Brazilian offshore drilling operations are carried out in a highly demanding and complex working environment. The geological characteristics of the most productive Brazilian reservoirs, located on the so-called Pre-Salt basin, actually implies for their exploration the overcoming of water depths greater than 1,500 meters and the construction of wells that can reach up to 7,000 meters of length. In such environment, human reliability plays a primordial role regarding safety issues. On the same token, in the field of risk analysis, the consideration of human behavior holds a unique position and its relevance for the consubstantiation of accidents is widely recognized throughout the literature. Nonetheless, a comprehensive way to model it is still an ongoing effort. In this challenge, human error, understood both as a success or a failure probability, provided the first base for the development of techniques capable to infer the outcome towards man machine interaction (MMI). Such stand point gave birth to a series of tools and methodologies, usually called as human reliability analysis (HRA) first generation tools. In an attempt to address the perceived deficiencies of the first-generation tools, the decade of the 1990’s saw the introduction of HRA models based on cognitive assumptions, naturally called HRA second-generation tools. On its turn, the cognitive modeling perspective has demanded the adoption of more sophisticated architectures that, ultimately, have been leading to the dynamically account of the cognitive process. In this context, the present work aims to contribute for this debate analyzing the use of the Dominance, Influence, Steadiness and Compliance (DISC) personality test in the assessment of accidents likelihood on offshore drilling operations in Brazil. By means of actual data collected during the years 2016 and 2017, the paper develops a qualitative discussion of the foreseen outcomes regarding accident proneness considering the working and the under-pressure profiles advocated on DISC.
{"title":"The Use of Dominance, Influence, Steadiness and Compliance (DISC) Personality Test in the Assessment of Accidents Likelihood on Offshore Drilling Operations","authors":"C. Morais, Ulrico Barini Filho, M. Martins","doi":"10.1115/omae2020-18864","DOIUrl":"https://doi.org/10.1115/omae2020-18864","url":null,"abstract":"\u0000 Brazilian offshore drilling operations are carried out in a highly demanding and complex working environment. The geological characteristics of the most productive Brazilian reservoirs, located on the so-called Pre-Salt basin, actually implies for their exploration the overcoming of water depths greater than 1,500 meters and the construction of wells that can reach up to 7,000 meters of length. In such environment, human reliability plays a primordial role regarding safety issues. On the same token, in the field of risk analysis, the consideration of human behavior holds a unique position and its relevance for the consubstantiation of accidents is widely recognized throughout the literature. Nonetheless, a comprehensive way to model it is still an ongoing effort. In this challenge, human error, understood both as a success or a failure probability, provided the first base for the development of techniques capable to infer the outcome towards man machine interaction (MMI). Such stand point gave birth to a series of tools and methodologies, usually called as human reliability analysis (HRA) first generation tools. In an attempt to address the perceived deficiencies of the first-generation tools, the decade of the 1990’s saw the introduction of HRA models based on cognitive assumptions, naturally called HRA second-generation tools. On its turn, the cognitive modeling perspective has demanded the adoption of more sophisticated architectures that, ultimately, have been leading to the dynamically account of the cognitive process. In this context, the present work aims to contribute for this debate analyzing the use of the Dominance, Influence, Steadiness and Compliance (DISC) personality test in the assessment of accidents likelihood on offshore drilling operations in Brazil. By means of actual data collected during the years 2016 and 2017, the paper develops a qualitative discussion of the foreseen outcomes regarding accident proneness considering the working and the under-pressure profiles advocated on DISC.","PeriodicalId":297013,"journal":{"name":"Volume 2A: Structures, Safety, and Reliability","volume":"68 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121876173","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}
T. Turkalj, S. Cravero, M. Valdez, F. Arroyo, P. Darcis
Large diameter Sour Service Pipelines are designed for the safe and efficient transportation of production fluids containing H2S. This service condition exposes the pipe to hydrogen embrittlement mechanisms and demands a material with high Sulfide Stress Cracking (SSC) resistance, and thus, a high fracture toughness in a representative sour environment. Engineering Critical Assessment (ECA) procedures are usually employed to determine the suitability of a pipeline design, These procedures require the correct determination of the material fracture mechanical properties. Although Method D of NACE TM0177_16 [1] using DCB specimens is the currently recognized testing methodology to evaluate SSC pipe performance, other type of tests could be employed for the purpose of an ECA. In the present paper, a fracture mechanics experimental program in sour environment is presented. Parent Pipe and Weld Material of Longitudinal Submerged Arc Welded (LSAW) large diameter pipes in H2S were studied. Fracture Toughness Parameters, such K-limit from standard DCB tests and K-threshold from Single Edge Notch Tension (SENT) specimens under constant loading, are compared and discussed. Furthermore, the fracture toughness values obtained from SENT specimens in sour environment are used to estimate the burst pressure using an ECA procedure.
