A Study on the Origins of Permeability within the Point Pleasant Formation, Eastern Ohio
The Point Pleasant Formation has been at the forefront of unconventional drilling in eastern Ohio, owing to its high total organic carbon (TOC) content and brittleness due to abundant calcite. For this research, EMF Geoscience, Inc. and Artex Energy Group have provided two cores and seven wireline logs for wells in eastern Ohio. The study area spans Noble, Muskingum, Guernsey, Coshocton, and Tuscarawas Counties. Within this region, the Point Pleasant Formation has two prominent high resistivity zones that have an epicenter in Muskingum County and fade away to the east, south and west. These zones display a significant separation between the shallow and deep resistivity logs; traditionally, this separation indicates that the formation is permeable enough for drilling fluids to infiltrate. The Point Pleasant Formation is retrogradational but does display some coarsening upward intervals, potentially representing parasequences. The upper high resistivity interval coincides with one of the coarsening upward sequences and is apparent in both the Muskingum County and Noble County cores. These sequences coarsen upward from unfossiliferous black mudstones to a skeletal packstone with thin mudstone laminations. Preliminary investigations reveal three possible theories for the separation. Bedding planes are increasing the permeability, organic porosity has enhanced permeability and finally, preserved primary porosity or developed secondary porosity of the carbonates have interconnected the pores. These ideas are based on computed tomography scans and positive correlation between porosity and TOC. Further studies will focus on organic matter microscopy and elemental chemostratigraphy. The results of this research will better our understanding on the controls of porosity and permeability within the Appalachian Basin and other unconventional reservoirs.
AAPG Datapages/Search and Discovery Article #90373 © 2019 AAPG Eastern Section Meeting, Energy from the Heartland, Columbus, Ohio, October 12-16, 2019