Methane 95.8 Ethane 0.0 Ethane 0.0 Nitrogen 0.4 100.0 Nitrogen Total 0.8 Total 100.0 Specific gravity Btu/cu ft Specific gravity Btu/cu ft Calculated 0. 58 Gross 983 Calculated 0. 58 Gross 983 Measured 0. 57 Net 885 Measured 0. 56 Net 885 100 80 60 50 40 100 80 60 50 40 30 20 FREEBURG GAS POOL I. H. REINHEIMER 3, SW- SW-SE 32-IS-7W 2. LORTZ BROS. I, SE-NE-NW 8-2S-7W fed open fit 3. LORTZ BROS. 2, SE-NW-NW 8-2S-7W ■ Projec fed open now ' 'ed open flow / / 4 LANTER- ■SCHICKEDANZ 1, SE-SW-NW 9 -2S-7W " " Projec ted open flow / / ' / ' .3 .4 .5.6 .8 LO 2 3 4 568 10 Rote of flow, MMcf per day .3 .4 .5.6 .8 1.0 2 3 4 5 6 8 10 Rate of flow, MMcf per day Fig. 2. - Thirty-minute back-pressure tests on four Freeburg Gas pool wells, GAS TESTING PROCEDURE The open-flow gas measurements listed in table 2 were taken by the author through 2-inch connections at the well heads. A 2-inch by 2-foot flow nipple was inserted into the available 2-inch gate valve that was standard equipment on all of the wells. For checking build-up pressures and for back-pressure tests a i- inch steel needle valve on a i-inch nipple welded into the 2-inch by 5^-inch swage nipple below the 2-inch gate valve also was available. The open flows were measured by the orifice well tester on wells up to 890, 000 cubic feet per day and with a Pitot tube on wells ranging from 1, 400, 000 to 3,780, 000 cubic feet per day. In addition, the side static pressure method four diameters from the outlet of the flow nipple was used on three wells ranging from 2, 860, 000 to 3, 700, 000 cubic feet per day. ILLINOIS STATE GEOLOGICAL SURVEY Farm and well Table 2. - Results of Tests on Wells in the Base Beech Creek (Bar- 5g- in. Approximate Elev. low) above Gas Total casing location ft. sea level depth* depth set att Shut- ■in pressure psi** 154 G 164 D 163 D 164 G 163 D 153 G 164 D 165 G 165 G 165 G 164 G 165 G 164^ ■ D 163^ • G 165 G 164 G 164 D 154 D 163" G 152-* ■ D W. Baltz 1 SE SW NW 32-1 S-7W 479 H. Reinheimer 3 SW SW SE 32-1 S-7W 467 Ed Stoneman 1 SE NW NE 32-1 S-7W 478 Elmer Stoneman 1 NE SE SW 32-1 S-7W 473 W. H. Stoneman 2 SW SW SW 32-1 S-7W 470 Behrens 1 SW SW NW 33-1 S-7W 460 W. Beisiegel 3 SE SW SW 4-2S-7W 452 Sheppard-Sentry 1 SW NW SW 4-2S-7W 474 W. Beisiegel 1 NE NW SE 5-2S-7W 437 W. Beisiegel 2 SE SW SE 5-2S-7W 454 John Frisch Heirs 1 NE SW NW 5-2S-7W 456 John Frisch Heirs 2 SE SW SW 5-2S-7W 447 Sylvester Frisch 1 NE NE NW 5-2S-7W 470 Sentry Royalty 1 NW SW NE 5-2S-7W 453 Sentry Royalty 2 SE SE NE 5-2S-7W 442 Sentry Royalty 3 SW NE NE 5-2S-7W 447 Sentry Royalty 4 SE NE SW 5-2S-7W 450 Virgin & Frisch 1 NW NW NW 5-2S-7W 465 Cortner 1 NE SE SE 6-2S-7W 448 Edward Groth 1 SW SE NE 6-2S-7W 461 158 343-360 377 342 159 334-368 368 338 112 154 152 140 392-420 478 391 337-369 369 337 173 362-369 B 373 373 A 114 372-406 400 455 C 138 335-374 374 350 127 376-416 420 376 144 314-350 350 312 140 340-383 383 342 158 320-358 359 331 323-344 344 316 150 342-380 379 345 322-359 359 323 136 329-376 376 334 334-377 377 325 147 323-366 372 335 175 296-324 324 293 153 343-358 358 342 150 335-352 372 335 Footnotes on page 6. FREEBURG GAS POOL Freeburg 3a s Po 3l, St. Clair County, Illinois Open flow Open-fl Mcf p ow volume er daytt Bui ld-up ps pressure ig projected from 5 min. 10 min. 15 min. Longer (min. ) i 2 min. 1 min. 2 min. 3 min. 4 min. 5 min. 10 min. Longer (min. ) Date tested back pres- sure flow 2200 1980 1910 1760 (40) 90 112 122 127 130 133 138 1-58 1450 3180 2860 (55) 114 125 135 139 141 143 148+ 152 (15) 11-57 2800 380 355 345 340 (20) 38 60 94 114 125 133 146 11-57 2830 2630 2610 2600 (20) 139 145 150 153 154 155 158 1-58 2800 185 162 152 139 (35) 7 14 25 