Wildcat Drilling: One Chance in Twenty (OG-16)
A wildcat well is one drilled for petroleum not known to be oil bearing. Today the term applies to wells drilled 1 to 2 miles from existing production or to find deeper pays in existing oil and gas fields. The name originated in the early Pennsylvanian oilfields, when night-drilling crews would hear wildcats howling. The worlds oil needs were supplied for 60 years largely by random drilling at shallow depths in favorable areas. A na shallow well occasionally came in with such production that it paid for itself in a day. That could and did happen many times. But it is uncommon now. Today oil is hard to find, and drilling often goes to great depths. A wildcat well drilled on land in the United States is considered to have about 1 chance in 9 of being a producer, 1 chance in 20 of finding petroleum in paying quantities, and 1 chance in 50 of finding a million barrels of oil or its equivalent in natural gas.

Our Hoosier State Beneath Us: Oil and Gas