Overburden Drilling Systems

Ground Engineering Products

Symmetrix and Odex
--leading casing drilling solutions

Today, drilled casings are one of the most popular methods for foundations, reinforcement work, and well drilling. They especially lend themselves to urban work such as bridge, utility line, wharf, and building construction. In fact, with the development of DTH drilling and the introduction of special drilling systems like Symmetrix and Odex, casing advancing in overburden has become more refined.

Two systems to cover your needs - Atlas Copco offers two ranges of overburden drilling equipment. Odex, a retrievable drilling system for smaller holes. And Symmetrix, an all-round overburden drilling system for holes of any depth or size. Together they represent the latest technology in overburden drilling.

Any rock and any length - Odex is the specialist in normal overburden conditions and shorter holes. Where there's medium to hard ground or a need for larger diameter casings, then Symmetrix is the right choice. In fact there is almost no limit to the depth Symmetrix can drill - just keep adding on casings.

Odex - for smaller casings - Odex is an eccentric retrievable drilling system that's ideal for short holes up to 10-3/4" (273 mm) in diameter. Well drillers often have an Odex drill bit at hand for simultaneous casing of water and geothermal wells. The advantage is that Odex drills and installs the casing quickly and efficiently, while the ingenious bit system allows the complete drill bit to be retrieved - ready to drill the next hole.

Symmetrix - the all-rounder - Symmetrix is a concentric drilling system with retrievable pilot bits. They can be used for holes from 3" (76 mm) up to 48" (1220 mm). This system drills in any direction and in any type of ground condition. It is, in fact, the most flexible and efficient overburden system on the market today.

DTH or tophammer rigs - These two systems are so flexible that they can be used on DTH rigs or tophammer rigs. Even pile boring rigs, exploration rigs, or cranes can be adapted for use.

A multitude of applications - From anchoring to slope stabilization, from micropiling to curtain grouting, from tunnel forepoling to marine piling applications. Wherever the ground is unstable, drilled casings offer the basis of an excellent solution.

Odex - the retrievable small holes specialist

Wherever there's a well to be drilled, there's always a need to case the overburden layer. This is where this tried and tested eccentric casing drilling system has proven itself to be the ideal solution. In fact, Odex has become synonymous with water well casing drilling.

Pioneers in casing drilling - Odex has become the standard for casing in water wells, geothermal wells, and for shallow micropiling work. In fact, in some countries this is referred to as Odex drilling. Atlas Copco has continuously developed the product, and today it still outperforms other eccentric systems. Drill through overburden and bedrock - Odex is ideal for short holes in consolidated overburden. This means it's perfect for most water and geothermal well drilling. Even contractors working with short micropiles find Odex the best solution.

Ingenious eccentric system - Odex is an ingeniously designed eccentric drilling system which consists of a pilot bit and reamer "wing." The pilot bit protrudes beneath the casing pipe and, as the drill rotates, a specially designed "wing" folds out and acts as a reamer. This creates the space for the casing pipe to advance. Once through the overburden Odex makes a socket in the bedrock, allowing the casing to be fixed in place. Then, by simply reversing the drilling rotation, the wing retreats into the pilot bit and the whole drillstring can be removed from the hole, leaving the casing pipe in place.

Odex casing a water well

Retrievable and reusable - For well drillers, it's imperative to have a casing drilling system that's easy to drill with any DTH drill rig. That's where Odex comes into its own. Thanks to the ingenious reaming wing the bit is retrievable and can be used at the next well.

Push or pull casing pipes - Odex can be equipped with a casing shoe shoulder or without one. By using a casing shoe shoulder, the casing pipe is pulled into the hole. Where there is no casing shoe shoulder present, the casing pipe is pushed into the hole.

Available for tophammer or DTH drill rigs - Currently, Odex is available in eight diameters from 3" to 8" DTH hammers. They have also become very popular with tophammer drillers and are available in three different sizes from 38 mm to 51 mm threads.

Symmetrix - a revolution in casing advancement

Symmetrix is a truly revolutionary product. Not only is it an all-round multipurpose concentric drilling system, it also has opened the way for engineering consultants to utilize new construction methods that save contractors time and money, not to mention offer new business opportunities.

Can drill through almost any ground condition - Atlas Copco's philosophy for casing advancement is that a retrievable eccentric system, such as Odex, is the ideal for shorter holes, whereas for deeper and larger diameter holes concentric systems are the best solutions. Thanks to its concentric system, Symmetrix can drill through almost any ground condition. Whether there's sand or boulders, Symmetrix drills on until the required depth is reached.

Not only a product--it's a drilling concept - Over the past 10 years Symmetrix has replaced many other methods, such as auger drilling, pile drilling, etc. Its simplicity and efficiency have opened many engineering consultants' eyes to alternative methods for foundations and reinforcement work. Today this product is used in micropiling, underpinning, anchoring, tunneling, marine work, and horizontal drilling - to name a few. All this work can be carried out quicker and deadlines made tighter.

Straighter and faster - When piling, it's imperative that the casing pipe is drilled at exactly the right angle. Any slight deviation means the supporting capabilities are weakened. That's where Symmetrix is outstanding. With no extra reaming wings, the concentric drill heads drive straight through any obstacles without straying from its goal. And thanks to the optimum drill bit design, the job is done quickly and efficiently.

From DTH rigs to cranes - Symmetrix is highly flexible and can be used on a wide range of drill rigs, the most common being DTH rigs. When very long casings are needed, cranes can be easily adapted to use DTH hammers. And as Symmetrix requires less torque than other overburden drilling systems, smaller rigs such as exploration and tophammer rigs can be used with excellent results.

Symmetrix casing an end-bearing pile

A unique concentric drill bit design - Symmetrix consists of three main components:

• A pilot bit that drills and guides the drillstring.
• A casing shoe that's welded onto the casing pipe.
• A ring bit that, together with the pilot bit, drills the hole and makes room for the casing to advance down the hole.

There are three different types of ring bit and casing shoe assemblies:

• A solitary ring bit with no connection to a casing shoe.
• A welding ring that holds a ring bit and casing shoe together.
• A factory assembled ring bit set with integrated ring bit and casing shoe.

The pilot bit locks into the ring bit and commences drilling, while the casing pipe is pulled down by the pilot bit's casing shoe shoulder. Once the hole is finished, drilling rotation is reversed, the pilot bit is released and removed, leaving the casing pipe in place.

Highly versatile Symmetrix can be used in a multitude of applications, handling casings from 3" to 48" (76 to 1220 mm) to almost any depth. There are six standard models.

Pilot bit Casing shoe Welding ring Ring bit

Drilling with Rotary and DTH in the same hole

Due to Symmetrix's unique locking system it is possible to drill with a tricone bit or drag bit and with a DTH hammer in the same hole. A special ring adapter is used when drilling with the tricone or drag bit in order to rotate the ring bit. When DTH drilling is required, the drill string is lifted out and the DTH hammer with Symmetrix pilot bit is locked into the ring bit.

A multitude of applications

Over the years Atlas Copco overburden drilling systems have opened a multitude of new business opportunities for contract drillers worldwide. Here's a presentation of a few of them.