Structural Integrity Control of Ageing Offshore Structures: Repairing and Strengthening With Grouted Connections

2013 ◽  
Author(s):  
S. M. S. M. K. Samarakoon ◽  
R. M. Chandima Ratnayake ◽  
S. A. S. C. Siriwardane
Keyword(s):  
Structural Integrity ◽  
Oil And Gas ◽  
Load Transfer ◽  
Fatigue Loading ◽  
Offshore Structures ◽  
Future Research ◽  
Offshore Platforms ◽  
Historical Evidence ◽  
Design Service Life ◽  
Pros And Cons

Structural integrity control (SIC) is an increasingly important element of offshore structures. Not only is it used in newly built and existing offshore structures (e.g. oil and gas (O&G) production & process facilities (P&PFs), wind turbine installations, etc.), but SIC is also essential for ageing offshore platforms which are subjected to an extension of their design service life. In these cases, SIC programs must be performed to assess the platforms. If any significant changes in structural integrity (SI) are discovered, then it is essential to implement an appropriate strengthening, modification and/or repair (SMR) plan. Currently, welded and grouted repairs are mostly used for SMR. Although a welded repair may typically restore a structure to its initial condition, if the damage is due to fatigue loading and welded repairs have been carried out, then historical evidence reveals that there is a high potential for the damage to reappear over time. On the other hand, mechanical connections are significantly heavier than grouted connections. Consequently, grouted repairs are widely used to provide additional strength, for instance, to handle situations such as preventing propagation of a dent or buckle, sleeved repairs, leg strengthening, clamped repair for load transfer, leak sealing and plugging, etc. This manuscript examines current developments in grouted connections and their comparative pros and cons in relation to welded or mechanical connections. It also provides recommendations for future research requirements to further develop SMR with grouted connections.

A method of technical diagnostics for offshore structures

1994 ◽  
Vol 16 (2) ◽  
pp. 43-48
Author(s):  
Do Son
Keyword(s):  
Diagnostic Method ◽  
Joint Venture ◽  
Oil And Gas ◽  
Residual Life ◽  
Life Time ◽  
Offshore Structures ◽  
Technical Diagnostics ◽  
Offshore Platforms ◽  
South Vietnam ◽  
Local Destruction

This paper describes the results of measurements and analysis of the parameters, characterizing technical state of offshore platforms in Vietnam Sea. Based on decreasing in time material characteristics because of corrosion and local destruction assessment on residual life time of platforms is given and variants for its repair are recommended. The results allowed to confirm advantage of proposed technical diagnostic method in comparison with others and have been used for oil and gas platform of Joint Venture "Vietsovpetro" in South Vietnam.

Value Co-Creation Practices in the Decommissioning of Offshore Platforms: A Case Study Approach

2021 ◽  
pp. 239496432110320
Author(s):  
Francesca Loia ◽  
Vincenzo Basile ◽  
Nancy Capobianco ◽  
Roberto Vona
Keyword(s):  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Future Research ◽  
Offshore Platforms ◽  
Gas Industry ◽  
Study Approach ◽  
Collaborative Interactions ◽  
Exploratory Approach ◽  
Italian Context

Over the years, value co-creation practices have become increasingly more important by supporting collaborative interactions and the achievement of sustainable and mutual competitive advantage between the ecosystem’ actors. In this direction, the oil and gas industry is proposing a sustainable re-use of offshore platforms based on value co-creation and resources exchange between the actors involved. According to this consideration, this work aims at re-reading the decommissioning of offshore platforms in the light of value co-creation practices, trying to capture the factors that governments and companies can leverage to pursue a sustainable development of local communities. To reach this goal, this work follows an exploratory approach by using, in particular, the case study. Specifically, one of the most notably projects in the Italian context have been chosen, the Paguro platform, in order to provide empirical insights into the nature of these value co-creation processes. Five value co-creation practices have been identified which highlight the importance of synergistic efforts of institutions, companies and technology-based platforms for improving the ability to co-create and capture value in the process of decommissioning. This exploratory work establishes a foundation for future research, and offers theoretical and managerial guidance in this increasingly important area.

scholarly journals Integrity Management of Marine Structures; With Emphasis on Design for Structural Robustness

