Indiana University-Purdue University Indianapolis (IUPUI) / Deep injection of waste CO2 and fluids from regional energy plants into the St. Peter Formation of the Illinois Basin, could effectively provide long term deep geologic storage. This research aims to explore the viability of this proposed injection. There are some basic criteria that must be met to effectively store waste in a geologic reservoir. First, the reservoir must have sufficient porosity and permeability for both injectivity and for migration of the injected fluid through the reservoir. Second, the reservoir must be overlain by some form of impermeable seal or cap layer(s). Third, the reservoir should be sufficiently isolated from interaction with surface and near surface water. Finally, the formation must contain enough storage volume to handle significant amounts of injected material. Massive sandstone formations that host large saline aquifers have the potential to serve as high capacity storage sites. Much of the research targeting the potential suitability and storage capacity attributes of these formations has been promising, but reproducibility of the results has been less than ideal. Some of this variability has been attributed to petrological differences in the sandstone reservoirs that are not readily evident when studying the target formation over a geographically significant area. Based on the criteria, a promising candidate for injection and storage is the St. Peter Sandstone of the Illinois Basin. This study investigates the viability of liquefied CO2 storage within the St. Peter Sandstone on a micro scale. Initial porosity and permeability of the formation plug samples ranged from 16% to 19% and 26 to 981 millidarcies (mD), respectively. The wide difference in permeability is attributed to variations in strength of the cement, in this case quartz overgrowth in the sandstone. This preliminary evidence indicates that the storage capacity of the formation will remain constant or increase depending on injection location, suggesting that the St. Peter Formation will lend itself well to future storage.

The purpose of this study is to document and describe newly observed marine fossils from the upper part of the Degonia Sandstone and to infer the depositional setting of this horizon. Previous studies have shown that the Degonia Sandstone (Elviran Stage, Chesterian Series, Mississippian Subsystem) contains sedimentological evidence of several depositional environments (i.e. terrestrial, fluvial, nearshore deltaic, tidal, and possible marine zones); however, no body fossils had been observed. The only fossils identified in the Degonia are non-diagnostic trace fossils and Carboniferous plant remains such as Lepidodendron trunks and Stigmaria casts, suggesting a terrestrial environment. In 2010, Mary Seid and Joseph Devera of the Illinois State Geological Survey found marine fossils in the upper Degonia Sandstone in a stream bed located within the Wolf Creek Fault Zone. They associated these fossils with a marine environment, contradicting earlier assessments. Four study localities were found throughout the study, one each in the Gorham, Cobden, Glendale, and Raddle Quadrangles of southern Illinois. Sampling localities were found using geologic maps to locate the Degonia-Kinkaid contact, specifically areas where large stream valleys cut through the Kinkaid Formation and into the Degonia Sandstone throughout southern Illinois. The boundaries between the Degonia Sandstone and the overlying Kinkaid Formation were walked in order to find indicators of the marine zone (i.e. the presence of the shaly layer of the upper Degonia Sandstone). The reference section (the Gorham locality) contains the largest diversity of fossils and represents a storm deposit. The Cobden locality appears to contain a zone of dwarfed specimens and a zone of normal sized specimens, and represents a storm deposit. The Glendale locality is dominated by a single bivalve and represents brackish water conditions. The Raddle locality is non-fossiliferous, but was within the intertidal zone. The fauna identified by this study consists of four Phyla: Arthropoda, Brachiopoda, Bryozoa, and Mollusca. The only Arthropoda observed was a burrowing barnacle (Acrothoracica). The Brachiopoda observed consist of Diaphragmus nivosus, Orthotetes kaskaskiensis, Anthracospirifer occiduus, and Composita sp. The Bryozoa observed include Fenestrate and Trepostome. The Mollusca are the most diverse phyla observed, consisting of bivalves (Wilkingia walkeri, ?Edmondia sp., Aviculopecten winchelli, Promytilus illinoisensis, Myalina sp., ?Septimyalina sp., Myalinella meeki, ?Sphenotus monroensis, and four species of unknown bivalves), cephalopods (Reticycloceras sp., Endolobus sp., Liroceras sp., Metacoceras sp., and Domatoceras sp.), and gastropods (Euconospira sturgeoni, ?Eotrochus cf. marigoldensis, and an unknown gastropod). Other fossils observed were crinoid stem molds and plant material. The characterization of invertebrate fossils occurring in the upper Degonia supports the previous suggested marine sedimentological features of the Degonia Sandstone.

