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Oil & Gas
Influence of Hydrogen From CP On the Fracture Susceptibility of 25%Cr Duplex Stainless Steel - FE Modeling of Constant Load Testing Using Hydrogen Influenced Cohesive Zone Elements.
Olden, Vigdis (NTNU Norwegian University of Science and Technology, Dept. of Engineering Design and Materials & Sintef, Institute of Materials and Chemistry, Dept. of Applied Mechanics and Corrosion Trondheim, Norway) | Thaulow, Christian (NTNU Norwegian University of Science and Technology, Dept. of Engineering Design and Materials) | Berstad, Torodd (Sintef, Institute of Materials and Chemistry, Dept. of Applied Mechanics and Corrosion Trondheim, Norway) | Østby, Erling (Sintef, Institute of Materials and Chemistry, Dept. of Applied Mechanics and Corrosion Trondheim, Norway) | Nyhus, Bård (Sintef, Institute of Materials and Chemistry, Dept. of Applied Mechanics and Corrosion Trondheim, Norway)
ABSTRACT Cohesive zone modeling of hydrogen induced stress cracking in 25% Cr duplex stainless is performed. The simulations represents constant load tensile testing of notched samples in 3.5% NaCl aqueous solution under cathodic protection. A user defined polynomial traction separation law including reduced cohesive energy with increasing hydrogen concentration is applied. FE simulations and laboratory experiments suggests that the net section stress should be kept below 580 MPa for a V-notch sample with radius 0.25mm and below 620 MPa for a U-notch sample with radius 2.0mm to avoid HISC induced fracture in 25%Cr duplex stainless steel. INTRODUCTION Hydrogen produced during cathodic protection has in recent years been found to cause cracking and failure in stainless steel subsea pipelines and fittings. Duplex stainless steel is traditionally regarded as safe due to the duplex structure of ferrite and austenite with the ductile austenite acting as a crack stopper. However, at the low corrosion protection potentials applied in the North Sea, the hydrogen production is considerable. Combined with stresses during production hydrogen induced stress cracking, HISC, is observed also in 25%Cr duplex stainless steel. Diffusion in duplex stainless steel mainly takes place in the ferrite phase. Diffusion in the austenite phase is very slow and has an insignificant influence on the effective diffusion coefficient. However, the diffusion is still much slower than in plain ferrite steels. This is an effect of an increased diffusion length in the ferrite due to the austenite islands and trapping at the austenite phase boundaries. Aspects as the shape, size and spacing of the austenite islands will influence both diffusion length and trapping. Fine dispersed austenite islands will typically promote more tortuous diffusion paths and trapping compared to a structure consisting of coarse austenite island and larger intermediate ferrite "paths".
- Materials > Metals & Mining > Steel (1.00)
- Energy > Oil & Gas (1.00)
Turbulent Solitary Wave Boundary Layer
Sumer, B.M. (Technical University of Denmark, MEK, Coastal, Maritime and Structural Engineering Section Lyngby, Denmark) | Jensen, P.M. (Technical University of Denmark, MEK, Coastal, Maritime and Structural Engineering Section Lyngby, Denmark) | Sørensen, L.B. (Technical University of Denmark, MEK, Coastal, Maritime and Structural Engineering Section Lyngby, Denmark) | Fredsøe, J. (Technical University of Denmark, MEK, Coastal, Maritime and Structural Engineering Section Lyngby, Denmark) | Liu, P.L.-F. (School of Civil and Environmental Engineering, Cornell University, Ithaca, NY, USA)
ABSTRACT This paper summarizes the results of an experimental investigation of turbulent solitary wave boundary layers. The wave induced flow has been simulated by a solitary motion in an oscillating tunnel. The experiments show that the boundary layer flow remains laminar for Re numbers smaller than Re=5x10. The experiments further show that the bed shear stress reverses during the deceleration stage of the free-stream flow. In a narrow sub-range of Re number (2x10 ≤ Re < 5x10) in the laminar regime, the boundary layer flow experiences a regular array of vortices near the bed over a short period of time during the deceleration stage. The transition-to-turbulence at Re=5x10 is associated with the emergence of turbulent spots, revealed by single/multiple, or, sometimes, quite dense spikes in the bed shear stress variations. Flow resistance in terms of wave friction coefficient including the phase information has also been worked out for both the acceleration and deceleration stages of the free-stream flow of the wave. INTRODUCTION Although much research has been done on boundary layers under harmonic progressive waves (Lundgren and Jonsson, 1961, Hino et al., 1983, Sleath, 1987, Jensen et al., 1989, Lodahl et al., 1998, Dixen et al., 2008, on the experimental side, and Fredsøe, 1984, Spalart and Baldwin, 1987, Justesen, 1988, Lohmann et al., 2006, on the theoretical side, to give but a few examples), to the authors' knowledge, Liu et al. (2007) were the first to study boundary layer flows under solitary waves in details. They derived analytical solutions, based on (1) those of Liu and Orfilla (2004) for viscous boundary layer flows under transient long waves, and (2) the solutions for the nonlinear boundary layer equations. They also carried out laboratory measurements that include the free-surface displacement, PIV-resolved velocity fields of the boundary layer, and the bottom shear stress.
