Meeting the Drilling Industry’s Demand for Auxiliary Air

A key trend in the types of drilling services is the greater need for fast, deep, large-diameter hole drilling, reports Atlas Copco. Often, on-board compressors just can’t provide the necessary penetration rate and bailing air required for these jobs.

In response, the company’s Compressor Technique business acquired the Hurricane air and gas booster compressor business based in Franklin, Indiana, USA in April 2008, which was integrated with the Portable Air Division. These boosters complement the existing Atlas Copco product range, enabling Compressor Technique to deliver air pressures up to 275 bar, possibly higher.

Then, in November, the Portable Air Division team based in Antwerp, Belgium introduced a new auxiliary range that provides the most powerful air supply available from a portable compressor. Intended primarily for drilling contractors, these machines have also achieved the lowest specific fuel consumption per unit air delivered. The 25 bar (365 psi) XRVS and 30 bar (435 psi) XRXS models in this DrillAir line were launched in November 2008 and the 35 bar (510 psi) XRXY versions in late March this year. Atlas Copco anticipates the main markets for these new compressors will be in the mineral exploration, water well and geothermal drilling sectors and also in oil and gas development.

Indian Pioneer

One company taking advantage of Atlas Copco auxiliary air is London AIM-listed Great Eastern Energy Corp. Ltd (GEECL). Working on a concession in West Bengal, GEECL is the first private sector business in India to work on the potential of coal bed methane (CBM) as a fuel to help meet India’s fast growing energy needs. The company is drilling holes to depths of 4,167 ft (1,270 m) using an Atlas Copco RD20 drill rig linked to an Atlas Copco XRVS 1250 CD 6 portable compressor and a Hurricane booster supplying auxiliary air.

Because of the volume of drilling GEECL was forecasting—300 wells—the company decided to purchase the RD20 because of its depth capacity and Atlas Copco's commitment to the Indian market, and the fact that the RD20 was designed for the CBM industry. The company expects to drill 100 wells in the next 2½ years and 50 to 60 wells a year thereafter so purchase of a second drilling rig is likely.

The drilling depths average 3,300 ft (1,000 m) with the deepest well to date at 4,167 ft (1,270 m). From the surface, a 17½-in. (45-cm) hole is set with 14-in. (35-cm) conductor casing. A 12¼-in. (31-cm) hole is then drilled and set with 9-in. (24-cm) surface casing. To complete the well, an 8-in. (20-cm) hole is drilled and set with 5½-in.(14-cm) production casing. These holes are drilled with air circulation using the Atlas Copco TD80 and QL120 down-the-hole hammers.

However, the compressor onboard the RD20 delivers 350 psi of pressure at 1,250 cfm so to speed up the drilling an XRVS 1250 auxiliary compressor was added to the drilling operation, the air from the two compressors being combined and fed through the Hurricane booster and vented directly into the discharge line. The wheeled XRVS delivers 1,273 cfm at 365 psi. With this set up, the RD20 is drilling and casing the deepest holes in only five days.

Chief driller Jerry Tennel, originally from West Texas, has experience with double and triple conventional rigs as well as 25 years in the business. He says: "We have more than enough air running the onboard air and the XRVS 1250 auxiliary compressor boosted to 800 psi at the 4,167 ft depth."

DrillAir Advantages

At the Portable Air premises in Antwerp, Dr. Gathuru Mburu, product manager–large compressors, introduced the DrillAir product range. Dr. Mburu, who learned the business in his native Kenya, explained that to meet customers’ expressed preferences, each model is available in a metric version and an imperial equivalent.

The 25 bar XRVS 617 and XRVS 647 provide free air deliveries (fad) of 606 liter/sec to 630 l/s and their 365psi Imperial equivalents deliver 1,284 to 1,335 cfm. The 30-bar XRXS 567 and XRXS 607 models deliver 566 to 591 l/s and the 435-psi versions provide 1,198 to­­­­­­­­­ 1,252 cfm fad. Both the 30-bar and 435-psi versions can also be optionally fitted to offer dual switching for operation at 25 bar (365 psi) to meet the application requirement. The latest 35-bar model DrillAir 35 and 510-psi DrillAir 510 are also available in two metric specifications— XRYS 557 and XRYS 577—and two imperial—XRYS 1220 CD 7 and XRYS 1260 CD 7—versions, offering free air delivery rates of 33 to 34.2 m³/min (1,165 – 1,207 cfm).

The DrillAir models are available as a skid-mounted, support-mounted, tandem or wagon versions. The skid-mounted unit can be placed directly onto any surface while the support-mounted version has integrated fork lift slots for positioning on a flat deck. The tandem unit has central dual axles that facilitate excellent maneuverability and high towing speeds. In the wagon version these dual axles are placed at the end of the unit providing ease of transport and stable movement on uneven work sites.

Powerful Package

A major feature of the DrillAir, explained Mburu, is the screw element design, the latest result of a continuous development process. This achieves a 4% reduction in energy consumption compared with the previous design, a reduced risk of leakages and a thrust load that has been increased by 15%. Mburu pointed out that through one year the 4% fuel saving would equate to €14,400.