{"title":"Fracture Toughness Characterization of LSAW UOE Pipes in Sour Media and Implications on Burst Pressure","authors":"T. Turkalj, S. Cravero, M. Valdez, F. Arroyo, P. Darcis","doi":"10.1115/omae2020-18319","DOIUrl":"https://doi.org/10.1115/omae2020-18319","url":null,"abstract":"\u0000 Large diameter Sour Service Pipelines are designed for the safe and efficient transportation of production fluids containing H2S. This service condition exposes the pipe to hydrogen embrittlement mechanisms and demands a material with high Sulfide Stress Cracking (SSC) resistance, and thus, a high fracture toughness in a representative sour environment.\u0000 Engineering Critical Assessment (ECA) procedures are usually employed to determine the suitability of a pipeline design, These procedures require the correct determination of the material fracture mechanical properties.\u0000 Although Method D of NACE TM0177_16 [1] using DCB specimens is the currently recognized testing methodology to evaluate SSC pipe performance, other type of tests could be employed for the purpose of an ECA.\u0000 In the present paper, a fracture mechanics experimental program in sour environment is presented. Parent Pipe and Weld Material of Longitudinal Submerged Arc Welded (LSAW) large diameter pipes in H2S were studied. Fracture Toughness Parameters, such K-limit from standard DCB tests and K-threshold from Single Edge Notch Tension (SENT) specimens under constant loading, are compared and discussed. Furthermore, the fracture toughness values obtained from SENT specimens in sour environment are used to estimate the burst pressure using an ECA procedure.","PeriodicalId":297013,"journal":{"name":"Volume 2A: Structures, Safety, and Reliability","volume":"122 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115146125","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}
Nowadays, the most used methodology to predict line tensions is the short-term coupled analysis, where the mooring system responses are obtained by a time-domain analysis for only some specific design combinations of extreme environmental conditions. This mooring analysis demands certain considerations and it is not the best way to obtain the offshore structure responses. The advances in both quantity and quality of collected environmental data and the increase of the computers processing power has enabled to consider the approach of more accurate long-term methodologies for mooring systems design. This paper proposes a numerical/computational procedure to obtain the extreme loads (ULS) acting on offshore platforms’ mooring lines. The work is based on the methodology of long-term analysis, employing a 10-yr long short-term environmental dataset of 3-h sea-states, where each short-term environmental condition is composed of the simultaneously observed environmental parameters of wave (sea and swell), wind and current. The methodology is applied to the analysis of three different mooring systems: a) spread-moored FPSO, b) Semi-Submersible platform and c) turret-moored FPSO. The Bootstrap approach is employed in order to take into account the statistical uncertainty associated to the estimated long-term most probable extreme response due to the limited number of short-term environmental conditions. The work was carried out using Dynasim software [1] to generate the time domain tension time series, which were later post-processed by using computational codes developed with Python software. Longer short-term numerical simulations lengths than the short-term period (3-h) have been investigated in order to understand the influence of this parameter on the final extreme long-term top tensions.
