Volume 5: Pipelines, Risers, and Subsea Systems最新文献

{"title":"New Flow Assurance System With High Speed Subsea Fiber Optic Monitoring of Pressure and Temperature","authors":"J. Hedengren, D. Brower, J. Wilson, G. High, Karl Witherow","doi":"10.1115/OMAE2018-78079","DOIUrl":"https://doi.org/10.1115/OMAE2018-78079","url":null,"abstract":"Subsea production control systems are instrumented to constantly monitor flowline pressure and temperature at key locations to prevent plugging and introduce mitigating control strategies. New fiber optic sensors with ruggedized construction and non-electrical components are subjected to accelerated aging tests and deployed in several installations with long service life. An overview of current progress with fiber optic technology is provided for fatigue monitoring, temperature, pressure, and strain sensing. Recent developments include improved service life, novel bonding methods, pipeline sensor station improvements, sensor calibration, and long-term fatigue analysis.\u0000 The latest advancements are validated on multiple installations on a subsea tieback in the deepwater Mississippi Canyon of the Gulf of Mexico at 6,500 ft depth. A prior third-party sensor design experienced multiple non-recoverable sensor failures. A new sensor station design is employed on two Flowline Terminations to monitor pressure and temperature at a rate of 100 Hz. Subsea tiebacks are susceptible to flow assurance issues caused by plugging events such as hydrate formation. The system was originally designed to track pig location but transitioned to pressure and temperature sensing. An issue with the transition was the lack of calibration relating the fiber Bragg grating (FBG) strain levels to the actual process conditions. A novel method is presented for in situ adjustment of the sensor array calibration.\u0000 During the calibration procedure, the sensors produced unanticipated results during pipeline flow shut-in and later startup operations. The sensors helped uncover a configuration of the flowline and sensor locations that is valuable for detecting hydrate forming conditions at a key junction location. The sensors are located before and after the junction of two flowlines in the mixing zone of the pipeline streams. The novel contributions of this study are the high speed data collection, in situ fiber optic calibration, review of advancements in fiber optic sensing technology, and a field case study with multiple sensing arrays.\u0000 The developments are part of the Clear Gulf study, a collaboration between the offshore energy industry and NASA that was formed in 2010. The objective of the Clear Gulf study is to employ space technology and testing facilities for use in the up-stream industry to advance subsea sensor technology. The highly sensitive monitoring systems developed as part of this study are used to give early warnings for flow assurance issues, structural failures, or catastrophic events.","PeriodicalId":155568,"journal":{"name":"Volume 5: Pipelines, Risers, and Subsea Systems","volume":"99 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115341000","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Subsea Cable Stability on Rocky Seabeds: Comparison of Field Observations Against Conventional and Novel Design Methods","authors":"T. Griffiths, S. Draper, Liang Cheng, F. Tong, A. Fogliani, D. White, Fraser Johnson, D. Coles, S. Ingham, Caroline Lourie","doi":"10.1115/OMAE2018-77130","DOIUrl":"https://doi.org/10.1115/OMAE2018-77130","url":null,"abstract":"As offshore renewable energy projects progress from concept demonstration to commercial-scale developments there is a need for improved approaches beyond conventional cable engineering design methods that have evolved from larger diameter pipelines for the oil and gas industry. New approaches are needed to capture the relevant physics for small diameter cables on rocky seabeds to reduce the costs and risks of power transmission and increase operational reliability.\u0000 This paper reports on subsea cables that MeyGen installed for Phase 1a of the Pentland Firth Inner Sound tidal stream energy project. These cables are located on rocky seabeds in an area where severe metocean conditions occur. ROV field observation of these cables shows them to be stable on the seabed with little or no movement occurring over almost all of the cable routes, despite conventional engineering methods predicting significant dynamic movement.