2018 ◽  
Author(s):  
Torgeir Moan
Keyword(s):  
Structural Damage ◽  
Structural Integrity ◽  
Oil And Gas ◽  
Offshore Structures ◽  
Design Standards ◽  
Limit States ◽  
Fabrication Errors ◽  
Integrity Management ◽  
Operational Errors ◽  
And Control

Based on relevant accident experiences with oil and gas platforms, a brief overview of structural integrity management of offshore structures is given; including an account of adequate design criteria, inspection, repair and maintenance as well as quality assurance and control of the engineering processes. The focus is on developing research based design standards for Accidental Collapse Limit States to ensure robustness or damage tolerance in view damage caused by accidental loads due to operational errors and to some extent abnormal structural damage due to fabrication errors. Moreover, it is suggested to provide robustness in cases where the structural performance is sensitive to uncertain parameters. The use of risk assessment to aid decisions in lieu of uncertainties affecting the performance of novel and existing offshore structures, is briefly addressed.

Developing the Structural Integrity Management System for Ageing Fixed Offshore Oil Platforms in Indonesia

2017 ◽  
Vol 862 ◽  
pp. 265-270
Author(s):  
Raditya Danu Riyanto ◽  
Murdjito
Keyword(s):  
Management System ◽  
Structural Integrity ◽  
Offshore Structures ◽  
Offshore Platforms ◽  
Offshore Structure ◽  
Element Analysis ◽  
East Kalimantan ◽  
Ranking Criteria ◽  
Life Years ◽  
Integrity Management

Offshore structure, particularly fixed offshore structures, should be kept in the performance for the fit-for-purpose condition during their operating lifetime. For fixed offshore structures that exceed their designated life years, the proper Structural Integrity Management System (SIMS) should be developed and applied. Despite the fixed offshore platforms have their service life, there are still platforms that continue to operate exceeding their service lifetime. These ageing platforms should be taken care thoroughly to avoid the consequences that could take casualties. This paper will propose the proper initiation of SIMS development for ageing fixed offshore platforms in Indonesia, by taking an example at Bekapai Field Platforms in East Kalimantan. Using HAZID technique and several ranking criteria, the platforms are assessed and ranked. Platforms that categorized in critical condition are grouped based on similarities in geometry and function. The highest rank is analyzed in computer Finite Element Analysis (FEA) Software with modification based on latest inspection result. This method is proven to be a proper method to be used as a maintenance program for ageing fixed offshore platforms in Indonesia.

scholarly journals Development of Risk-Reliability Based Underwater Inspection for Fixed Offshore Platforms in Indonesia

2018 ◽  
Vol 147 ◽  
pp. 05002
Author(s):  
Ricky L. Tawekal ◽  
Faisal D. Purnawarman ◽  
Yati Muliati
Keyword(s):  
Structural Reliability ◽  
Structural Integrity ◽  
Damage Mechanism ◽  
Offshore Structures ◽  
Probability Of Failure ◽  
American Petroleum Institute ◽  
Offshore Platform ◽  
Risk Level ◽  
Offshore Platforms ◽  
Fixed Offshore Platform

In RBUI method, platform with higher risk level will need inspection done more intensively than those with lower risk level. However, the probability of failure (PoF) evaluation in RBUI method is usually carried out in semi quantitative way by comparing failure parameters associated with the same damage mechanism between a group of platforms located in the same area. Therefore, RBUI will not be effective for platforms spread in distant areas where failure parameter associated with the same damage mechanism may not be the same. The existing standard, American Petroleum Institute, Recommended Practice for Structural Integrity Management of Fixed Offshore Structures (API RP-2SIM), is limited on the general instructions in determining the risk value of a platform, yet it does not provide a detail instruction on how determining the Probability of Failure (PoF) of platform. In this paper, the PoF is determined quantitatively by calculating structural reliability index based on structural collapse failure mode, thus the method in determining the inspection schedule is called Risk-Reliability Based Underwater Inspection (RReBUI). Models of 3-legs jacket fixed offshore platform in Java Sea and 4-legs jacket fixed offshore platform in Natuna Sea are used to study the implementation of RReBUI.

