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Introduction of Integral Triangular Spiral Drill Pipe-Yining Technology
Release time:
2021-05-28
Author:
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In order to solve the problems of sticking and burying in drilling construction of spiral drill pipe, wide blade drill pipe and triangular drill pipe in soft outburst coal seam, a kind of integral triangular spiral drill pipe is introduced, the structural characteristics of the drill pipe are discussed, the processing technology is studied, and the drill pipe is trial-produced. Through the on-off test and fracture analysis of the drill pipe sample, it is proved that the torsional strength of the drill pipe meets the design requirements. The integral triangular spiral drill pipe was tested in the drilling industry with a ZDY-3200S full hydraulic drilling rig, and the hole-forming rate was 100%. In the process of coal mining, gas extraction is the prevention and control of coal and gas outburst and explosion.
for solvingauger drill pipe, wide blade drill pipe andtriangular drill pipeIn the soft outburst coal seam drilling construction is prone to problems such as sticking, buried drilling and so on, this paper introduces a kind of integral triangularauger drill pipeThe structural characteristics of the drill pipe are discussed, its processing technology is studied, and the drill pipe is trial-produced. Through the on-off test and fracture analysis of the drill pipe sample, it is proved that the torsional strength of the drill pipe meets the design requirements. The integral triangular spiral drill pipe was tested in the drilling industry with a ZDY-3200S full hydraulic drilling rig, and the hole-forming rate was 100%.
In the process of coal mining, gas extraction is the fundamental measure to prevent coal and gas outburst and explosion. As one of the fundamental measures to prevent and control coal mine gas disasters and accidents, coal seam drilling gas extraction technology has been widely used. However, for soft outburst coal seams, especially in areas with high in-situ stress, drilling construction is very difficult, and abnormal phenomena such as jet hole, hole collapse, drill sticking, etc. are prone to occur, resulting in low drilling rate and shallow drilling depth. The drilling depth in soft coal seam drilling is generally not more than 100m, which seriously affects the gas drainage effect of drilling.
At present, the drill pipe used in the drilling construction of soft outburst coal seam in coal mine is mainlyauger drill pipe, wide blade drill pipe andtriangular drill pipe.
① Spiral drilling is a dry rotary drilling method. The spiral drill pipe and the drilling hole form a spiral conveyor belt, and the spiral drill pipe continuously conveys the rock slag crushed by the drill bit to the outside of the hole. Spiral drilling effectively solves the problem of slag discharge, but it is difficult to make holes because of the large disturbance to the drilling.
② The wide blade drill pipe is based on the spiral drill pipe. Under the condition of not changing the helix angle and pitch, the height of the spiral blade is reduced and the thickness of the blade is increased, so that the drill pipe can pass through the inner through hole of the gyrator chuck and the holder, thus realizing the drill pipe screwing and unloading without using the active drill pipe. At the same time, the scraping of the inner wall of the drill hole by the spiral blade (wing) is reduced, and the drilling is improved. However, the slag discharge space of the wide blade drill pipe is smaller than that of the spiral drill pipe, and the slag discharge efficiency is lower.
③ The slag discharge mechanism of the triangular drill pipe is to form three arc spaces between the drill pipe and the borehole wall, which expands the channel for removing coal powder and gas. In the process of drilling, the pulverized coal is stirred up, which can play the role of secondary coal crushing. The pulverized coal is blown out by the pressure air in the moving state, which can effectively solve the problem of blockage of the slag discharge channel of the spiral drill pipe, and the phenomenon of sticking and holding is not easy to occur during drilling. However, the processing quality of the triangular drill pipe is difficult to control, and the strength is lower than that of other drill pipes of the same specification, and the phenomenon of broken rods and lost drilling often occurs in the drilling process, which increases the cost of drilling. Therefore, the author designed the integral triangular spiral drill pipe to solve the above-mentioned problems in the drilling construction of the spiral drill pipe, the wide blade drill pipe and the triangular drill pipe in the soft outburst coal seam.
1, Integral triangular spiral drill pipe structure and working principle
The structure of the integral triangular spiral drill pipe is shown in Figure 1. The drill pipe is an integral structure, the two ends are male and female joints respectively, the outer contour of the drill pipe body section is similar to that of the triangular drill pipe, but the outer wall of the drill pipe is provided with a discontinuous spiral groove.
The integral triangular spiral drill pipe combines the advantages of the spiral drill pipe and the triangular drill pipe. The triangular prism structure increases the annular flow area between the outer wall of the drill pipe and the hole wall. The rotation of the drill pipe in the soft and protruding coal seam can cause vortex flow. The coal powder deposited at the bottom of the borehole is raised by the three edges of the drill pipe, so that the coal powder in the hole is always in a moving state to avoid the accumulation of coal powder in the borehole;
At the same time, the spiral groove on the outer wall of the drill pipe can assist in slag discharge. When the drill is stuck or buried, the collapsed hole can be dredged by means of the hole stripping function of the spiral groove.
The integral triangular spiral drill pipe has the following characteristics:
① The integral structure improves the torsional strength and bending strength of the drill pipe;
The joints at both ends of the drill pipe are designed to be thickened, which effectively ensures the wall thickness of the threaded end;
③Compared with the spiral drill pipe, the blade has high hardness, high strength and good wear resistance;
④ Compared with the triangular drill pipe, the spiral groove can continuously transport the cinder moving in the hole to the outside of the hole;
⑤ The wide blade structure reduces the scraping of the blade to the hole wall and ensures the stability of the hole wall.
2. Processing technology of drill pipe
The material of the integral triangular spiral drill pipe is 42CrMo thick-walled pipe material with high strength and good toughness. The overall hardening and tempering treatment has a hardness of HRC32 ~ 37 to ensure that the drill pipe has good comprehensive mechanical properties.
According to the structure of the drill pipe to determine the drill pipe processing process includes the following 4 processes:
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