ISGS - September 2004 Activity Highlights
ISGS - September 2004 Activity Highlights
Waterloo Homeowners Seek Cause of Localized Soil Subsidence
In the Lakewood Estates subdivision in Waterloo, Illinois, two houses have suffered significant damage from localized subsidence of the soil beneath their foundations. Geologists mapped lineaments and fractures in and around the houses, and geophysicists ran a shear-wave seismic reflection profile using the land streamer and a resistivity survey to try to determine the underlying cause of the problem. The studies provided strong evidence that a cave in limestone had collapsed, disrupting the overlying sandstone that forms the bedrock surface. The geophysical data show what appear to be large crevices in the bedrock surface that are the focal points for continued sapping of the soil beneath the houses. The sandstone is a significant aquifer for the area, and enhanced withdrawals may be creating strong currents in the crevices that are carrying away the soil. A report explaining the scientists' findings was presented to the homeowners. (Contacts: S. Panno, T. Larson)
New Geoscience Educational Series Publications Discuss Natural Resource Issues
Three new publications discuss geological perspectives on groundwater resources, land-use decisions, and the Illinois Caverns State Natural Area. In Illinois Groundwater: A Vital Geologic Resource, authors Myrna M. Killey and David R. Larson explain how the geology of Illinois affects the availability and quality of groundwater from place to place. The influence of local geologic factors on groundwater availability, the potential for groundwater contamination, and hazards and the proper use of geologic mapping in making informed land-use decisions are reviewed in Land-Use Decisions and Geology: Getting Past "Out of Sight, Out of Mind" by Myrna M. Killey and Richard C. Berg. In Guide to the Illinois Caverns State Natural Area, authors Samual V. Panno, Sallie E. Greenberg, C. Pius Weibel, and Patricia K. Gillespie describe the significance, origin, and evolution of the natural features of Illinois Caverns and the sinkhole plain area of southwestern Illinois. (Contacts: authors)
ISU Students and ISGS Interns Continue Study Begun with IBHE Funds
Data acquisition continued on a joint project with ISU at NiCor's Troy Grove gas storage field. ISU students, originally trained through support from the IBHE funding that ended on June 30, have continued to use ISGS seismic equipment and methods to acquire shear-wave reflection data over the gas field. Meanwhile, a second crew led by ISGS interns Sarah Mueller and Mike Welch acquired several miles of P-wave data in the same area. The projects, now funded by a grant from NiCor, are investigating whether there is a relationship between reports of leaking gas and shallow geologic structures. The preliminary results from the studies show structures in the shallow bedrock that may allow gas to escape. (Contact: A. Pugin)
New Technologies Aid in Describing Illinois River Sand and Gravel Deposits
To safely study the sand and gravel deposits in the high wall of an open-pit mine near Lacon, scientists for the first time used a reflectorless total station surveying instrument to accurately measure the thickness and lateral extent of the individual layers of sand and gravel within the sixty-foot-tall face of the pit. ISGS photographer Joel Dexter worked with the scientists to provide extensive documentation of the various types of bedding structures exposed in the pit face and panoramic views of the entire exposure. The study found previously unrecognized unconformities in the sand and gravel layers, indicating at least three separate events depositing sand and gravel. The causes of the separate events here are unknown, although evidence elsewhere indicates that several major floods that originated near Kankakee coursed down the Illinois River during the Wisconsin episode. Further study of sand and gravel sequences elsewhere along the Illinois River valley may help us understand the number and magnitude of the different events. This knowledge could be invaluable in assessing the Illinois River Valley's sand and gravel resources and provide guidance for making resource management decisions. (Contact: C. Stohr)
Coalbed Methane Production and CO2 Sequestration Studies Continue
The ISGS is continuing its work on the federal and state-funded coalbed methane assessment project. Gas desorbed from samples of coal and shale from the Wasem #9 reconnaissance well drilled in southeastern White County contains 80 to 90% methane and higher hydrocarbons, 10 to 15% nitrogen, 2 to 2.5% carbon dioxide, and very small amounts of hydrogen (0.15 to 0.51%). Experts from the Illinois, Indiana, and Kentucky geological surveys have used statistical methods to estimate a probable range of values for permeability, gas content, adsorptive capacity, and other reservoir parameters of Illinois coals for use in the COMET3® coalbed methane/CO2 injection reservoir simulation model. The model is being used to estimate the potential effectiveness of CO2 injection for enhanced coalbed methane recovery and for the permanent sequestration of CO2. The parameters that control CBM production and CO2 sequestration of a particular coal bed are expected to vary with the burial depth and degree of coalification of the coal, so the COMET3® model also is being used to estimate the effects of that variation on CBM production and CO2 sequestration. Several of the important parameters, such as the relative permeability, capillary pressure, and compressibility of Illinois Basin coals, are not well known and have been a source of considerable discussion among the experts. (Contact: S. Frailey)
Geologic Mapping Products Released Online
The Illinois State Geological Survey is pleased to announce the release to the public of thirty-seven online geologic map products. These high-resolution PDF format files can be downloaded from the ISGS Web site. These maps have been published as part of the Illinois Geologic Quadrangle (IGQ) or Illinois Preliminary Geologic Map (IPGM) series or represent early versions of maps delivered to the U.S. Geologic Survey as required for contracts awarded through the STATEMAP appropriation to the National Cooperative Geologic Mapping Program (NCGMP). Most of these maps are published at the standard 1:24,000 scale for 7.5-minute quadrangles and show surficial geology, bedrock geology, or other data. New downloadable maps will be added to the site as they are completed and released. Maps produced through EDMAP, a part of the NCGMP that supports mapping projects by students at Illinois universities, will soon be added to the Web site. High-quality, full-size printed copies of IGQ and IPGM maps also may be ordered directly from the ISGS. The new system significantly increases the public's access to the Survey's growing supply of geologic map products. (Contact: J. Domier)
