IDENTIFYING THE POINT PLEASANT FORMATION’S CONDENSED INTERVALS WITH XRF CHEMOSTRATIGRAPHY

The Point Pleasant Formation is a major unconventional drilling target in eastern Ohio; however, obstacles arise from its highly variable total organic carbon (TOC). This research focuses on mapping the organic-rich condensed intervals (CI) of seven wells, using a sequence stratigraphic framework. The Point Pleasant Formation is problematic for traditional methods of sequence stratigraphy, due to the complex nature of mixed carbonate-siliciclastic systems and a lack of distinct facies changes within the monotonous section. These issues have been circumvented with the use of geochemical analyses. Relative elemental abundances are measured with a handheld X-ray fluorescence (pXRF) spectrometer. Strata displaying unique geochemical trends have been grouped into chemofacies. The trends observed come from proxies for terrigenous sedimentation (Ti, Zr and Rb), marine sedimentation (Ca and Sr), clay sedimentation (Al and K), upwelling (P), pyrite minerals (Fe and S) and biogenic quartz (Si/Al). The chemofacies present in the core suggest the presence of Lowstand Systems Tract (LST), Transgressive Systems Tract (TST) and the Highstand Systems Tract (HST). Condensed intervals are associated with the end of the Transgressive Systems Tract (TST) and capped by the Maximum Flooding Surface (MFS). Two cores and wireline logs of seven wells from eastern Ohio, donated by EMF Geoscience Inc. and Artex Energy Group LLC, are used to demonstrate that this pattern is mappable and laterally reproducible. Identifying sequence stratigraphic surfaces, along with the log and core analysis, will create a framework to identify the CI in the two wells with core and to predict the CI in the remaining five wells without core.