简介：Varel公司最近推出其新的牙轮钻头系列，专门用于欠平衡钻井。它能增加密封和轴承的使用寿命，延长钻头寿命。

Varel has launched the A-Force roller cone bit series, a line built specifically for underbalanced applications including air, foam, and mist.

The technology in the series works to improve the longevity of the seal and the bearing system and to extend the life of the drill bit, the company says.

A-Force bits include a heat shield disc deployed between the seal and the inner bearing. This shield acts as a thermal insulator, protecting the seal from excessive thermal energy, lowering the operating temperature for the seal and extending seal life.

The bits are also equipped with a conical seal gland that positions the seal in such a way that it can better handle pressure fluctuations and still maintain a preferred sealing location and interface.

The series incorporates a more robust and more tightly toleranced journal bearing capable of supporting increased levels of weight on bit, the company says

A-Force series drill bits include additional material improvements:
• A new grease formulation that is stable at increased operating temperatures. This grease reduces internal bearing heat generation allowing the bearings to remain cooler

• A more wear resistant hardmetal inlay that works to prevent wear to the journal surface extending the effective life of the bearing

• Redesigned head forgings that provide for increased leg strength, reduced bit length, and improved steerability.

A-Force bits incorporate Varel's High Energy Tumbled (HET) processed carbide inserts and are equipped with both cutting structure designs and carbide grades specific to underbalanced applications.