7 7/8″ MR845 牙轮钻头

齿型结构与适用地层

外排椭球形齿、内排卵尖形齿。适用于极硬地层（高抗压强度），常见岩性：磁铁石英岩、石英岩、花岗岩。

ORIGINAL · ENOvoid on gage, ogive on inner rows. Designed for extremely hard and abrasive formations with high compressive strengths such as magnetite quartzite, quartzite, granite.

保径保护

掌背镶硬质合金；保径唇口与掌背加焊耐磨碳化钨。

ORIGINAL · ENHardmetal on lug; Wear resistant carbide on shirttail lip and lug.

• 直径 7 7/8″ / Φ200mm，重 34kg
• 接头 4 1/2″ API，轴承 Roller-Ball-Roller-Thrust Button/Sealed Bearing
• 推荐钻压 39,380–63,000 lbs，转速 50–80 rpm