A Study On the Rotating Flow In an Annulus
Kim, Young-Ju (Korea Institute of Geoscience and Mineral Resources(KIGAM), Daejeon, Korea) | Yoon, Chi-Ho (Korea Institute of Geoscience and Mineral Resources(KIGAM), Daejeon, Korea) | Park, Yong-Chan (Korea Institute of Geoscience and Mineral Resources(KIGAM), Daejeon, Korea) | Park, Jongmyung (Korea Institute of Geoscience and Mineral Resources(KIGAM), Daejeon, Korea) | Kang, Joong Seok (Korea Institute of Geoscience and Mineral Resources(KIGAM), Daejeon, Korea) | Kwon, Seok-Ki (Korea Institute of Geoscience and Mineral Resources(KIGAM), Daejeon, Korea) | Woo, Nam Sub (School of Mechanical Engineering, Sungkyunkwan University Suwon, Korea) | Hwang, Young Kyu (School of Mechanical Engineering, Sungkyunkwan University Suwon, Korea)
ABSTRACT Lift forces acting on a fluidized particle play a central role in many importance applications, such as the removal of drill cuttings in horizontal drill holes, sand transport in fractured reservoirs, sediment transport and cleaning of particles from surfaces. An experimental and numerical investigation is conducted to study a solid-liquid mixture upward-transporting hydraulically by Newtonian fluid and non- Newtonian fluid such as sodium carboxymethyl cellulose(CMC) solution by weight in a slim hole concentric annuli with rotation of the inner cylinder. Annular fluid velocities varied from 0.2 m/s to 2.0 m/s under the actual drilling operational condition. Macroscopic behavior of solid particles, averaged flow rate, and particle rising velocity are observed. For both waater and CMC solutions, the higher the concentration of the solid particles are, the larger the pressure gradients become. Also, CMC solutions have been observed to provide better capability to mobilize and transport particles. The mean diameter of particles was 0.1 cm and a material density of 2.55 g/cm3 were used in the experiment. INTRODUCTION Among the various industrial unit operations involved with multiphase systems, agitation of solid-liquid systems is quite commonly encountered such as catalytic reactions, drilling operation of oil well, etc. Although there are many industrial applications of solid-liquid flows in technology, the available knowledge about particle flows is not complete due to the difficulties encountered in analyzing these complex systems. Rotating flows in annular passages are important, since they have many engineering applications in bearings, rotating-tube heat exchangers and, especially, annulus flows of mud in case of slim hole drilling of oil well. When an oil well is drilled, it is necessary to transport the cuttings up to the ground. To this end, fluid is pumped through the center of drill pipe and back up to the ground through the annular gap between the drill pipe and the drilled hole.
