{"name":"Herley David F Drilling Activity in Jefferson County, Illinois","publisher":"Buckhead Energy","url":"https://www.buckheadenergy.com/operators/herley-david-f/illinois/jefferson-il","license":"https://creativecommons.org/licenses/by/4.0/","dataAsOf":"2026-08-06","source":"Public state oil & gas well-header records (permits, spuds, completions).","operator":"Herley David F","operatorSlug":"herley-david-f","state":"IL","county":"Jefferson","totalWells":96,"producingWells":0,"permits24mo":0,"spuds24mo":0,"ducCount":0,"topFormation":null,"rankInCounty":5,"firstPermitDate":"1970-01-01","lastPermitDate":"1993-04-21"}