Lateral telescopic casing-following drilling tool

Abstract

The invention discloses a lateral telescopic casing-following drilling tool. The lateral telescopic casing-following drilling tool mainly comprises a drill bit body, a reamer bit and a center bit, wherein the reamer bit is located between the drill bit body and the center bit, the two side faces of the reamer bit are in sliding fit with rectangular grooves formed in the drill bit body, and a cylindrical pin of the reamer bit is arranged inside a curvature control groove in the center bit. When the casing-following drilling tool is driven to rotate clockwise and anticlockwise to control the reamer bit to extend out or retract, and since friction resistance exists at the bottom of the center bit, the drilling bit body and the center bit rotate relatively, and through a mutually constrained relationship, a movable freedom degree is generated when the reamer bit extends out or retracts. The curvature control groove is provided with a transitional curvature segment and a hole shrinkage curvature segment, in this way, a reinforcing effect is realized, under the condition that hole bottom friction force is insufficient or the reamer bit suffers clamping stagnation, it is guaranteed that the reamer bit extends out or retracts, and the working reliability of the casing-following drilling tool is improved.

Description

technical field [0001] The invention relates to a laterally telescopic follower pipe drilling tool, which is applied in the fields of rock and soil drilling, water well construction and the like. Background technique [0002] When the DTH hammer drills into unstable formations, it usually uses the pipe drilling process to drill. The most commonly used supporting pipe drilling tools are single eccentric pipe drilling tools. The outer diameter is larger than the outer diameter of the casing. After the drilling is completed, the drilling tool is reversed. The eccentric drill bit in the reaming part retracts. The outer diameter is smaller than the inner diameter of the casing. The drill can be pulled out from the inner hole of the casing. [0003] There are some problems in the actual use of single eccentric drilling tools. First of all, due to the asymmetric structure of the eccentric drill bit, the drill tool, including the drill bit, bears asymmetric force and moment and sup...

AI Technical Summary

Problems solved by technology

[0008] 1. Due to the lack of a diameter-gauge structure for the tubular drill bit, the reaming state is maintained by the driving torque or the drilling pressure of the drilling tool. However, when reaming and drilling, the geological conditions are extremely complicated, especially the impact force is relatively large Under certain working conditions, there is a probability of retraction of the reaming bit, and there is a certain fluctuation in the outer diameter of the reaming, which affects the drilling quality and will inevitably increase the resistance of the follow-up pipe, which will inevitably affect the follow-up pipe depth and follow-up efficiency. At the same time, it is easy to have adverse effects on pipe boots, casings, etc.

[0009] 2. Although new structures of tubular drilling tools have been developed in recent years, these structures do not have a transmission pair that extends and retracts the reaming like single eccentric tubular drilling tools, and is completely closed to avoid rock formation. Therefore, these structures all have problems of work reliability and adaptability. In practical applications, there must be problems of one kind or another, and it is difficult to stand on the construction site for a long time.

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