Cap Rock A poorly permeable or impermeable layer that overlies a geothermal reservoir. The term is borrowed from the oil industry and was once considered an essential feature of a producing...

Casing Shoe In geothermal wells, this is the bottom of the cemented casing string. Below the casing shoe, the well may be unprotected and open to the surrounding rock or lined with a...

Cement Bond Log A geophysical well log that is obtained using a sonic-type tool on a wireline. The result helps to confirm the integrity of the hardened cement that was injected to form a...