36 45 54 90 10-58 350 303 206 (50)E 63 77 85 92+ 97 115 140 (25) 10-56 1170 1050 998 890 (30) 80 97 129 135 138 140+ 149 153 (15) 8-58 990 1910 1860 1820 1850 (20)F 135 147 151 153 154 155 158 6-58 2400 1730 1560 1400 (30) 80 108 123 131 136 139 147 4-58 1400 293 279 269 264 (20) 26 46 76 96 111 121 144 152 (15) 6-58 3710 3780 3780 (20) 131 139 142 145 148 150 156 158 (15) 11-57 4100 2310 2270 2250 2230 (20) 146 153 157 158 159 160 162+ 6-58 2900 2860 2700 (25) 120 134 142 146 148 150 155+ 11-57 2700 3120 3120 127 138 144 148 150 152 157 1-58 2700 2050 1960 1900 (25) J 96 122 138 142 146 148 154 4-58 1650 2650 2380 2300 1950 (50) 110 123 129 133 136 143 4-58 2000 2280 2170 2140 2040 (30) 126 135 141 145 147+ 149 155 159 (15) 6-58 2400 1735 1720 1720 116 129 137 140 142 144 148 150 (15) 11-57 1780 162 162 16 32 51 69 82 94 1-58 746 746 76 109 129 134 138 140 145 4-58 620 Footnotes on page 7. ILLINOIS STATE GEOLOGICAL SURVEY Table 2. - Results of Tests on Wells in the Farm and well Base Beech Creek (Bar- Approximate Elev. low) above Gas 5g- in. Shut-in Total casing pressure location ft. sea level depth* depth set att psi Joe Lanter 1 John Lanter 1 John Lanter 2 Lortz Bros 1 Lortz Bros 2 Lortz Bros 3 Lortz Heirs 1 Fischer- Beisiegel 1 Lanter- Schickedanz 1 SE NE SW 8-2S-7W SW SW NE 8-2S-7W SE NE SE 8-2S-7W SE NE NW 8-2S-7W SE NW NW 8-2S-7W SE SW NW 8-2S-7W SE NE NE 8-2S-7W NW NW SE 9-2S-7W SE SW NW 9-2S-7W 448 456 488 451 454 448 499 387 440 154 148 150 143 136 160 146 110 150 320-350 360 324-363 366 365-395 405 326-365 368 334-362 367 312-348 350 375-405 415 304-322 350 310-360 362 321 328 367 327 335 315 374 305 310 164+ D 162+ D 159 D 163 D 164+ D 164+ D 164+ D 164 G 164 D * B - Lower gas sand only. t A = Perforated 366 to 371 feet; original total depth = 2008 feet. C = 4-inch casing, perforated 389 to 393 feet; original total depth = 2000 feet. ** D = Dead-weight tester. G = Pressure gauge. Gas gravities were measured and gas samples analyzed by the Illinois State Geological Survey. Shut-in pressures were measured by using a dead-weight tester on 16 wells and by a standard Bourdon pressure gauge on the other wells, which were either low-pressure wells or were difficult to reach, such as wells in muddy fields . BACK PRESSURE TESTING Isochronal back-pressure tests (fig. 2) and the projected open-flow readings from back-pressure tests (table 2) were measured with a 2-inch Critical -Flow Prover by K. Robertson and William May of the Illinois Power Company. Back-pressure tests were made for several reasons: 1) they reveal the open- flow capacity of the well; 2) they determine its ability to deliver gas against dif- ferent pressures; and 3) they eliminate the risky operation of flowing the well wide open for an open-flow gauge, which is especially dangerous on a large-volume well producing from friable sandstone. FREEBURG GAS POOL Freeburg Gas Pool, St. Clair County - continued Open-flow volume Mcf per daytt 5 10 15 Longer mm. nun. min. (min. ) 1940 1820 1750 1620 (40) 1800 1660 1620 1570 (25) 950 830 800 750 (40) 2500 2400 2360 2300 (35) 4100 3910 3780 3380 (50) 2500 2400 2320 2320 (20) 746 703 672 593 (50) H 960 K 810 L 4550 4080 3940 3700 (40) Build-up pressure psiq i 1 2 3 4 5 10 Longer min. min. min. min. min. min. min. (min.) 96 118 132 138 142 145 152 104 123 133 137 142 145 153 72 98 120 130 135 138 146 112 128 139 144 147 149 155 116 126 134 138 140 142 148 124 138 148 153+ 156 158 162 52 76 102 115 123 129 141 110 125 138 143 146 148 154 119 132 139 143 146 148 153 Date tested Open flow projected from back pres- sure flow 10-58 1450 9-58 1500 10-58 950 7-58 2250 9-58 3400 9-58 1850 8-58 700 10-58 9-58 