A surrogate model for evaluation of maximum normalized dynamic load factor in moving load model for pipeline spanning due to slug flow
- Sultan, Ibrahim, Reda, Ahmed, Forbes, Gareth
- Authors: Sultan, Ibrahim , Reda, Ahmed , Forbes, Gareth
- Date: 2012
- Type: Text , Conference proceedings
- Full Text:
- Description: Understanding the problem of slug-flow-induced fatigue damage is of particular importance to the reliable operation of pipelines. Slug flow, across unsupported pipeline spans, produces dynamic vibrations in the pipeline resulting in cyclical fatigue stresses. These dynamic effects will cause the pipeline to fail at a point of stress concentration if proper design procedure is not followed. The response of a pipeline span, under the passage of slug flow, can be represented by dynamic load factors that are functions of the speed ratio and damping characteristics of the span. The aspects of these functional relationships are investigated, in this paper by conducting multiple simulations at different speed ratios and damping factors. The data obtained from the steady state Fourier expansion will, consequently, be used to produce a surrogate model with a level of accuracy that adequately qualifies it for use in determining dynamic loading of pipelines. The closed-form surrogate model can be used to eliminate the need to employ costly mathematical procedures or finite element packages for the analysis. The model will also provide a solid ground for optimization studies and help designers gain an insight into how various model parameters impact the system response. This paper will demonstrate the aspects of a proposed surrogate model and endeavor to obtain parameter domains within which the model's reliability is ensured. A numerical example will be demonstrated to prove the concepts presented in the paper and confirm the validity of the proposed model. Copyright © 2012 by ASME.
- Description: C1
- Authors: Sultan, Ibrahim , Reda, Ahmed , Forbes, Gareth
- Date: 2012
- Type: Text , Conference proceedings
- Full Text:
- Description: Understanding the problem of slug-flow-induced fatigue damage is of particular importance to the reliable operation of pipelines. Slug flow, across unsupported pipeline spans, produces dynamic vibrations in the pipeline resulting in cyclical fatigue stresses. These dynamic effects will cause the pipeline to fail at a point of stress concentration if proper design procedure is not followed. The response of a pipeline span, under the passage of slug flow, can be represented by dynamic load factors that are functions of the speed ratio and damping characteristics of the span. The aspects of these functional relationships are investigated, in this paper by conducting multiple simulations at different speed ratios and damping factors. The data obtained from the steady state Fourier expansion will, consequently, be used to produce a surrogate model with a level of accuracy that adequately qualifies it for use in determining dynamic loading of pipelines. The closed-form surrogate model can be used to eliminate the need to employ costly mathematical procedures or finite element packages for the analysis. The model will also provide a solid ground for optimization studies and help designers gain an insight into how various model parameters impact the system response. This paper will demonstrate the aspects of a proposed surrogate model and endeavor to obtain parameter domains within which the model's reliability is ensured. A numerical example will be demonstrated to prove the concepts presented in the paper and confirm the validity of the proposed model. Copyright © 2012 by ASME.
- Description: C1
Evaluation of slug flow-induced flexural loading in pipelines using a surrogate model
- Sultan, Ibrahim, Reda, Ahmed, Forbes, Gareth
- Authors: Sultan, Ibrahim , Reda, Ahmed , Forbes, Gareth
- Date: 2013
- Type: Text , Journal article
- Relation: Journal of Offshore Mechanics and Arctic Engineering Vol. 135, no. 3 (2013), p. 8
- Full Text:
- Reviewed:
- Description: Slug flow induces vibration in pipelines, which may, in some cases, result in fatigue failure. This can result from dynamic stresses, induced by the deflection and bending moment in the pipe span, growing to levels above the endurance limits of the pipeline material. As such, it is of paramount importance to understand and quantify the size of the pipeline response to slug flow under given speed and damping conditions. This paper utilizes the results of an optimization procedure to devise a surrogate closed-form model, which can be employed to calculate the maximum values of the pipeline loadings at given values of speed and damping parameters. The surrogate model is intended to replace the computationally costly numerical procedure needed for the analysis. The maximum values of the lateral deflection and bending moment, along with their locations, have been calculated using the optimization method of stochastic perturbation and successive approximations ( SPSA). The accuracy of the proposed surrogate model will be validated numerically, and the model will be subsequently used in a numerical example to demonstrate its applicability in industrial situations. An accompanying spreadsheet with this worked example is also given.
- Description: C1
Guidelines for safe cable crossing over a pipeline
- Reda, Ahmed, Rawlinson, Andrew, Sultan, Ibrahim, Elgazzar, Mohammed, Howard, Ian
- Authors: Reda, Ahmed , Rawlinson, Andrew , Sultan, Ibrahim , Elgazzar, Mohammed , Howard, Ian
- Date: 2020
- Type: Text , Journal article
- Relation: Applied Ocean Research Vol. 102, no. (2020), p.
