The paper provides a detailed estimation of the interfaces that exist in a split SURF-SPS execution model and provides a qualitative comparison to an integrated SURF-SPS execution model. A comprehensive matrix of dependencies between SURF and SPS is presented and is categorized into engineering, procurement, construction/fabrication and installation work packages. The matrix is used to illustrate the exact scope dependencies and thus, the sources of interfaces. A hypothetical greenfield development has been assumed to develop the interface matrix and to use it for comparison of the two execution models. The comparison also reveals how interfaces are naturally eliminated in an integrated SURF-SPS execution model. In each of the workstreams (E-P-C-I), top risks have been identified and monetary liability estimates for those risks have been provided. By transfer of these risks from company to contractor, monetary liability gets transferred to the contractor, thus, resulting in significant savings for operating companies. The following tangible results are provided in the paper: a) % of interface(s) reduced in the E-P-C-I areas; b) Risk reduction in monetary terms for operators – estimated values. This paper justifies the fact that there is a significant interface scope and risk reduction for operators, if they adopt an integrated SURF-SPS execution model.
{"title":"Interface Risk Reduction in an Integrated SURF-SPS Scope Execution","authors":"Hemant Priyadarshi, D. Nickel, Seban Jose","doi":"10.1115/omae2021-62925","DOIUrl":"https://doi.org/10.1115/omae2021-62925","url":null,"abstract":"\u0000 The paper provides a detailed estimation of the interfaces that exist in a split SURF-SPS execution model and provides a qualitative comparison to an integrated SURF-SPS execution model. A comprehensive matrix of dependencies between SURF and SPS is presented and is categorized into engineering, procurement, construction/fabrication and installation work packages. The matrix is used to illustrate the exact scope dependencies and thus, the sources of interfaces.\u0000 A hypothetical greenfield development has been assumed to develop the interface matrix and to use it for comparison of the two execution models. The comparison also reveals how interfaces are naturally eliminated in an integrated SURF-SPS execution model. In each of the workstreams (E-P-C-I), top risks have been identified and monetary liability estimates for those risks have been provided. By transfer of these risks from company to contractor, monetary liability gets transferred to the contractor, thus, resulting in significant savings for operating companies.\u0000 The following tangible results are provided in the paper: a) % of interface(s) reduced in the E-P-C-I areas; b) Risk reduction in monetary terms for operators – estimated values. This paper justifies the fact that there is a significant interface scope and risk reduction for operators, if they adopt an integrated SURF-SPS execution model.","PeriodicalId":240325,"journal":{"name":"Volume 4: Pipelines, Risers, and Subsea Systems","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128966559","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}
L. C. Sevillano, A. Faanes, Tor Berge Gjersvik, S. Sangesland
The oil and gas industry faces many challenges as it is committed to provide energy to a world in transition. Declining prices impose constraints to new developments, either greenfield or brownfield. Additionally, the industry’s commitment to long-term value creation with reduced carbon footprint is confronted with the traditional solutions for well construction, production and processing, which consume significant amount of energy with corresponding high CO2 emissions. In this scenario, subsea production and processing technology has been a key enabler for the exploitation of oil and gas resources. This paper presents a holistic review of trends in subsea technology development over recent years which have direct impact on the heart of the subsea production system, namely the subsea tree. The technological developments considered are in different subsea applications such as robotic automation, communication systems, and all-electric systems. The objective of the ongoing research is to perform structural and fundamental analysis of subsea production and injection systems and address the question on how technological developments can be utilized to design an overall better subsea production system so the industry may fully benefit from the economic and ecological impact brought by the joint use of these technologies. Opportunities for reevaluating barrier philosophy to identify technical and economic opportunities for design simplifications of subsea trees that still leave enough pressure barriers in all operational modes are also considered. The analyses presented indicate the current stage of the examined technologies and their potential at reducing both capital and operational cost of subsea systems. These results will be the basis for the future evaluation of improved and new design solutions within the scope of the ongoing project performed by the Norwegian University of Science and Technology and its industrial partners.