3650 tt Steady flow on last test, no decline. H = Steady water stream. K = With water spray. L - Valve was partially closed until water disappeared. E = Slugs of water in 47 min., valve was partially closed until water disap- peared. F = With fair oil spray. J = With good oil spray. In figure 2, Pr = formation or reservoir pressure and P s = the sand face pres- sure. The back pressures for datum points in graph 1 are 158 psid for 200 Mcf, 152 psid for 400 Mcf, 141 psid for 700 Mcf, and 107 psid for 1500 Mcf. In graph 2, back pressures are 149 psid for 400 Mcf, 135 psid for 700 Mcf, and 94 psid for 1400 Mcf. In graph 3, back pressures are 155 psid for 400 Mcf, 146 psid for 700 Mcf, and 116 psid for 1700 Mcf. In graph 4, back pressures are 155 psid for 400 Mcf, 147 psid for 700 Mcf, and 119 psid for 1700 Mcf. In other words, these wells will produce about 400 Mcf with an average well-head back pressure of 153 psi, about 700 Mcf with a well-head back pressure of 142 psi, and about 1600 Mcf for 109 psi back pressure. CORE ANALYSES Core analyses listed in table 3 were furnished by the Illinois Power Company. The majority of the wells have been cored in the Cypress Formation, and the cores of the sandstone section have been analyzed. 8 ILLINOIS STATE GEOLOGICAL SURVEY The typical permeability of the sandstone in core analyses from four wells is 195 millidarcys; the average porosity is 21 percent. Analyses of cores taken from wells in the north part of the field show that the sandstone there is slightly less permeable and the open-flow gauges are lower. The permeability of the lower sandstone section in the Lanter-Schickedanz No. 1 well in the south section of the field is nearly 1000 millidarcys, which is high for sandstone of the Cypress Formation in Illinois. Table 3. - Partial Core Analyses from Four Wells in the Freeburg Gas Pool Lanter-Schickedanz No. 1 Lanter-Schickedanz : No . 1- SE£ SVv r | NWJ sec. 9, T. 2S., R. 7 W. continued Depth Horizontal Porosity Depth Horizontal Porosity (ft) permeability (md) 230.0 (%) 21.9 (ft) permeability ( md) (%) 317 352 700.0 23.5 318 179.0 21.0 353 816.0 25.0 319 512.0 23.3 354 800.0 23.4 320 336.0 23.3 355 880.0 23.3 321 665.0 22.5 356 533.0 24.2 322 595.0 22.5 357 896.0 23.3 323 910.0 23.2 358 770.0 23.4 324 201.0 24.3 359 720.0 22.7 325 287.0 23.2 360 994.0 23.4 326 327 328 96.0 632.0 525.0 23.3 22.7 22.3 Average permeability Average porosity 404 23 329 330 331 475.0 34.0 176.0 23.3 21.9 20.4 John Frisch Heirs No. 2 SW{ SW{ SW| sec. 5, T. 2S. , R. 7W. 332 245.0 21.0 322 27.0 17.4 333 287.0 24.1 323 71.0 20.7 334 359.0 23.6 324 573.0 22.7 335 220.0 23.3 325 45.0 22.3 336 69.0 20.4 326 627.0 20.7 337 70.0 22.3 327 431.0 21.9 338 188.0 23.7 328 348.0 21.9 339 78.0 23.8 329 627.0 23.8 340 137.0 25.5 330 193.0 21.9 341 94.0 24.7 331 261.0 19.7 342 108.0 24.1 332 382.0 23.2 343 11.0 19.0 333 25.0 17.1 344 6.1 17.2 334 197.0 20.5 345 110.0 24.2 335 190.0 17.5 346 416.0 24.7 336 IMP 3.3 347 299.0 23.5 337 96.0 14.6 348 249.0 23.7 338 418.0 21.4 349 678.0 23.3 339 159.0 18.5 350 584.0 23.4 340 340.0 19.5 351 610.0 23.3 341 251.0 18.8 FREEBURG GAS POOL Table 3. - Continued Depth Horizontal Porosity (ft) permeability (md) (%) John Frisch Heirs No. 2- continued 342 152.0 Average permeability Average porosity 19.0 271.0 20.2 W. Baltz No. 1 SE± SW{ NW£ sec. 32, T. 1 S., R. 7 W. 345 81.0 24.3 346 124.0 23.0 347 127.0 25.4 348 128.0 24.5 349 91.0 24.1 350 80.0 19.6 351 120.0 22.3 352 125.0 22.9 353 79.0 20.0 354 70.0 22.7 355 30.0 21.7 356 16.0 17.8 357 11.0 17.5 358 7.0 16.0 359 360 0.8 14.3 361 0.9 18.9 362 1.7 17.3 363 0.4 16.9 Average permeability 46.6 Average porosity 19.6 