(Applicable conditions) 3.
For the large number of abnormal drilling and drainage in the gas control area, the feasibility of supplementary drilling and repair drilling should be analyzed, and the supplementary measures should be comprehensively determined·
.
That is, the coal and rock slag in the borehole will be discharged out of the hole to ensure the smoothness of the hole; b) Punching or slotting.
That is, special nozzle is used for hydraulic punching or slotting to expand the diameter of drilling hole and realize coal pressure relief and transparency; c) Cleaning and drainage.
7.
The construction operation of drilling repair machine generally includes the following procedures: a) drilling and plugging removal.
If conditions permit, peep or detect inside the borehole to further determine whether there is blocking factor.
After the repair, clean the hole wall and switch the compressed air to drain the accumulated water in the hole.
When the drilling repair machine is used for drilling repair operation, it shall be ensured that the coal ballast or broken extraction pipe and other sundries in the hole are discharged after each repair, and the extraction hole can be resealed if necessary.
After the completion of drilling repair, continuous observation, analysis and evaluation of the pumping effect shall be carried out.
The drilling repair machine is mainly composed of flexible steel pipes with an outer diameter of 16mm and different function nozzles.
The drilling repair machine shall be used together with the high-pressure punching system, and the main technical parameters are as follows: a) The pressure of the punching pump is 30~45MPa; b) The rated flow of the punching pump shall not be less than 200L/min; c) The return pipe tension of the repair machine shall not be less than 10kN; d) The pull-back speed of the repair machine is generally 6 m/min; e) The lifting height range is 0~2.28m, and the rotation angle is 360 °; f) The diameter of the continuous winding steel pipe of the repair machine is generally 16mm.
5.
High pressure water is conveyed to the front nozzle through flexible steel pipe to form a high pressure water jet, which can realize secondary hydraulic strengthening operation for the extraction drilling hole or clean and dredge the blocked drilling hole.
2.
If the pumping effect is significantly improved, the drilling repair is effective; Otherwise, the abnormal situation of gas drainage should be further analyzed.
6.
4.
If the pumping flow of the borehole is significantly lower than that of other pumping boreholes around or there are abnormal phenomena such as rapid attenuation, and there are no factors such as string holes and gas leakage after troubleshooting, the drilling repair operation can be considered.
1.
