Varel International’s new Compass Series roller cone drill bits are for slimhole applications. The tungsten carbide insert bits are available in sizes ranging from 95 to 187 mm and are targeted for applications such as reduced size casing programs, horizontal drilling, re-entries, multi-laterals and coiled tubing drilling which all require steerability, reliability and maximised rates of penetration. This series has been system engineered to perform well at low weight on bit, run longer hours and to withstand high rpms typical of motor applications.

Through the incorporation of an advanced cutting structure design and the inclusion of the highly successful High Energy^TM technology suite, drill bit designers optimised the series for slimhole applications. Benefits of the design include enhanced steerability, a lower cost per metre average and reduced bit trips due to improved rates of penetration (ROP) and distance drilled.

Field tests have shown an above average ROP improvement in multiple applications. The responsiveness and durability of the bits have minimised costs associated with additional drill bit runs and tripping in areas where they have been tested.

In one slimhole application for a major operator in Western Canada, a 158.8 mm Compass bit was challenged to increase metres drilled while maintaining an acceptable ROP. This application requires the bit to pass through increasingly hard formations including the abrasive, sharp sands of the Cadomin/Nikanassin formations. Varel supplied the operator with the Compass CM44DMRS bit which successfully drilled 180 m to a total depth of 1,985 m. This performance netted a 19.4% improvement in metres drilled when compared to the closest competitor offset, the company reports. “Using this same competitor offset, a 31% improvement in ROP was realised.”

Features of the line include:

• Advanced Cutting Structure and Gage Design – Cutting structures are designed for speed and steering responsiveness with advanced shirttail protection for longer life in directional applications
• Patent Pending Heat Shield – The heat shield ring is deployed between the seal and inner bearing and acts as a thermal insulator to the seal from heat generated in the bearing
• Patent Pending Conical Seal Gland – The newly designed seal gland is constructed to resist cuttings packing into the seal area. Its unique geometry provides significant benefits during high angle drilling
• Improved Bearing Grease – Compass bits have incorporated a high temperature, high lubricity bearing grease assisting in the reduced generation of internal bearing heat allowing bearings to last longer
• High Capacity Reservoir – A new reservoir provides a 13% volume increase over previous designs and is configured to be ‘self-draining’
• Advanced Bearing Metallurgy – The inclusion of advanced bearing metallurgy increases the durability and reliability of the products: silver plated bushings in 143 to 187 mm sizes and high cobalt hardfacing in 95.3 to 139.7 mm sizes.