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Making connections in gas pipelines that may not be taken out of service requires special techniques. Hot tapping is often applied. Split tees are welded to pipelines that are and remain completely operational. The split tees are placed on the pipeline and then welded together using longitudinal welds to make one tee piece. After inspection, circumferential welds are made to create the connection between the tee piece and the pipeline. This same welding technique is also used to repair damage to pipelines. This can be in the form of a buttering up (surfacing) repair as part of a pipeline rehabilitation program or installing full-encirclement repair sleeves. Installing repair sleeves can also be a follow-up to an in-line inspection that has established that there is damage to the pipeline or to an activity that has been reported as doing damage as a result of external interference (e.g., excavation, trenchless techniques for installation of cables or other pipelines, plowing). N.V. Nederlandse Gasunie has had research conducted since 1978 by, among others, Netherlands Organization for Applied Scientific Research (TNO) in order to obtain a sound basis for a reliable and safe way to weld on live gas pipelines. This article covers over 20 years of operational experience with welding on live gas transmission pipelines. The article addresses regulations, critical aspects of welding on operational gas pipelines, and the control of these critical aspects. The metallurgical background issues are also discussed. [ABSTRACT FROM AUTHOR]

In this paper the development of a welding procedure for the joining of steel type UNS S32760 (Super duplex F55) for use in the off-shore application is described. The joint was realized by means of the TIG (GTAW) manual process for the first passes and by a manual filling process with stick electrode (SMAW), in order to obtain the combination of mechanical and microstructural characteristics desired by the customer. The results obtained from the tests on the joints must provide proof of successful completion of all the tests to be part of the joint in accordance with the contractual requirements and stabilized the base for actual use in the production. The particularity of the case, in addition obviously to the inherent difficulties posed by the type of steel chosen, consisted in the request by the customer of a combination of mechanical and microstructural characteristics to the limit of the possibilities of a welding procedure suitable for use in production mode and times compatible with the internal market and production requirements. It was therefore necessary to design the welding procedure and choose the most suitable process parameters to achieve the required results. The evaluation of the joints to achieve in production and the characteristics to be obtained, has led to decide to perform welding with welding processes previously mentioned and in the welding position-frontal plane (PB/2G). The main problems to be considered in the design phase of the welding procedure, are to be found in the value of the maximum heat input, interval of interpass temperatures to be observed and the type of shielding gas to use with which material can be welded to avoid the formation of intermetallic microstructure phases of the joint and sappers of corrosion resistance. [ABSTRACT FROM AUTHOR]

This paper, starting with an introduction of passive and active thermography method, describes the possible control procedures and applications of this method in the oil industry. In particular, on the basis of in service experiences are described: predictive analysis (furnaces, boilers, fume pipes, chimneys, reactors, etc.) for the quantitative valuation of the insulating I refractory surfacing to recover during TA; coke search in ovens, with a focus on intervention procedures, monitoring of the thermal distribution (heat exchangers, air coolers or condensers) to verify the efficiency of the heat exchange; continuous monitoring of TIP temperature during transients (for example, during hydrogen plant start-up) in order to prevent critical events of such components; predictive analysis of electrical substations in order to monitoring thermal gradients, thermal map of the sliding contacts of turbine shafts to verify wear resistance, resulting in maintenance plan. [ABSTRACT FROM AUTHOR]

EST Plant (Eni Slurry Technology) consists of about 300 pressure vessels in the following principal units and section: * EST unit (unit 90); * Hydrogen production plant (Unit 95); * SWS sulphur recovery and tail gas treatment (Unit 92 and 94). More than 100 "critical" equipments exist in the EST complex, divided in units and sections on the basis of their type of service. In detail, the considered critical items include: carbon steel and low alloy steels heavy wall pressure vessels for high temperature, high-pressure hydrogen service; carbon steel pressure vessels in sour (wet H^S service) and amine service. For fabrication of such "critical" items special base materials and filler metals were adopted according to specific material requirement, special welding processes and fabrication sequences (including advanced automatic systems for non destrucutive testing) were used. This paper shows an overview on some critical aspects and experience of fabrication of main "critical" equipments of EST Plant. [ABSTRACT FROM AUTHOR]

Presently, many economical and technical efforts are made by pipeline industry aimed to satisfy the needs to transport gas from far away regions to the final market and to set new solutions in terms of both design criteria and new high performance materials. Due to the fact that easy Oil and Gas is largely exploited and new fields will be more and more in deeper water (it means water depths greater 305 m), that means higher pressures and temperatures and more corrosive environments, material requirements are increasing. In this situation low-alloy carbon steels tend to be structurally satisfactory, but lack in terms of corrosion resistance. On the other hand stainless steels and nickel alloys resist to corrosion environments but are lack in terms of strength or extremely costly. Clad pipes, low-alloy carbon steel with a thin layer of a corrosion-resistant alloy, is presently considered, more and more, a suitable solution to the most demanding requirements of strength, corrosion resistance and cost-effectiveness. In a cladded pipe, the (generally) unalloyed carbon steel outer pipe handles the internal and external pressure, while the high-alloy cladding provides the corrosion protection. The paper describes the pipes and fittings production starting from metallurgical clad plates. In particular the experience developed by Allied Group is described. The developed products and components represent the ideal candidate for the most severe offshore and subsea applications typical of the Oil&Gas sector. [ABSTRACT FROM AUTHOR]

In the recent past, reheat cracking phenomena have been shown in 2.25 Cr 1Mo 1/4V weld metal of heavy wall pressure vessels. For monitoring these phenomena, chemical and mechanical methods have been developed: Glow Discharge Mass Spectrometry method, which gave Kf para-meter, and Gleeble® thermo-mechanical test, performed at low strain rate. Depending on a few Gleeble® test parameters, the test results couldn't be obtained in laboratories other than Industeel Research Centre. To overcome this limit, European Mini JIP project started in early 2010. This paper describes these two test methods developed for monitoring these phenomena and giving a Mini JIP project achievement report. [ABSTRACT FROM AUTHOR]

The application of RCM methodology to the Life Cycle Cost reduction of Oil & Gas systems. The RCM methodology can provide a real and concrete con-tribution to the optimization of maintenance policies, from both a technical-operating and economic standpoint; the ap-plication of this approach to process plants and in particular to those of the Oil & Gas, represents a real opportunity for all those companies which are thinking to adopt it. For the "stabilization " of benefits over time, with positive ef-fects on the entire life cycle of a plant, it is necessary that the Reliability Centered Maintenance is not limited to an isolated project, but is instead implemented as a permanent business process, with an organizational dedicated structure, made up of figures and competences to guide and run the most efficient and effective choices. The most advanced maintenance poli-cies: the predictive (PdM) and condition-based (CBM), can be configured and defined thanks to a timely application of RCM maintenance decisions for the most critical single items within a plant, resulting in an optimal management of techni-cal, operational and organizational resources. [ABSTRACT FROM AUTHOR]