A two square mile (5.2 square kilometer) 3-D seismic reflection survey was completed in northeastern White County, Illinois for petroleum exploration in January of 2008. Well log data was made available from Royal Drilling and Producing, who contracted the seismic survey, and additional data was retrieved from the ILOIL database. Raster (TIFF format) images that were available for nearly every well location in the study area were calibrated for depth and stratigraphic tops picked. The purpose of this study is to analyze the Aux Vases formation using 3-D seismic reflection data and attribute analysis by comparing this data to well log information that is greatly available in the study area. Synthetic seismograms were calculated to calibrate seismic reflection data time to actual geological depth to a formation. The synthetic seismograms were calculated using wavelets extracted from the 3-D seismic data and edited, digital (LAS format) sonic and density logs measured in three wells. Geophysical log data from wells in the area were used to interpret formation top and bottoms. With the Aux Vases and Ste. Genevieve top information, an isopach was generated. Horizons were handpicked in all 318 seismic lines and isochron maps were generated to compare time thickness to actual thickness of the isopach maps. Attribute analysis was performed on horizon and volume cubes to interpret the Aux Vases formation in the study area. These attributes included instantaneous phase, instantaneous amplitude, and instantaneous frequency. Additionally, multiple spectral decomposition cubes (from four SEG-Y volumes) were generated for 520-580 ms intervals and interpreted at 550 ms. The combination of this data lead to identification of two larger stratigraphic bodies and several smaller ones in the study area. Thickness comparison between these attributes and isopach maps was completed and found similarities that can be used to determine potential thickness. A thickness estimate was completed at Well B using the frequency from spectral decomposition. A channel was mapped in the western edge of the survey using spectral decomposition and other attributes. Finally, a fault was identified in the southeastern portion of the survey area.

The Big Clifty (Jackson) Sandstone Member of the Golconda Formation is the most important of the Mississippian (Chesterian) heavy-oil reservoirs in the southeastern Illinois Basin. Heavy oil reservoirs, or asphalt rock deposits, have been studied extensively in south central and western Kentucky, and ~2 billion barrels of original oil in place (OOIP) have been proposed to occur in the Big Clifty Sandstone. Despite high OOIP estimates, heterogeneities in the reservoir negatively impact the production of heavy oil deposits. Heterogeneities related to depositional facies changes are poorly understood in the Big Clifty Sandstone of Kentucky, where it has been mostly described as a 60-120 feet thick sandstone unit. In some locations, the Big Clifty occurs as two distinct sand bodies with intercalated mud-rich units and, most typically, with the greatest clay- and silt-rich units present between sandstone bodies. Questions exist as to how such muddy facies occur in the reservoir. This study couples sedimentary facies analysis with sequence stratigraphy to assess how lithological factors affect the occurrence of petroleum in Big Clifty reservoirs. Multiple datasets were integrated to develop a depositional model for lithologic facies observed in this study. Datasets include core, exposure descriptions, petrographic analysis, bitumen concentrations, electrical resistivity tomography (ERT), and borehole geophysical analysis. This study occurred in Logan, Warren, and Butler counties, with emphasis on an active asphalt-rock mine in Logan County. Surface geophysical methods aided in demarcating Chesterian limestones, sandstone bodies and, in particular, highly resistive heavy-oil laden Big Clifty channel bodies. In Warren County, located E-NE of the Stampede Mine, the Big Clifty coalesces into a single amalgamated sandstone channel or a series of superimposed stacked channels as observed in outcrop along Indian Creek at McChesney Field Station and at Jackson’s Orchard. In these locations, the tidal influence is subtle with large-scale trough cross bedding dominating, and the contact on the Beech Creek Limestone is sharp. Facies changes related to the environment of deposition greatly impact the quality of heavy-oil reservoirs and must be taken into consideration during exploration and siting of asphalt rock mines.

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Thesis (M.S.)--Miami University, Dept. of Geology, 2005. / Title from first page of PDF document. Document formatted into pages; contains [1], v, 72 p., [64] plates : ill. Includes bibliographical references (p. 65-71).