\u0000 We cite recent research undertaken by the University of Western Australia (UWA) to more accurately assess the hydrodynamic forces and geotechnical interaction of cables on rocky seabeds. We quantify the conformity between the cables and the undulating rocky seabed, and the distributions of cable-seabed contact and spanning via simulations of the centimetric-scale seabed bathymetry. This analysis leads to calculated profiles of lift, drag and seabed friction along the cable, which show that all of these load and reaction components are modelled in an over-conservative way by conventional pipeline engineering techniques. Overall, our analysis highlights that current cable stability design can be unnecessarily conservative on rocky seabeds. Our work foreshadows a new design approach that offers more efficient cable design to reduce project capex and enhance through-life integrity management.","PeriodicalId":155568,"journal":{"name":"Volume 5: Pipelines, Risers, and Subsea Systems","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122099077","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Basin Tests and Numerical Simulations of Wake-Induced Oscillations of In-Line Risers in Subcritical/Critical Regime","authors":"V. Levasseur, C. Leca, B. Rousse, François Pétrié","doi":"10.1115/OMAE2018-77842","DOIUrl":"https://doi.org/10.1115/OMAE2018-77842","url":null,"abstract":"This paper adresses Wake Induced Oscillations in the transition between subcritical and critical regime. Both experimental and numerical approaches are proposed and compared here to model tandem risers motion. The main purpose is to enlarge our insights of the behavior of different arrangements of risers in this very tricky range of incoming flow (Re ∈ [134,000; 300,000]) and to assess the CFD ability as an industrial design tool.","PeriodicalId":155568,"journal":{"name":"Volume 5: Pipelines, Risers, and Subsea Systems","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128402240","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Qualification Testing of Titanium Stress Joints Designed for Galvanic Hydrogen Mitigation Conveying Hot, Sour Well Fluids","authors":"R. Schutz, Gabriel Rombado, D. Baker, Heath W. Walker, C. Caldwell","doi":"10.1115/OMAE2018-78105","DOIUrl":"https://doi.org/10.1115/OMAE2018-78105","url":null,"abstract":"A three-phase laboratory test qualification program for Titanium Stress Joint (TSJ) use in an offshore steel catenary riser (SCR) system handling hot, marginally sour well brine fluid offers guidance for expanded, safe TSJ use in hot sour well service. Phase 1 results indicated a reasonable concern and risk for long-term excessive hydrogen uptake and damage to the TSJ when directly coupled with the steel riser and steel topside piping. An alternative TSJ design, incorporating an Alloy 625 cathode buffer transition between adjoining steel tubulars, was proposed for mitigation of galvanic hydrogen charging uptake and damage prevention for hot sour fluid service. This “Tri-Metal couple” design was modeled in Phase 2 using polarization curves as input, and simulations projected insignificant hydrogen charging on TSJ bore surfaces exposed to “Worst-Case Sour” brine fluid at 250°F (121°C). Phase 3 aimed at qualifying the TSJ welds for even more severe and acidic sour well fluid service conditions up to 275°F (135°C), via fatigue crack growth rate (FCGR) and J-R fracture toughness testing of weld metal, and S-N fatigue and slow strain rate (SSR) tensile testing of cross-welds. These tests confirmed the high degree of hot sour environmental resistance for Grade 29 Titanium welded joints, and reasonable compatibility with TSJ design requirements.","PeriodicalId":155568,"journal":{"name":"Volume 5: Pipelines, Risers, and Subsea Systems","volume":"113 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124146697","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Steel Lazy Wave Riser for Turret vs. Spread-Moored FPSO in Extreme and Wave-Induced Fatigue Conditions","authors":"D. Szczepanski, Cheslav Balash, M. Martens","doi":"10.1115/OMAE2018-78736","DOIUrl":"https://doi.org/10.1115/OMAE2018-78736","url":null,"abstract":"Here, the performance of a steel lazy-wave riser (SLWR) was numerically investigated and compared to a conventional steel catenary riser (SCR) for an internal turret and spread-moored FPSO in extreme 100-yr return and ambient metocean conditions. As expected, the SLWR demonstrated favourable characteristics by the elimination of local dynamic buckling in the touch down zone (TDZ) via a wave configuration that decouples surface-motion, hence significantly reducing the maximum stress and fatigue damage. Non-collinear waves and current in the oblique direction relative to the vessel heading showed amplified stress concentrations in the sag and hog sections as a response to the increased compressive (heave and pitch) vessel motions. Correspondingly, in the ultimate limit state, a SLWR showed similar stresses for both turret and spread-moored FPSOs. However, the turret-mounted SLWR demonstrated a less superior fatigue life compared