- Full Text:
- Reviewed:
- Description: High voltage submarine cables are increasingly being installed in existing and new offshore oil and gas fields for power supply and control purposes. These power cables are both large and with a high submerged weight, which poses a challenge when designing a safe, maintenance free (economical), and fit-for-purpose crossing over a pipeline. Damage to subsea pipeline crossings caused by deterioration of a crossing support, field joint materials and cover components is well known in the industry, particularly with old pipelines. Crossing cables over an existing pipeline should be avoided whenever economical and practical. However, it is inevitable in some situations to use the existing pipeline (unburied) as the crossing support to a new cable/umbilical. In these situations, crossing the cable/umbilical over the existing pipeline may be a cost-effective and worthy consideration. However, there are no explicit guidelines or criteria in the industry concerning the acceptable practice of design and construction of crossings. The only clear recommendation is relating to pipeline separation distances. This paper documents a recent case study of damage of a field joint coating at a crossing of an existing pipeline by a 132 kV subsea cable of 191 mm outside diameter. Investigation of the damage on site revealed that it was caused by lateral movement of the cable under the influence of hydrodynamic forces. Further to investigation and assessment of the damage of the case study presented here, the paper proposes some guidelines for the safe design and construction of cable crossing. Another objective of this paper is to invite further evaluation of the proposed guidelines so that appropriate crossing design requirements can be further developed and standardised. © 2020 Elsevier Ltd
- Authors: Reda, Ahmed , Rawlinson, Andrew , Sultan, Ibrahim , Elgazzar, Mohammed , Howard, Ian
- Date: 2020
- Type: Text , Journal article
- Relation: Applied Ocean Research Vol. 102, no. (2020), p.
- Full Text:
- Reviewed:
- Description: High voltage submarine cables are increasingly being installed in existing and new offshore oil and gas fields for power supply and control purposes. These power cables are both large and with a high submerged weight, which poses a challenge when designing a safe, maintenance free (economical), and fit-for-purpose crossing over a pipeline. Damage to subsea pipeline crossings caused by deterioration of a crossing support, field joint materials and cover components is well known in the industry, particularly with old pipelines. Crossing cables over an existing pipeline should be avoided whenever economical and practical. However, it is inevitable in some situations to use the existing pipeline (unburied) as the crossing support to a new cable/umbilical. In these situations, crossing the cable/umbilical over the existing pipeline may be a cost-effective and worthy consideration. However, there are no explicit guidelines or criteria in the industry concerning the acceptable practice of design and construction of crossings. The only clear recommendation is relating to pipeline separation distances. This paper documents a recent case study of damage of a field joint coating at a crossing of an existing pipeline by a 132 kV subsea cable of 191 mm outside diameter. Investigation of the damage on site revealed that it was caused by lateral movement of the cable under the influence of hydrodynamic forces. Further to investigation and assessment of the damage of the case study presented here, the paper proposes some guidelines for the safe design and construction of cable crossing. Another objective of this paper is to invite further evaluation of the proposed guidelines so that appropriate crossing design requirements can be further developed and standardised. © 2020 Elsevier Ltd
State-of-the-art review of composite marine risers for floating and fixed platforms in deep seas
- Amaechi, Chiemela, Reda, Ahmed, Shahin, Mohamed, Sultan, Ibrahim, Beddu, Salmia, Ja'e, Idris
- Authors: Amaechi, Chiemela , Reda, Ahmed , Shahin, Mohamed , Sultan, Ibrahim , Beddu, Salmia , Ja'e, Idris
- Date: 2023
- Type: Text , Journal article
- Relation: Applied Ocean Research Vol. 138, no. (2023), p.
- Full Text:
- Reviewed:
- Description: The need for the utilisation of marine risers in deep seas has increased in recent years and this is due to increased drilling explorations with the shift in trend from shallower to deep and deeper waters. Also, there have been increased applications in sea-crossing infrastructure resulting in the need for longer risers, leading to a significant weight increase of marine risers used. Composite materials can thus be utilised in marine riser engineering to provide lightweight, fatigue-resistant, corrosion-resistant, low-bending stiffness and high-strength characteristics. In this paper, the history and potential of composite marine risers, including the first successful deployment of a composite riser joint offshore on the Heidrun Platform in 1995, are reviewed. The paper also discusses the advances achieved on composite marine risers for deep waters and presents some recommendations on their use, in light of their current significance and growth. © 2023 The Author(s)
- Authors: Amaechi, Chiemela , Reda, Ahmed , Shahin, Mohamed , Sultan, Ibrahim , Beddu, Salmia , Ja'e, Idris
- Date: 2023
- Type: Text , Journal article
- Relation: Applied Ocean Research Vol. 138, no. (2023), p.