Non-steady Growth Modeling of Anaerobic Consortium of Microorganisms Around Methane Seepage
Yamazaki, Tetsuo (Natl. Inst. of Advanced Industrial Science and Technology Tsukuba, Japan) | Monoe, Daisuke (Chuden CTI Co., Ltd. Nagoya, Japan) | Oomi, Tomoaki (Chuden CTI Co., Ltd. Nagoya, Japan) | Nakata, Kisaburo (Tokai University Shizuoka, Japan) | Takeuchi, Rika (Univ. of Tokyo Tokyo, Japan) | Fukushima, Tomohiko (Ocean Policy Research Foundation Tokyo, Japan)
ABSTRACT As a part of fundamental understanding of ecosystem functions around seafloor methane seepage, the non-steady growth modeling of anaerobic oxidation of methane and anaerobic sulfate reduction by consortium of microorganisms is studied numerically. The model and results of preliminary test calculation are introduced. INTRODUCTION Natural cold seepages are characterized as rapid upward transports of methane from deeper parts of geological structures to the seafloor. Thermogenic and/or biogenic methane generated in deep strata moves up to seafloor, and major part of methane are consumed by microorganisms living in anoxic marine sediments. When the supply of methane is very large or rapid, remaining unconsumed methane escapes from the seafloor to the water column. Methane itself has a considerable impact on the greenhouse effect, if it is released into the atmosphere in the global carbon cycle. It is reported that methane emission from oceans is ca. 5.6 % in percent of total emission (Lelieveld et al. 1998, cited after the Intergovernmental Panel on Climate Change (IPCC) 2001), but detailed numerical explanation of methane emission and consumption in ocean has not been cleared yet. In Japan, the potential use of natural methane hydrate as an energy resource has been highlighted, and a national R&D project named MH21 to locate deposits and to develop exploitation technologies has been conducted (). Since there are less domestic oil and natural gas resources in Japan, the highly attractive possibility for energy resource and the many potential areas in ocean around Japan are the alternative reasons of the project. Less CO2 discharge from methane compared with coal, oil and conventional natural gas when the same calorie value we get is considered as the advantage for energy resource. However, becausemethane hydrate distributes in shallower sediment layer in ocean floor
- Geology > Mineral > Sulfate (0.40)
- Geology > Sedimentary Geology > Depositional Environment > Marine Environment (0.34)
Prediction Method of Transient Temperature Distribution In Friction Welding of Two Similar Materials of Steel
Isshiki, Yoshihiro (Faculty of Engineering, Setsunan University, Neyagawa, Osaka, Japan) | Kawai, Gosaku (Faculty of Engineering, Osaka Sangyo University Daito, Osaka, Japan) | Ochi, Hiizu (Incubation Laboratory, Osaka Institute of Technology, Asahi-ku, Osaka, Japan) | Ogawa, Koichi (Faculty of Liberal Arts and Sciences, Osaka Prefecture University Sakai, Osaka, Japan)
ABSTRACT A numerical method was proposed to predict transient temperature distribution in friction welding of two similar materials of steel. In this method, heat input was estimated using the data of thrust pressure and rotation speed which could be easily measured under a commercial friction welder. The estimated heat input was given as a boundary condition of heat flux at the weld interface, and a finite element method was used for solving an unsteady heat conduction problem of two-dimensional axis symmetry. Transient temperature distributions during whole friction welding process were calculated using variable thermal properties of the specimen materials of mild steel and stainless steel respectively. Calculated results were compared with experimental results, and the relationship between calculated temperature distribution and measured hardness distribution was investigated in the vicinity of weld interface. INTRODUCTION Friction welding is a solid-state welding process for joining two similar or dissimilar materials. It is used widely throughout many manufacturing processes where high production rates are required. Friction welding conditions for the process are generally selected on the basis of past experience or study report. However, establishment of a method to decide the friction welding conditions in response to the phenomena which occur during friction welding has been needed because optimum welding conditions depend on each welding machine. Accordingly, many researchers have investigated the relationship between mechanical work, namely heat input, during friction welding and joint performance. Shinoda et al. (1993) revealed that the mechanical properties were correlated with the heat input, and they concluded that the optimum welding condition was obtained with large heat input. Sawai et al. (1999; 2001; 2002) have demonstrated that the mechanical work in the upsetting stage affects tensile strength of the weld joints.
- Energy > Oil & Gas > Upstream (0.92)
- Materials > Metals & Mining (0.92)
ABSTRACT The interest in Direct Electrical Heating (DEH) is increasing and the system is being planned for flow assurance in development of oil fields on continental shelf around the world. The DEH system is selected due to several advantages:Allow production of fields that earlier is considered as not feasible Effective solution with high heat input Easy to install and operate Reliable components Can be retrofitted on pipelines in operation Implementation require minor modification The running costs are considerably reduced compared to traditional methods utilising chemicals. At present it is installed on several subsea pipelines in the North Sea and DEH is applied actively to prevent hydrate formation during shut downs for a total accumulated use of 1 year during the lifetime of the field. For the new fields being planned with DEH there are several challenges due to extended design basis regarding:Continuously use of DEH during the lifetime of the field. Flow assurance of waxy unprocessed wellstream, requiring large heat input to the pipeline. Impact of steel armoured concrete pipe weight coating Use in shallow water Heating of risers and spool-pieces. As the pipeline is an active conductor in the heating system a special anode design is required, both to ensure sufficient grounding for the heating system and for corrosion protection regarding ac (alternating current). The design of the anode system is strongly related to time of use. This is one of the main challenges with continuous operation of DEH. Furthermore the design of the electrical cables is important regarding mechanical and thermal stresses. The lifetime of the cable depends on several factors. The lifetime of the DEH installation decreases with increasing cable temperature and with frequent use.