{"title":"Enabling Technologies for Low Cost Subsea Field Development","authors":"L. C. Sevillano, A. Faanes, Tor Berge Gjersvik, S. Sangesland","doi":"10.1115/omae2021-62862","DOIUrl":"https://doi.org/10.1115/omae2021-62862","url":null,"abstract":"\u0000 The oil and gas industry faces many challenges as it is committed to provide energy to a world in transition. Declining prices impose constraints to new developments, either greenfield or brownfield. Additionally, the industry’s commitment to long-term value creation with reduced carbon footprint is confronted with the traditional solutions for well construction, production and processing, which consume significant amount of energy with corresponding high CO2 emissions. In this scenario, subsea production and processing technology has been a key enabler for the exploitation of oil and gas resources.\u0000 This paper presents a holistic review of trends in subsea technology development over recent years which have direct impact on the heart of the subsea production system, namely the subsea tree. The technological developments considered are in different subsea applications such as robotic automation, communication systems, and all-electric systems.\u0000 The objective of the ongoing research is to perform structural and fundamental analysis of subsea production and injection systems and address the question on how technological developments can be utilized to design an overall better subsea production system so the industry may fully benefit from the economic and ecological impact brought by the joint use of these technologies. Opportunities for reevaluating barrier philosophy to identify technical and economic opportunities for design simplifications of subsea trees that still leave enough pressure barriers in all operational modes are also considered.\u0000 The analyses presented indicate the current stage of the examined technologies and their potential at reducing both capital and operational cost of subsea systems. These results will be the basis for the future evaluation of improved and new design solutions within the scope of the ongoing project performed by the Norwegian University of Science and Technology and its industrial partners.","PeriodicalId":240325,"journal":{"name":"Volume 4: Pipelines, Risers, and Subsea Systems","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131378368","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}
Flexible risers are regularly used to produce oil and gas in subsea production systems and by nature interconnect the subsea production system to the floating or fixed host facilities. Unbonded flexible pipes are made of a combination of metallic and non-metallic layers, each layer being individually terminated at each extremity by complex end fittings. Mostly submerged in seawater, the metallic parts require careful material selection and cathodic protection (CP) to survive the expected service life. Design engineers must determine whether the flexible pipe risers should be electrically connected to the host in order to receive cathodic protection current or be electrically isolated. If the host structure is equipped with a sacrificial anode system, then electrical continuity between the riser and the host structure is generally preferred. The exception is often when the riser and host structure are operated by separate organizations, in which case electrical isolation may be preferred simply to provide delineation of ownership between the two CP systems. The paper discusses these interface issues between hull and subsea where the hull is equipped with an impressed current cathodic protection (ICCP) system, and provides guidance for addressing them during flexible pipe CP design, operation, and monitoring. Specifically, CP design philosophies for flexible risers will be addressed with respect to manufacturing, installation and interface with the host structure’s Impressed Current Cathodic Protection (ICCP) system. The discussion will emphasize the importance of early coordination between the host structure ICCP system designers and the subsea SACP system designers, and will include recommendations for CP system computer modeling, CP system design operation and CP system monitoring. One of the challenges is to understand what to consider for the exposed surfaces in the flexible pipes and its multiple layers, and also the evaluation of the linear resistance of each riser segment. The linear resistance of the riser is a major determinant with respect to potential attenuation, which in turn largely determines the extent of current drain between the subsea sacrificial anode system and the hull ICCP system. To model the flexible riser CP system behavior for self-protection, linear resistance may be maximized, however the use of a realistic linear resistance is recommended for evaluation of the interaction between the host structure and subsea system. Realistic flexible linear resistance would also reduce conservatism in the CP design, potentially save time during the offshore campaign by reducing anode quantities, and also providing correct evaluation of drain current and stray currents.