Sentry Royalty No. 3 T. 2 S. SW| NEJ NE| sec. 5 329 330 331 332 333 334 335 336 337 338 339 340 341 342 R. 7 W. 2.9 17.4 38.0 19.7 56.0 20.2 47.0 21.5 20.0 20.9 51.0 19.1 37.0 19.3 16.0 18.7 41.0 21.5 65.0 21.9 62.0 21.7 69.0 17.9 48.0 23.8 60.0 24.3 Nfo. 3- continued 45.0 20.4 58.0 18.1 16.0 23.2 84.0 23.5 83.0 23.7 68.0 22.7 57.0 23.1 65.0 22.9 66.0 22.9 60.0 22.1 55.0 21.7 76.0 20.7 70.0 21.0 56.0 21.7 57.0 23.9 17.0 18.6 93.0 21.0 105.0 22.3 Depth Horizontal Porosity (ft) permeability (md) (%) Sentry Royalty No 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 Average permeability 5 7.6 Average porosity 21.3 STRUCTURE The Freeburg gas reservoir is a stratigraphic trap about 25 feet below the base of the Beech Creek. (Barlow) Lime- stone (fig. 3). The sandstone in the Cy- press Formation (figs. 3, 4), which is about 50 feet thick on the east side of the pool, thins out to shale updip to the west side. The shale interval between the base of the Beech Creek. (Barlow) Limestone and the Cypress gas sand, where the sand is present, ranges from 28 feet on the east and south sides to 16 feet on the north side. The structure at the base of the Beech Creek (Barlow) Limestone appears to be a double anticlinal nose dropping some 60 feet to the east, which is the normal regional dip into the Illinois Basin. The Beech Creek also dips about 50 feet to the north and to the south of the pool, the length of this north- south section being four to five miles, according to available 10 ILLINOIS STATE GEOLOGICAL SURVEY R 7 W # Gas well -O- Plugged, cool mine stripping -- Ory hole a> Structure test (plugged with cement ) o Not completed _^^ Structure contour on the |}0 s base of the Beech Creek (Barlow) Limestone interval 10 feet Scale of Miles z I ' ' -i i Fig. 3. - Freeburg Gas pool showing structure contours on top of the Beech Creek (Barlow) Limestone. FREEBURG GAS POOL 11 8 8 8 o o o o s ■B - Ol ^ r^^-j^ i? o p Vrf ■ y ■ 9 ® Li. "1 / .J .•;/• 0) rp c 5 (5 J3 ai tj c • U] u (0 * « 1- u> t CO in C a> a j= Sn ■*-* O o ^-< 0) a •n *+-< o a c 3 .,_. o 3 O CD in to 0) rn C u in u Tl m C 1 — 1 in u tl -*-> O (1) 1 1 u 1 a* oopoooo oooooo giCNiD ifi 5 rt £j — O CD ^ 12 ILLINOIS STATE GEOLOGICAL SURVEY well data. A well drilled in the NE^ SE^ sec . 19, T. 2S., R. 7W., encountered the base of the Beech Creek (Barlow) Limestone at an elevation of 134 feet above sea level. The cross section of electric logs (fig. 4) shows a large body of sandstone in well No. 4 and indicates that it splits into two benches in wells No. 2 and No. 3, The shut-in gas pressure of well No. 2 indicates by its low psi reading that the up- per sandstone bench of that well does not correlate with the upper bench of well No. 3. The reading in No. 2 was 152 psi compared to the normal reading of 164 psi in No. 3. It would seem that the upper sandstone of No. 2 well represents a lens or constitutes a separate reservoir. The limit of No. 6 Coal (fig. 3) roughly encircles the northern part of this structure and continues eastward around the eastern projection of the structure in- to sec. 9, T. 2 S., R. 7 W. The coal is probably eroded in section 16. Fig. 5. - The horizontal white line drawn on the photograph marks the top of the Jamestown Limestone at the left. It shows that the limestone dips 10 feet within the distance,as marked, but it actually dips 20 feet within three- eighths of a mile. The exposure was in the highwall of Peabody Coal Company's River King Mine. Figure 5 shows the northeast dip of the Jamestown Limestone above the No. 6 Coal through sec. 33, T. IS., R. 7 W. The rock face exposed in this pic- ture is about three-eighths of a mile long and