Boom Times in the Oil Patch
The recovery of the energy drilling industry has been good for machine tool providers, responding to new rotary rig installations
By Bruce Morey
Pumping fluid and sand under very high pressure into rock formations to crack and open previously played out fields has dramatically improved the economics in North America. This is in addition to today’s measure-while-drilling strings, acting like electronic moles that sniff oil as they drill. They are certain to find what they seek with far fewer dry holes. Good news also means challenges. Wells are now even deeper, where pressures and temperatures are intense. Keeping up with demand means working as efficiently as possible.
All of this has upped the ante for machine tool suppliers. While turning remains the mainstay, turning centers must produce more accurate, high-quality threads to exacting tolerances than ever before, according to Brian Papke, president of Mazak Inc. (Florence, KY). Complex parts, such as drill string heads or fracking pump parts, need multitasking machines that turn, thread, mill pockets, make angular cuts, and mill internally. He also notes that materials are getting harder and more exotic to withstand the heat and pressures of wells miles under the surface.
In response, Papke reports that combination machining and turning centers like Mazak’s Integrex e-670 are popular. The five-axis e-670 Multi-Tasking machine for large complex shaft-type workpieces is on the larger end of the Integrex series, able to machine lengths up to 238.1" (6048 mm), with outer diameters of 42.13" (1070 mm). With tool storage capacity up to 120, the idea is to get it done in one setup. “Sometimes those machines are delivered with long boring bar changers, multiple spindles, and multiple steadyrests,” he remarks. An equally popular machine is Mazak’s QTN 450-II MY Multi-Tasking machine that provides turning and milling along with Y-axis capability. “We also make the QTN 450-II MY/LBB with a long boring bar capability designed for the oil industry work,” says Papke. To make complex valves, Mazak recently introduced the Orbitec 20 for valve body production. The four-axis machine, featuring a unique Mazak patented headstock design, processes more than 75% of valve applications in one setup, according to the company.
“The trick to serving the oil and gas market is to offer a wide variety of machines with a wide range of applications,” he says. Helping customers match applications to technology is Mazak’s new Energy Services Technology Center in Houston, TX. Opened in June 2011, the center helps customers develop processes specifically tuned to their needs.
Hydraulic Fracturing on the Rise
“The biggest growth driver in the industry is hydraulic fracturing,” agrees Jim Yeakley of SB Machine Tools (Schaumburg, IL). He notes that these high-pressure, reciprocating plunger pumps are typically designed in two pieces, a frame that holds the pistons and a fluid end shaped like a manifold that discharges the mud water.
"In oil and gas, we are seeing a need to machine more components that are being consumed for fracking,” says Richard Klein, application engineer for OKK USA.
“There is a lot of internal profiling in the bores of fluid ends,” he says. The most popular machine his company delivers to the industry is a Nomura table-type horizontal boring mill (HBM), in either a 4.3 or 5.31" (109 or 135-mm) spindle size. “For oil and gas, boring mills have the advantage of usually larger tables compared to machining centers, there is more horsepower, and the ballscrews are bigger, delivering more torque and thrust,” he explains. For example, the HBA-110T-R3 with a 4.3" spindle provides maximum torque of 2615 ft-lbs (3545 N•m) with a spindle thrust of 4400 lb (19,571 N). He also notes that for oil and gas, the most common application is to use a contouring head, a U-axis head, along with the machine’s native X, Y, Z, and W axes. “The in-and-out stroke of the quill drives an [additional] facing head U axis, creating a two-axis movement. You can turn your mill into a lathe, if you will, and you can program ID profiles with G-code to make the machine more versatile,” he remarks.
Another key element of the oil patch is blowout preventers (BOP), subsea devices used to monitor and control oil and gas wells. Roger Santi, senior product specialist for MAG IAS (Fond du Lac, WI), reports that the original manufacturer must now maintain and recertify by these devices. “Our VTC Series vertical turning centers that range in size from 1.6 to 2.5 m are most popular for oil and gas,” he says. Repair of BOPs means disassembling, cleaning, remachining critical sealing surfaces, inlay welding with Inconel, and machine features like new. “These big chunks of steel that can weigh as much as 80,000 lbs [36.3 t] have long cycle times,” he says. “Some parts are on the machine three or four days.” He reports MAG’s VTC 1000–3500 series as most popular and provide a maximum torque of 77,164 N•m with a thrust bearing load up to 113,400 kg for the tough machining of these big pieces. He also reports that MAG IAS provides HBMs to oil and gas customers as well, including floor types with 4 m to virtually unlimited X-axis travel and high weight capacity.
