August 22, 2012
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Home / Issue Archive / 2010 / January #1 / New Challenges Test Pipe Makers

№ 1 (January 2010)

New Challenges Test Pipe Makers

   VNIIST is Russia’s main domestic R & D center for pipeline construction. Its specialists define quality standards of tomorrow, create modern technical policies, promote new technology and conjure up the pipelines of the future. Georgy Makarov, Ph.D in Sciences, professor, deputy general director for Science at VNIIST Institute LLC discusses new ideas and technologies with Oil&Gas Eurasia.

By Alexei Chesnokov

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Oil&Gas Eurasia: What some are the current trends in main pipelines construction?
Georgy Makarov: The strategy of scientific and technical development of oil pipeline transport, which focuses on safe and durable performance over pipelines’ entire service life, suggests creation of a new generation of main pipelines with a service life of 20-25 years more than that of current main pipelines. Implementing this new generation demands a portfolio of new organizational and technical means, as well as enhanced construction technologies across all stages of the oil pipeline life cycle.

   VNIIST is a designer of the "Concept of Oil Pipeline Transport Enhanced Reliability" for AK Transneft, substantiating the key research and development related to new technologies, equipment, structures and materials enabling higher reliability and environmental safety of all elements the of oil pipeline transportation system.

   A successful example of reliable and safe performance of new-generation main oil pipelines is the creation of a specialized regulatory technical documentation base for design and construction of especially complicated facilities such as the East Siberia – Pacific Ocean (ESPO) pipeline system. Currently, this ESPO regulatory technical documentation base includes over 140 documents (technical specifications, procedures, etc.). Technical specifications form the primary links in the chain of design and production processes.

Pacific Pipeline Challenges Pipe Makers

   The necessity for creation of specialized regulatory technical documentation packages is also related to the application of performance standards of oil pipelines, the measurements of which exceed values recommended in SNiP 2.05.06-85* “Main Pipelines” (with working pressure up to 12.5 MPa in individual segments, where the forecasted seismic impact level is above 9 units on the MSK-64 scale). The ESPO regulatory technical documentation package also includes the requirements for engineering and construction of oil pipelines in the following severe environmental and climatic conditions:
– permafrost and rocky areas;
– rock stream and buried ice areas;
– large and small river crossings;
– areas where pipelines traverses landslides and active tectonic faults.

OGE: What kind of new ideas and technological innovations are being used in ESPO construction?
Makarov: The design of the ESPO main oil pipeline has included up-to-date advancements made in the pipeline construction industry, technical conditions monitoring, SCADA, pipes manufacturing technologies, protection coating, welding and assembly operations. Most of innovative technical designs and applied technologies have set the trends of pipeline transport for many years ahead and have set the standards that the new generation pipelines will follow. We should mention first the fundamentally new level of pipe quality and the application of automatic welding for circular welds based on a continuous step-by-step technology.

   The guidelines, which have not been regulated before, include specifications such as banded structure and grain size, contamination by non-metal agents, requirements to KCV notched specimens’ impact hardness at 40°C, are being introduced for the first time. Base metal and factory-made pipe welds using NDT methods have been brought under regulation. To improve the versatility of welding and assembly operations we introduced exclusive standards for the geometry of groove faces, special requirements for temperature conditions during welding (induction heating and heat input value during welding), and tougher requirements for the pipes’ surface finish. A new requirement of obligatory mechanical expansion of pipes over their entire length has been added, which was not previously observed by a number of manufacturers.

Tougher Regulations Spur Tech Boom

OGE: How did the Russian pipe producers respond to such high demands?
Мakarov: It should be noted that VNIIST-specified tougher requirements for ESPO pipes spurred the implementation of new technologies by domestic steelmakers  and pipe mills, contributing to retooling and enhancement of production standards in the pipeline industry. This also brought about and to introduction of new technologies such as converter steel continuous casting.

   The ESPO project uses cold-resistant pipes 1,067-1,220 mm in diameter and 18-27 mm thick walls fabricated of steel grades K56, K60, K65 and K70 designed for 14.0 MPa pressure and safe performance at earthquake forces exceeding 9 units.

   To increase ESPO pipeline reliability, special technical specifications for the key equipment types have been designed such as for shutoff, control and safety valves, pumping equipment, cleaning and intelligent ping launchers and receivers. A novel approach is the requirement to preserve pipeline’s strength, anti-leak tightness and performance at earthquake loads. All earthquake-proof equipment shall preserve strength, tightness and performance during and after a load caused with a 9-unit earthquake. In case of a 10-unit earthquake load the equipment shall preserve its strength and leaktightness only.

   This reprensents the first time when specifications provide for shutoff valve seismic resistance qualification tests with the help of a special test bench that offers earthquake load simulation up to 10 units (MSK 64 scale). Testing also includes gate valve performance after seismic resistance. Similar requirements are also specified for control and safety valves.

OGE: Have the requirements for welding been modified?
Makarov: They have been fundamentally changed.
Advanced methods of automatic welding of pipes’ circular field welds and recent introductions of new examples of high-tech welding equipment have driven the recent trend of complete elimination of manual arc welding from welding and assembly operations and led the introduction of automatic flux-cored gas-shielded welding. This eliminates any necessity to have pipe-welding stations.
The construction of ESPO main oil pipeline is based on a continuous/split automatic flux-cored gas-shielded welding technology with the help of high production M33-S welding heads. Continuous step-by-step technology suggests simultaneous use of several workplaces by a welding assembly team, i.e. welding stations located in individual shelters Weld types are: root, hot, filling and trimming welds. One type of weld only is fulfilled at each workplace with the help of two specially adjusted welding heads moving along the joint perimeter in different directions. Upon completion of a specific cycle of operations at each workplace the team moves ahead. The productivity rate of the welding/assembly team may achieve 90-100 joints per day. All operators of M300-S welding head units qualified for this work at ESPO pipeline project were re-trained in VNIIST Welding School.

