OK Rig 1A

Foremost DR24 Dual Rotary Drill

This Dual Rotary rig is designed for extreme drilling conditions. Capable of 100+ metres, we can drill solid rock using a down hole hammer and top drive or drill unconsolidated material such as boulders, pea gravel and sand. Using the continuous casing option, and a tri cone bit, slant holes are also an option with capabilities of drilling up to 45 degrees. For extreme drilling conditions, the DR24 can get the job done.

• 2001 T800 Kenworth
• Cat C15 475 HP Engine
• Total GVW 61,700 (28,000 KG)
• Independent top and lower drives
• Deck mounted Atlas Copco 950 CFM Compressor
• 18” drill stem 20 ft. (6.1m) joints 2575 lbs (1175kg) each
• Rigged to drill 20” (508mm) or 24” (610mm) hole with cone bit or down hole hammer
• Down hole hammer approximately 6500 lbs (2950 kg) when rigged with 23” bit, stabilizer and crossover sub.

Foremost Dual Rotary drills feature two rotary drives, including a unique lower rotary drive that is used to advance steel casing through unconsolidated overburden such as sand, gravel, glacial till and boulders. The lower drive feeds and rotates the casing independently of the top drive. The casing is held securely in the lower drive by a set of power-operated jaws. A carbide-studded casing shoe, welded to the casing bottom, cuts through the overburden. Once the desired casing depth is reached, the DR continues drilling open-hole like a conventional top drive drill. There is no need to trip out or change tools when transitioning to open-hole drilling.

The independent rotary top drive simultaneously handles a drill string, which can be equipped with a down-the-hole hammer or tri-cone bit.

The upper and lower rotary drives feed independently on separate hydraulic cylinders. This means that the bit position can vary in relation to the casing shoe. In most situations, the bit is advanced slightly ahead of the casing for best penetration rates. In heaving formations (sand or silt), or at times when it is desirable to obtain a clean sample of the formation, the casing can be advanced ahead of the drill bit.

Over the years, the Dual Rotary method has proven very effective for advancing steel casing in difficult unconsolidated overburden. In addition to the primary benefit of effective penetration, the rotation of the casing results in very straight holes and casing can be extracted using the lower drive.