{"title":"Cathodic Protection Design Consideration for an Offshore Flexible Riser Connected to an Impressed Current System","authors":"Thierry Dequin, C. Weldon, M. Hense","doi":"10.1115/omae2021-62302","DOIUrl":"https://doi.org/10.1115/omae2021-62302","url":null,"abstract":"Flexible risers are regularly used to produce oil and gas in subsea production systems and by nature interconnect the subsea production system to the floating or fixed host facilities. Unbonded flexible pipes are made of a combination of metallic and non-metallic layers, each layer being individually terminated at each extremity by complex end fittings. Mostly submerged in seawater, the metallic parts require careful material selection and cathodic protection (CP) to survive the expected service life. Design engineers must determine whether the flexible pipe risers should be electrically connected to the host in order to receive cathodic protection current or be electrically isolated. If the host structure is equipped with a sacrificial anode system, then electrical continuity between the riser and the host structure is generally preferred. The exception is often when the riser and host structure are operated by separate organizations, in which case electrical isolation may be preferred simply to provide delineation of ownership between the two CP systems.\u0000 The paper discusses these interface issues between hull and subsea where the hull is equipped with an impressed current cathodic protection (ICCP) system, and provides guidance for addressing them during flexible pipe CP design, operation, and monitoring. Specifically, CP design philosophies for flexible risers will be addressed with respect to manufacturing, installation and interface with the host structure’s Impressed Current Cathodic Protection (ICCP) system. The discussion will emphasize the importance of early coordination between the host structure ICCP system designers and the subsea SACP system designers, and will include recommendations for CP system computer modeling, CP system design operation and CP system monitoring.\u0000 One of the challenges is to understand what to consider for the exposed surfaces in the flexible pipes and its multiple layers, and also the evaluation of the linear resistance of each riser segment. The linear resistance of the riser is a major determinant with respect to potential attenuation, which in turn largely determines the extent of current drain between the subsea sacrificial anode system and the hull ICCP system.\u0000 To model the flexible riser CP system behavior for self-protection, linear resistance may be maximized, however the use of a realistic linear resistance is recommended for evaluation of the interaction between the host structure and subsea system. Realistic flexible linear resistance would also reduce conservatism in the CP design, potentially save time during the offshore campaign by reducing anode quantities, and also providing correct evaluation of drain current and stray currents.","PeriodicalId":240325,"journal":{"name":"Volume 4: Pipelines, Risers, and Subsea Systems","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128897126","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}
Fernando Geremias Toni, Rodrigo Provasi, Clovis de Arruda Martins
To correctly model the structural behavior of a flexible pipe, the contribution of all the layers must be completely understood, among them the interlocked carcass. That carcass is a metallic layer designed to provide radial stiffness to a flexible pipe, mainly supporting pressure differentials and thus preventing failure modes such as collapse and crushing, but its behavior under other loads is worth of investigation. This paper contributes to understanding the carcass behavior under tension. Given its complex helical and interlocked geometry, modelling the carcass through the Finite Element Method is a challenging task, not only due to the large size of the models, but also due to the nonlinearities and convergence difficulties that arise from the self-contacts at the interlocking. For these reasons, most works developed over the past decades have adopted an equivalent layer approach, in which the carcass is replaced by an orthotropic cylindrical layer with equivalent mechanical properties. Although practical, this approach disregards the effects from the interlocking, such as stiffness variations and stress concentrations. Therefore, aiming a more realistic representation and a better understanding of the mechanical behavior of the interlocked carcass, this work presents four different carcass finite element models to analyze this layer under tension loads. The first one is a complete three-dimensional finite element model of an interlocked carcass discretized with second order isoparametric solid elements and surface-to-surface contact elements. The second model consists of a version of the first one with the addition of an inner polymeric sheath. As for the third and fourth models, it was adopted the simplifying ring hypothesis, that is, a carcass with 90 degree lay angle, thus allowing the axisymmetric modelling of the two previous configurations, representing a substantial computational gain by using two-dimensional meshes. The results of those models are then presented and compared, and the validity of the adopted simplifying hypothesis is verified.