- Europe > United Kingdom > North Sea (0.24)
- Europe > Norway > North Sea (0.24)
- Europe > North Sea (0.24)
- (2 more...)
- Production and Well Operations > Production Chemistry, Metallurgy and Biology > Inhibition and remediation of hydrates, scale, paraffin / wax and asphaltene (0.68)
- Facilities Design, Construction and Operation > Flow Assurance > Hydrates (0.68)
- Facilities Design, Construction and Operation > Pipelines, Flowlines and Risers > Offshore pipelines (0.67)
Chemical And Physical Factors Influencing Behavior of Sodium Silicate-Cement Grout
Chun, Byung-Sik (Department of Civil Engineering, Hanyang University Seoul, Korea) | Yang, Hyung-Chil (CGM Corp. Seoul, Korea) | Park, Duk-Hyum (Department of Civil Engineering, Hanyang University Seoul, Korea) | Jung, Hyuk-Sang (Department of Civil Engineering, Hanyang University Seoul, Korea)
ABSTRACT This paper evaluates the influence of the additive on the compressive strength of the sodium silicate-cement grouts. When not using any additive, the compressive strength of silicate-cement grout homogel showed limited increase. It is estimated that complex salts (Na2O․ 3SiO2․ CaSO4․ H2O) were produced by the sodium silicate and the plaster retard the hydration of cement. The strength of the homo-gel increased significantly when using Sodium TripolyPhosphate as the additive. The strength is further increased when using the Circulation Grinding-Mixing method, which reduces the particle size of cement from 100-150 μm to 50-100 μm. In addition to laboratory tests, in-situ tests were performed to characterize the influence of the grout on the ground permeability. The test results indicated that the grouting significantly reduces the permeability of the ground. INTRODUCTION Since 1980 it is applied in South Korea and Japan, the age compressive strength of LW grouting was lower than data (refer to fig. 2). Thus, it was investigated into effect of concentration of sodium silicate on strength of Homo-gel when it varies the content of the sodium silicate in A solution 150 ℓ, 200 ℓ, 250 ℓ and fix the content of the cement is 200 kg in B solution. When the cement hydrate (calcium hydroxide) was 20% of cement weigh and the Molar Ratio was less than 1.0, the strength of the Homo-Gel was not higher than 5 kg/cm within 3 days. The results showed that Calcium Aluminate and Ferrite Complex Salts(Lea, 1971)and sodium hydroxide(NaOH) made cement hydrate delay. When sodium silicate gel, much calcium hydroxide which is essential to crystallization of a particle of cement is used. Based on calcium hydroxide poverty, the strength was not revealed(Yone kura et al., 2000).
- Asia > South Korea (0.35)
- Asia > Japan (0.25)
ABSTRACT Application of information technologies raises interest to preparation of high-qualified experts, quality management in operation of marine structures. Theoretical positions, principles of functioning, an assumptions and restrictions of decision system are given. Identification of problem area is carried out. Requirements of reliability, efficiency, protection of the information are provided. Methods and means of gathering and transfer of the information, a quality monitoring of the input information, language of inquiries, menu, helps, etc. are described. Graphic interpretation of structure of base of knowledge is given, the features of structure caused by character of tools are described, dependencies of factors the examinations connected with indistinct or probabilistic nature of knowledge are proved. The generalized reliability of offshore structures is determined by multiplication of physical, functional and external wear factors. The three stages of formation of information cone from raw data to information and then to synthesis of knowledge are considered. On every stage the cognitive maps are developed for three levels (meta-, macro- and microlevel). INTRODUCTION According to Federal program of water transport renovation up to 2010 the cargo turnover will be increased on 82% from 182 to 332 mln. t. There are 22 ports on Russia Far East from Posyet harbor to Tiksi port. The harbour structures need in investments accounting for development of offshore projects, exploration of Siberia and Yakutiya resources and usage of North transport route. At the present time the main problems are definition of wear and development of design procedures which are taking into account change of reliability during operation. Numerous defects of designs because of errors of designers and builders have turned with the course of time in critical ones.
