Oil field technology: the machining of threads on delivery pipes and casings perfected
06.10.2014 - Oliver Hagenlocher
Whether we are talking about North America, Asia or Russia, the oil and gas industry is possessed by a spirit of optimism. Geological discoveries have led to a massive increase in the estimated reserves of many countries. This coincides with the opening up of new potentials for the use of innovative technologies. According to the experts’ estimates, oil production in the Gulf of Mexico alone will rise from the present 1.3 million to 1.7 million barrels a day during the next decade, with demands for the highly sophisticated technological equipment required to accomplish it increasing proportionately. Two examples are delivery pipes and casings. How the two can be connected safely and in perfect alignment depends on the threads on the pipe ends. With its USC turning machines, the specialists from EMAG Leipzig have not only created a tool that specialises in this application – and one that has perfected the production sequence for these threads – but also developed complete solutions that guarantee component quality and process integrity.
Economic key performance indicators for suppliers to the oil and natural gas industry change rapidly. An impressive example of this is to be found in the USA. The country intends to reduce its dependence on oil imports and instead invest massively in new technology. An indicator are its imports of equipment technology for the American oil and gas industry, for which the statistics from the U.S. Department of Commerce for 2012 show an increase of 33 percent, compared to the previous year. The experts also expect a production boom in South America and Asia. For Brazil, for instance, the foreign trade experts at Germany Trade and Invest (GTAI) predict a “high level of growth in new reserves“. And on the other side of the globe, the investment volume in the oil and gas sector of Vietnam alone has reached 40 billion USD, according to GTAI.
The experts at EMAG Leipzig are very much aware that this extraordinary dynamic has direct consequences on the production of the required technology. For decades, the machine builders at Leipzig have been specialising in the machining of delivery pipes and casings for the oil and gas industry. Many users can no longer do without their special know-how in demanding thread production. Frank Schiffler, Head of Sales, fills us in on the background: “We are talking about a gigantic production output. One steel mill produces up to 2 million metric tons of pipes per annum. And the question of component quality is paramount, as the pipe threads have to be totally leak-proof and must carry the enormous total weight of pipe and oil during the latter’s delivery. The machining centres used must ensure that the quality and efficiency of the threads produced is 100%.“
Flexible solutions for the production of pipes
The USC series from EMAG Leipzig Maschinenfabrik represents an extraordinary, technically sophisticated solution for this particular production requirement. Flexibility is of the utmost importance in the construction of these turning machines. Not only do the different machine sizes allow for the complete-machining of greatly differing sizes of pipes with external and internal threads to API and GOST standards, they can also cut all proprietary threads. “The larger oil field technology producers have their own thread standards. We can adjust our machines perfectly to their demands“, explains Mr. Schiffler. For instance, all workholding and centring equipment is configured to suit individual requirements. The same applies to all automation components. As a result, the customer possesses an extremely fast production solution that automatically loads and unloads the components and in 12 to 20 seconds (depending on pipe size and thread type) carries out the 3-part threading process – from facing to chamfering and finally thread cutting. The output ratio thus increases enormously, compared with that of conventional turning machines.
However, there are two important factors to be taken into account when machining threads on delivery pipes and casings: processing quality and process integrity. The quality is guaranteed by a perfectly adjusted machine, in which well proven EMAG technology and the know-how of the speciality machine builders from Leipzig come together. The whole process benefits from the following most important design details:
- The machine base in Mineralit (a polymer concrete) guarantees the stability and the vibration-resistance of all machine components.
- The main drive forms an integral part of the spindle unit. Its frequency-controlled, maintenance-free AC asynchronous motor provides a high torque rate, which allows for the simultaneous machining of both ends of the pipe.
- The pipes are safely clamped in front and rear chucks that – dependent on workpiece requirements – can be actuated pneumatically, hydraulically or mechanically.
- The pipe ends are stabilised during the machining process by the insertion of vibration-reducing mandrels, resulting in the highest possible precision.
“This quality is a feature of all our USC series machines“, acknowledges Herr Schiffler. Depending on the machine used, the max pipe diameter can be anything from 2⅜” to 20”.
Complete solutions guarantee process integrity
When faced with high production rates, fast machining processes and expensive pipe blanks, machine downtimes are particularly costly for the manufacturer. For this very reason, the process integrity of these machines is another key development area in Leipzig. “We design complete solutions for our customers, who - in turn – benefit from the quality of the EMAG components“, explains Herr Schiffler. “In addition to that, we integrate, for instance, measuring stations, crack detection equipment, embossing and plating units and, of course, a monitoring system that covers all components. At the end, what we supply is a production system that guarantees the greatest possible degree of process integrity.“ Of similar importance in this context is the worldwide service presence of the specialists. Not only are both user and maintenance staff trained to perfection, a 24-hour 365-day telephone service is also available. This ensures that possible machine downtimes are reduced to an absolute minimum.
Projects from A to Z
How do the special machine manufacturers assess their market opportunities over the next few years? Herr Schiffler’s judgement on the market’s dynamic is a positive one: “We already are the market leader for machines for the threading of oil and gas pipes; and we intend to further extend this position.“ One formula for success in this field is the famous “Made in Germany“ – as ever a sign for quality. Over 70 percent of the machine components are made and assembled at EMAG in Germany. Every customer comes to Leipzig for the machine acceptance, where the first test run, using the actual pipe blanks, is carried out. Only then will the machine be installed at the production site. “Our particular quality of service kicks in long before the machine is built, or the central claim made by EMAG Leipzig would not be a valid one. Our name stands for projects that are carried through to perfection from A to Z, and that represent all-round solutions.“