We are conducting an integrated study, including reservoir characterization, geomodel building, and reservoir simulation, of three Midcontinent karst-modified reservoirs: the Permian San Andres in west Texas, the Mississippian Spergen in Colorado, and the Ordovician Arbuckle in Kansas, in order to address our project goal of developing innovative seismic-based workflows for the incremental recovery of oil from karst-modified reservoirs within the onshore continental United States. During this third reporting period, from October 1, 2005, through March 31, 2006, we have made significant progress in reservoir characterization for our three study areas and have developed a workflow for geomodel building. Our primary focus for the San Andres and Mississippian study areas has been to estimate key petrophysical parameters from core and log data and make seismically-based interpretations of reservoir compartment boundaries and vertical fluid conduits for input into reservoir geomodels. For the Arbuckle study area, we have characterized karst geomorphology on a regional scale, since different terrains exhibit differences in oil productivity. We have also used geostatistical analyses of the 3-D seismic data to predict the probability of untapped remnant Arbuckle highs between existing wells in areas where there is no seismic data.