{"title":"Long-Term Analysis Applied to Mooring Systems Design","authors":"Pedro Seabra, L. Sagrilo, P. Esperança","doi":"10.1115/omae2020-18211","DOIUrl":"https://doi.org/10.1115/omae2020-18211","url":null,"abstract":"\u0000 Nowadays, the most used methodology to predict line tensions is the short-term coupled analysis, where the mooring system responses are obtained by a time-domain analysis for only some specific design combinations of extreme environmental conditions. This mooring analysis demands certain considerations and it is not the best way to obtain the offshore structure responses. The advances in both quantity and quality of collected environmental data and the increase of the computers processing power has enabled to consider the approach of more accurate long-term methodologies for mooring systems design. This paper proposes a numerical/computational procedure to obtain the extreme loads (ULS) acting on offshore platforms’ mooring lines. The work is based on the methodology of long-term analysis, employing a 10-yr long short-term environmental dataset of 3-h sea-states, where each short-term environmental condition is composed of the simultaneously observed environmental parameters of wave (sea and swell), wind and current. The methodology is applied to the analysis of three different mooring systems: a) spread-moored FPSO, b) Semi-Submersible platform and c) turret-moored FPSO. The Bootstrap approach is employed in order to take into account the statistical uncertainty associated to the estimated long-term most probable extreme response due to the limited number of short-term environmental conditions. The work was carried out using Dynasim software [1] to generate the time domain tension time series, which were later post-processed by using computational codes developed with Python software. Longer short-term numerical simulations lengths than the short-term period (3-h) have been investigated in order to understand the influence of this parameter on the final extreme long-term top tensions.","PeriodicalId":297013,"journal":{"name":"Volume 2A: Structures, Safety, and Reliability","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125720368","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}
E. Lone, B. Leira, T. Sauder, Vegard Aksnes, Ø. Gabrielsen, K. Larsen
Studies published in recent years have documented a significant mean load effect on fatigue capacity for offshore mooring chain, and show that a reduction of the mean load gives an increase in fatigue life. However, current S-N design curves are based on fatigue tests performed at a mean load of 20% of minimum breaking load (MBL), which is well above the typical mean loads for most mooring systems. This paper investigates the mean loads experienced during fatigue damage accumulation for the mooring system of a typical production semi-submersible, operating in Norwegian Sea conditions. The study is based on numerical, time-domain simulations, using environmental conditions defined from a series of hindcast data. A parameterized S-N design curve suggested by Fernández et al. (2019), incorporating a Smith-Watson-Topper mean stress correction model, is applied for fatigue damage calculation and compared to results for the S-N design curve prescribed by current standards. For the semi-submersible unit considered there is negligible difference in basing the correction on 3-hour mean load compared to the mean load of individual stress cycles, due to small low frequency tension variations. On this basis, a single correction factor is proposed to allow for mean load correction based on results available from a standard fatigue analysis.
