1St Overlying Aquifer I 5.0 X Lo-'" I
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Edward Mehnert, Craig . Gendron, and Ross D. Illinois State Geological Survey Final Report Prepared for United States Environmental Protection Agency Office of Drinking Water David Morganwalp, Project Officer EPA Cooperative Agreement No. CR-813508-01-0 and Hazardous Waste Research and Information Center Department of Energy and Natural Resources Jacqueline Peden, Project Officer ENR Contract No. HWR 86022 1990 ENVIRONMENTAL GEOLOGY 135 HWRlC RR 051 ILLINOIS STATE GEOLOGICAL SURVEY Natural Resources Building 615 East Peabody Drive Champaign, Illinois 61820 HAZARDOUS WASTE RESEARCH AND INFORMATION CENTER One East Hazelwood Drive Champaign, Illinois 61820 C INVESTlG 8 TE ctural Def init he or Long-Term Injection ypothetical Conduits ory and practical application sf S DIX B Reduction and analysis of geophysical lo APPENDIX C Bnrcite formation: proposed mechanis APPENDIX D Sensitivity analysis iii Location of investigation site Generalized areal geology of the bedrock surface Generalized statewide cross sections of Illinois Description of rock units and their hydrogeologic roles Geologic structures in lillinois Seismic risk map for Illinois Earthquake epicenters in Illinois Oil and gas fields of the Illinois Basin Location of underground gas storage projects in lllinsis Generalized thickness and distribution of the Cross section from Rockford to Cairo showing position of base of the USD Generalized thickne distribution of the Hunton Supergroup and the TDS boundary for U Generalized thickness and distribution of the New Albany Gr Generalized thickness and TDS boundary for USD Geologic column for the injection system at Stratigraphic correlation utilizing resistivity I outhwest -northeast cross section 28 Qualitative permeability correlation utilizing permeability indicator logs for southwest-northeast cross section Stratigraphic correlations utilizing resistivity logs for north-south cross section Structure contour map of the top of the Lingle Formation in the vicinity of the Velsicol plant lnjection system in WDW2 indicating permeable and impermeable units delineated with available geophys Injection system in WDW2 indicat le and impermeable units delineated after ph Injection system in ating permeable and impermeable units delineated after ph Core locations for WDW2 Core permeabilities (air and water) versus depth for WDW2 Core permeabilities versus core porosities for WDW2 Unit locations for WDW2 Water level record for the Devonian Observation Well (DOW), inclu data from injection test Plot of data used for Cooper-Jacob analysis Schematic for WDW2 Schematic for DOW Relationship between waste viscosity and specific gravity The compressibility of water and various NaCl solutions versus temperature Comparison of model-predicted drawdowns with results from Theis analysis Comparison of model-predicted drawdowns versus time with Hantush analysis Conceptual model 1 of the injection system Comparison of model-predicted Ah versus field data Head buildup versus radial distance for q = 1.82~1 m3/sec lnjection scenario 1 : head buildup and decline with time at the DO lnjection scenario 2: head buildup and decline with time at the DO lnjection scenario 2: head buildup and decline with time at WD Conceptual model 2 of the injection system hysical logs run in the DO physical logs run i formation characteristics Fluid loss percentage calculated from CSFL Gore location and analysis Results of core analysis Summary of hydrogeological data for a portion of the disposal zone Additional hydrogeological data for primary injection sections Selected chemical and physical properties of water injected during injection test Volume injected into W2 during injection test Analysis of injection Selected parameters for fluids injected via Chemical analysis of waste an Compressibility of waste and brine lnput data far the Theis solution lnput data for leaky aquifer simulation Selected input data for model calibration Comparison of transmissivity (T) and storativity (S) values Permeability of the microannulus Data from geophysical logs run in the DO Data from existing geophysical logs run in WDW2 Summary of important formation characteristics Core p~rositiesand brucite concentration Effect of brucite concentration on total flow Effect of boundary conditions on head buildup Printed by authoriv of the State of ll/inois/1990/1000 vi Ivi cal rati ss sts de 16) I ir tireless assis not . Cahill, Beverly S logical Survey (IS % the core, waste strea Evans, ISGS, for csmpilin IC wastes. r the U.S. Envirsn ency, for his assis- roject manager, and sistance and patience during this rian Visocky, Illinois State Water Survey, for his a se, Bruce R. Hensei, Timothy Larson, Janis D. Tre S,for their insighfful review