During drilling process. LB type junk sub is applied mainly for fishing of shivers and fallen objects such as carbide tooth. drill bit and bearing which cannot be carried out of hole by conventional fluid circulation, etc. It possesses important functions to keep hole cleaning increase bit service life reduce and prevent drill bit from unexpected damage. The tools are available with all sizes and super performance.
Overturn plank overshot is used to fish small diameterpipe with that fishing head is upset or pumping collar in ig annulus such as good rumping downhole instrument with upset up.