Chisel Bit DTH Drill Rods / Water Well Drill Rods With 42mm - 114mm Hole Diameter

Causes of drill pipe fracture of drilling rig

The main causes of drill pipe fracture are:

1, The bending moment of drill pipe is too large during reaming and pipeline pullback;

2, The causes of excessive bending moment are as follows: first, the actual curve of the guide hole deviates greatly from the theoretical curve; Second, the hole after reaming is irregular, which makes the pipe form an angle with the reamer and the drill pipe axis.

Other reasons:

1, In order to save investment, the directional drilling equipment used by the construction contractor (i.e. Party A) does not match the actual needs of the project construction. The tonnage of the directional drilling equipment is too small, the maintenance is not timely, and the failure rate is high, which makes the directional drilling force uneven. At the same time, the stop and go construction makes the hole forming quality poor, the hole irregular, the drilling tool is easy to lock, resulting in the fracture of the drill pipe;

2, The selection of reamer model is unreasonable. Failure to select the matching rule model according to the actual geological conditions, resulting in increased drilling torque, increased drill pipe wear and fracture;

3, When the rock reamer reams or cleans the hole, the drill pipe is not connected at the back, and the reamer swings greatly in the hole, which may cause the drill pipe and the main shaft of the reamer to break;

4, The selection of drill rods is unreasonable. Due to the lack of tracking and management of drill rods and the lack of drill rod detection data statistics, the life of a set of drill rods used is not uniform, and the drill rods with large wear are broken due to stress concentration;

5, The deviation control of the guide hole is unreasonable and the deviation is too large. During the later correction process, the actual curve is unreasonable, and the bending moment borne by the drill pipe is too large, which may easily lead to the increase of the drill pipe stress or the fracture of the drill pipe surface due to the excessive friction force. In particular, the drill pipe joint bears a high eccentric friction force, which causes a large amount of heat to be generated during the periodic contact friction with the hole wall, so that the surface material of the joint is subject to periodic heating and cooling, The surface becomes brittle, and the longitudinal crack of the internal thread of the drill pipe joint is caused under the influence of the excessive bending moment;

6, The reaming classification is unreasonable. The construction unit reduces the reaming classification in order to speed up the construction period, which greatly increases the drilling torque and easily leads to the increase of drill pipe wear and fracture;

7, Because the geological conditions are not ideal, the holes are broken and collapsed, and the drilling cuttings are too much, which makes the anti lock ability of the drilling tool low and the locking risk increased, resulting in the fracture of the drill pipe