May Luncheon - Maxwell Pommer, Stratoscope Geologic

Stratigraphic, petrographic, geochemical, and petrophysical data from a core in the Central Basin region of the Uinta Basin indicate abundant hydrocarbon-saturated reservoir porosity in lower Green River Formation organic-matter(OM)-rich and OM-bearing mudrocks. Poresystems in these rocks are interpreted to have evolved with variable detrital and near-surface diagenetic components and fabrics overprinted by differential burial diagenesis into the oil window (mean Ro=0.97). The core spans ~1,100ft of section from the Castle Peak Shale to the Lower Garden Gulch. It is comprised predominantly of cyclically interbedded: 1) sandstones and sandy conglomerates, 2) OM-lean siliciclastic mudrocks, 3) OM-bearing and OM-rich siliciclastic mudrocks and argillaceous conglomerates, and 4) OM-bearing and OM-rich carbonate mudrocks and intraclast rudstonesfloatstones. Substantial pore volumes occur in sandstones and sandy conglomerates (mean=8.8%), as well as OM-lean siliciclastic mudrocks (mean=9.9%), predominantly comprised of clay-hosted and interparticle micro/nanopores, however these tend to be water-saturated (mean=63.5 and 75.3% respectively). OM-rich and OMbearing siliciclastic mudrocks and argillaceous conglomerates contain variable amounts of interparticle & clay-hosted micro/nanopores, as well as OM-hosted nanopores. Measured pore volumes range from 5.2% to 13.6% (mean=10.1%), and hydrocarbon saturations range from 3.2% to 84.2% (mean=43.2%). OM-rich and OM-bearing carbonate mudrocks and intraclast rudstones-floatstones host variable amounts of interparticle and intercrystalline micro/nanopores as well as OM-hosted nanopores. Measured pore volumes range from 3.4% to 15.0% (mean=8.2%), and hydrocarbon saturations range from 19.3% to 94.1% (mean=63.8%). Pore volumes are, on average, higher in OM-rich and OM-bearing siliciclastic mudrocks than carbonate mudrocks, however hydrocarbon saturations and volumes of hydrocarbon-saturated porosity are higher in carbonate mudrocks (mean BVHC=4.4% for siliciclastic mudrocks and 5.2% carbonate mudrocks).