{"title":"Finite Element Analysis of a Flexible Pipe Interlocked Carcass Under Tension Loads","authors":"Fernando Geremias Toni, Rodrigo Provasi, Clovis de Arruda Martins","doi":"10.1115/omae2021-62442","DOIUrl":"https://doi.org/10.1115/omae2021-62442","url":null,"abstract":"\u0000 To correctly model the structural behavior of a flexible pipe, the contribution of all the layers must be completely understood, among them the interlocked carcass. That carcass is a metallic layer designed to provide radial stiffness to a flexible pipe, mainly supporting pressure differentials and thus preventing failure modes such as collapse and crushing, but its behavior under other loads is worth of investigation. This paper contributes to understanding the carcass behavior under tension. Given its complex helical and interlocked geometry, modelling the carcass through the Finite Element Method is a challenging task, not only due to the large size of the models, but also due to the nonlinearities and convergence difficulties that arise from the self-contacts at the interlocking. For these reasons, most works developed over the past decades have adopted an equivalent layer approach, in which the carcass is replaced by an orthotropic cylindrical layer with equivalent mechanical properties. Although practical, this approach disregards the effects from the interlocking, such as stiffness variations and stress concentrations. Therefore, aiming a more realistic representation and a better understanding of the mechanical behavior of the interlocked carcass, this work presents four different carcass finite element models to analyze this layer under tension loads. The first one is a complete three-dimensional finite element model of an interlocked carcass discretized with second order isoparametric solid elements and surface-to-surface contact elements. The second model consists of a version of the first one with the addition of an inner polymeric sheath. As for the third and fourth models, it was adopted the simplifying ring hypothesis, that is, a carcass with 90 degree lay angle, thus allowing the axisymmetric modelling of the two previous configurations, representing a substantial computational gain by using two-dimensional meshes. The results of those models are then presented and compared, and the validity of the adopted simplifying hypothesis is verified.","PeriodicalId":240325,"journal":{"name":"Volume 4: Pipelines, Risers, and Subsea Systems","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122103324","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}
Daowu Zhou, Lingjun Cao, T. Sriskandarajah, M. Lewis, D. Manso
Welding acceptance criteria derived through ECA is typically performed after the detailed design. The design loads, together with pipeline and girth weld material testing data, are inputs to ECA and used to evaluate the pipeline girth weld integrity for determining the criticality of potential weld flaws. With ever increasing challenging environment (deepwater, HP/HT, aggressive fluid composition etc) in the oil and gas field, the fatigue damage and fracture failure may become a serious concern, consequently limiting the productivity of the pipeline fabrication. It is therefore essential to integrate ECA into the design loop to remove the uncertainty and risk to achieve a practically workable fabrication solution. In this paper, a strategy to integrate early ECA into pipeline detailed design phase is presented. A case study in a deepwater subsea channel crossing demonstrates that an early ECA engagement effectively mitigates the significant fatigue and fracture risk and obtains workable welding acceptance criteria for fabrication.
{"title":"Early Engagement of ECA in Offshore Deepwater Pipeline Design","authors":"Daowu Zhou, Lingjun Cao, T. Sriskandarajah, M. Lewis, D. Manso","doi":"10.1115/omae2021-63005","DOIUrl":"https://doi.org/10.1115/omae2021-63005","url":null,"abstract":"Welding acceptance criteria derived through ECA is typically performed after the detailed design. The design loads, together with pipeline and girth weld material testing data, are inputs to ECA and used to evaluate the pipeline girth weld integrity for determining the criticality of potential weld flaws.\u0000 With ever increasing challenging environment (deepwater, HP/HT, aggressive fluid composition etc) in the oil and gas field, the fatigue damage and fracture failure may become a serious concern, consequently limiting the productivity of the pipeline fabrication. It is therefore essential to integrate ECA into the design loop to remove the uncertainty and risk to achieve a practically workable fabrication solution.\u0000 In this paper, a strategy to integrate early ECA into pipeline detailed design phase is presented. A case study in a deepwater subsea channel crossing demonstrates that an early ECA engagement effectively mitigates the significant fatigue and fracture risk and obtains workable welding acceptance criteria for fabrication.","PeriodicalId":240325,"journal":{"name":"Volume 4: Pipelines, Risers, and Subsea Systems","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129317604","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}
Harvey Jamieson, A. Stanning, M. Legge, R. Sathananthan
This paper details a new flowline thermal performance control system in which the overall heat transfer coefficient (U-value) of a pipe-in-pipe system can be varied. Large scale physical testing was carried out as part of the technology qualification to verify the system and design models developed. The solution is ideally suited for the increasing numbers of High Pressure High Temperature (HPHT) field developments being made; where the fluid temperature, pressure and flowrates will change significantly over the field life. It allows a new approach to flowline thermal design and operation to be taken for various types of field development. A qualification program has been performed with independent verification body assessment of the work and results and confirms the predicted performance. This paper describes the qualification method to DNVGL-RP-A203 and associated Technology Readiness Level (TRL) assessment of the components. The physical design of the system is presented along with examples of how benefits can be realised through its use.
