Three common wrong operations of drill pipe in well drilling rig
Don’t underestimate the small sticks like drill pipes. Some inexperienced drillers often make mistakes in their operations, which will have a great impact on the drilling team. Therefore, Zhengyang water well drilling rig manufacturer Xiaobian summarizes three common wrong operations based on our service engineer’s experience, hoping to give you some reference and guidance.
The first kind
In the process of drilling, the front crawler of the water well drilling rig tilts, the back of the mast, the first section of the rod is forced by the backward force F1 of the power head, and the inner section of the rod remains vertical force F2. The two forces form a moment to break the first section of the rod flap. The top group of pressure table and inclined key of the first section of the rod are most likely to be broken.
The second kind
In the process of running down the drill pipe, there is no buffer when the two adjacent rods contact, which leads to the impact between the inner rod rotating ring and the inner key of the outer rod, and the outer rod is bulged.
The third kind
When pressurizing, do not find the pressure point, and use the locking rod as a friction rod. The contact surface between the inner key of the first rod and the inclined key of the second rod is very small. In a short time, the upper end face of the inner key of the first rod and the side face of the inclined key of the second rod are seriously worn, resulting in the rod sticking or rolling.
The above three points should be paid attention to when using the water well drilling rig. When using the drill pipe, we should choose the drill pipe suitable for specifications and models based on the torque, push-pull force and the minimum curvature radius of the drill.
Remember not to connect large diameter drill pipe with small diameter drill pipe, in other words, mix the size of drill pipe, which is very easy to cause the small drill pipe to be broken or deformed.
When clamping the drill pipe with a vice, do not clamp the female part of the female joint to prevent the female from being clamped and deformed. Before the drill pipe is installed, the water channel hole shall be cleaned to prevent the mud system from holding pressure due to the blockage of the channel by sundries.
When assembling and connecting drill pipe, the pre tightening force of make-up should be controlled within 15MPa to prevent the difficulty of break-up due to excessive pressure. Avoid using fire to bake the joint, reduce the mechanical properties of the joint (especially the female joint) and affect the service life.
When the thread connection is not pre tightened, it swings, the thread grinds with each other, the top of the tooth becomes sharp, and ridges are produced on the side, which leads to thread damage and thread sticking.
If the screw thread is not pre tightened and the female thread step is not pressed tightly, the root of the male thread will be fatigued and broken. Under the action of high-pressure liquid flow, the female joint will be punctured, which will cause the longitudinal crack of the female joint.
Finally, it is not allowed to mix different types of drill pipes, even if they are not produced by the same manufacturer (because the technical parameters, processing methods, props and mechanical equipment of drill pipes manufactured by different manufacturers are different, the tolerance and tight distance of drill pipes processed must be different).
If the difference between the old and the new is too big, and the wear degree is too big, the drill pipe should not be mixed to avoid construction danger.