- Full Text:
- Reviewed:
- Description: The need for the utilisation of marine risers in deep seas has increased in recent years and this is due to increased drilling explorations with the shift in trend from shallower to deep and deeper waters. Also, there have been increased applications in sea-crossing infrastructure resulting in the need for longer risers, leading to a significant weight increase of marine risers used. Composite materials can thus be utilised in marine riser engineering to provide lightweight, fatigue-resistant, corrosion-resistant, low-bending stiffness and high-strength characteristics. In this paper, the history and potential of composite marine risers, including the first successful deployment of a composite riser joint offshore on the Heidrun Platform in 1995, are reviewed. The paper also discusses the advances achieved on composite marine risers for deep waters and presents some recommendations on their use, in light of their current significance and growth. © 2023 The Author(s)
Design of subsea cables/umbilicals for in-service abrasion - part 1 : case studies
- Reda, Ahmed, Thiedeman, James, Elgazzar, Mohamed, Shahin, Mohamed, Sultan, Ibrahim, McKee, Kristoffer
- Authors: Reda, Ahmed , Thiedeman, James , Elgazzar, Mohamed , Shahin, Mohamed , Sultan, Ibrahim , McKee, Kristoffer
- Date: 2021
- Type: Text , Journal article
- Relation: Ocean Engineering Vol. 234, no. (2021), p.
- Full Text:
- Reviewed:
- Description: Submarine cables play a vital role in a myriad of industries around the globe, including power transmission and communication. Failure of submarine cables can have significant economic and technical implications worldwide. Current design methods for submarine cables focus on the ultimate limit states that address the cables structural integrity and on-bottom stability. However, abrasion of the outer protective layers (i.e. yarn and extruded sheaths) can progressively lead to damage and failure of submarine cables when the integrity of the armour sheathing is compromised. This paper documents several case studies of severe abrasion of submarine cables/umbilicals and undertaken corrective measures. The paper also presents some guidelines to be considered in the design process of submarine cables concerning abrasion. The findings of this paper suggest that abrasion should be considered a limit state that must be addressed in the design process of submarine cables and umbilicals. A detailed analysis of the underlying abrasion failure mechanisms is presented and explained in a companion paper (i.e., Part II: Mechanisms). © 2021 Elsevier Ltd
- Authors: Reda, Ahmed , Thiedeman, James , Elgazzar, Mohamed , Shahin, Mohamed , Sultan, Ibrahim , McKee, Kristoffer
- Date: 2021
- Type: Text , Journal article
- Relation: Ocean Engineering Vol. 234, no. (2021), p.
- Full Text:
- Reviewed:
- Description: Submarine cables play a vital role in a myriad of industries around the globe, including power transmission and communication. Failure of submarine cables can have significant economic and technical implications worldwide. Current design methods for submarine cables focus on the ultimate limit states that address the cables structural integrity and on-bottom stability. However, abrasion of the outer protective layers (i.e. yarn and extruded sheaths) can progressively lead to damage and failure of submarine cables when the integrity of the armour sheathing is compromised. This paper documents several case studies of severe abrasion of submarine cables/umbilicals and undertaken corrective measures. The paper also presents some guidelines to be considered in the design process of submarine cables concerning abrasion. The findings of this paper suggest that abrasion should be considered a limit state that must be addressed in the design process of submarine cables and umbilicals. A detailed analysis of the underlying abrasion failure mechanisms is presented and explained in a companion paper (i.e., Part II: Mechanisms). © 2021 Elsevier Ltd
Design of subsea cables/umbilicals for in-service abrasion - part 2 : mechanisms
- Reda, Ahmed, Elgazzar, Mohamed, Thiedeman, James, McKee, Kristoffer, Sultan, Ibrahim, Shahin, Mohamed
- Authors: Reda, Ahmed , Elgazzar, Mohamed , Thiedeman, James , McKee, Kristoffer , Sultan, Ibrahim , Shahin, Mohamed
- Date: 2021
- Type: Text , Journal article
- Relation: Ocean Engineering Vol. 234, no. (2021), p.