Keeeping Corrosion at Bay for Half a Century

OGE: Will you please describe the automated technology developed by your Institute?
Makarov: The introduction of variable frequency drive pumps, as well as new applications of microprocessors inspired implementation of a unified automated control system for main oil pipeline production, the key advantage of which is minimization of emergencies caused by human error. VNIIST has developed proprietary specifications for pumping units, establishing higher requirements for earthquake-resistant main pipeline pumping units with 10 MPa working pressure and high efficiency (86-89.5 percent). The requirements for pumping units’ high reliability ensure:
40,000 hours time to failure (on condition that end seals and bearings are replaced, respectively, after 16,500 h and 25,000 h);
63,000 h overhaul life.  Regulatory documents outlining implementation of a unified automated system for main oil pipeline control a package have been prepared which contain special technical requirements for a control system and basic monitoring  including:
Systems of automation, telemechanics and communications;
Block-boxes for monitoring against unauthorized access and control stations;
Transducer for technical conditions monitoring: corrosion rate indicators, seismic pickups and stations, intelligent insertable sensors for checking pipe wall stress or deformation, submerged sensors for soil displacement monitoring during slides, leak detectors, and cleaning and intelligent ping sensors;
Sensors for a general security system, fire alarm system, and a system monitoring unauthorized access to equipment such as vents, wells and cathodes. A unified automated system for a main oil pipeline control includes the following approaches:
Guarantee of uninterrupted power supply (hook-up to an along-the-route power transmission line and use of standby power sources for any equipment);
Redundancy of all network equipment, servers, processor modules of programmable logic controllers;
Creation of ethernet information networks based on loop protocol (including network self-recovery).
The unified automated control system is a modular one comprising a real control room: monitoring and control unit, with instrumentation and automatic sensors. An innovative technical solution is the application of modular monitoring and control units, which are completely stand-alone automatic assemblies of high protection and survivability level.

OGE: What corrosion protection technologies are currently used to protect the pipelines?
Makarov: The key trend in protective coatings for the pipelines, which are currently under construction, is the end of the practice of coating pipes in the field; instead using only factory-coated pipes. VNIIST has developed requirements for pipes with a three-layer factory-applied insulation coating based on 3-milimeter-thick extruded polyethylene, as well as requirements for pipes with factory-applied heat insulation made of polyurethane foam for large-diameter main oil pipelines. The circular welds of such pipes are insulated with the help of heat-shrinking collars. All insulation materials undergo a set of preliminary special integrity tests in VNIIST Test Center, wherein their compliance with the developed requirements is verified. We can confidently say, that corrosion challenges for new pipelines has been eliminated. Coatings applied in accordance with our requirements guarantee protection against corrosion for the entire pipeline’s entire service life (45–50 years).

OGE: What about the state of previously constructed pipelines?
Makarov: Presently, AK Transneft operates about 50,000 km of main pipelines from 420 mm to 1,220 mm in diameter, the majority of which was built during Soviet times. Within the framework of the Technical Re-equipment, Reconstruction and Capital Repairs (TRR and CP) Program, some segments of pipeline are currently under scheduled replacement to bring them into compliance with regulatory requirements. For example, replacement of the pipelines with backing ring welds: the internal bushing currently in place prevents the launching of modern intelligent pings.
VNIIST has designed a new approach to the assessment of a pipeline’s technical state based on: internal diagnostics and inspections that aid in deciding whether the pipeline contains a hazard of any revealed defect (or combination of defects) stemming from a stress or strain in the area of a defect, the level of actual loads being carried, and the condition of materials and welds at certain points in the service life.
VNIIST has designed an industrial standard for AK Transneft “Industrial Standard. Main Oil Pipelines. Assessment of Strength and Durability of Pipes and Welds Containing Defects”, using a test method of strength and durability design of structures containing defects. This standard is based on theoretical elastoplastic tendencies  and respective boundary problems of fracture mechanics. Note that the initial data on mechanical properties of pipes and welds of main oil pipelines came from testing of standard and special samples cut out of pipeline segments under inspection.

New Generation Pipes

OGE: Running pipelines years beyond their design life often results in accidents. What needs to be done to minimize safety risks?
Makarov: Unlike oil pipelines, gas trunklines suffer stress-corrosion. This problem appeared in the 1990s, when the core part of the main gas pipeline system built back in the 1960s and 1970s had begun to wear out. Stress-corrosion cracking is caused by a combination of two factors: aggressive fluid stresses and mechanical stresses in a pipe wall. To this day there is no authoritative mathematical description of this phenomenon, so we have not had a chance to draft additional requirements for pipes or welded joint. The most effective method of protection against stress corrosion is a high quality anti-corrosion plan, and for gas main pipelines, this includes reapplying anticorrosives to pipes and welded joints.

OGE: What innovations are currently being developed by the specialists of the Institute?
Makarov: I would lay emphasis on two new trends in achievement of main pipelines safety and reliability:
– creation of new generation pipes with improved performance characteristics;
– probability-based safety analysis (PSA) providing for higher levels of design reliability due to additional (above standard) technical solutions throughout the course of pipeline construction in critical areas such as water crossings or near protected natural areas, etc.
The requirements for new generation pipes drafted by VNIIST ensure regulation with a considerably larger number of performance charateristics such as crack resistance, elasticity, hardness and weld properties. These new generation pipes will enable further reduction of material safety margin values in wall thickness. The design of such pipelines fabricated from the new pipes and used under current conditions will reduce the required estimated wall thickness by 5-10 percent. 
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