{"title":"Influence of Mean Tension on Mooring Line Fatigue Life","authors":"E. Lone, B. Leira, T. Sauder, Vegard Aksnes, Ø. Gabrielsen, K. Larsen","doi":"10.1115/omae2020-18628","DOIUrl":"https://doi.org/10.1115/omae2020-18628","url":null,"abstract":"\u0000 Studies published in recent years have documented a significant mean load effect on fatigue capacity for offshore mooring chain, and show that a reduction of the mean load gives an increase in fatigue life. However, current S-N design curves are based on fatigue tests performed at a mean load of 20% of minimum breaking load (MBL), which is well above the typical mean loads for most mooring systems.\u0000 This paper investigates the mean loads experienced during fatigue damage accumulation for the mooring system of a typical production semi-submersible, operating in Norwegian Sea conditions. The study is based on numerical, time-domain simulations, using environmental conditions defined from a series of hindcast data. A parameterized S-N design curve suggested by Fernández et al. (2019), incorporating a Smith-Watson-Topper mean stress correction model, is applied for fatigue damage calculation and compared to results for the S-N design curve prescribed by current standards.\u0000 For the semi-submersible unit considered there is negligible difference in basing the correction on 3-hour mean load compared to the mean load of individual stress cycles, due to small low frequency tension variations. On this basis, a single correction factor is proposed to allow for mean load correction based on results available from a standard fatigue analysis.","PeriodicalId":297013,"journal":{"name":"Volume 2A: Structures, Safety, and Reliability","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129015867","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}
Haibo Chen, Tommy Bauge, L. Reinås, Paul Landeråen
Technical, operational and organization barrier elements related to the emergency disconnect on dynamically positioned mobile offshore drilling units on the Norwegian Continental Shelf are identified. Position loss scenarios are analyzed based on the published station-keeping incidents by IMCA (International Marine Contractors Association). How these barrier elements may fail in different types of position loss scenarios are addressed qualitatively and quantitatively in an event tree model. A case study is provided in the paper and notational probability of failure to disconnect given position loss is calculated. Risk reduction effect of various barrier elements are investigated by sensitivity studies. The paper provides insights into risk given position loss and failure of emergency disconnect on DP MODUs. It offers decision support for risk management of DP drilling and well operations in shallow water and harsh environment.
{"title":"Barrier Analysis of Emergency Disconnect on DP Mobile Offshore Drilling Units","authors":"Haibo Chen, Tommy Bauge, L. Reinås, Paul Landeråen","doi":"10.1115/omae2020-19184","DOIUrl":"https://doi.org/10.1115/omae2020-19184","url":null,"abstract":"\u0000 Technical, operational and organization barrier elements related to the emergency disconnect on dynamically positioned mobile offshore drilling units on the Norwegian Continental Shelf are identified. Position loss scenarios are analyzed based on the published station-keeping incidents by IMCA (International Marine Contractors Association). How these barrier elements may fail in different types of position loss scenarios are addressed qualitatively and quantitatively in an event tree model. A case study is provided in the paper and notational probability of failure to disconnect given position loss is calculated. Risk reduction effect of various barrier elements are investigated by sensitivity studies. The paper provides insights into risk given position loss and failure of emergency disconnect on DP MODUs. It offers decision support for risk management of DP drilling and well operations in shallow water and harsh environment.","PeriodicalId":297013,"journal":{"name":"Volume 2A: Structures, Safety, and Reliability","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133525262","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}
The paper proposes an approach for estimating the long-term statistics of random wave crests occurring over a certain space–time domain. Such a problem is relevant for a number of marine engineering applications, as classical analyses based, exclusively, on time domain approaches underestimates wave crest amplitudes associated with a given return period. The return period of a certain wave crest is derived by combining the Trapezoidal Storm (TS) Model, based on DNV GL storm profile, with the Euleric Characteristic (EC) of an excursion set concept, recently applied to the study of sea wave statistics. By computing the average EC, an explicit solution for the probability distribution of the wave crests during a sea storm can be derived by an approximation of the EC. Return period of linear wave crests is derived in the paper. The proposed solution is applied for the calculation of extreme waves during an ocean storm over a certain area. The results presented can be used as good approximation in design work of offshore installations. An extension of the proposed approach to account for nonlinearities of sea surface will be a subject of future research.