to its midship-mounted, spread-moored counterpart, owing to riser hangoff location differences and correspondingly varied motions experienced by the riser.","PeriodicalId":155568,"journal":{"name":"Volume 5: Pipelines, Risers, and Subsea Systems","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128133288","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Considerations in Design of Centralizers for Pipe-in-Pipe Systems","authors":"S. Manouchehri","doi":"10.1115/OMAE2018-77535","DOIUrl":"https://doi.org/10.1115/OMAE2018-77535","url":null,"abstract":"For un-bonded (sliding) Pipe-In-Pipe (PIP) systems, one of the main components is the centralizers (also called spacers). The main functions of the centralizers are to centralize the inner pipe inside the outer pipe, to transfer the loads between inner pipe and outer pipe and to safeguard the insulation material in the annulus from excessive compression during fabrication, installation and operation.\u0000 Centralizers must also have good thermal insulation properties so that the heat loss is minimized. Different designs are now available for centralizers but the majority are based on two half shells which are bolted together. During fabrication, installation and operation, centralizers subject to different loads under which they are required to continue functioning properly.\u0000 This paper provides an overview of centralizer design aspects and then focuses on the loading history during installation using reeling method. The main contributing parameters to centralizer loading during reeled installation technique are discussed and conclusions are drawn. It is believed that this will enable Pipeline Engineers to select the most appropriate material and design for centralizers.","PeriodicalId":155568,"journal":{"name":"Volume 5: Pipelines, Risers, and Subsea Systems","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127907248","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Theoretical Method to Estimate the Fatigue Life of Tensile Armors of Flexible Pipes","authors":"Kaien Jiang, Yutian Lu, Yong Bai","doi":"10.1115/OMAE2018-77175","DOIUrl":"https://doi.org/10.1115/OMAE2018-77175","url":null,"abstract":"This paper mainly focuses on a theoretical methodology to calculate the fatigue life of tensile armor of flexible pipes. This approach employs the local model of flexible pipe that converts forces and moments obtained in time-domain global analyses into stresses in the spiral tendons of tensile armor layer. The stresses are then processed by rainflow counting methods, and S-N curves are adopted to evaluate the fatigue damage of tensile armors. Finally, Miner linear cumulative damage theory is used in order to calculate the accumulated fatigue damage. A case study on the fatigue life of a flexible pipe employing this methodology is presented, and the fatigue life of flexible pipe is obtained. The main points addressed in the study are the effect of mean stress and friction coefficients. The results indicate that the inner tensile armor at suspension point is the most prone to fatigue damage, in addition, mean stress correction and friction coefficients strongly influence the fatigue life of flexible pipes.","PeriodicalId":155568,"journal":{"name":"Volume 5: Pipelines, Risers, and Subsea Systems","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129557915","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical Evaluation of Mechanical Property Change and Collapse Strength of ERW Pipes Considering Manufacturing Process","authors":"Seong-Wook Han, Soo-Chang Kang, J. Yi, Ho-Kyung Kim","doi":"10.1115/OMAE2018-77729","DOIUrl":"https://doi.org/10.1115/OMAE2018-77729","url":null,"abstract":"Along with the development of the energy industry, demand for oil and gas pipelines has increased, and as the low oil price era has been prolonged, more economical pipe design and construction are required. Typical examples are ERW pipes used as OCTG or reel-lay pipeline. The ERW pipe is made by passing the plate through continuous rollers, where repetitive loading and unloading causes unintentional plastic deformation and changes in initial steel properties. So, this study focused on both the change of mechanical properties during manufacturing process and collapse strength of ERW pipe considering the Bauschinger effect in order to produce more economical and high performance steel pipe.