John Rupp Dr. Poul Emsbo, US Geological Survey
Dr. Thijs Vandenbroucke, U. Ghent, Belgium
Julie De Weirdt, PhD student, U. Ghent, Belgium
Indiana University - Indiana Geological & Water Survey
||: The Maquoketa Group has the potential to serve both as an unconventional reservoir and as a seal for fluid storage in the Illinois Basin. However, the current state of knowledge about the characteristics of this interval across the basin is rudimentary. Recent preliminary chemostratigraphic analysis suggests that the organic-rich (1-3% TOC) shale facies of the Maquoketa Group in the Illinois Basin is restricted to a small number of unconformity bound stratal packages with varying spatial domains. The current depth distribution of these strata in the basin, their organic maturation in relation to depth/temperature gradients and hydrothermal fluid flow, and other petrographic qualities will yield insights into their potential for future hydrocarbon development. No major petrographic or sequence stratigraphic studies have been completed on the Maquoketa in this area. Preliminary work by Gray (1972), Rupp (1989), Hohman (1998) and Guthrie (1994) provide some baseline data, but lack chronostratigraphic context. Further, while significant petrophysical and geomechanical assessments of sealing capacity have been conducted on the Eau Claire Formation and, to a lesser extent, on the New Albany Shale, the Maquoketa has not been evaluated in this regard. Large volume fluid injection and storage for both CO2 and co-produced (with gas) brine will potentially rely on the physical and chemical integrity of this unit to serve as a confining unit overlying storage reservoirs in the underlying carbonate rock sequence.
||This project will establish the age and petrophysical characteristics of the various lithofacies present with the Maquoketa Group in the Illinois Basin. Such an evaluation will begin to approach the challenges of establishing if the organic-rich facies are time-specific or diachronous, and understanding the physical and chemical characteristics of the various rocks types present in the interval. The information gleaned in the proposed study could have a substantial influence on future exploration of unconventional reservoirs and for effective seals.
Specifically, we seek to: 1) characterize the elemental composition of Maquoketa units along multiple cross-basin transects, 2) establish the relative ages of these units, 3) integrate elemental and geophysical data sets of time-rock units to generate basin-wide isopachs 4) combine new organic carbon analyses with previously published reports to characterize oil and gas production potential of each unit and 5) characterize the pore size distribution, capillary entry pressures, and strengths of a select set of lithofacies that represent the stratigraphic interval .
||This project will draw from the broad expertise and collaborations of several IGS staff. We will characterize several Maquoketa stratigraphic units/facies through pXRF elemental analysis. The age of these units will be assessed in Indiana and Illinois through C-isotope and conodont analysis of representative sections. Integration with existing geophysical datasets will occur in Petra drawing on over 200 digitized logs. Organic matter characterization will be accomplished through rock-eval pyrolysis and biomarker analysis of a select suite of samples. Pore system and geomechanical characterization will be conducted using both in house analytical capabilities and as well as outside commercial laboratory analyses.
||We anticipate a short paper to be submitted to AAPG Bulletin and application for external funding from the American Chemical Society Petroleum Research Fund and the National Science Foundation.
||Significant knowledge gains about the relative age and physical character of the Maquoketa Group will advance efforts in regional petroleum exploration and carbon sequestration. Additionally, the Maquoketa project brings together several IGS research staff in a collaborative study for the first time and will lay the ground work for future collaborative works.