First ISGS Publications on CD-ROM are Released
The first ISGS books to be released in an electronic-only form are Circular 563, Groundwater Geology of DeKalb County, Illinois, with Emphasis on the Troy Bedrock Valley by R.C. Vaiden, E.C. Smith, and T.H. Larson, and Circular 564, Delineation of the Coalbed Methane Resources of Illinois by I. Demir, D.G. Morse, S.D. Elrick and C.A. Chenoweth. The first report presents findings from a study of the geology and shallow groundwater resources of DeKalb County, with particular emphasis on the sand and gravel aquifers of the glacially derived deposits that fill the buried Troy Bedrock Valley. Several of these aquifers have potential for future development as important new sources of groundwater. The information in this report can help water well drillers and local government officials provide for the water needs of the growing population of the area. The second report presents data on the gas contents, rank, thickness, burial depth, elevation, and cleat directions of major coals in Illinois and the chemical and isotopic compositions of the gas samples and methane isotherm curves released from the coal and black shale samples collected during a drilling program in 2001-2002. The information presented in the report can help producers understand and assess the potential for development of the coalbed methane resources of the state. The publications are being released as CDs, but can also be ordered as books printed on demand either in black and white or in full-color. More information about the publications is available under the new publications section of the ISGS home page. (Contact: authors; C. Nimz)
Midwest Geological Sequestration Consortium Reports Results
The Project Advisory Group (PAG) for the Midwest Geological Sequestration Consortium met on September 15, 2004, in Champaign to review the results of the first year's studies. Among various CO2 capture and separation alternatives that could be used at the more than 100 power generation plants and nearly 40 industrial sites that are major CO2 emitters in the Illinois Basin region, ISGS engineers determined that chemical adsorption with monoethanol amine (MEA) is the most feasible technology for CO2 separation. Industry representatives and consultants in the consortium reported that, for the short-term, truck transport is the most feasible delivery method for field demonstrations of CO2 sequestration but that CO2 pipelines will be needed for long-term sequestration projects. Scientists for the Illinois, Indiana, and Kentucky geological surveys gave progress reports on their work on characterization of the unminable coal beds, oil reservoirs, and deep, saline formations that may be used as CO2 sinks. In addition to estimating the CO2 storage capacity of each sink, the potential for enhanced coalbed methane production and enhanced oil recovery as a consequence of CO2 injection is to be investigated. The PAG represents electric utilities, oil and gas associations, coal mining companies, ethanol plants, agricultural associations, and state and federal agencies. (Contacts: S. Frailey, R. Finley)
Limestone and Dolomite Resources for Power Plant Sulfur Scrubbing Reported to ICCI
Through a grant from the Illinois Clean Coal Institute, the ISGS has created a database on the quality and quantity of limestone and dolomite resources near existing and potential Illinois utility sites in the southern half of the state that will potentially use this material to remove sulfur dioxide from their stack gases. Limestone, primarily suited for use in flue gas scrubbers, is abundant in the southern half of Illinois and adjacent parts of Indiana, Kentucky, and Missouri. Dolomite, which is especially suited for use in fluidized bed combustion systems, is relatively rare in the southern half of Illinois, but substantial dolomite resources occur near the Illinois border in southeastern Missouri. Calculated sulfur reactivities indicate that limestones should be the best sorbents for flue gas desulfurization (FGD) systems. Sulfur reactivities varied among the tested limestones, and the differences seemed to depend on the proportions of typical limestone constituents (fossil fragments, microcrystalline calcite matrix, sparry calcite cement, non-skeletal grains, etc.) in the rock. Sulfur reactivities in fluidized bed combustion (FBC) systems indicated that dolomites are better than limestones for these systems, but the reactivities appear to be highly dependent on the dolomites' crystal size and absorption. Dolomites with the smallest crystal size and greatest absorption rates are the most reactive under FBC conditions. The information from this study will be useful to the utility industry, limestone producers, and government agencies seeking the best scrubbing agents for the FGD or FBC systems to be used at existing or planned coal-fired power plants. (Contacts: Z. Lasemi, S. Koenig, R. Norby, M. Rostam-Abadi)
Tests Continue at Coalbed Methane Production Test Site
In southeastern White County, the ISGS directed the drilling of a new coalbed methane exploration well. The well was drilled to a total depth of 1,030 feet, and the coal- and black shale-bearing sections of the succession were cored, and detailed core descriptions were compiled. Gas desorption tests of the collected samples are in progress, but preliminary results show that most of the coals and one of the shales hold considerable volumes of methane gas.
At the site in northern White County where the coalbed methane production test will be performed, ISGS geologists met with officials of the drilling company and the site operator to discuss a plan and cost structure to allow for comparison tests of well completion and stimulation techniques different from those used by most Illinois Basin coalbed methane operators. (Contact: D. Morse)
Updated 08/08/2012 SLD