The Cavern Tool was developed as a mechanical means to enlarge well bores. The volume of a well bore grows exponentially with its radius, but to drill a large well bore the entire depth of a well is extremely costly. So it makes sense to enlarge or underream the well bore only where it will do the most good – through the productive zone. Standard size well bores and even those conventionally underreamed to twice the diameter of their casing have only slight increases in open surface area and often have static fluid levels providing only a few barrels to less than a barrel of total well bore volume. The Cavern Tool, however, cuts a diameter many times the casing size, which equates to large increases in open surface area and well bore volume increases in the order of 10 fold, 100 fold or more. From coal bed methane wells to low pressure wells, to heavy oil wells or simply old wells needing deposits or skin damage removed, the Cavern Tool is a simple, low cost solution. Whether a new well or a workover, the Cavern Tool can: Increase Borehole Volume Exponentially ,Open Coal Seams or Tight Formations ,Increase Rock to Well Bore Interface ,Open Cavern for Horizontal Drilling ,Remove Cement From Fractures ,Stop Sand and Fines Production ,Underream Below Tight Spots ,Increase Sump Exponentially ,Remove Formation Damage ,Help to Avoid Water Legs ,Intersect More Fractures ,Clean Inside of Casing ,Increase Flow Rates