{"title":"Pipe-in-Pipe Thermal Management System With Adjustable U-Value During Field Life","authors":"Harvey Jamieson, A. Stanning, M. Legge, R. Sathananthan","doi":"10.1115/omae2021-63123","DOIUrl":"https://doi.org/10.1115/omae2021-63123","url":null,"abstract":"\u0000 This paper details a new flowline thermal performance control system in which the overall heat transfer coefficient (U-value) of a pipe-in-pipe system can be varied. Large scale physical testing was carried out as part of the technology qualification to verify the system and design models developed. The solution is ideally suited for the increasing numbers of High Pressure High Temperature (HPHT) field developments being made; where the fluid temperature, pressure and flowrates will change significantly over the field life. It allows a new approach to flowline thermal design and operation to be taken for various types of field development.\u0000 A qualification program has been performed with independent verification body assessment of the work and results and confirms the predicted performance. This paper describes the qualification method to DNVGL-RP-A203 and associated Technology Readiness Level (TRL) assessment of the components.\u0000 The physical design of the system is presented along with examples of how benefits can be realised through its use.","PeriodicalId":240325,"journal":{"name":"Volume 4: Pipelines, Risers, and Subsea Systems","volume":"226 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123082498","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}
Pipe bends are peculiar structures. Although the mechanisms that determine their behaviour are not that different from those of initially straight pipe, their relative contribution can be. This is amplified by shorter bend radii and thinner walls. Typical bends used in an offshore environment will have a radius of three to ten times their cross-section diameter and will behave differently than straight pipe of comparable dimensions. This paper aims to identify and quantify the key mechanisms that drive the behaviour of pipe bends in a deep-water environment. Their behaviour has been studied at global and local scales. The behaviour of bends seems not fully understood amongst academia and in the industry. This paper endeavours to demystify some of those peculiar behaviours, for example, why pipe bends tend to straighten during a mill pressure test.
{"title":"What You May Not Know About Pipe Bends","authors":"R. Selker, Ping Liu, C. Sicilia","doi":"10.1115/omae2021-62896","DOIUrl":"https://doi.org/10.1115/omae2021-62896","url":null,"abstract":"\u0000 Pipe bends are peculiar structures. Although the mechanisms that determine their behaviour are not that different from those of initially straight pipe, their relative contribution can be. This is amplified by shorter bend radii and thinner walls. Typical bends used in an offshore environment will have a radius of three to ten times their cross-section diameter and will behave differently than straight pipe of comparable dimensions. This paper aims to identify and quantify the key mechanisms that drive the behaviour of pipe bends in a deep-water environment. Their behaviour has been studied at global and local scales. The behaviour of bends seems not fully understood amongst academia and in the industry. This paper endeavours to demystify some of those peculiar behaviours, for example, why pipe bends tend to straighten during a mill pressure test.","PeriodicalId":240325,"journal":{"name":"Volume 4: Pipelines, Risers, and Subsea Systems","volume":"219 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123151872","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}
R. Naik, Y. Urthaler, S. McNeill, Rafik Boubenider
Certain subsea jumper design features coupled with operating conditions can lead to Flow Induced Vibration (FIV) of subsea jumpers. Excessive FIV can result in accumulation of allowable fatigue damage prior to the end of jumper service life. For this reason, an extensive FIV management program was instated for a large development in the Gulf of Mexico (GOM) where FIV had been observed. The program consisted of in-situ measurement, modeling and analysis. Selected well and flowline jumpers were outfitted with subsea instrumentation for dedicated vibration testing. Finite Element (FE) models were developed for each jumper and refined to match the dynamic properties extracted from the measured data. Fatigue analysis was then carried out using the refined FE model and measured response data. If warranted by the analysis results, action was taken to mitigate the deleterious effects of FIV. Details on modeling and data analysis were published in [5]. Herein, we focus on the overall findings and lessons learned over the duration of the program. The following topics from the program are discussed in detail: 1. In-situ vibration measurement 2. Overall vibration trends with flow rate and lack of correlation of FIV to flow intensity (rho-v-squared); 3. Vibration and fatigue performance of flowline jumpers vs. well jumpers 4. Fatigue analysis conservatism Reliance on screening calculations or