Santi is seeing a change towards using more ceramic insert cutting tools in just the last two years, reflecting a move towards higher speed machining techniques. “This means improving speeds from 150 to 200 fpm [45.75–60.96 m/min] surface feed to 400–600 fpm [122–183 m/min].” Another is a move towards higher feeds, over 300 ipm (7620 mm/min). Why? “High feed, shallow depth-of-cut techniques reduce cutting forces and cycle times and allow extended reach for machining and contouring,” he says.
MAG IAS has also been pioneering cryogenic cooled machining. This process uses cooled liquid nitrogen that boils away as a gas, instead of cutting fluid, to cool the tool. The most significant benefits are with tough materials like titanium, stainless steel, hardened alloy steels, Inconel, and tough irons like compacted graphite iron (CGI). These are metals you find in the oil patch.
“What is striking about working with oil and gas components compared to other industries is not just the size [and weight] of some of these components, but the intricacy and exact specifications required,” says Jeff Wallace manager-DMG / Mori Seiki Centers of Excellence of DMG / Mori Seiki (Hoffman Estates, IL). “These are complicated devices whose specifications sometimes even exceed those for jet engine parts.” Some parts made of Inconel are up to 4-m long and require 300 features on them, according to Wallace. “We are now seeing titanium parts as weight is becoming an issue when you stick a part down a hole that is two miles deep,” he says. One of the more popular machines for downhole components from his company is their NT6600 DCG mill-turn center, with a maximum turning length of 236" (5994 mm) and a part diameter of 42.1" (1069 mm).
Large expensive parts means doing it right the first time is critical. “[Manufacturers of downhole components] are asking for more on-machine metrology. These pieces are large, cumbersome, expensive, and made of expensive materials. They do not want to pull them out of a machine to do in-process checks,” he says. He reports delivering everything from traditional touch probes to sonic inspection systems that check wall thickness—all integrated into the machining center.
Sophisticated Smaller Companies Embrace Technology
“What is striking about oil and gas machining is how much better these businesses are run than even five or ten years ago,” remarks Anthony Fettig, president of UNISIG (Menomonee Falls, WI). In part, he attributes this to affordable technology, from CAD to CAM to the specialized deep-hole drilling that is UNISIG’s specialty. UNISIG offers machines that drill both on-center and off-center deep holes to demanding tolerances. Some examples of machines they provide include USK and UNX machines for off-center gundrilling of small holes, ranging from 5 to 20 mm in diameter up to 5 m in depth. Others include their B-Series machines for on-center BTA drilling of larger holes, ranging from 20 to 300 mm in diameter up to 12 m in depth or USC machines for off-center gundrill and BTA drilling heavy parts.
UNISIG serves many industries from automotive to defense, giving Fettig a unique perspective. The difference in materials stands out. “Exotic materials are not exotic for oil and gas customers,” he explains, ranging from the hardest superalloys and Inconels. “We get a wide mixture of parts and raw materials for our test runs.”
This means fine-tuning the process to ensure proper mating of machine, tooling, part, and controls is vital to success, according to Fettig. “We have started putting histograms on the interface [of our drilling machines] so that we can dynamically graph spindle, thrust and other loads over time,” he explains. This allows operators to track down causes of anomalies. Fettig predicts this trend continuing, with a focus on controls and the process of monitoring accompanying mechanical innovations such as faster spindles, higher thrust, and more power.