is facing southeast. The Jamestown Limestone drops about 10 feet from the left-hand side of the picture to the first shovel and about 20 feet for the length of the cut. The white line across the cen- ter of the picture is level. FREEBURG GAS POOL 13 STRATIGRAPHY A thin cover of glacial drift overlies the bedrock in the area of the Freeburg gas pool. Pennsylvanian rocks underlie the drift and are exposed in the high wall of the Peabody Coal Company's River King Mine in sees. 32 and 33, T. 1 S., R. 7 W. (fig. 5). D. L. Reinertsen in 1958 described the section in detail, as follows. Thickness (ft. in.) Pleistocene Series Glacial drift 15± Pennsylvanian System McLeansboro Group Interval, partially covered. Appears to be mainly composed of medium greenish gray shale with an 18-inch to 2-foot sandstone (?) zone near the base (not accessible) 7± Limestone or claystone (inaccessible) 1± Shale, gray to medium dark gray with greenish cast 2± Cutler Limestone, brownish gray, very hard, argillaceous, dense 1± Shale, greenish gray, appears to be fissile but is plastic when wet; in beds up to 6 inches thick interbedded with very ar- gillaceous nodular limestone bands up to \\ inches thick that become thicker and more abundant toward top; very ir- regular top 3± Bankston Fork Limestone, gray to brownish gray, dense to finely crystalline, somewhat argillaceous in part, thick- bedded to massive 2 3 Shale, gray to dark gray with a slight greenish cast in part, containing a zone of flattened calcareous nodules up to 1 inch thick 5 inches from the top 3± Shale, light to medium gray, rather poorly bedded in lower part; better bedded and dark gray to black toward top 4 Jamestown Limestone, brownish gray, massive, very dense and hard, somewhat argillaceous 2 Shale, dark gray to black, fairly well bedded, somewhat slaty in part with numerous flattened oval ironstone concretions 7 Jamestown Coal, normally bright-banded with some calcite on vertical facings; fairly hard; considerable oxidation on surface 3 Clay-shale, dark gray to black, soft, crumbly, weathered, with a semblance of bedding downward 2 Herrin Limestone, medium to dark gray, fairly hard, very fos- siliferous, very silty and argillaceous. Grades downward into: 11 Limestone, light to medium gray, massive to thick-bedded, hard, fossiliferous. Thickness increases toward east of pit 20-72+ 14 ILLINOIS STATE GEOLOGICAL SURVEY Thickness (ft. in.) Shale, black to dark gray, slaty and hard in part, containing dense, hard, dark gray to black calcareous concretions up to 10 inches thick and 2 feet across (not well exposed) 6-84 Herrin (No. 6) Coal, normally bright-banded 6 Underclay The Pennsylvanian System is 138 feet thick over the top of the gas produc- ing area in the Walter Stoneman No. 2 well in the SWJ SW| SW{ sec. 32, T. 1 S., R. 7 W. Rotary cuttings from this well of formations below the Pennsylvanian are described by E. Atherton below. Thickness Depth (ft.) (ft.) Mississippian System Chester Series Hardinsburg Formation "Shale" 22 160 Golconda Formation "Lime" "Shale" "Lime" Limestone, cherty, light brownish gray, very fine to coarse, fossiliferous, trace of glauconite, streaks of dolomite Shale, gray, flaky; trace of shale, red Limestone, oolitic, light brownish gray to light brown, medium to coarse; little dolomite, gray, extra fine 9 230 Shale, gray, flaky; limestone, light grayish green, sub- lithographic Shale, gray, flaky Limestone, light brownish gray to light brown, fine to coarse, fossiliferous Shale, gray, light greenish gray, flaky Limestone (Beech Creek Member), very argillaceous, brownish gray, gray, dense, few carbonaceous specks 10 288 Limestone (Beech