How to Choose Tricone Drill Bits According to the lithology of the drilled formation, the following principles should be followed when selecting the type of drill bit: a. In the shallow well section where the rock is cemented and loose, the drilling speed of the drill bit and the prevention of mud packs should be considered; b. In the deep well section where the trip is long, the footage of the drill bit should be considered; c. When the outer row teeth of the drill bit out of the well are severely worn, a bit with gauge teeth should be used; d. In the easy deviating well section, a bit with small slip and many short teeth should be used; e. Wedge-shaped tooth drills should be used when selecting insert drills; f. For diamond limestone, it is advisable to use double-cone-tooth and projectile-shaped tooth drill bits; g. When there is more shale in the formation or the density of drilling fluid is higher, a bit with a larger slip amount should be selected; h. When the stratum is limestone or sandstone, and a bit with a smaller slip amount should be selected; i. When drilling hard and highly abrasive stratum, it is advisable to use pure rolling button and double bevel bit. In order to optimize the hydraulic parameters of bit, the longer nozzle and unequal diameter combined nozzle bit should be preferred.| Basical Specification | |
| Size of Rock Bit | 8 3/8 inches |
| 212.70 mm | |
| Bit Type | Steel Teeth Tricone Bit |
| Thread Connection | 4 1/2 API REG PIN |
| IADC Code | IADC137 |
| Bearing Type | Journal Bearing |
| Bearing Seal | Elastomer sealed or Rubber sealed |
| Heel Protection | Available |
| Shirttail Protection | Available |
| Circulation Type | Mud Circulation |
| Drilling Condition | Rotary drilling,high temp drilling,deep drilling,motor drilling |
| Total Teeth Count | 84 |
| Gage Row Teeth Count | 35 |
| Number of Gage Rows | 3 |
| Number of Inner Rows | 5 |
| Jounal Angle | 33° |
| Offset | 8 |
| Operating Parameters | |
| WOB (Weight On Bit) | 16,628-50,108 lbs |
| 74-223KN | |
| RPM(r/min) | 300~60 |
| Recommended upper torque | 16.3KN.M-21.7KN.M |
| Formation | Soft formation of low crushing resistance and high drillability. |
8 3/8" is the special sizes in oil well rock drilling fields.It is working well with small capacity drilling rigs and widely used in the world. Choose the correct model is important during the drilling project. Rocks hardness could be soft, medium and hard or very hard, hardness of one type of rocks may be also a little different, for example, limestone,sandstone, shale has soft limestone, medium limestone and hard limestone, medium sandstone and hard sandstone, etc. In drilling project, Far Eastern have 15 years and more than 30 countries services experience to supply the drill bits and advanced drilling soulutions for many different applications. The application including oil field,natural gas,geological exploration,driectional boring,water well drilling ,The various drill bits can be customized as per different rock formation becasue we have our own API & ISO certified factory of tricone drill bits. We can give our engineer's solution when you can supply specific conditions, such as hardness of rocks,types of drilling rig,rotary speed,weight on bit and torque. 
