Pre-frac pressure analyses were done on the Oriskany or Huntersville Chert/ Oriskany combination in wells located in Ohio and Pennsylvania. The pre-treatment pump-in tests were designed to pump several thousand gallons of chemically treated fresh water at multiple pump rates. Upon pump shutdown at the end of this "mini-frac", the wellhead pressure decline was monitored for an extended time period. Using a commercially available computer software program, the pump rate vs. pressure data and the pressure decline data were analyzed. Pressure decline analysis incorporated a Horner plot for reservoir pressure and permeability along with regression analyses including the Nolte G Function to identify normal leak-off or pressure dependent leak-off and fracture height recession.

Subsequent to the above analyses, hydraulic fracturing treatments were performed on the wells. The treatment designs were tailored to each individual well incorporating the information obtained from the mini fracs about reservoir properties and hydraulic fracture behavior. Use of a Net Pressure Plot of the fracturing treatment was used to validate leakoff behavior identified in the mini fracs.

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