Topographical Change of the Sandbar And Estimation of Suspended Solid Flux In the Nakdong River Estuary, Korea - Focused On Jinudo -
Lim, Sung-Pil (Department of Ocean Engineering, Pukyong National University) | Lee, In-Cheol (Department of Ocean Engineering, Pukyong National University) | Na, Won-Bae (Department of Ocean Engineering, Pukyong National University) | Kim, Heon-Tae (Department of Ocean Engineering, Pukyong National University) | Yoon, Han-Sam (Research center for Ocean Industrial Development, Pukyong National University Busan, Korea)
ABSTRACT In this study, to establish a countermeasure from marine casualties as a basic study for long-term prediction of topographical change around Jinudo in the Nakdong river estuary, Korea, spatio-temporal topographical change monitoring and Suspended Solid (SS) net flux estimation were carried out. From the result of monitoring, the annual mean ground level and deposition rate were estimated about 158.8 mm and 0.431 mm/day, respectively. Moreover, the depth averaged values of the latitudinal and longitudinal SS net fluxes during spring tide were approximately 6.0 times higher than those during neap tide. INTRODUCTION It is difficult to predict for environmental change in river estuary because this zones undergo constant changes due to the interaction between marine and fluvial systems. The zones in coastal area such as the tidal flat and salt marsh, is gradually decreased and changed due to large scale of coastal development projects, land reclamation, dike construction, and large amounts of soil dredging and so on (Tonis et al., 2002; van der Wal et al., 2002). The Nakdong river estuary, Korea, is located in the south-eastern part of Korea, is very famous for the largest Asian habitat for migratory birds. However, this estuary is suffering from the changes in the water circulation and topographical changes caused by the generation and migration of sandbars. The Suspended Solid (denoted as SS) originates from the materials such as clays, nutrients, polluted organic matters, and heavy metals. The transport of SS in shelf seas attracts more and more attention of scientists from different disciplines, as it plays an important role for many processes in the marine environment, not only for marine geology but also for the marine ecosystem (Jiang et al., 2004). As a result, many experiments have been undertaken to analyze topographical change.
- Energy > Oil & Gas > Upstream (1.00)
- Water & Waste Management > Water Management > Lifecycle > Treatment (0.81)
Critical Thermal, Corrosion And Material Issues Related to Flowline Pipe-in-Pipe (PIP) Systems
Jukes, Paul Jukes Paul (J P Kenny, Inc / IONIK Consulting Houston, TX, USA) | Singh, Binder (J P Kenny, Inc / IONIK Consulting Houston, TX, USA) | Garcia, Jose (J P Kenny, Inc / IONIK Consulting Houston, TX, USA) | Delille, Francois (J P Kenny, Inc / IONIK Consulting Houston, TX, USA)
ABSTRACT The common method of achieving enhanced thermal insulation performance of flowlines (U values of 1.0 W/m2K, or less) requires a ‘Pipe-In-Pipe’ (PIP) insulation system, in which the inner pipe carrying the fluid is encased within a larger outer pipe separated by an annulus insulation material. However, with all PIP systems it is important to ensure that the structural integrity is maintained for both installation and operational loads for each of the PIP components (thermal insulation, linepipe, centralisers, waterstop seals, and loadshares). The temperature of the internal contents of a PIP system can have a significant effect on the long term degradation and performance of materials. It is not uncommon for recent designs of pipelines to be considered for temperatures up to 350°F (177°C). Also it is important to ensure integrity for the entire life of the project, and that undesirable degradation of the thermal and structural performance does not occur. The effects of temperature on the PIP components are discussed within this paper. Various insulation materials are considered and these consist of mineral wools, polyurethane foam, granular or microporous materials, ceramics and Aerogels. Annulus related corrosion integrity issues including monitoring, inspection and on-going degradation and aging management are addressed. Performance of insulation in terms of thermal, heat transfer and effects of corrosion under wetting conditions and cathodic protection at the field joints will also be considered. The new technology presented in this paper is; a discussion into the critical aspects of testing PIP components for high temperature applications, a critical evaluation of different thermal insulation materials, mechanisms of MICC "Microbially Influenced Crevice Corrosion" and the hidden annular "Corrosion under Insulation" for pipelines, and inspection methods. Hence, this paper discusses key issues associated with PIP systems in terms of the structural integrity, corrosion and material integrity with regards to the PIP components.
- North America > United States (0.28)
- North America > Canada (0.28)
- Research Report (0.34)
- Overview > Innovation (0.34)
- North America > Cuba > Gulf of Mexico (0.89)
- Europe > United Kingdom > North Sea (0.89)
- Europe > Norway > North Sea (0.89)
- (2 more...)
- Well Completion > Well Integrity > Subsurface corrosion (tubing, casing, completion equipment, conductor) (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 > Piping design and simulation (1.00)
- Facilities Design, Construction and Operation > Pipelines, Flowlines and Risers > Materials and corrosion (1.00)