How to use the bit well is the key to achieve drilling effect. In actual production, the situation that the bit is scrapped in advance due to improper use method often occurs. In order to ensure the normal use of PDC bit, the following suggestions are given.
1) Reasonable drilling tool gradation should be selected to ensure smooth operation of drill bit and prevent damage of cutter due to uneven force.
2)PDC bit cutters have poor impact resistance, so they should be lightly loaded during transportation and handling. Smashing, touching and throwing bits are strictly prohibited. The drill should be stored in a dry and ventilated environment.
3) When taking the drill out of the packing box, it should be padded with soft materials first. It is not allowed to collide or roll the drill on steel or other hard materials to prevent damage to the cutters and threads.
4) Before using the drill, on-site inspection shall be carried out on all parts, including whether the drill diameter meets the requirements, whether the connection thread is intact, whether the cutter is damaged, whether there is foreign matter in the drill hole, and whether the water hole water tank is
smooth.
5) When installing and removing the drill, do not hit the drill with a hammer to avoid damage to the cutting gear and diameter parts. Grease should be applied to the thread parts before installation.
6) Before opening holes, the opening points should be trimmed into pits to avoid damage caused by too much swing of the bit during drilling. In the opening of the hole or after two drilling, should first use light pressure, slow rotation, appropriate pump volume (absolutely not allowed dry drilling) drilling 0.2 ~ 0.3m, after the completion of the hole bottom modeling, and then gently and evenly increase the weight on bit, speed and pump volume, and then drill in accordance with the normal drilling procedures.
7) The drilling speed should be slow to prevent the rock probe and falling rock from damaging the bit cutter. Before the drill gets close to the bottom of the hole, start the water pump to fully flush the bottom of the hole and check whether the water is normal to prevent blockage of the drill hole.
8) When drilling, ensure that the bottom of the hole is clean. If there are foreign bodies such as missing cutters, caliper cemented carbide and steel parts in the hole, it is easy to lead to early damage of PDC directional bit.
9) As low temperature solder is used to weld the PDC composite sheet with the bit body, sufficient circulating flushing fluid must be provided to ensure cooling and cleaning of the bit during operation. It is strictly prohibited to cut off water during drilling to avoid the occurrence of drilling burning accidents, and prevent repeated breaking of pieces and cuttings, which will affect the service life of the bit.
10) The drilling process should be carefully operated, always pay attention to the bottom of the hole conditions, such as abnormal vibration or no penetration, pump pressure significantly increased or decreased, mechanical drilling rate suddenly decreased, torque increase and other phenomena, should be timely investigation, if necessary, lifting inspection, not forced pressure drilling.
11) When a PDC directional bit is drilled into a highly abrasive interlayer, the wear of its cutters will increase with the increase of rotational speed and weight on bit. To extend the life of the bit, use low RPM and the lowest weight on bit possible. When encountering formation changes or interlayers, the weight on bit and rotational speed should be adjusted in time to achieve the best bit life and drilling speed and achieve the best drilling results.
12) During normal drilling, the product of weight on bit and speed should be taken as the constraint condition. The highest weight on bit and the highest speed should not be used at the same time. During drilling, the operation should be stable.
13) Hole reaming with PDC bit should be avoided as far as possible. If hole reaming is required in short hole segments, small weight on bit, moderate speed and large pump volume should be used.
14) During the late use of the bit, the bearing area is increased due to the wear of the cutter, so the weight on bit should be increased appropriately to maintain the drilling speed.
15) When multiple drill bits are used in the same drilling hole, the drill bits should be used in line and rotation. The big outside diameter is used first, and then the small outside diameter is used later.
16) When drilling into soft rock and viscous strata, the bit sometimes has mud bag phenomenon, which affects normal drilling. The main symptoms are the sudden drop in drilling rate and torque, and the increase in pump pressure. At this time, the bit should be cleaned.
17) Before starting drilling, drilling specification parameters should be gradually reduced to stop bit rotation so that weight on bit can be gradually released; In complex strata such as expansion, the drilling speed should not be too fast, so as to avoid hole collapse or outburst accidents caused by "suction" effect.
