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Talking about the Working Conditions of Directional Drill Pipe and Directional Drill Bit
Release time:
2021-03-09
Author:
Source:
The working conditions of the directional drill pipe is an elastic system, in the process of directional drilling, the size and direction of the load on the drill pipe are changing, the directional drill pipe in the three-dimensional space to bear complex alternating tension, compression, torsion, bending, vibration and other loads, coupled with wear and corrosion, after a period of aging is likely to fracture at the stress concentration site. At the same time, with the change of geological conditions and the occurrence of accidents such as sticking and burying, the force of the directional drill pipe will become more complex. The working conditions of the directional drill pipe determine that the directional drill pipe will be a component with complex force and harsh working conditions in the drilling process. Directional drill pipe bearing
Working conditions to the drill pipe
The drill string composed of directional drill pipe is an elastic system, in the process of directional drilling, the size and direction of the load on the drill pipe are changing, the directional drill pipe in the three-dimensional space bear complex alternating pull, pressure, torsion, bending, vibration and other loads, plus wear and corrosion, after a period of aging is likely to fracture at the stress concentration site. At the same time, with the change of geological conditions and the occurrence of accidents such as sticking and burying, the force of the directional drill pipe will become more complex. The working conditions of the directional drill pipe determine that the directional drill pipe will be a component with complex force and harsh working conditions in the drilling process.
The basic load of the directional drill pipe is:
1) tension and pressure. During the drilling process, when the directional drill pipe applies axial pressure to the directional drill bit, the drill pipe is compressed, and when lifting the drill, the drill pipe is pulled. When handling the accident in the hole and pulling out, the drill pipe will be subjected to a large pulling force.
2) Reverse. Since one of the main functions of the drill pipe is to bear or transmit torque, the drill pipe is in a twisted state and produces torsional stress. Especially when dealing with in-hole accidents (the cable-type drill pipe can rotate when dealing with in-hole accidents), the turning of the drill pipe suddenly stops. At this time, the turning kinetic energy of the turning part of the drilling machine and the drill pipe string makes the turning drill pipe subject to torsional impact, resulting in great torsional stress.
3) Bend. In the regular drilling construction, due to the instability of the drill pipe under the action of centrifugal force and axial pressure, bending, bending stress is generated inside the drill string. In the process of constructing directional holes, it is necessary to constantly adjust the drilling trajectory, which will cause the bending deformation of the drill pipe in the hole. When the bent drill string is rotated, the alternating stress generated in the drill pipe is easy to cause the fatigue failure of the drill pipe.
4) Elastic vibration. The drill string is an elastic system, which can vibrate longitudinally and transversely under the combined action of bending and torsion. In severe cases, the vibration of the drill string makes the drilling rig and other supporting equipment forced to vibrate, affecting the life of the drilling tool and supporting equipment.
Key words:
Orientation, drill pipe, bending, rotation, generation, accident, vibration, stress, drilling