Horsepower and torque is a selling point for the TM series of turning centers from Hurco (Indianapolis, IN), according to Jay Bryan, new product development manager for the company. “In particular the TM 18 and 18L series delivers 1721 ft-lbs [of torque] from a 73-hp [54.4-kW] motor,” says Bryan. “We now use a 4:1 ratio gearbox. It is a step function for us in terms of power and torque from any other machine that we offer.” He noted that this was Hurco’s first model with a gearbox, signaling the company’s commitment to a high-torque offering. “Oil and gas customers need this because of the sheer size of the parts they are turning, such as drill casings. We have a 6 1/2" [165-mm] bore through the spindle on the TM 18 model,” he explains. While acknowledging that many oil field parts are much larger than this machine accommodates, what may be unique is the power and torque in a machine this size. Bryan reports that the major use is machining precise threads on drill casings and other tubes.
More Consumables in the Offing
The advent of fracking also means more wear parts. “In oil and gas, we are seeing a need to machine more components that are being consumed for fracking,” says Richard Klein, application engineer for OKK USA (Glendale Heights, IL). These are primarily laterals, unions, and connections between shafts. “Machining these components requires high Z-axis thrust and spindle torque to utilize 3 and 4" [76 and 102-mm] diameter drills in steel forgings,” he explains. He reports that OKK’s KCV800 vertical machining center is popular, configured with a geared head, 120" (3048-mm) long X-axis travel, and a Tsudakoma rotary table for four-axis flexibility. ”Using a rotary table with a large bore clearance and high clamping force allows us to load a long shaft, position it and mill it in different positions for keyways and other features on the shafts.”
The advent of fracking also means more wear parts. “In oil and gas, we are seeing a need to machine more components that are being consumed for fracking,” says Richard Klein, application engineer for OKK USA (Glendale Heights, IL). These are primarily laterals, unions, and connections between shafts. “Machining these components requires high -axis thrust and spindle torque to utilize 3 and 4" [76 and 102-mm] diameter drills in steel forgings,” he explains. He reports that OKK’s KCV800 vertical machining center is popular, configured with a geared head, 120" (3048-mm) long -axis travel, and a Tsudakoma rotary table for four-axis flexibility. ”Using a rotary table with a large bore clearance and high clamping force allows us to load a long shaft, position it and mill it in different positions for keyways and other features on the shafts.”
OKK also recently introduced a heavy duty, high torque horizontal machining center that is right for the oil field industry, according to Klein. The MCH 8000 features a three-step gearbox that delivers 1828 N•m from a 35-hp (26-kW) spindle motor. The machine features a highly rigid structure using a hybrid boxway and B-axis design. It delivers high torque with spindle speeds ranging from 20 to 6000 rpm. To Klein, this is a trend back to heavy cutting from the now popular high speed machining techniques. “You just cannot use a high-speed machining approach efficiently on many of the metals available today,” he explains, such as superalloys. “Exotic metals require high thrust and a lot of torque. We are not abandoning high-speed machining, of course, but complementing it with these heavy cutting machines.”
Bill Gore, regional manager for Fuji Machine (Vernon Hills, IL) is also seeing a high demand for consumable parts like pipe couplings. Individual manufacturers can produce in excess of 15,000 such couplings per day. Other such parts include valves and valve seats of the reciprocating fracking pumps. “The materials being pumped are so abrasive, they may only get 20–40 hours of usable life out of them,” he explains. “Our company’s focus is complete modular turn, drill/mill solutions from a single source. [ideal for valves, valve seats and couplings,]” he says. He also believes turning centers with integrated robotics, also from Fuji, are ideal in these high-volume applications.
“Our equipment is designed with an overhead boxway. This is better than a traditional commodity flat bed or slant bed lathes, especially for an automated system, because it controls chips, and coolant better through a 90° bed layout with the overhead boxways which are not exposed to chips collecting at the bottom,” he explains. Integrated automation is a key feature.
For example, Fuji’s ANW series features a Fuji swing-arm robot integrated within the machine for automated material handling. The robot is isolated from the cutting zone by a separate set of doors allowing parallel tasking including auto gaging and part marking. Takt times are reduced because the robot is working while parts are being cut. Fuji offers modular integrated robot turning and drill/mill solutions without the need to resort to additional material handling automation. ME
This article was first published in the February 2012 edition of Manufacturing Engineering magazine. Click here for PDF.