predictive FE analysis could lead to overly conservative operational limits or a high degree of fatigue life uncertainty in conditions vulnerable to FIV. It is proposed that in-situ vibration measurements followed by analysis of the measured data in alignment with operating conditions is the best practice to obtain a realistic understanding of subsea jumper integrity to ensure safe and reliable operation of the subsea system. The findings from the FIV management program provide valuable insight for the subsea industry, particularly in the areas of integrity management of in-service subsea jumpers; in-situ instrumentation and vibration measurements and limitations associated with predictive analysis of jumper FIV. If learnings, such as those discussed here, are fed back into design, analysis and monitoring guidelines for subsea equipment, the understanding and management of FIV could be dramatically enhanced compared to the current industry practice.
{"title":"Managing Flow Induced Vibration in Subsea Jumpers","authors":"R. Naik, Y. Urthaler, S. McNeill, Rafik Boubenider","doi":"10.1115/omae2021-61849","DOIUrl":"https://doi.org/10.1115/omae2021-61849","url":null,"abstract":"\u0000 Certain subsea jumper design features coupled with operating conditions can lead to Flow Induced Vibration (FIV) of subsea jumpers. Excessive FIV can result in accumulation of allowable fatigue damage prior to the end of jumper service life. For this reason, an extensive FIV management program was instated for a large development in the Gulf of Mexico (GOM) where FIV had been observed.\u0000 The program consisted of in-situ measurement, modeling and analysis. Selected well and flowline jumpers were outfitted with subsea instrumentation for dedicated vibration testing. Finite Element (FE) models were developed for each jumper and refined to match the dynamic properties extracted from the measured data. Fatigue analysis was then carried out using the refined FE model and measured response data. If warranted by the analysis results, action was taken to mitigate the deleterious effects of FIV. Details on modeling and data analysis were published in [5]. Herein, we focus on the overall findings and lessons learned over the duration of the program. The following topics from the program are discussed in detail:\u0000 1. In-situ vibration measurement\u0000 2. Overall vibration trends with flow rate and lack of correlation of FIV to flow intensity (rho-v-squared);\u0000 3. Vibration and fatigue performance of flowline jumpers vs. well jumpers\u0000 4. Fatigue analysis conservatism\u0000 Reliance on screening calculations or predictive FE analysis could lead to overly conservative operational limits or a high degree of fatigue life uncertainty in conditions vulnerable to FIV. It is proposed that in-situ vibration measurements followed by analysis of the measured data in alignment with operating conditions is the best practice to obtain a realistic understanding of subsea jumper integrity to ensure safe and reliable operation of the subsea system.\u0000 The findings from the FIV management program provide valuable insight for the subsea industry, particularly in the areas of integrity management of in-service subsea jumpers; in-situ instrumentation and vibration measurements and limitations associated with predictive analysis of jumper FIV. If learnings, such as those discussed here, are fed back into design, analysis and monitoring guidelines for subsea equipment, the understanding and management of FIV could be dramatically enhanced compared to the current industry practice.","PeriodicalId":240325,"journal":{"name":"Volume 4: Pipelines, Risers, and Subsea Systems","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129451179","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}
Analytical, experimental and computational models have historically been heavily simplified, linearized, and otherwise reduced. This paper shows how such model reductions eliminate the fundamental geometric changes that determine real behavior in cables, strings, moorings, guys, pipelines, riser, plates, skins, subsea hulls, and other such slender and thin structures. The paper details each physical quantity that we must add back into our overly reduced models to improve the basic nature, evolution, and accuracy of the resulting motions and vibrations. For example, even slight changes in local rotation anywhere along a cable can create large nonlinear changes in the dynamic nature of its behavior. The evolved complexity of the resulting global motions and vibrations in space and time often defy what we normally expect from such a simple structure. Although this paper focuses on the modeling of deep-water moorings and risers of an ocean platform, the same geometric effect is fundamental to most science and engineering models. Understanding how small changes in geometry can nonlinearly affect any structured behavior will help demystify much of the poorly-understood motions and vibrations in a large diversity of applications, including induced vibrations, sound, structural acoustics, aero-elasticity, sound, light and atomic radiation.