Creek Member), oolitic in part, brown- ish gray, medium dark gray, fine to coarse, fossilifer- ous, scattered black grains 9 297 Cypress Formation Shale, gray, red; sandstone, shaly, calcareous, argil- laceous, greenish gray, very fine, angular, friable; siltstone, gray, coarse 16 313 Sandstone, gray, very fine to little fine, angular, friable, slight show of oil 22 335 Shale, red; sandstone, as above, very fine 6 341 Shale, gray; sandstone, olive gray to dark gray, quartzitic 12 353 7 167 8 175 20 195 2 197 24 221 6 236 16 252 6 258 20 278 FREEBURG GAS POOL 15 Thickness Depth (ft.) (ft.) Shale, gray, slightly carbonaceous; little shale, red; sandstone, gray, very fine, compact, slightly car- bonaceous 9 362 Sandstone, light gray, very fine to fine, angular, friable, oil show 2 364 Sandstone, gray, very fine, angular, friable, black specks, oil show 4 368 Paint Creek Formation Limestone, light brownish gray, coarse, very fossilifer- ous; shale, extra-fossiliferous, sandy, red and light grayish green 12 380 Shale, red, greenish gray 7 387 Limestone, sandy in part, light brownish gray, mostly coarse, very fossiliferous; streaks of shale, green- ish gray 7 394 Shale, silty, greenish gray, red streaks; little shale, yellow 5 399 Siltstone, very shaly, greenish gray 9 408 Yankeetown (Benoist) Formation Sandstone, calcareous, medium light gray, very fine, compact, slightly micaceous; trace of sandstone, white, fine, angular, friable Renault Formation Shale, gray, green, red, yellow, purple Aux Vases Formation Sandstone, light gray, fine to little medium, angular to subangular, friable Siltstone, dark green; shale Valmeyer Series Ste. Genevieve Limestone (samples from depth 490 to 560 feet probably out of place; log unreliable) Limestone, oolitic, light brownish gray, fine to coarse, crinoidal, glauconitic in part 6 500 Limestone, oolitic, pale buff, medium to coarse, light- shelled ooliths; limestone, sandy to very sandy, pale gray, fine to coarse, slightly glauconitic; limestone, hematitic, gray, fine to coarse, very fossiliferous, Shale, red, green, gray Sandstone, light gray, light greenish gray, very fine, friable; limestone, silty to very silty, gray Limestone, oolitic in part, sandy in part, light brownish gray, fine to coarse Limestone, oolitic to obscurely oolitic, light brownish gray, fine to coarse, rather dense Limestone, oolitic, grayish brown, fine to coarse, in part with sand grains, medium to coarse, sub-rounded; little dolomite, cherty, light brownish-gray, extra fine 35 620 17 425 24 449 43 492 2 494 10 510 5 515 10 525 30 555 30 585 16 ILLINOIS STATE GEOLOGICAL SURVEY Thickness (ft.) Depth (ft.) St. Louis Limestone Limestone, cherty, medium light brownish gray, sub- lithographic Limestone, medium light brownish gray, dense; little dolomite, brownish gray, very fine, vuggy Limestone, slightly cherty, light brownish gray, sub- lithographic; limestone, as above; dolomite, very calcareous, light gray, extra fine "Limestone" Limestone, cherty, medium light brownish gray, sub- lithographic to dense; little limestone, oolitic, grayish brown, fine to medium, dense; little lime- stone, dolomitic, gray, extra fine Limestone, light brownish gray, dense Dolomite, calcareous, light brownish gray, extra fine Limestone, cherty, medium light brownish gray, dense "Limestone" Limestone, cherty, grayish brown, dense, in part ob- scurely oolitic Salem Limestone "Limestone" Limestone, oolitic, medium light brownish gray, mostly very fine to fine, few microfossils Limestone, slightly oolitic, medium light brownish gray, little grayish brown, very fine to fine, coarse, fos- siliferous, Endothyra Limestone, oolitic, brownish