DeviDrill™ —
Directional core barrel

The DeviDrill is a steerable wireline core barrel. The design of the N-size tool was introduced in 2001. Today it is successfully applied in various projects all over the world, from geotechnical investigations to the mining industry.

The DeviDrill reduces the cost of exploration drilling programs by hitting targets quicker and more accurately than with traditional core drilling methods. By making multiple branches from a mother-hole it dramatically reduces both the time spent and the cost, and, in addition, you get the geological information from wherever you want. No time is lost on moving the drill rig, drilling through the overburden, and drilling further down to where you almost were with your previous hole.

Cdn. Patent 2,749,316

Technical Specifications

Total weight	57 kg / 125 lbs
Total weight with ITA	74 kg / 163 lbs
Total length	4.5 m / 14.5 ft
Length front section	3.2 m / 10.5 ft
Weight front section	45 kg / 99 lbs
Length rear section	1.3 m / 4.3 ft
Weight rear section	12 kg / 26 lbs
Bit diameter	NWL
Reamer diameter	NWL
Tool body diameter	72.0 mm / 2.83”
Core diameter	31.5 mm / 1.24”
Core length	3 m / 10 ft
Length inner assembly	4.5 m / 10.5 ft
Weight inner assembly	17 kg / 37 lbs
Instrument barrel length	20 cm m / 8″
Instrument barrel diameter	51 mm / 2.01”
Pumping/latching unit	Longyear NQ™
Landing ring	Longyear NQ™
Landing indication	Yes
Core block indication	Yes
Pull out by-pass valve	Yes
Use of additives	Optional
Dogleg severity (DLS)	0-20º/30 m / 0-20º/100 ft
Operating pressure	20 bar + circulation pressure
Feeding force (max)	4500 kg / 9900 lbs
RPM	300-1200

Recommended parameters

Dogleg severity, NQ™ rods	9º pr. 30 m / 9º pr. 100 ft (180 m / 590 ft radius)
RPM	300 – 800
Feeding force (Bit weight + sliding force)	1500 – 2500 kg
Typical penetration rate	3 m/h / 10 ft/h
Typical production rate	9 – 27 m/12 h / 30 – 90 ft/12 h (50% – 75% of conventional wireline drilling)

Time and money saver

Clients have reported time and cost savings of up to 80 percent in projects where the DeviDrill was used. A satisfied geologist stated: “Devico forced the hole down in inclination, and the 1000 meter deep hole switched from total failure to great success.”

The DeviDrill uses a normal drill string and is fully compatible with the N-size wireline system. There is no need for additional water pumps, drill strings, or survey instruments. Devico’s survey tools are a fully integrated part of the tool, as they stay on board and measure while drilling. With the DeviGyro the DeviDrill can now also offer gyro while drilling (GWD) surveying that further optimizes the control of the drilling direction in any rock formation.

Coring during steering provides a complete record of the geology. It leaves nothing in the hole – except a bend. The curvature or dogleg can be adjusted from completely straight to more than 20 deg/30 meters. However, the recommended curvature from the drill rod manufacturer is 9 deg/30 meters, as any greater deviations will result in extensive wear on the drill rods.

How it works

The principle behind the tool is a drive shaft running through a bushing offset from the centre line of the tool. Expanding pads operated by a differential pressure is keeping the DeviDrill in a fixed toolface while drilling in a curve. The inner assembly carries an inner tube collecting the core, a muleshole system, and an instrument barrel with the survey tool recording inclination and tool orientation. Data is stored inside the tool and downloaded wirelessly to a PDA after each run.

There is no need to trip drill rods in and out of the hole during directional coring, surveying and orientation, as this is all wireline operated.

The DeviDrill has been proved to work well in both igneous and sedimentary rocks. Over time, Devico has gained much experience in how the DeviDrill behaves under different conditions, and possesses valuable information about directional planning and drilling.

To ensure rapid and trouble-free implementation into your drilling program, directional ore drilling with the DeviDrill is offered as a service to our clients by highly trained and experienced Devico staff or selected qualified license users throughout the world.