{"title":"The Evolved Motions of a Marine Riser or Pipeline","authors":"R. Zueck","doi":"10.1115/omae2021-62970","DOIUrl":"https://doi.org/10.1115/omae2021-62970","url":null,"abstract":"\u0000 Analytical, experimental and computational models have historically been heavily simplified, linearized, and otherwise reduced. This paper shows how such model reductions eliminate the fundamental geometric changes that determine real behavior in cables, strings, moorings, guys, pipelines, riser, plates, skins, subsea hulls, and other such slender and thin structures. The paper details each physical quantity that we must add back into our overly reduced models to improve the basic nature, evolution, and accuracy of the resulting motions and vibrations.\u0000 For example, even slight changes in local rotation anywhere along a cable can create large nonlinear changes in the dynamic nature of its behavior. The evolved complexity of the resulting global motions and vibrations in space and time often defy what we normally expect from such a simple structure.\u0000 Although this paper focuses on the modeling of deep-water moorings and risers of an ocean platform, the same geometric effect is fundamental to most science and engineering models. Understanding how small changes in geometry can nonlinearly affect any structured behavior will help demystify much of the poorly-understood motions and vibrations in a large diversity of applications, including induced vibrations, sound, structural acoustics, aero-elasticity, sound, light and atomic radiation.","PeriodicalId":240325,"journal":{"name":"Volume 4: Pipelines, Risers, and Subsea Systems","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131314387","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}
Flexible pipes are compounded by many concentric layers, with different structural and operational functions. These layers are usually made of distinct materials, including metal and plastic. To accurately meet the working requirements of the pipes and reduce its production cost, the primary purpose of this paper is to present the cross-sectional design procedure and the case study for a specific unbonded flexible pipe is also illustrated. In this paper, the mathematical analysis and finite element analysis are employed to study the properties of pipe under different working conditions. A theoretical model for stresses and deformations of the pipe have been studied, and the obtained results have been compared with the ones from the FEM which is used to simulate the pipe under different working conditions. Additionally, the several models will be developed to study mechanical responses of pipes subjected to several loads. The results and FEA models can be useful for the designing structure of flexible pipes.
{"title":"Cross-Sectional Design and Case Study for Flexible Pipe","authors":"Q. Zuo, L. Ali, Yong Bai","doi":"10.1115/omae2021-60368","DOIUrl":"https://doi.org/10.1115/omae2021-60368","url":null,"abstract":"\u0000 Flexible pipes are compounded by many concentric layers, with different structural and operational functions. These layers are usually made of distinct materials, including metal and plastic. To accurately meet the working requirements of the pipes and reduce its production cost, the primary purpose of this paper is to present the cross-sectional design procedure and the case study for a specific unbonded flexible pipe is also illustrated. In this paper, the mathematical analysis and finite element analysis are employed to study the properties of pipe under different working conditions. A theoretical model for stresses and deformations of the pipe have been studied, and the obtained results have been compared with the ones from the FEM which is used to simulate the pipe under different working conditions. Additionally, the several models will be developed to study mechanical responses of pipes subjected to several loads. The results and FEA models can be useful for the designing structure of flexible pipes.","PeriodicalId":240325,"journal":{"name":"Volume 4: Pipelines, Risers, and Subsea Systems","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126570611","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}
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