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Previous studies have identified δ¹³C events in the Carboniferous that imply major shifts in the carbon cycle. However, inherent in this interpretation is the assumption that epicontinental seas are chemically representative of the global ocean. Our study uses stable isotope and trace element analyses of brachiopod shells to examine changes in climate and circulation of the North American epeiric sea. Formations were selected for study to provide shallow marine environments with geographic coverage of North America. These units include the Grove Church and Mattoon Formations (Illinois Basin), Glenshaw Formation (Appalachian Basin), Bird Spring Formation (Bird Spring Basin), and Oread Formation (US midcontinent). In all, 98 brachiopod shells were found to be well preserved based on screening with plane light and cathodoluminescence microscopy of thin-sections, and trace element analyses. Upper Chesterian Grove Church (Illinois Basin) samples have δ¹³C and δ¹⁸O averages of 1.1% and -3.1% respectively. These low values are interpreted as a local or regional effect caused by terrestrial runoff. Terrestrial influences are also suggested by the depositional environment: nearshore marine. Chesterian samples from the Bird Spring Formation at Arrow Canyon, Nevada average 3.7% and -1.4% for δ¹³C and δ¹⁸O respectively. The higher δ¹³C and δ¹⁸O values, compared with samples from the time equivalent Grove Church, likely reflect the freer exchange with the Panthalassa Ocean at this most western edge of North America, and best represent open-ocean conditions. Samples from the Virgilian Ames-Shumway-Plattsmouth cyclothem show a progression of δ¹³C and δ¹⁸O enrichment moving west from near the Appalachians (1.9% and -3.8%) to the Illinois Basin (3.2% and -2.4%) and finally to the US midcontinent (4.2% and -1.5%). This is interpreted as the transition from nearshore, terrestrial influence with enhanced organic matter oxidation and lower salinity to well-mixed conditions with normal salinities and potential for seafloor ventilation and upwelling. This is supported by published sediment ΣNd(t) values from the Appalachian Basin (ΣNd(t) = -9) that increase further westward (ΣNd(t) = -6) due to higher influence from the eastern Panthalassa Ocean. Mass balance calculations based on the δ¹⁸O of the brachiopod shells suggest salinities of 25 and 31 psu for the Appalachian and Illinois Basins, respectively, assuming salinities of 34.5 psu for the US midcontinent. Trace element analyses do not show a systematic east-west trend similar to stable isotopes. In both time slices, spiriferids from the intermediately-located Illinois Basin are enriched in Mg/Ca and Sr/Ca relative to those in other basins. This Mg and Sr enrichment in Illinois Basin brachiopods suggests delivery of Sr-rich fresh waters and restricted circulation in that basin.

The New Albany Shale is an Upper Devonian organic-rich gas shale located in the Illinois Basin. A factor influencing gas production from the shale is the natural fracture system. I test the hypothesis that a combination of outcrop and core observations, rock property tests, and geomechanical modeling can yield an accurate representation of essential natural fracture attributes that cannot be obtained from any of the methods alone. Field study shows that New Albany Shale outcrops contain barren (free of cement) joints, commonly oriented in orthogonal sets. The dominant set strikes NE-SW, with a secondary set oriented NNW-SSE. I conclude that the joints were likely created by near-surface processes, and thus are unreliable for use as analogs for fractures in the reservoir. However, the height, spacing, and abundance of the joints may still be useful as guides to the fracture stratigraphy of the New Albany Shale at depth. The Clegg Creek and Blocher members contain the highest fracture abundance. Fractures observed in four New Albany Shale cores are narrow, steeply-dipping, commonly completely sealed with calcite and are oriented ENE-WSW. The Clegg Creek and Blocher members contain the highest fracture abundance, which is consistent with outcrop observations. Fractures commonly split apart along the wall rock-cement interface, indicating they may be weak planes in the rock mass, making them susceptible to reactivation during hydraulic fracturing. Geomechanical testing of six core samples was performed to provide values of Young’s modulus, subcritical index, and fracture toughness as input parameters for a fracture growth simulator. Of these inputs, subcritical index is shown to be the most influential on the spatial organization of fractures. The models predict the Camp Run and Blocher members to have the most clustered fractures, the Selmier to have more evenly-spaced fractures, and the Morgan Trail and Clegg Creek to have a mixture of even spacing and clustering. The multi-faceted approach of field study, core work, and geomechanical modeling I used to address the problem of fracture characterization in the New Albany Shale was effective. Field study in the New Albany presents an opportunity to gather a large amount of data on the characteristics and spatial organization of fractures quickly and at relatively low cost, but with questionable reliability. Core study allows accurate observation of fracture attributes, but has limited coverage. Geomechanical modeling is a good tool for analysis of fracture patterns over a larger area than core, but results are difficult to corroborate and require input from outcrop and core studies. / text

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