Integrity Management of Offshore Structures With Emphasis on Design for Structural Damage Tolerance

2020 ◽  
Vol 142 (3) ◽  
Author(s):  
Torgeir Moan
Keyword(s):  
Structural Damage ◽  
Structural Integrity ◽  
Oil And Gas ◽  
Damage Tolerance ◽  
Progressive Failure ◽  
Offshore Structures ◽  
Limit States ◽  
Safety Level ◽  
Integrity Management ◽  
Conservative Values

Abstract Based on relevant accident experiences with oil and gas platforms, structural integrity management of offshore structures is briefly outlined, including adequate design criteria, fabrication and operational procedures, as well as life cycle quality assurance and control. The focus is on developing an operational design standard for accidental collapse limit states to ensure robustness or damage tolerance. The focus is to ensure an acceptable safety level against progressive failure leading to total loss in view of initial damage caused by accidental actions due to operational errors and abnormal structural damage due to fabrication errors and abnormal deterioration during operation as well as the actions on the damaged structure and inherent uncertainties. Moreover, the damage tolerance required for achieving safety by inspection, monitoring and repair strategies, is briefly addressed. While the basic damage tolerance requirement refers to the survival of the structure in certain damage conditions, wider aspects of robustness in terms of the structure’s sensitivity to the deviation of action effects and resistances from normal conditions are also briefly addressed. In particular, it is suggested to provide robustness in cases where the structural performance is sensitive to uncertain parameters, by choosing conservative values of these parameters.

The State-of-the-Art in Structural Integrity Management: A Review and Proposed Data-Driven Approach

2019 ◽  
Author(s):  
YeongAe Heo
Keyword(s):  
Risk Management ◽  
Environmental Conditions ◽  
Structural Integrity ◽  
State Of The Art ◽  
Cost Effective ◽  
Offshore Structures ◽  
Data Driven ◽  
Future Research ◽  
Network Systems ◽  
Management Approaches

Abstract Probabilistic risk-based approaches have been used for cost-effective structural design and maintenance guidelines. The effectiveness of these provisions, however, has yet to be adequately validated. Also, current risk management approaches are hardly adaptable to changes in operational and environmental conditions as well as structural properties over the service life of structures. As the need and demand of real-time monitoring systems have increased dramatically for high-value and high-risk facilities such as offshore structures particularly, it is important to discuss directions for future research to advance the risk-based management approaches by utilizing the invaluable “big-scale” field data obtained from sensor network systems. Therefore, knowledge gaps in the current state-of-the-art structural risk management approaches are discussed in this paper. Subsequently, a novel risk management framework is presented in this paper integrating physics-based data into a data-driven decision model. The proposed decision framework will improve system adaptability to future performance requirements due to changing operational and environmental conditions and will be applicable to any structural systems instrumented by sophisticated SHM systems such as complex naval and marine systems.

Deformation Monitoring of Offshore Platform Using the Persistent Scatterer Interferometry Technique

2014 ◽  
Vol 567 ◽  
pp. 325-330 ◽  
Author(s):  
Abdul Nasir Matori ◽  
Amir Sharifuddin Ab Latip ◽  
Indra Sati Hamonangan Harahap ◽  
Daniele Perissin
Keyword(s):  
Structural Integrity ◽  
Oil And Gas ◽  
Deformation Monitoring ◽  
Offshore Platform ◽  
Offshore Platforms ◽  
Persistent Scatterer Interferometry ◽  
Reservoir Compaction ◽  
Persistent Scatterer ◽  
Deformation Velocity ◽  
Global Positioning

One of the problems that occur during the exploitation of oil and gas is offshore platform deformation. It could occur due to the environments load as well as the extraction of oil and gas itself under the seabed that caused reservoir compaction. Offshore platform deformation may affect the platform structural integrity and cause loss of production, thus it is very important to monitor its occurrences. Offshore platform deformation monitoring has been carried out using the satellite-based Global Positioning System (GPS) technique until recently. Even though the technique has proven its worth for the job, it has however some limitations, the most prominent is it could only monitor selected portion of the offshore platform. Thus, this study presents an attempt of detecting and monitoring the deformation phenomenon of an offshore platform using the Persistent Scatterer Interferometry (PSI) technique. This technique would overcome some of the limitations of the previous (GPS) deformation monitoring technique. A total of 11 high resolution TerraSAR-X images (i.e., 3 m in StripMap mode) were acquired from Aug, 2012 to Apr, 2013 for this purpose, while one of the offshore platforms in South China Sea is being used as monitored platform. Preliminary results showed that detail and sensitive deformations could be detected by this technique. In addition, analysis results in the form of mean deformation velocity map and displacement time series would allow us to further understand the behaviour of offshore platform deformation.

