Wellbore drill bit having shear cutters and gouging cutters

Abstract

A fixed cutter drill bit includes a bit body and at least one primary blade formed in the bit body and defining a surface profile on the bit body. The at least one primary blade extends from a first selected radial distance from a center or rotation of the bit body to a gage portion. At least one shear cutter affixed to the at least one blade. At least one gouging cutter affixed to the bit body rotationally ahead of the at least one blade. At least one nozzle is disposed in the bit body in a rotational position between the at least one primary blade and the at least one gouging cutter.

What is claimed is: 
     
         1 . A fixed cutter drill bit, comprising:
 a bit body;   at least one primary blade formed in the bit body and defining a surface profile on the bit body, the at least one primary blade extending from a first selected radial distance from a center or rotation of the bit body to a gage portion;   at least one shear cutter affixed to the at least one blade;   at least one gouging cutter affixed to the bit body rotationally displaced from the at least one blade; and   at least one fluid orifice disposed in the bit body in a rotational position between the at least one primary blade and the at least one gouging cutter.   
     
     
         2 . The fixed cutter drill bit of  claim 1  further comprising at least one secondary blade formed in the bit body and circumferentially spaced apart from, the at least one secondary blade extending from a second selected distance from the center or rotation and extending radially to a gage portion, the second distance greater than the first distance. 
     
     
         3 . The fixed cutter drill bit of  claim 2  further comprising at least one shear cutter on the at least one secondary blade. 
     
     
         4 . The fixed cutter drill bit of  claim 2  wherein the at least one secondary blade defines a surface profile located at a selected distance less extensive along a longitudinal dimension of the bit body than a corresponding surface profile defined by the at least one gouging cutter. 
     
     
         5 . The fixed cutter drill bit of  claim 2  wherein the at least one secondary blade comprises at least one shear cutter thereon, the at least one shear cutter on the at least one secondary blade defining a surface profile located at a selected distance lower along a longitudinal dimension of the bit body than a corresponding surface profile defined by the at least one gouging cutter. 
     
     
         6 . The fixed cutter drill bit of  claim 1  wherein the at least one shear cutter on the at least one primary blade defines a surface profile located at a selected distance lower along a longitudinal dimension of the bit body than a corresponding surface profile defined by the at least one gouging cutter. 
     
     
         7 . The fixed cutter drill bit of  claim 1  wherein the at least one shear cutter comprises a polycrystalline diamond compact cutter. 
     
     
         8 . The fixed cutter drill bit of  claim 1  wherein the at least one gouging cutter comprises a tungsten carbide insert. 
     
     
         9 . The fixed cutter drill bit of  claim 1  wherein the at least one shear cutter is disposed at a radial distance from a center of rotation of the bit body less than a gage diameter defined by the bit body.