How to use the drill bit of the down-the-hole drill pipe correctly

Classification:

Company News

Release time:

2019-08-21

【Summary Description】 How to use the drill bit of the down-the-hole drill pipe correctly

潜孔钻杆

1. Type selection of drill bit

For soft stratum, steel teeth or insert bits with shifting axis, super top, compound cone, large tooth profile and few teeth should be selected to give full play to the shearing and rock breaking effect of the bit.DTH Drill PipeAs the rock hardness increases, the drill bit moves its axis, exceeds the top, and the complex cone value should be reduced accordingly, and the teeth should be shortened or densified accordingly. Abrasive formations are especially easy to wear the gauge teeth of the cone, back cone and palm tip of the teeth, resulting in small diameter of the drill bit, borehole diameter reduction and sealing failure. Special gauge structure with palm back reinforcement should be selected for inclined drilling, drill bits with small shaft shifting or shaft shifting should be selected to reduce the slippage of the drill bit at the bottom of the well and prevent well deviation.In the formation of soft and hard alternating, the bit type of hard rock in this formation should be selected.

2. Drilling situation analysis

DTH Drill PipeThe operation of surface equipment, cuttings, weight on bit, torque, penetration rate, pressure and other surface instruments can directly reflect the downhole conditions, and should be closely watched, especially torque, pump pressure, penetration rate and cuttings.

The torque change depends on the bottom hole condition and speed change, the normal torque value is relatively stable, the torque value is low in the soft or plastic homogeneous formation, the torque value is in the middle of the soft to medium hard homogeneous formation, the torque value of the hard formation is large and there is a certain range of fluctuations. Torque variation may include: ream of centralizer, wear of drill bit, interlayer, objects falling at the bottom of the well, keyway or dog leg in the well, excessive weight on bit, speed variation, mud bag of drill bit or bottom hole assembly, drilling tool leakage or dry drilling, etc.

Unstable pump pressure: bit mud, debris accumulation in annulus, flow fluctuation, drilling to broken formation or clump formation, poor centration.

DTH Drill PipeROP may change: formation change, mud property change, weight on bit or speed change, bit wear or mud bag, cleaning effect change, drilling tool puncture leakage.

Through the cuttings, we can know the formation type and lithology change, pressure zone, whether the borehole is collapsed, the working condition and wear of the drill bit, and whether the drilling parameters are reasonable.

潜孔钻杆

Key words:

weilida drill