{"title":"Space-Time Statistics via Trapezoidal Storm Model for Offshore Installations","authors":"V. Laface, A. Romolo, E. Bitner-Gregersen","doi":"10.1115/omae2020-18822","DOIUrl":"https://doi.org/10.1115/omae2020-18822","url":null,"abstract":"\u0000 The paper proposes an approach for estimating the long-term statistics of random wave crests occurring over a certain space–time domain. Such a problem is relevant for a number of marine engineering applications, as classical analyses based, exclusively, on time domain approaches underestimates wave crest amplitudes associated with a given return period. The return period of a certain wave crest is derived by combining the Trapezoidal Storm (TS) Model, based on DNV GL storm profile, with the Euleric Characteristic (EC) of an excursion set concept, recently applied to the study of sea wave statistics. By computing the average EC, an explicit solution for the probability distribution of the wave crests during a sea storm can be derived by an approximation of the EC. Return period of linear wave crests is derived in the paper. The proposed solution is applied for the calculation of extreme waves during an ocean storm over a certain area. The results presented can be used as good approximation in design work of offshore installations. An extension of the proposed approach to account for nonlinearities of sea surface will be a subject of future research.","PeriodicalId":297013,"journal":{"name":"Volume 2A: Structures, Safety, and Reliability","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122537656","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}
Casing collapse capacity was identified by Equinor as a critical operational parameter on one of its fields in production. This led to re-evaluation and detailed studies of the overall well design, specifically the production casing’s collapse capacity, together with consequence and risk evaluations in case of a potential casing failure. As an important and useful input to the risk evaluations, the present paper presents a structural reliability analysis for casing collapse. Initially, the casing collapse capacity was evaluated using API TR 5C3 / ISO 10400 [1], with insufficient capacity being documented. In order to investigate further, physical material testing and collapse testing were performed. Two kinds of collapse tests have been performed: i) tests of unsupported pipe and ii) test of pipes with external support from the cement and formation surrounding the pipe. While a paper from 2018 (OMAE2018-78767) considered casings without external support, the present paper pays attention towards supported pipes. Five collapse tests have been performed where test lengths of the 9 5/8” casing were installed inside a thick-walled pipe that simulates the support. A small gap leaves an annulus between the casing and the supporting pipe, allowing a controlled pressure to increase until collapse. The tests have been simulated by finite element analyses. Good correspondence was obtained, providing confidence that FE simulations can be used to predict the collapse capacity of supported pipes. While the tests were only performed for an idealized case with support around the whole circumference, a large number of FE simulations have been carried out for different combinations of support conditions together with variations in pipe ovality and internal wear from drilling. Ideally, the space between the casing and the rock formation is filled by cement. However, in practice there may be channels where there is no cement, likely to occur if the casing is eccentric in the well bore during cementing. These results from these FE simulations have been used to generate a response surface. Subsequent structural reliability analyses have been performed, in which well specific uncertainty associated with the above parameters is considered. Measurements and logging are used to minimize the uncertainty in these inputs and thereby leading to a reduction in the calculated failure probability. The probability of casing collapse is calculated conditional on different magnitude of the differential pressure of the pipe. By using SRA the potential over-conservatism in the conventional deterministic analysis is avoided. The SRA results were used to assist in the risk evaluation resulting in an allowance for continued production on existing wells.
Equinor将套管抗塌能力确定为其生产中的一个油田的关键操作参数。这导致了对整体井设计的重新评估和详细研究，特别是生产套管的抗塌能力，以及潜在套管损坏的后果和风险评估。作为一种重要的、有用的风险评估输入，本文提出了套管坍塌的结构可靠性分析。最初，使用API TR 5C3 / ISO 10400[1]对套管抗塌能力进行了评估，并记录了抗塌能力不足的情况。为了进一步研究，进行了物理材料试验和倒塌试验。进行了两种坍塌试验:i)无支撑管道试验和ii)管道周围有水泥和地层外部支撑的管道试验。2018年的一篇论文(OMAE2018-78767)考虑了没有外部支撑的套管，而本论文关注的是有支撑的管道。在模拟支撑的厚壁管中安装了测试长度的9 5/8”套管，进行了5次坍塌测试。套管和支撑管之间有一个小的间隙，使压力可控，直至坍塌。对试验进行了有限元模拟分析。得到了较好的对应关系，为有限元模拟预测支撑管道的坍塌能力提供了信心。虽然这些测试只是在理想的情况下进行的，但对于不同的支撑条件组合，以及管道椭圆度和钻井内部磨损的变化，已经进行了大量的有限元模拟。理想情况下，套管和岩层之间的空间由水泥填充。然而，在实际操作中，如果在固井过程中套管偏心，可能会出现没有固井的通道。这些有限元模拟的结果已用于生成响应面。随后进行了结构可靠性分析，其中考虑了与上述参数相关的井特定不确定性。测量和测井用于最小化这些输入的不确定性，从而降低计算出的失效概率。根据不同的管压差大小，计算了套管坍塌的概率。通过使用SRA，避免了传统确定性分析中潜在的过保守性。SRA结果用于协助风险评估，从而允许现有井继续生产。
