Repulsing clays on drill bits

Abstract

Bit balling is prevented by impressing a negative electrical charge on the drill bit by the use of bi-metallic electromotive potential differences, batteries or other electrical energy sources.

What is claimed is: 
     
       1. Process for drilling wellbores in earth formations containing materials which attach to the drill bit and drill collars comprising: positioning a metal with a substantially higher electromotive force than the drill bit at a point in the drill string directly adjacent the drill bit and between the drill collars and the drill bit for impressing a negative electrical charge on the drill bit during such time as the attaching materials are being drilled. 
     
     
       2. The process of claim 1 wherein the high electromotive force metallic member is an annularly shaped magnesium metal which is press fit on a conventional drill bit sub. 
     
     
       3. A process for drilling wellbores through a sticking shale earth formation comprising: applying a rotating drill bit to the formation; and impressing a negative charge to the drill bit while drilling through the shale formation by locating directly adjacent the drill bit a metal having a higher electromotive force than that of the drill bit. 
     
     
       4. Apparatus for drilling through earth formations having a high concentration of fine materials including clays comprising: a drill bit .Iadd.having teeth.Iaddend.; drill pipe attached to the drill bit and extending to the surface; and means for impressing a negative charge on the drill bit, said impressing means being a metal which is located between the teeth on the drill bit .Iadd., said metal including magnesium.Iaddend.. .[.5. The apparatus of claim 4 wherein the metal includes magnesium and is located between the teeth of the drill bit..]. 
     
     
           A method for preventing the attachment of certain materials to a drill bit when drilling through earth formations having a high concentration of materials which attach to the drill bit comprising: positioning a metal member with a higher electromotive force than the drill bit in the drill string directly adjacent the drill bit and below drill collars in the drill string, rotating the drill string, and applying the rotating drill 
     
     
        bit to the formation. 7. The method of claim 6 and further including positioning the metal member in the drill string by press fitting an 
     
     
        annular metal sleeve on the drill bit sub. 8. Apparatus for preventing the attachment of certain materials to a drill bit when drilling through earth formations having a high concentration of materials which attach to the drill bit, including: a drill string extending to the surface and having drill collars and a drill bit at its lower end; means .Iadd.including a metal member having a higher electromotive force than said drill bit .Iaddend.positioned in .[.the.]. .Iadd.said .Iaddend.drill string below .[.the.]. .Iadd.said .Iaddend.drill collars for impressing a negative charge on .[.the.]. .Iadd.said .Iaddend.drill bit. .[.9. The apparatus of claim 8 wherein the impressing means is a metal member having a higher 
     
     
        electromotive force than the drill bit..]. 10. The apparatus of claim 8 wherein the impressing means is a magnesium sleeve press fitted on the drill bit sub.