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Abstract Continuous energy developments around the world provide both an opportunity and challenge to develop linepipe microalloyed steels with superior properties and performance for the oil and gas industry. To fulfill these requirements a fundamental understanding of the composition-processing-microstructure-property relationship is needed. The objective of the present work was to define the optimal microstructure to achieve the required strength-toughness properties. Different thermodynamic software packages and mean flow stress (MFS) models were used to study the effect of the composition and thermomechanical processing (TMP) conditions on the final microstructure. The validation stages were performed by laboratory studies and industrial scale trials. Impact tests were used to evaluate the toughness. Advanced characterization techniques; electron optics (SEM, HRTEM) and Electron-Backscattered Diffraction (EBSD) microstructural analysis were carried out to quantify the microstructure, texture, precipitation and the evaluation of crack propagation paths. The X-70 microalloyed steel exhibited an excellent package of strength-toughness properties. These properties were obtained by a combination of fine bainitic ferrite, fine precipitations and small volume fraction of fine MA islands. The fine bainitic ferrite was the result of the microstructural conditioning of the austenite prior to the transformation and cooling conditions. It provided excellent resistance to crack propagation.
- North America > United States (0.47)
- South America > Brazil (0.47)
- Asia > China (0.28)
ABSTRACT Since oil discoveries are moving towards ultra-deepwater areas, such as Pre-Salt in Brazil, collapse resistance is a key factor in the design of the pipelines. Large diameter UOE pipes are being increasingly used for the construction of such pipelines. It is known that the cold forming, and the final expansion in the UOE linepipe manufacturing process, reduces the compression resistance for elastic collapse. Due to this, the DNV collapse formula includes a fabrication factor that de-rates by a 15% the yield strength of UOE Pipes. However, DNV also recognizes the effect of thermal treatments and the code allows for improvement of the fabrication factor when heat treatment is applied. This paper presents the qualification of UOE pipes with enhanced collapse capacity focusing the use of a fabrication factor (alpha fab, afab) equal to 1. TenarisConfab has performed a technology qualification process according to DNV-RP-A203 " Qualification Procedures for New Technology" and the main aspects of the qualification process are presented in this paper which included significant material and full scale testing, including combine load testing, compression testing and a final analysis. The qualification process achieved successful results and this will allow TenarisConfab use of a fabrication factor equal to 1 directly in deepwater and ultra-deepwater offshore pipeline projects with a possible reduction in material and offshore installation costs and also potentially enhancing the feasibility of many challenging offshore projects. INTRODUCTION The exploration of oil and gas reserves at distant points from coast is bringing significant challenges to Oil & Gas industry. Some fields are located at hundreds of kilometers from the coast and are placed at water depths up to 3,000 meters. Deepwater pipelines will be subject to a large net external pressure and collapse capacity may be governing for the wall thickness design. In this condition, the pipe resistance becomes an important challenge due to present installation methods and due to the considerable loads caused by the pipe weight due to the heavy wall thickness necessary to resist the external collapse pressure. The need to produce and transport large volumes of gas in safe conditions demands the use of large diameter steel pipes produced by UOE-SAWL process which is a confident alternative and has already been applied in some important projects. Considering this harsh environment, it is necessary to study and develop a pipe with enhanced collapse resistance capable to resist ultradeep water pressures and also reduce installation loads by optimizing wall thickness. The great majority of the pipelines worldwide are designed following DNV-OS-F101 [2]. The collapse resistance of the pipe is significantly influenced by a number of factors related to pipe properties and hence pipe manufacturing process. Furthermore, through a proper control of the pipe making process and understanding of linepipe properties, improvements in the collapse resistance of UOE linepipe are possible. [5]
- South America > Brazil (0.89)
- North America > United States (0.68)
Abstract The necessity of oil and gas exploration to attend the worldwide demand led to new challenges for engineering and materials development. The reserves of Pre-Salt in Brazilian coast is an example of such challenge, since it combines fields that are located at approximately 250 km off the coast, up to 3,000 meters deep water and corrosive environments. All these factors are detrimental to the pipeline making it necessary to develop new products that are capable to comply with demanding requirements for hostile environments, considering corrosion resistance in the presence of H2S, high strength, high toughness and heavy wall thickness to resist the external collapse pressure and good weldability for field installation. The UOE-SAWL process for pipe production enables the transportation of large amounts of oil and gas using large diameter pipes in safe conditions. In order to attend the main Brazilian projects, special requirements including DNV-OS-F101 have to be fulfilled by the pipe manufactures taking into account the as mentioned challenges to be overcome. The