{"title":"Benefit From Structural Reliability Analysis in Risk Evaluation of Collapse of Externally Supported Casing","authors":"T. Hørte, A. Bjo̸rset, D. Zaharie, S. Pettersen","doi":"10.1115/omae2020-18887","DOIUrl":"https://doi.org/10.1115/omae2020-18887","url":null,"abstract":"\u0000 Casing collapse capacity was identified by Equinor as a critical operational parameter on one of its fields in production. This led to re-evaluation and detailed studies of the overall well design, specifically the production casing’s collapse capacity, together with consequence and risk evaluations in case of a potential casing failure. As an important and useful input to the risk evaluations, the present paper presents a structural reliability analysis for casing collapse.\u0000 Initially, the casing collapse capacity was evaluated using API TR 5C3 / ISO 10400 [1], with insufficient capacity being documented. In order to investigate further, physical material testing and collapse testing were performed. Two kinds of collapse tests have been performed: i) tests of unsupported pipe and ii) test of pipes with external support from the cement and formation surrounding the pipe. While a paper from 2018 (OMAE2018-78767) considered casings without external support, the present paper pays attention towards supported pipes. Five collapse tests have been performed where test lengths of the 9 5/8” casing were installed inside a thick-walled pipe that simulates the support. A small gap leaves an annulus between the casing and the supporting pipe, allowing a controlled pressure to increase until collapse. The tests have been simulated by finite element analyses. Good correspondence was obtained, providing confidence that FE simulations can be used to predict the collapse capacity of supported pipes.\u0000 While the tests were only performed for an idealized case with support around the whole circumference, a large number of FE simulations have been carried out for different combinations of support conditions together with variations in pipe ovality and internal wear from drilling. Ideally, the space between the casing and the rock formation is filled by cement. However, in practice there may be channels where there is no cement, likely to occur if the casing is eccentric in the well bore during cementing. These results from these FE simulations have been used to generate a response surface. Subsequent structural reliability analyses have been performed, in which well specific uncertainty associated with the above parameters is considered. Measurements and logging are used to minimize the uncertainty in these inputs and thereby leading to a reduction in the calculated failure probability. The probability of casing collapse is calculated conditional on different magnitude of the differential pressure of the pipe.\u0000 By using SRA the potential over-conservatism in the conventional deterministic analysis is avoided. The SRA results were used to assist in the risk evaluation resulting in an allowance for continued production on existing wells.","PeriodicalId":297013,"journal":{"name":"Volume 2A: Structures, Safety, and Reliability","volume":"79 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124080210","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}
Deep-water natural gas hydrate has high environmental risk and high technical difficulty in drilling and production. In order to promote the development of gas hydrate, we develop the assessment methods and control technologies for the operation risk during hydrate drilling and production. The work completed includes: (1) Safety analysis of conductor and wellhead for the hydrate drilling and production Establish a pipe-wellhead stability model to determine the drilling and working conditions under different working conditions. (2) Risk assessment of wellbore blockage in hydrate drilling and production Construct a wellbore multiphase flow analysis model to determine the amount of drilling inhibitor injection; obtain the location and extent of the hydrate blockage. (3) Risk assessment of wellbore instability in hydrate production Combined with hydrate formation properties, ground stress distribution and casing mechanics model, the position of the formation instability, and the damage of casing crushing is determined. (4) Gas diffusion risk assessment due to hydrate decomposition in water Study the distribution of underwater gas diffusion formed by large-area decomposition of hydrate to get the overflow flow risk. (5) Safety model and process risk assessment of hydrate drilling operations Conduct hazard identification and operation safety analysis of hydrate drilling operations, determine the risk level of each operation stage, and support the drilling operation.