- Full Text:
- Reviewed:
- Description: This paper is the second of two companion papers about the design of subsea cables/umbilicals for in-service abrasion. Several case studies of severe abrasion of submarine cables/umbilicals and corrective measures undertaken have been documented and presented in the first paper (Part I: Case Studies). The mechanisms of failure due to abrasion are explained in this paper. The effect of repeated lateral movement on LLDPE (linear low-density polyethylene) extruded outer sheaths of two cable samples was investigated. In the first test, a cable sample was displaced the equivalent of 12 km over a crushed mineral aggregate while in the second test, a cable was subjected to 3 km of displacement under conditions that replicated the touchdown point of a dynamic cable. The results of the first test indicated that the overall abrasion was low and acceptable. In the second test however, the outer sheath was completely worn through. The authors recommend the thickness of the outer sheath be increased for cables where uniform abrasion is expected, and high abrasion protection units be employed where localized abrasion is expected. Empirical data is provided to support these recommendations. © 2021 Elsevier Ltd
- Authors: Reda, Ahmed , Elgazzar, Mohamed , Thiedeman, James , McKee, Kristoffer , Sultan, Ibrahim , Shahin, Mohamed
- Date: 2021
- Type: Text , Journal article
- Relation: Ocean Engineering Vol. 234, no. (2021), p.
- Full Text:
- Reviewed:
- Description: This paper is the second of two companion papers about the design of subsea cables/umbilicals for in-service abrasion. Several case studies of severe abrasion of submarine cables/umbilicals and corrective measures undertaken have been documented and presented in the first paper (Part I: Case Studies). The mechanisms of failure due to abrasion are explained in this paper. The effect of repeated lateral movement on LLDPE (linear low-density polyethylene) extruded outer sheaths of two cable samples was investigated. In the first test, a cable sample was displaced the equivalent of 12 km over a crushed mineral aggregate while in the second test, a cable was subjected to 3 km of displacement under conditions that replicated the touchdown point of a dynamic cable. The results of the first test indicated that the overall abrasion was low and acceptable. In the second test however, the outer sheath was completely worn through. The authors recommend the thickness of the outer sheath be increased for cables where uniform abrasion is expected, and high abrasion protection units be employed where localized abrasion is expected. Empirical data is provided to support these recommendations. © 2021 Elsevier Ltd
Guideline for the decommissioning/abandonment of subsea pipelines
- Reda, Ahmed, Amaechi, Chiemela, Diaz Jimenez, Luis, Sultan, Ibrahim, Rawlinson, Andrew
- Authors: Reda, Ahmed , Amaechi, Chiemela , Diaz Jimenez, Luis , Sultan, Ibrahim , Rawlinson, Andrew
- Date: 2024
- Type: Text , Journal article , Review
- Relation: Journal of Marine Science and Engineering Vol. 12, no. 1 (2024), p.
- Full Text:
- Reviewed:
- Description: The operating lifespan of pipelines is limited, defined by their specific design codes and specifications, with the economic justification for this being determined primarily by the pipeline owner. During its operational lifespan, a pipeline’s integrity is affected mainly by the quality of the hydrocarbons being transported. The integrity of a pipeline can be maintained with regular inspections and maintenance/cleaning programmes followed from installation to commissioning. As production matures and declines, operators face several decisions concerning the pipeline’s future. There are several potential scenarios, and each should be assessed on a case-by-case basis for any specific pipeline in question. The industry best practices outline the minimum requirements for the safe decommissioning of pipelines. However, there currently need to be international specifications to be followed for the decommissioning of disused offshore pipelines. This paper aims to provide insight into the decommissioning and abandonment of offshore pipelines. Also, this article provides case studies for the decommissioning of subsea pipelines. © 2023 by the authors.
- Authors: Reda, Ahmed , Amaechi, Chiemela , Diaz Jimenez, Luis , Sultan, Ibrahim , Rawlinson, Andrew
- Date: 2024
- Type: Text , Journal article , Review
- Relation: Journal of Marine Science and Engineering Vol. 12, no. 1 (2024), p.
- Full Text:
- Reviewed:
- Description: The operating lifespan of pipelines is limited, defined by their specific design codes and specifications, with the economic justification for this being determined primarily by the pipeline owner. During its operational lifespan, a pipeline’s integrity is affected mainly by the quality of the hydrocarbons being transported. The integrity of a pipeline can be maintained with regular inspections and maintenance/cleaning programmes followed from installation to commissioning. As production matures and declines, operators face several decisions concerning the pipeline’s future. There are several potential scenarios, and each should be assessed on a case-by-case basis for any specific pipeline in question. The industry best practices outline the minimum requirements for the safe decommissioning of pipelines. However, there currently need to be international specifications to be followed for the decommissioning of disused offshore pipelines. This paper aims to provide insight into the decommissioning and abandonment of offshore pipelines. Also, this article provides case studies for the decommissioning of subsea pipelines. © 2023 by the authors.
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