Rig count does not tell the whole story of oil and gas exploration and development. It is certainly a good measure of activity, but it is not a measure of success.
After a well is drilled it is either classified as an oil well, natural gas well or dry hole. The percentage of wells completed as oil or gas wells is frequently used as a measure of success. In fact, this percentage is often referred to as the success rate.
Immediately after World War II 65 percent of the wells drilled were completed as oil or gas wells. This percentage declined to about 57 percent by the end of the 1960s. It rose steadily during the 1970s to reach 70 percent at the end of that decade. This was followed by a plateau or modest decline through most of the 1980s.