{"title":"Risk Assessment and Countermeasure on Drilling and Production Process of Deep Water Gas Hydrate in the South China Sea","authors":"Zhu Yuan, L. Kang, Chan Guoming","doi":"10.1115/omae2020-18532","DOIUrl":"https://doi.org/10.1115/omae2020-18532","url":null,"abstract":"\u0000 Deep-water natural gas hydrate has high environmental risk and high technical difficulty in drilling and production. In order to promote the development of gas hydrate, we develop the assessment methods and control technologies for the operation risk during hydrate drilling and production. The work completed includes:\u0000 (1) Safety analysis of conductor and wellhead for the hydrate drilling and production\u0000 Establish a pipe-wellhead stability model to determine the drilling and working conditions under different working conditions.\u0000 (2) Risk assessment of wellbore blockage in hydrate drilling and production\u0000 Construct a wellbore multiphase flow analysis model to determine the amount of drilling inhibitor injection; obtain the location and extent of the hydrate blockage.\u0000 (3) Risk assessment of wellbore instability in hydrate production\u0000 Combined with hydrate formation properties, ground stress distribution and casing mechanics model, the position of the formation instability, and the damage of casing crushing is determined.\u0000 (4) Gas diffusion risk assessment due to hydrate decomposition in water\u0000 Study the distribution of underwater gas diffusion formed by large-area decomposition of hydrate to get the overflow flow risk.\u0000 (5) Safety model and process risk assessment of hydrate drilling operations\u0000 Conduct hazard identification and operation safety analysis of hydrate drilling operations, determine the risk level of each operation stage, and support the drilling operation.","PeriodicalId":297013,"journal":{"name":"Volume 2A: Structures, Safety, and Reliability","volume":"666 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133301012","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}
G. Rinaldi, P. Thies, L. Johanning, P. McEvoy, G. Georgallis, A. Moraiti, Carlos Cortés Lahuerta, M. Vidmar
Future offshore wind technology solutions will be floating to facilitate deep water locations. The EUH2020 funded project FLOTANT (Innovative, low cost, low weight and safe floating wind technology optimized for deep water wind sites) aims to address the arising technical and economic challenges linked to this progress. In particular, innovative solutions in terms of mooring lines, power cable and floating platform, specifically designed for floating offshore wind devices, will be developed and tested, and the benefits provided by these components assessed. In this paper a purpose-built Failure Modes and Effect Analysis (FMEA) technique is presented, and applied to the novel floating offshore wind components. The aim is to determine the technology qualification, identify the key failure modes and assess the criticality of these components and their relative contributions to the reliability, availability and maintainability of the device. This will allow for the identification of suitable mitigation measures in the development lifecycle, as well as an assessment of potential cost savings and impacts of the specific innovations. The methodology takes into account inputs from the components developers and other project partners, as well as information extracted from existing literature and databases. Findings in terms of components innovations, their main criticalities and related mitigation measures, and impacts on preventive and corrective maintenance, will be presented in order to inform current and future developments for floating offshore wind devices.
