Formed in April 2007 to meet growing worldwide demand for coiled tubing products and related services, Global Tubing manufactures the widest selection of coiled tubing in the industry. Sizes range from three-quarter inch outside diameter all the way up to five inch, with the widest range of wall thicknesses: from 0.080 to 0.337 inches. Commenting on the decision to launch the company, C. Robert Bunch, Global Tubing Chairman and CEO, said: “The idea was to create a company different from the principal existing competitors. It was time for the third major participant in the market; the one that would be focused exclusively on the coiled tubing business and provide a focus on customer service.” According to Bunch, the edge of the Company is based on three principal things: TEAM, TECHNOLOGY and SERVICE.

 

TEAM

“I’ve been very pleased with the team. We’ve attracted some of the most experienced people in the industry,” Bunch asserts. With over 20 members currently, Global Tubing personnel have an aggregate of 211 years coiled tubing manufacturing and service experience. Several members of the Global Tubing team participated in the founding and start-up of the other two coiled tubing manufacturers - Quality Tubing and Tenaris.

 

We’ll give you a brief sketch. C. Robert Bunch, Chairman and CEO, has more than 30 years experience in oil service industry, being former CEO of Maverick Tube Corp. (owner of Precision Tube). Rodney G. Bond, vice president of operations, spent 17 years with Precision Tube Technology, occupying leading management positions, after field experience that involved using coiled tubing at Otis Engineering. Experience of Doug Wheeler, vice-president of sales and marketing, includes more than 30 years in the exploration and production industry, most recently with ION Geophysical. Ray Rowland, the Company’s Manager – Mill Operations, has over thirty years experience manufacturing tubular products, including 10 years as Precision’s mill manager.

 

TECHNOLOGY

Global Tubing is a leading innovator in coiled tubing technology.

 

The company is the only coiled tubing manufacturer using friction stir welding to join strip ends. This technology has been used extensively in the aerospace industry. Rodney Bond explains: “Applying friction stir welding is considered to be a real benefit in terms of tube quality. This technology should result in better fatigue life as well as improved resistance to corrosion compared to coiled tubing containing bias welds performed with conventional arc welding techniques.”

 

The welding process goes as follows: the base material is softened by frictional heat into a plastic state and “stirred” together with a rotating tool without the necessity of filler material or melting. Base metals are softened by frictional and deformation heat, stirred, and forged together (Figure 1).

 

This approach produces a finer grain structure in the weld area and eliminates solidification defects, property variations across the weld zone and cast-like weld characteristics common with arc welding (Figure 2). The result is a stronger, more reliable weld that promotes longer life and cost effectiveness.

 

In addition to improved fatigue life, resistance to corrosion and better joint reliability and quality, benefits of this step-change technology include reduced environmental effect, and safer manufacturing. Among other innovations, forming the Company’s technological supremacy, are the latest tube milling, inspection and service technology available today.

 

SERVICE

Global Tubing provides the most comprehensive range of coiled tubing services in the industry, including spooling, welding, hydrotesting, installation and preventative maintenance. “Being entirely focused on coiled tubing market, we believe we have an unmatched level of service and attention to the customer. I would be disappointed if our customers think we don’t have the highest level of service, responsiveness and focus,” Bunch points out.

 

FACILITY

Global Tubing’s commitment to technology is readily apparent throughout its new manufacturing complex. The facility features nearby rail access and is convenient

to major highways and the Port of Houston.

 

Situated on 61 acres only 45 minutes from Central Houston, Global Tubing’s five-building campus includes corporate headquarters, two mill operations buildings with laboratory facilities, service operations and training facilities. The mill and service buildings are equipped with overhead bridge cranes. The use of bridge cranes significantly reduces reliance on forklifts and improves personnel safety.

 

Global Tubing’s own electrical substation provides clean, uninterruptable power supply directly from primary transmission lines. “We’re situated next to a high voltage power transmission line which operates at 138,000 volts. We’ve built our own switch yard and substation to pull power off it. Also we’ve put our own distribution line on the transmission system here. What that means to us as well as our customers is fewer shutdowns relating to power fluctuations that typically occur in public distribution lines. Power fluctuations can shut a mill down, so we feel like it gives us a little bit of an edge in ability to meet the operators’ demands”, explains Rodney Bond, who kindly gave us a tour round the plant.

 

As you enter the mill building, you see racks of raw steel strips. The first step in tube making is to slice flat strips from the roll of sheet steel, and this step is usually performed by a company specializing in this operation. The strip’s thickness establishes the CT wall thickness and the strip’s width determines the OD of the finished CT. Unlike its competitors, Global Tubing currently sources all of its steel in the United States. The steel sheet is manufactured using a continuous-cast hot rolling process to ensure final chemistry and mechanical properties. Parent strip tests are used to ensure specifications.

