| The Ferron Sandstone (Cretaceous) of east-central Utah is a significant reservoir rock for a prolific gas play in the region. Three facies are present in core of the sandstone. Coarsening upward sequences of laminated shale and siltstone that grade upward to horizontally laminated fine-grained sandstones make up the delta front. Coal, carbonaceous shale and oyster coquina make up the delta plain environment, and massive sandstone bodies represent a shallow shelf environment. Ichnofacies seen in core range from high energy beach sandstone (Skolithos) to low energy, mud-rich marsh deposits ( Thalassinoides). Several zones within the sandstone have high porosity, but most of the primary porosity has been filled by calcite cement. Partial dissolution of the calcite cement has created porous zones. However, the cement has restricted pore throats making the effective porosity low. |