Risers Stability Under External Pressure, Axial Compression and Bending Moment Considering the Welded as Geometrical Imperfection

2006 ◽  
Author(s):  
He´ctor A. Sa´nchez Sa´nchez ◽  
Carlos Corte´s Salas
Keyword(s):  
Structural Integrity ◽  
Numerical Models ◽  
Local Buckling ◽  
Offshore Structures ◽  
External Pressure ◽  
Critical Conditions ◽  
Offshore Platforms ◽  
Theoretical Methods ◽  
Geometrical Imperfection ◽  
Bending Capacity

In Mexico, PEMEX manage more than 60,000 Km of oil and gas land and marine pipelines. Therefore, their structural integrity must be carefully assessed. The current development of offshore structures requires the design of better risers capable of assuring an optimal level of security. For that, some factors must be taken into account, which in critical conditions might become risky. It is common to find situations, in the performance of fixed offshore platforms, in which risers might be found empty due to maintenance or repairing. This condition could represent an unfavorable situation that in many cases might become highly critical given the conditions they are found in. Several studies had been completed with the aim to define a design methodology for the local buckling of pipes. In this paper, the bending capacity of the empty steel marine pipelines (risers) with girth-welded, placed to the legs of the offshore platforms very near to the deep sea, is studied by numerical models. The objective is to study the behavior and local buckling of these pipes submitted to combine loads, bending, external pressure and axial force, considering the girth-welded as the geometrical imperfection and to estimate the bending capacity of the pipes. Critical pressure of buckling, and modal configurations are evaluated by theoretical methods and numerical approaches such as finite element method (FEM). The numerical results are compared with theoretical methods.

Disconnectable Mooring System for Ice Class Floaters

2009 ◽  
Author(s):  
John Murray ◽  
Apurva Gupta ◽  
Foo Kok Seng ◽  
Asbjorn Mortensen ◽  
Wong Toh Tung
Keyword(s):  
Oil And Gas ◽  
Offshore Structures ◽  
The Arctic ◽  
Normal Operation ◽  
Release Mechanism ◽  
Mooring System ◽  
Offshore Platforms ◽  
Floating Structure ◽  
Arctic Regions ◽  
External Assistance

Designs for offshore structures that will be deployed in arctic regions have to consider ice forces, which can be the governing design load. In shallow-water areas (< ∼100 m), fixed bottom caisson designs and artificial islands usually offer the best solutions. In deeper water, however, moored floating systems such as the ship-shaped Floating Production Unit (FPU), the Spar and the Single Column Floater (SCF™) are practical solutions. Even in shallower water where earthquakes are a threat, a moored floater can be a better option because of its ability to avoid seismic effects of the quake due to its suspension in the water above the sea floor. It is estimated that about 30% of the remaining oil and gas reserves lie in the arctic regions of the world. Special care has to be taken to design offshore platforms to survive these extreme arctic environments. Along with severe environmental conditions, there is a possibility of icebergs and multi-year ice sheets as well. A practical solution is to remove the floating structure in case of the expected loads on the structure exceed the maximum design loads. The platform can be brought back to location after the extreme environmental condition has passed. This paper describes a design for a disconnectable mooring system that comprises of external fairleads, submerged chain locker boxes and diverter units along with quick release mechanism and a single handling winch for each group of lines. The system works in tandem with the rig’s ROV and an anchor handling tugboat when connecting the system, while disconnection is automatic without any external assistance other than an emergency release signal. The paper provides the rationale for selecting this configuration based on its strength, redundancy requirements, quick disconnectable ability, without interfering with normal operation and presents a range of applications for this design.

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