Diamond drag bit for soft formations

A drag bit for relatively soft earth formations, said drag bit forming a body having a first opened pin end and a second cutting end, said pin end being adapted to be threadably connected to a mud transporting drill string, said cutting end of said drag bit body comprising;

• a drag bit face, at said cutting end of said bit, said face containing at least one rounded projection extending from said face, said rounded projection extending from said face is a tungsten carbide insert having a first base end and a second cutting end, said second cutting end being a rounded, dome shaped polycrystalline diamond bonded to said tungsten carbide insert;
• said face further containing at least one cutter insert projection spaced from said rounded dome shaped insert projection and positioned substantially in a trailing location behind said at least one rounded insert projection, said at least one trailing cutter is an insert having a first base end and a second cutting end, said second cutting end forms a cutting edge with a positive rake angle with respect to said borehole, said cutting edge substantially faces the direction of rotation of said drag bit, said trailing cutter projection serves to cut off the earth formation moved aside by the leading rounded projection when said drag bit is rotated in the earth formation thereby advancing the drag bit to further penetrate a borehole formed in said formations;
• and
• at least one nozzle formed in said drag bit face, said nozzle serves to direct said mud toward a borehole bottom formed in said earth formation and across said drag bit face thereby removing detritus from the borehole bottom and cooling and cleaning the drag bit face.