gray, medium to coarse, fossiliferous; little limestone, brownish gray, sub- lithographic; dolomite, calcareous, silty, gray, extra fine Limestone, oolitic in part, medium light brownish gray, fine to coarse, abundant microfossils Limestone, brownish gray, sublithographic Limestone, oolitic, light brownish gray, medium to coarse Limestone, slightly cherty in part, grayish brown, very fine to coarse, fossiliferous; streaks of dolomite, brown 30 650 25 675 13 688 10 698 30 728 12 740 6 746 10 756 10 766 8 774 10 784 12 796 34 25 10 10 20 30 ish gray, very fine, few carbonaceous flakes Limestone, very dolomitic in part, light brownish gray, little light gray, very fine to coarse, fossiliferous, carbonaceous flakes " Limestone" Limestone, dolomitic in part, light gray, grayish brown, fine to coarse, very fossiliferous, crinoidal Limestone, light brownish gray, mostly coarse, very fos- siliferous, crinoidal, in part with black grains and gray bryozoa Limestone, light grayish brown, light gray, fine to coarse, very fossiliferous, crinoidal, some chalky white bryozoa, few dark bryozoa 20 10 20 30 20 830 855 865 875 895 925 935 955 985 1005 1025 FREEBURG GAS POOL 17 Thickness Depth (ft.) (ft.) Limestone, as above, dolomitic in part; dolomite, light grayish brown, extra fine 31 1056 Warsaw Formation Dolomite, gray, extra fine, in part very calcareous, fos- siliferous; geode quartz 14 1070 Dolomite, as above; limestone, gray, fine to coarse, very fossiliferous, glauconitic; little geode quartz 10 1080 Dolomite, as above, slightly glauconitic; little geode quartz 16 1096 Dolomite, gray, extra fine, in part calcareous, fossilif- erous; limestone, very cherty, very fossiliferous, light gray, gray, with dark grains and fossils, fine to coarse 12 1108 Dolomite, cherty, dark gray, extra fine, shaly, in part calcareous, fossiliferous 22 1130 Burlington-Keokuk Limestone Limestone, very cherty, light gray, mostly coarse, very fossiliferous 8 1138 Shale, red, light green 7 1145 Limestone, very cherty, light gray, coarse, very crinoidal 43 1188 Limestone, very cherty, slightly dolomitic, light gray, very fine and coarse, crinoidal 10 1198 Limestone, as above; dolomite, cherty, medium light gray, extra fine 10 1208 Limestone, very cherty, dolomitic, light gray, very fine and coarse, crinoidal; grading to dolomite, very fine 20 1228 Limestone, very cherty, dolomitic, light gray to pale buff, very fine and coarse, fossiliferous, bryozoan; grading to dolomite 20 1248 Same, mostly dolomite, light gray, extra fine, very cherty Dolomite, medium light gray, extra fine "Limestone and dolomitic limestone" Limestone, very cherty, light buff, very fine and coarse, very fossiliferous; little chert, dolomitic, light gray, extra fine, glauconitic Limestone, as above; dolomite, cherty, gray, extra fine, slightly glauconitic Chert, gray, light blue-gray; little dolomite, gray, extra fine, slightly glauconitic Limestone, very cherty, light buff, brownish gray, fossil- iferous; dolomite, very cherty, gray, extra fine Dolomite, cherty, gray, little brownish gray, extra fine, black specks, slightly glauconitic; little limestone, cherty, brownish gray, fossiliferous, rather dense 15 1373 Limestone, extra cherty, very dolomitic in part, brownish gray, little light gray, extra fine; dolomite, very cherty, light gray, extra fine, very glauconitic 10 138 3 30 1278 10 1288 40 1328 5 1333 10 1343 5 1348 10 1358 8 1402 15 1417 13 1430 2 1432 18 ILLINOIS STATE GEOLOGICAL SURVEY Thickness Depth (ft.) (ft.) Limestone, extra cherty, brownish gray, dense; dolo- mite, extra cherty, brownish gray, extra fine; chert, very glauconitic 7 1390 Dolomite, extra