The Problem of Coring by Barrel Drilling on Rotary Drilling Rig

The barrel drill is a special drilling tool. By cutting a ring groove, the core can be broken by a punch or a screw bit.

Due to the different welding and cutting rings, the drill is divided into CB-I, CB-II, CB-III, CB-IV four kinds.

Operation notes: when drilling is full, you can lift the drill, and it must be slow when lifting the drill, because the drill has an internal exit edge, and the core or large drifter may be removed without coring the drill, if not, it is normal, because it mainly forms a cutting free surface for the sand bailer or spiral drill to drill.

It is difficult to drill directly with auger bit or rotary bit in hard bedrock, large drifter layer and hard permafrost layer, so it is necessary to drill with auger bit and sand bailer bit. It is divided into coring annular cylinder bit and non-coring annular cylinder bit. According to the different strata drilled, it can be divided into truncated ring drill bit for weathering bedrock and permafrost drilling and cone ring drill bit for hard bedrock drilling. The structure characteristics and principle of coring ring cylinder drill: the bucket body is divided into two layers of inner tube and outer tube, the main cutter is welded on the outer tube, the auxiliary cutter is welded on the inner tube, and the lower end of the inner tube is equipped with a hinge supporting the core.

When drilling, the core will open the hinge sheet into the pipe, and when lifting drilling, the hinge sheet will block the core in the inner pipe by its own weight in the horizontal position, and the core will be taken out of the hole. Structure characteristics and working principle of non-coring ring drill bit: the cutting teeth are welded directly in the lower part of the drill barrel. During drilling, the barrel drill first drills the formation ring into a cylinder, and then the spiral drill is lowered to break the round core into pieces, and then the sand hopper is used to fish out the pieces.

Operation notes: when drilling is full, you can lift the drill, and it must be slow when lifting the drill, because the drill has an internal exit edge, and the core or large drifter may be removed without coring the drill, if not, it is normal, because it mainly forms a cutting free surface for the sand bailer or spiral drill to drill.