Exploratory drilling decreased very slightly in Oklahoma during 1952, while development drilling was much greater than in 1951. No major fields were discovered last year, but the average initial potential of both discovery and development wells was greater than in the previous year. The average exploratory well for 1952 was 504 feet deeper than in 1951. Over-all reserves were increased due to accelerated development drilling and a continuing increase in secondary-recovery projects. The latter probably accounts for five to six per cent of total oil produced in Oklahoma.