cherty, light gray, extra fine, extra glauconitic 4 1394 Fern Glen Formation Shale, gray, glauconitic Shale, grayish green Shale, grayish green, gray Shale, red Kinderhook Series Chouteau Limestone Limestone, very silty, dolomitic, red, extra fine 2 1434 Limestone, light brownish gray, light gray, brown, light olive gray, sublithographic 5 1439 Limestone, brownish red, sublithographic 6 1445 Limestone, red, brown, sublithographic 8 1453 New Albany Shale Shale, very dark gray, few spores 6 1459 Silurian System Niagaran Series Thorn Group Dolomite, light gray, extra fine, few very fine vugs, few small spots of oil 8 1467 Limestone, silty, dolomitic, light gray to gray, light olive gray, sublithographic Dolomite, argillaceous, calcareous, gray, marly "Limestone" "Dolomite" Limestone, medium light olive gray, little light gray, gray, sublithographic 20 1555 Dolomite, calcareous, silty, gray, extra fine; limestone, dolomitic, silty, medium light olive gray, extra fine 18 1573 Limestone, medium light olive gray, sublithographic 7 1580 Limestone, very dolomitic, silty, light olive gray, light gray, extra fine 12 1592 Bainbridge Group Moccasin Springs Formation Dolomite, argillaceous, gray, greenish gray, red, extra fine; little shale, red 22 1614 Dolomite, argillaceous, greenish gray, red, extra fine; limestone, light olive gray, sublithographic 10 1624 Limestone, argillaceous, red, shaly 10 1634 Limestone, light gray, rather dense; limestone, light reddish brown, abundant red argillaceous grains 4 1638 Limestone, very silty, dolomitic, red, extra fine; little shale, calcareous, silty, red 20 1658 "Dolomite, argillaceous" 10 1668 31 1498 14 1512 14 1526 9 1535 FREEBURG GAS POOL 19 Thickness Depth (ft.) (ft.) Limestone, very silty, dolomitic, red, grayish green, extra fine; little shale, silty, red, grayish green 5 1673 Limestone, as above; little limestone, light brownish gray, sublithographic, scattered red grains 10 1683 St. Clair Limestone Limestone, light olive gray, sublithographic, few red grains 10 1693 "Limestone" 10 1703 Limestone, light brownish gray, little red, white, light brownish red, sublithographic, scattered red grains 31 1734 Alexandrian Series Limestone, cherty, light gray, little light greenish gray, sublithographic, glauconitic 14 1748 Limestone, cherty, light brownish gray, sublithographic, in part dolomitic; little dolomite, calcareous, brownish gray, extra fine 10 1758 Limestone, dolomitic, slightly cherty, light brownish gray, extra fine 5 1763 Dolomite, calcareous, light brownish gray, extra fine 5 1768 Ordovician System Maquoketa Shale Shale, medium dark greenish gray; sandstone, calcareous, gray to light gray, very fine, compact, pyritic in part, abundant black specks 27 1795 Shale, medium dark greenish gray; some laminae of silt- stone and sandstone, medium dark greenish gray "Shale" Shale, dark greenish gray Shale, as above; interlaminated siltstone, dark greenish gray Shale, dark greenish gray Shale, calcareous, dolomitic, dark greenish gray; dolo- mite, very calcareous, extra silty, olive gray, extra fine Dolomite, as above, with black specks Kimmswick ("Trenton") Limestone Limestone, light brownish gray, very fine to coarse, little white chalk, few fine dolomite crystals, in part with Receptaculites 49 1965 Limestone, as above; little limestone, very dolomitic, brown, light gray, very fine to fine 40 2005 Plattin Limestone Dolomite, slightly cherty, grayish brown, very fine to fine 4 2009 20 1815 15 1830 20 1850 10 1860 10 1870 40 1910 6 1916 Illinois State Geological Survey Circular 272 19 p., 5 figs., 3 tables, 1959 nnmni CIRCULAR 272 ILLINOIS STATE GEOLOGICAL SURVEY URBANA