A large-diameter two-stage combined synthetic diamond compact drill bit

Abstract

A large-diameter two-stage combined type artificial polycrystalline diamond compact drill bit comprises an inner drill bit body, an outer drill bit body, structural blocks, bayonet and resetting springs, limiting pin and resetting springs, bevel pins, jackscrews, transverse pins, sealing rings, bevel pin resetting springs, an inner pipe, plunger pin and resetting springs, limiting joints and an outer pipe. The overall structure of the drill bit is divided into an inner cutting transmission part and an outer protecting sleeve part. The bayonet and resetting springs, the limiting pin and resetting springs, the bevel pins, the transverse pins, the sealing rings and the bevel pin resetting springs are mounted in the structural blocks. The plunger pin and resetting springs are mounted in the limiting joints. The large-diameter two-stage combined type artificial polycrystalline diamond compact drill bit has the advantages that the problems that in the prior art, when drilling equipment encounters complicated geological circumstances such as soft geological stratifications, soft coal seams and fault fold zones, a drilling tool is prone to being locked, a hole is likely to be collapsed after being formed are avoided; the drilling diameter is increased to 300 mm or above, and the drilling depth is increased to 200 m or above; and the permeability of a coal seam is effectively increased,the gas extraction efficiency is improved, and the drill bit can be recycled.

Description

technical field [0001] The present invention relates to a new type of synthetic diamond composite drill bit, and in particular provides a large-diameter two-stage combined synthetic diamond compact drill bit, hereinafter referred to as a PDC drill bit. Background technique [0002] With the expansion and depth of coal mining, some original low-gas mines have also become high-gas mines, and some gas accidents have occurred from time to time. problems that urgently need to be resolved. Drilling pre-extraction of gas is an effective solution to control gas outburst accidents. [0003] However, the underground geological conditions of coal mines are complex, and drilling in areas with soft coal seams, structural coal and fault folds has the following problems: During the drilling process, the inner wall of the hole collapses, and the rock coal hugs the drilling tool, making it impossible for the drilling tool to continue drilling After the borehole is formed, the drill tool is...

AI Technical Summary

Problems solved by technology

[0003] However, the underground geological conditions of coal mines are complex, and drilling in areas with soft coal seams, structural coal and fault folds has the following problems: During the drilling process, the inner wall of the hole collapses, and the rock coal hugs the drilling tool, making it impossible for the drilling tool to continue drilling After the borehole is formed, the drill tool is pulled out, and the borehole collapses to form a waste hole; the borehole diameter is too small, resulting in a smaller screen pipe and low drainage efficiency; ordinary diamond composite drill bits have poor strength and wear resistance, and after wear Disadvantages such as time-consuming and labor-intensive replacement

In case of a collapsed hole, the drill bit and drilling tools are easily buried in the hole and cannot be taken out

[0004] The occurrence of the above problems makes the drilling rate of underground gas drainage in coal mines less than 30%, the depth of the holes is less than 100m, and the diameter of the holes is less than 130mm

The diameter of the borehole is small, resulting in a small radius of drainage; the depth of the borehole is short, resulting in a fast decay period of drainage

Coal seam permeability is low, which affects the reduction of drainage efficiency

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