Causes and service life of drill pipe fracture

The reason of drill pipe cracking is that the drill pipe is a kind of steel pipe with thread at the tail, which is used to connect the surface equipment of the drilling rig with the drilling and grinding equipment or bottom hole equipment located at the bottom of the drilling. The purpose of drill pipe is to transport drilling mud to the drill bit and to advance, lower or rotate the bottom hole equipment together with the drill bit. The common causes of drill pipe cracking may be as follows: 1. After long-term use, the drill pipe has more external damage, approaching or exceeding the fatigue life; 2. During operation, the drill bit encounters a hard object to generate a strong impact force, and the torque increases, causing the drill pipe to break or twist off; 3. The model selection of the reamer is unreasonable, and the matching selection cannot be stopped according to the theoretical geological conditions, which increases the drilling torque and the drill pipe wear and cracks; 4. The deviation control of the guide hole is unreasonable. If the deviation is too large, the bending moment accepted by the drill pipe is too large due to the unreasonable theoretical curve in the later correction process, which is easy to cause the drill pipe to crack; 5. Due to the unsatisfactory geological conditions, the hole is broken and fallen, and there are too many cuttings, which increases the risk of drilling tool locking and causes the drill pipe to crack; 6. Request the technical standard if the raw material and thickness of the drill rod body do not match. < span "= ""> How to effectively extend the service life of drill pipe? 1, the construction should be strictly in accordance with the allowable tension, torque and curvature diameter of various drill pipes to use drill pipes; 2. Before operation, alter the thread oil. The thread oil with good quality can effectively prevent the drill pipe from sticking, reduce the tripping torque and reduce the wear. When screwing up, it should be tightened gradually to reduce overheating and wear. 3. Insist on using drill pipes in turn to prevent the fixed drill pipes from being used for guiding and expanding back to cause broken rods; 4. Application of flushing fluid: When drilling in sand layer and gravel layer, use high-quality mud as flushing fluid. Mud forms mud skin on the outer wall of drill pipe, which plays a smooth and maintenance role; 5. The imported viewpoint should be as small as possible, and the viewpoint should be changed slowly according to the drill pipe safety request. Pay special attention to the change of viewpoint when changing into horizontal segments during drilling and into drilled ones during drilling. ; 6, timely check the drill pipe wear, circuitous, surface scratches, etc., to timely select excessive wear, significantly circuitous and surface scratches deep drill pipe. Usually, we should pay more attention to the maintenance of drill pipes, effectively extend the service life of drill pipes and operate more efficiently.