The new gear box configuration offers exerts less force on the bearing so that the working range of the element is greater. Improved lubrication also guarantees longer life and greater bearing efficiency. The system also provides improved cold weather operation. Similarly, correctly sized compressor oil filters extend screw element lifetime.

Also contributing to DrillAir’s performance is the Caterpillar C18 ACERT T3 diesel engine, rated at 429 kW/575 hp and fitted to all the models. Fuel is supplied from either the standard 975-liter (257.6-US Gallon) fuel tank or a 1,550-liter (409.5-US Gal) tank optionally available for the skid and support versions. Another option is an onboard electric pump which reduces refueling time and thereby operational downtime. The fuel filling set up is ergonomic, with a lockable fuel cap offering security and a breather line to prevent air locks. There is an engine oil filter to enhance engine life and an emergency shutdown switch. Exhaust gases from the crankcase are filtered, keeping the coolers free of oil mist. And FuelXpert controls engine speed in relation to air demand, making major fuel savings when the machine is operating at partial load.

Centralized and well-positioned service drains ensure easy access and rapid maintenance. An optional low pressure regulating valve and outlet is available to enable a 7-bar (100-psi) hose connection for cleaning the coolers or using pneumatic tools. An optional internal night light illuminates the unit to allow 24-hour inspection and maintenance.

Oiltronix V2

When the temperature of the oil/air mixture in the vessel is below the dewpoint, condensate is formed. This condensate can enter the oil system and cause bearing and element failures and accelerate oil degradation. The Oiltronix system was introduced to better regulate the oil temperature at a level just above the dewpoint in the vessel, so that water will not condense in the compressed air. The new improved Oiltronix V2 features a fully reliable valve assembly, combo sensor, controller and wiring. This system is standard on the larger units and optional on the 25-bar /365-psi units.

Safety and Security

Further safety features include a sliding valve incorporated in the air outlet for safe operation at higher pressure. A battery switch with lock facility is fitted, as many jobsites now require a lockout procedure for equipment during service and maintenance routines.

An optional Remote Control unit allows the DrillAir XRYS 557 (XRYS 1220 CD 7) to be operated from a distance of up to 200 m (600 ft) while the Cosmos mobile phone network-based remote monitoring system provides access to compressor operational information and remote diagnostics. It also sends alerts via email and text message on pre-specified events.


The XRYS 577 (XRYS 1260 CD 7) model also features a new patent-pending DrillAirXpert full variable regulating system with a small, easy control panel mounted in the compressor casing. Mburu explained that DrillAirXpert ensures full control of air pressure and flow, offering an improved alternative to the competitors ‘combo’ systems by allowing full flexibility on pressure and flow regulation. The variable system is able to easily provide the exact pressure required when needed between 22 and 35 bar (300–510 psi). It can also be set to provide a fully regulated flow output of up to 673 l/sec (1,500 cfm). With no manual regulating valves and associated regulating lines XRYS 577/XRYS 1260 CD 7 DrillAirXpert eliminates any associated freezing problems guaranteeing cold ambient operation.

DrillAirXpert also reduces fuel consumption by a further 3% so that over 10 years of operation the savings due to the airend would be €144,000 and those resulting from DrillAirExpert €108,000—€252,000 in all.

Pressure and Productivity

Extensive testing of DrillAir compressors drilling Swedish granite showed a linear increase in hole depth with higher pressure. Although the higher pressure machines use more fuel and have higher drill tool costs, overall they cost less per drill meter and generate more revenue per day, Mburu concluded. Thus the DrillAir product line matches the Portable Air Division strategy of selling high quality products with low cost of ownership that increase customer productivity and provide a total solution, added Geert Follens, the division’s president.

Portable Air’s sales are divided between construction (35%), oil & gas (25%), mining (20%), process (10%) and services/other (10%). The unit spends 2.5% of earnings on research and development, a policy that is reflected by the fact that 79% of 2008 sales revenue came from products three years old or less. Portable Air is also committed to training staff so they are able to sell the value of the products.

Lundin Chooses ESRI for Exploration

GIS Software Solutions

Lundin Mining Corp. recently selected ESRI as its global geographic information system (GIS) software provider and entered into a two-year multinational agreement (MNA) with ESRI. The MNA will be managed by ESRI (UK) Ltd. and will enable Lundin Mining to deploy the full suite of ArcGIS products in an open, scalable, and standards-based GIS architecture.

Lundin Mining is a diversified base metals mining company with operations in Portugal, Spain, and Sweden, producing copper, nickel, lead, and zinc. In addition, Lundin Mining holds a development project pipeline that includes the Tenke Fungurume copper/cobalt project in the Democratic Republic of the Congo. Lundin Mining also has an extensive exploration portfolio and interests in international mining and exploration ventures. Its corporate offices are in Canada and the United Kingdom.

“This MNA license agreement with ESRI gives our exploration geologists, geophysicists, and geochemists a common platform for effective collaboration and sharing of ideas with powerful data management, visualization, and analysis tools,” said Dick West, Lundin Mining’s exploration technology director. “This will increase our odds of exploration and development success and reduce the time to reach decision points.”

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