 

The second step in manufacturing process constitutes splicing the flat strips together to form a single continuous strip of the desired CT string length. This is performed with the help of friction stir welding described above. At once the result is subject to strip splice weld inspection. Rodney Bond comments: “This is where we X-ray the

weld”.

 

Then a flat strip of the desired length is put on an accumulative reel, which can carry up to 120,000 pounds of strip material. “Once accumulation of the right length strip is complete, it would be fed into the mill and milled according to the order”, Bond says.

 

The CT mill then utilizes a series of rollers to gradually form the flat strip into a round tube. Global Tubing makes use of New T&H Lemont Dual Capacity Quick Change Mill.

 

“First the edges are curved, and that’s the hardest part of the strip to form,” Bond continues. The final set of rollers forces the two edges of the strip together inside a high frequency induction welding machine that fuses the edges with a continuous longitudinal seam. This is where the electronic resistance welding takes place, and it is carried out with the help of Solid State Longitudinal Seam Welder – latest generation Thermotool® variable frequency with HAZControl technology for better weld quality.

 

This welding process does not use any filler material, but leaves behind a small bead of steel (weld flash) on both sides of the strip. “Once the welding is complete, there would be a weld bead, or scarf as we call it, on the ID and the OD. After the welding we trim the OD scarf off the tube. For most products the ID scarf stays in place, although for some products the customers wish the ID scarf be removed, and we do it as well. We do not trim the ID scarf for 1¼ and less, because it’s too small.”

 

The mill removes the external bead with a scarfing tool to provide a smooth OD. The weld seam is then normalized using highly localized induction heating. Then it goes though about a hundred feet of air cool. “We don’t want to cool it too rapidly. We cool it with treated water after a hundred feet. Shortly after being cooled it goes into a sizing station. When we mill the tubing, we mill it over the nominal diameter. This station squeezes it down to its target diameter,” Bond explains.

 

The product is tested to check For unwelded areas or any defects that might be on the surface of the tube. If the system detects a defect, it will signal an alarm. “We perform a number of non-destructive tests (X-ray, liquid penetrent, a number of surface hardness tests) for either proof or disproof of this defect. It’s very sensitive, and in many cases there won’t actually be a defect there, what we call false signals, but we have to look at every one of those,” Bond says.

 

Testing is carried out in sophisticated laboratory facilities: “We take the string and measure it for yield strength, tensile strength and elongation. We cut and mount the samples here for micro-hardness tests. We polish the surface to a very high polish and then we inspect it with a microscope. We also have a stereoscope here, so we can look at the cross-section in the steel.” X-raying is fulfilled with the help of computer radiography, which allows to zoom with enhanced resolution (Figure 3). “Everything we make has to pass vigorous multi-stage inspection in quality standards”, asserts Bond.

 

Once mill operation is complete, the tubing goes through almost a thousand feet of air

cooling until it gets to the winder building, where the tubing is spooled. The spools are for tubing of various diameters. The spool drum diameter is not less than forty times the tubing diameter to limit the plastic strain resulting from bending the tubing around the drum. Next the spool of coiled tubing is picked with a coil handler and put into the rail car to be delivered to the service building.

 

Once the spool of tubing has been milled, transported to the service area, the service crane takes the spool and transports it to the hydrotesting station. Bond points out: “We have 2 hydrotesting stations here: one for the products coming from the mill, the other test station is for service work. Having 2 stations avoids conflicts for resources.” Each test station is rated for 20,000 psi. Once the testing is complete, the tubing is attached to a nitrogen system for purging. A corrosion inhibitor is injected using the nitrogen gas which distributes the chemical across the ID.

 

The final stage is respooling, final inspection and packaging, after which the coiled tubing is ready for shipment.

 

Summarizing everything that was shown and mentioned, Rodney Bond, who actually played a leading role in designing and building the plant, shares the Company’s plans for the future: “This plant has quite a big expansion potential. As the business grows, there is capacity for two other mill buildings. Now we’ve got 22 employees, but we expect to be around 50 people by the end of the year and 300 by the end of 2014.”

 

GLOBAL PROSPECTS

Sales and marketing initiative of Global Tubing is indeed global, in keeping with its name. The Company is very much focused on serving the world-wide market, planning to sell in Europe, Middle East, North and Latin America and Russia. According to Bunch, Russia and CIS countries are quite promising markets. Moreover, Global Tubing Chairman and CEO made a nice observation, which is likely to please the Company’s Russian customers-to-be: “Interestingly, different countries, different cultures have different perceptions of new technology. Operators in many parts of the world tend to be very reluctant, very shy sometimes to adopt new technologies. But the Russians and the Canadians are two countries, two cultures that tend to embrace new technology, they are very technically sophisticated.”