114. 115.116.117 低抗壓強(qiáng)度高可鉆性的及軟地層,如粘土.泥巖.疏松砂巖.
The bits are used to drill low-compressive strength,soft formations. Long projection tooth lengths are used on high offset cones to provide the greatest penetration rates possible. Wear-resistant hard facing is used to control tooth wear.On the softest bi types this hard facing completely covers the bit teeth 0.35---0.8
124.125.126.127 低抗壓強(qiáng)度高可鉆性的及軟地層,如泥巖.石膏.鹽巖.軟頁巖.軟石灰?guī)r
Soft formation with low compressive strength and high drillability. Such as sandstone, anhydrite, salt, shale, limestone. 0.3---0.9
134.135.136.137 低抗壓強(qiáng)度高可鉆性的及軟至中軟地層,如中軟頁巖.硬石膏.中軟石灰?guī)r.中軟砂巖和有硬夾層的軟地層
Soft to medium formations with low compressive strength, such as shale, anhydrite, sand and so on for soft formation 0.33--1.0
216.217 低抗壓強(qiáng)度的軟到中等地層,如中軟頁巖.中軟石灰?guī)r.中軟砂巖.和有硬夾層的軟地層
Soft to medium formations with low compressive strength, such as shale, anhydrite, sand and so on for soft formation 0.4---1.0