Net thickness of the radioactive shale facies in the Huron and Chagrin members of the Ohio shale

The net thickness of radioactive shale is determined by first establishing a normal base line for each well based upon the gamma ray log response of shale units, such as Bedford, Chagrin, and certain units within the Olentangy, observed to be fairly consistently radioactive. Radioactive shales are then defined as those shales having a gamma ray response 20 API units or more to the right of the shale base line. The combined thickness of beds reaching the radioactive shale threshold value is reported as the net thickness of radioactive shale facies within the mapping unit