of vii numerical modelin study was conducte tigate the hydraulic effects of liquid waste in- jection on an injecti system. The site in was a chemical refinery with an operational Class I well and an ell, both completed in Devonian limestone. Input data for the model were obtained from available records and field investigations. The regional geologic investigation indicated that the injection system (defined here as the injec- tion zone and its associated confining units) was laterally continuous. The hydraulic response of the injection system was numerically modeled under two injection scenarios: average historical in- jection rate and maximum average permitted rate. For both scenarios, pressure buildup from ste injection during the simulated 30-year injection and 30-year postinjection periods did not ap- proach the pressure calculated to be necessary to initiate or propagate fractures in the injection system. Therefore, injected waste would be contained, and waste injection at this site and for the scenarios modeled would not endanger human health or the environment. This analysis assumes that hydraulic conductivity remains constant; however, the formation of brucite within the injection zone may invalidate this assumption and the preceding analysis. Brucite formation within the injection zone requires additional study. The model was also used to investigate the response of the injection system when a hypothetical conduit was introduced. This hypothetical conduit connected the uppermost injection zone with an overlying aquifer. Differences in head buildup were not monitorable in the injection well or in an observation well completed in the injection zone. onitorable head differences were observed only in the overlying aquifer, when the hydraulic conductivity of the hypothetical conduit was greater than or equal to 1x1 0-lo m2. viii Concern over the po water contamination from waste injection prompted faceted research eff US. Environmental Protection Agency (USEPA) an dustry. The research with data needed to determine if underground injection sf hamardou an health or the environment. One facet of this re- search effsat was an investigation of the hydraulic effects of deep-well injection on the injection system. The injection system includes the geologic units constituting the injection zone and the upper and units. The site of this investigation as a chemical refinery in Illinois that has an ction well and an observation well complete in Devonian limestone. ld be conducted, a hydrogeologic description of the site was developed from available records and geophysical logs. umerous records and logs were avail- able from oil- and gas-related tests and wells within a 10-mile radius of the site. Logs and records for on-site wells were also used. In addition, hydraulic tests and geophysical logs were run to obtain detailed hydrogeologic data on the injection system. TWOhydraulic tests ere run in the injection well: a continuous spinner flowmeter survey and a 15-day injection test. Sidewall cores were also retrieved from the injection well. The following geophysical logs were run in the observation well: Compensated Neutron Log, Borehole Compensated Sonic Log, Minilog, Dual Induction Spherically Focused Log, and Gamma Ray Log. Although analyses of the data from these logs and tests yielded much information concerning the hydrogeologic character of the injection system, there was one discrepancy-the results of the spinner flowmeter indicated that the waste was flowing through different zones of the injection sys- tem than had been theorized from the results of geophysical logging. To clarify this discrepancy, we conducted additional analyses (x-ray diffraction and scanning electron microscopy). The dis- crepancy can be explained briefly as follows. Because of its high pH, the injected wastewater g2+present in the injection zones or in solution, forming brucite ( Brucite accumulation reduces the permeability of the injection zone. Greater amounts of brucite apparently formed in the injection zone where the flow of fluid was greater; thus the zones with higher permeability were affected first. dditional work beyond the scope of this project is needed to verify the brucite-formation hypothesis. Also, the long-term effect of this decrease in per- meability on injectivity needs to be investigated. A description of the regional and site-specific stratigraphy, structural geology, and hydrogeology of the injection system was generated from a review of available data and the field work con- ducted during this project. This description formed the basis of input for the numerical model. Model input also included data on the physical and chemical characteristics of the injected waste- water and the native brine in the injection system. These data were employed as input data for