\u0000 In this paper, the ERW manufacturing process was divided into three stages: forming station, sizing station, and flattening station. The ERW manufacturing process was simulated as 3D nonlinear finite element models using ABAQUS (6.14-1). Then, the change of mechanical properties at each process station was examined through finite element analysis and PEEQ, Alpha, and residual stress in each process station were evaluated for maintaining continuity of analysis. And flattening station where the reverse bending gives a large change in the mechanical properties was also performed. Finally, the collapse strength of the ERW pipe was evaluated in consideration of the change in compression strength during the manufacturing process. The ABAQUS analytical model was verified by showing analytical results to be identical with the outer diameter measured from the full-scale size pipes. Using the developed analytical model, it is possible to numerically predict the mechanical properties and collapse strength of ERW pipe.","PeriodicalId":155568,"journal":{"name":"Volume 5: Pipelines, Risers, and Subsea Systems","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130079980","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reeled CRA Clad/Lined Pipeline Installation: Seastate Optimisation From Fatigue and Fracture Perspective","authors":"Daowu Zhou, T. Sriskandarajah, H. Bowlby, Ove Skorpen","doi":"10.1115/OMAE2018-78168","DOIUrl":"https://doi.org/10.1115/OMAE2018-78168","url":null,"abstract":"The deformation mechanism in reel-lay of corrosive resistance alloy (CRA) clad/lined pipes can facilitate defect tearing and low cycle fatigue crack growth in the girth welds. Pipe-lay after straightening will subject the CRA welds to high cycle fatigue. The permissible seastate for installation will be governed by failure limit states such as local collapse, wrinkling of the liner, fatigue and fracture.\u0000 By means of a recently completed offshore project in North Sea, this paper discusses seastate optimisation when installing pipelines with CRA girth welds, from a fatigue and fracture perspective. The additional limiting requirement in CRA welds to maintain CRA liner integrity can lead to significant assessment work since all critical welds shall be examined. AUT scanned defect data were utilised to maximise permissible seastates based on fatigue allowance from a fatigue crack growth calculation.\u0000 An alternative simplified approach to derive the crack growth based on a superposition method is studied. It enables a straightforward real-time prediction of crack growth and has the potential to be used during the offshore campaign to improve the installation flexibility.\u0000 Post-installation fracture assessment under more critical seastates is examined for CRA partial over-matching welds. A comparison of CDF between conventional ECA procedure and 3D FE is provided.","PeriodicalId":155568,"journal":{"name":"Volume 5: Pipelines, Risers, and Subsea Systems","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128970041","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analytical Approach on Dynamic Tension of Free Hanging Configuration","authors":"Motoyasu Kanazawa, R. Wada, M. Ozaki","doi":"10.1115/OMAE2018-77361","DOIUrl":"https://doi.org/10.1115/OMAE2018-77361","url":null,"abstract":"Free hanging is the most simple and basic model of a flexible riser, and has advantages in terms of low cost and easy operation, installation and maintenance compared to other configurations, such as Lazy-S or Steep-S. However, the dynamic motion of the top end has direct impact on the riser behavior near the touch down zone (TDZ) and causes axial compression. Since flexible pipe is vulnerable to axial compression, we usually adopt buffer configuration like Lazy-S or Steep-S. Some technical means have been made to reduce the axial compression of free hanging, such as non-uniform weight distribution for Steel Catenary Riser (SCR) and heavy material wrapping near TDZ for flexible pipe. Despite the achievements of such research, it is difficult to say that there is a systematic and comprehensive explication on how the parameters of dynamic motion or the configuration of pipe effect the dynamic tension of a riser. Linearized analysis in frequency domain with quite small number of lumped-mass model is discussed in this paper. The simplified linearized analytic solution support or modify empirical knowledge which parameter (weight in air or water, an angle of the riser against still water plane, the motion of the top end or added mass) effect dynamic minimum tension of the riser. The aim of this paper is to provide starting point of analytical approach and show its possibility. Most of the key parameters which are empirically known to estimate dynamic tension of the riser is driven from analytical model in this paper. Comprehensive numerical calculation by Orcaflex is performed to verify the assumptions and support the results.","PeriodicalId":155568,"journal":{"name":"Volume 5: Pipelines, Risers, and Subsea Systems","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128788312","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}