desired steel properties can be achieved by high end technologies in steelmaking, such as optimum rigorous alloying design, vacuum degassing and dynamic soft reduction, followed by Thermomechanical Control Process plus accelerated cooling (TMCP+ACC). The cleanness of the obtained steel associated with the accelerated cooled microstructure have an important role in the sour service resistance, weldability and mechanical properties. This paper presents the evaluation of mechanical properties and corrosive resistance of OD 24 in, WT 38.1 mm grade DNV 450 SFD produced according to DNV-OS-F101, supplementary requirements and corrosive tests carried out in conformance with NACE MR0175 and NACE TM0177. Good results were obtained in Charpy V-Notch tests of Base Metal, Heat Affect Zone and Weld, DWTT, CTOD and all the others required mechanical tests. Satisfactory results were also obtained in the HIC and SSC corrosive tests. The combination of all the obtained results make this pipe capable to face the challenges of the new exploration fields in Brazil. Introduction Nowadays long-distance offshore deepwater and ultra-deepwater pipelines have been and are still being built for the transportation of large quantities of oil and gas. The Brazilian offshore province began to attract the attention of the oil industry a couple of decades ago. The exploration of deepwater fields in the Presalt province and hence the necessity of oil and gas transportation, requires demanding material properties, leading pipe manufactures to seek for products excellence [1]. The pipes used for this application are commonly produced using the " UOE" process. This method provides many advantages in terms of product capacity, productivity, material properties and dimensional control. These applications require high strength, low D/t ratio in order to have good collapse resistance, high impact toughness, good weldability and sour resistance. In order to achieve the desired properties, the steel has been produced using the state of the art technology in steelmaking, such as optimum rigorous alloying design, vacuum degassing, dynamic soft reduction, etc. The effects of this technique, associated with the Thermomechanical Control Process plus the Accelerated Cooling (TMCP+ACC) resulted in enhanced material properties.
- Reservoir Description and Dynamics > Reservoir Characterization (1.00)
- Production and Well Operations > Production Chemistry, Metallurgy and Biology > Corrosion inhibition and management (including H2S and CO2) (1.00)
- Facilities Design, Construction and Operation > Pipelines, Flowlines and Risers (1.00)
Abstract Laser measurement systems (fixed and portable) have been developed by Tenaris to perform an automatic dimensional inspection of pipe ends. Measuring OD, ID and WT, this tool is helpful not only for pipeline producers, which can have a better knowledge of the manufactured pipe ends' geometry, but also for the laying companies and for the end users, giving useful information in order to perform more efficient pipe line-up prior welding. Since fatigue is normally the main limiting design criterion for fatigue sensitive products like flowlines and risers, representing a major engineering challenge, one way to minimize the risks of girth welds' fatigue failure is to reduce the pipes abutting Hi-Lo. This task could be accomplished by the use of laser pipe ends measurements analyses together with dedicated software. Improvement of line-up pipe is very important for offshore oil recovery industry, where the fatigue requirements of pipelines subject to high dynamic loads are continuously increasing, as the exploitation is moving in harsh environments. This paper describes the validation process and the implementation of automatic measurement systems for the inspection of the pipe ends' dimensions with high repeatability and precision. In addition, the following software applications are showed:–Division in families: determination of pipes groups according to their OD/ID/WT tolerances; –Best Matching: search of the alignments which minimize pipes abutting Hi-Lo; –Counter-Boring: analysis of the best pipe ends ID and/or OD to be machined and of the residual WT forecast after counter-boring. Introduction The increasing requirements of risers and flowlines subject to fatigue loads are leading to an interest of pipe ends laser measurements, aiming to enhance girth weld manufacturing and consequently their fatigue strength. Fatigue is becoming one of the most important aspects to be taken into account in the design of offshore floating production systems (e.g. Spar, Semi-submersible, Tension Leg Platform (TLP), Floating Production Storage and Offloading (FPSO)). Due to their highly compliant nature, fatigue loading is accentuated particularly if compared to traditional fixed-bottom platforms. Fatigue loading arises due to production systems' motions that are caused by current action and waves. Some of the most fatigue critical components of these systems are the import and export Steel Catenary Risers (SCRs). Wave motions transmit significant fatigue loading to SCR, in particular at the touchdown location where the nearly vertical riser curves to join the pipeline or flowline on the ocean floor. In addition, the riser can experience fatigue loading due to vibrations induced by sea currents, like Vortex Induced Vibrations (VIV). These vibrations can occur at any number of locations along the riser length depending on the dynamic response of the structure and the current profile.
- Facilities Design, Construction and Operation > Pipelines, Flowlines and Risers > Risers (1.00)
- Facilities Design, Construction and Operation > Pipelines, Flowlines and Risers > Piping design and simulation (1.00)
- Facilities Design, Construction and Operation > Offshore Facilities and Subsea Systems > Floating production systems (1.00)