In cooperation with drillers and drilling contractors, the SDS was developed to overcome these problems. The patented eccentric design and the Drop Off Ring (DOR) drill bits enable the drill string and casing to be lowered in the hole simultaneously with a conventional hammer drilling system.

The SDS eccentric designed bit rotates outward and drills a larger diameter hole than the casing, avoiding cave-ins, wash-outs and other problems common in normal drilling operations in soft and gravel type strata or loose rock. Since 90% of the world’s overburden drilling is in loose strata, potential utilization of the SDS is enormous.

After reaching the designated depth, the SDS reamer-bit is retracted by reversing the direction of the rotation and by applying tension on the reamer-bit, which has a taper and will retract into the casing for easy removal of the entire drill-string. This leaves the casing in place for other applications or for removal at a later date. The SDS method is designed for use with fl ush joint threaded pipe or welded type casing, and provides a bit size for a wide variety of different casing wall thicknesses.

Advantages of SDS

• Low capital investment
• High drilling performance
• No rotation of the casing
• Compatible with most drilling rigs
• Virtually no casing stress
• Casing is simultaneously lowered by the guide device and to deeper depths than other methods allow.
• Cost and on-site time reduced due to better penetration rates, easier bit changes and stable hole conditions.
• Smaller pilot bit for faster and better penetration

Applications

• Blast holes
• Water supply wells
• Bridge and building foundations
• Standard slant or horizontal drilling
• Mining air holes
• Environmental monitoring wells
• Grouting operations
• Seismic shot holes
• Soil sample and geotechnical applications.
• Ground anomaly and tiebacks
• Storage caverns and dam

Assembly of The Stratex System

The Stratex Drilling Method is used with air rotary drilling rigs and most manufacturers’ downhole hammers. The drill rod is connected to the rig top drive using a changeover sub or swivel sub. The drill rod is then connected to the down-hole hammer by the same method. The chuck nut and split rings are removed to insert the guide device shank and secured by replacing the split rings and chuck nut.

The reamer bit, in the closed position, is now inserted into the casing shoe. Since the percussion hammer is at the bottom of the hole, working directly above the drill bit, the force to pull down the casing tube is transferred by way of the casing shoe. The exhaust air from the drill redirects the loose cuttings up through the grooves on the guide device, forcing them up between the drill rod and the casing wall out through the discharge head, which is attached to the casing tube. By using a discharge head, drilling is not only safer, but also environmentally cleaner. Stratex can be used with foam or water injection to aid in cutting removal.

Good Flushing

Good Flushing is essential with any successful drilling operation or in using an overburden drilling system. The Stratex System provides air jets above and below the guide device, creating a vacuum across the face of the reamer bit, removing the cuttings with greater annular velocity. The gauge carbides along the side of the pilot and reamer bit act to crush the cuttings into fi ner particles, the majority of which are removed from the hole. The remaining cuttings are forced back into the walls of the cavity leaving less material to be extracted from the hole.

Advantages

• Efficient removal of cuttings from above the guide device which prevents the hammer from jamming and torque problems.
• Removal of fi ne cuttings from around the bit system and casing creates less friction and achieving deeper depths and easier casing removal.
• Reduction in losses due to circulation problems by increased vacuum in cutting removal.
• For unique applications, the annular velocity can be increased by changing the air fl ow in the reamer pilot system



The Stratex System utilizes a one-piece reamer and pilot bit that moves outward to full open position on an eccentric shaft by rotating a half turn to the right.

This reamer pilot bit system opens a larger diameter hole than the diameter of the casing. The casing is simultaneously lowered into the hole as the reamer pilot bit drills. The pilot bit is rotated at 10 to 40 rpm while drilling with the hammer.

When the designated drilling depth is reached, the reamer pilot bit system is retracted into the casing by applying slight tension and reversing the direction of the drilling rotation. The design of the reamer pilot bit system incorporates a closed bearing method that makes the loss of the pilot bit virtually impossible. This bit system, in the closed position, is easily removed through the casing shoe and casing.

Eccentric Under Reamer
Used for a Large Range of Diameter Requirements

• High performance drilling
• One-piece reamer
• One-piece guide device
• Made from tough heat-treated alloy steel
• Studded with an aggressive array of tungsten carbide inserts
• Lower drilling costs per foot
• Guaranteed performance*
• Guaranteed service
• Large range of accessories
• Manufactured under strict quality-controlled conditions

Drop-Off Ring Under Reamer
Used when concentric drilling is a requirement.

• High performance drilling
• One-piece reamer
• One-piece guide device
• Made from tough heat-treated alloy steel
• Studded with an aggressive array of tungsten carbide inserts
• Lower drilling costs per foot
• Guaranteed performance*
• Guaranteed service
• Large range of accessories
• Manufactured under strict quality-controlled conditions

The Stratex Centro
The latest concentric under-reamer used for large diameter requirements

• High performance drilling
• Five retractable wings
• Made from tough heat-treated alloy steel
• Studded with an aggressive array of tungsten carbide inserts
• Lower drilling costs per foot
• Guaranteed performance**
• Guaranteed service
• Large range of accessories
• Qualifi ed, dedicated staff
• Manufactured under strict quality-controlled conditions
• Sizes from 20”
• Custom sizes available

Hydraulic Casing Puller
Slips & Bowls

• Compact design
• Light weight
• Ready to be connected to your hydraulic pump
• Independent operation
• Vertical/horizontal operation

Threaded Casing, Drill Rods & Connections

• LH/RH thread
• Alloy steel threaded casing ends
• Flush joints
• API & custom-threaded specs available
• Casing sizes from 70mm
• Metric and Imperial sizes available
• Drill rod sizes from 2”

Accessories

• LH/RH thread
• Alloy steel threaded casing ends
• Flush joints
• API & custom-threaded specs available
• Casing sizes from 70mm
• Metric and Imperial sizes available
• Drill rod sizes from 2”
• Drop-off Ring (DOR) bits
• Drill pipe and subs
• Left threaded casings (left-hand HT allow ends)
• Casing drive shoes
• Stabilizers
• Hydraulic casing pullers
• Discharge heads
• Casing wing-nuts
• Shock subs
• Drill bits
• Fishing tools
• Air swivels

Download the Stratex Drill System Brochure

Contact:

Ervin Bata
403-250-5322
ebata@hyduke.com