{"title":"Informing Components Development Innovations for Floating Offshore Wind Through Applied FMEA Framework","authors":"G. Rinaldi, P. Thies, L. Johanning, P. McEvoy, G. Georgallis, A. Moraiti, Carlos Cortés Lahuerta, M. Vidmar","doi":"10.1115/OMAE2020-18349","DOIUrl":"https://doi.org/10.1115/OMAE2020-18349","url":null,"abstract":"\u0000 Future offshore wind technology solutions will be floating to facilitate deep water locations. The EUH2020 funded project FLOTANT (Innovative, low cost, low weight and safe floating wind technology optimized for deep water wind sites) aims to address the arising technical and economic challenges linked to this progress. In particular, innovative solutions in terms of mooring lines, power cable and floating platform, specifically designed for floating offshore wind devices, will be developed and tested, and the benefits provided by these components assessed. In this paper a purpose-built Failure Modes and Effect Analysis (FMEA) technique is presented, and applied to the novel floating offshore wind components. The aim is to determine the technology qualification, identify the key failure modes and assess the criticality of these components and their relative contributions to the reliability, availability and maintainability of the device. This will allow for the identification of suitable mitigation measures in the development lifecycle, as well as an assessment of potential cost savings and impacts of the specific innovations. The methodology takes into account inputs from the components developers and other project partners, as well as information extracted from existing literature and databases. Findings in terms of components innovations, their main criticalities and related mitigation measures, and impacts on preventive and corrective maintenance, will be presented in order to inform current and future developments for floating offshore wind devices.","PeriodicalId":297013,"journal":{"name":"Volume 2A: Structures, Safety, and Reliability","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130276139","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}
This paper has been influenced by a basic question: assuming a torpedo pile launching in a base case scenario, which parameters, when not well controlled, would affect more the pile final penetration depth? Aiming to provide an answer to this question, the methodology adopted in this study assumes the application of numerical simulations and statistical analyses in order to quantify the influence of the uncertainties of such parameters in the final penetration depth. From the assessment, one may expect responses in terms of which parameters shall be better controlled during a launching procedure in order to reduce the uncertainties associated to the target depth. For the development of the study, a simplified approach for the dynamic numerical analyses has been adopted in order to allow a massive data generation for the statistical treatment. The main parameters associated to the torpedo pile and the launching scenario have been generated taking into account their uncertainties. The Monte Carlo method has been considered and statistical treatment has been applied to quantify the influence of the parameters in the final penetration depth. The results demonstrate that apply the simplified method described in the paper is adequate to simulate both the subsea free fall and the pile driving phases to obtain the final penetration depths. The torpedo mass has been found as the physical parameter which influences more the final penetration depth. However, the study demonstrates that, given a standard launching procedure assessed by numerical simulations, uncertainties on physical parameters are much less significant for the final penetration depth than the uncertainties inherent to the assumptions and data applied to simulate the soil damping.
{"title":"Influence of Torpedo Piles Parameters When Assessing Final Penetration Depths","authors":"Leonardo Sant’Anna do Nascimento","doi":"10.1115/omae2020-18505","DOIUrl":"https://doi.org/10.1115/omae2020-18505","url":null,"abstract":"This paper has been influenced by a basic question: assuming a torpedo pile launching in a base case scenario, which parameters, when not well controlled, would affect more the pile final penetration depth? Aiming to provide an answer to this question, the methodology adopted in this study assumes the application of numerical simulations and statistical analyses in order to quantify the influence of the uncertainties of such parameters in the final penetration depth. From the assessment, one may expect responses in terms of which parameters shall be better controlled during a launching procedure in order to reduce the uncertainties associated to the target depth.\u0000 For the development of the study, a simplified approach for the dynamic numerical analyses has been adopted in order to allow a massive data generation for the statistical treatment. The main parameters associated to the torpedo pile and the launching scenario have been generated taking into account their uncertainties. The Monte Carlo method has been considered and statistical treatment has been applied to quantify the influence of the parameters in the final penetration depth.\u0000 The results demonstrate that apply the simplified method described in the paper is adequate to simulate both the subsea free fall and the pile driving phases to obtain the final penetration depths. The torpedo mass has been found as the physical parameter which influences more the final penetration depth. However, the study demonstrates that, given a standard launching procedure assessed by numerical simulations, uncertainties on physical parameters are much less significant for the final penetration depth than the uncertainties inherent to the assumptions and data applied to simulate the soil damping.","PeriodicalId":297013,"journal":{"name":"Volume 2A: Structures, Safety, and Reliability","volume":"105 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130576504","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：