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The purpose of this paper is to identify and discuss various factors that will influence the process of installing and maintaining subsea equipment in the oil and gas (O&G) industry.

Influencing factors and their attributes are identified using a case study on subsea installations conducted in the Norwegian O&G industry. A number of experts were interviewed. A survey was conducted to rank the importance of the influence factors.

The paper identifies, analyzes and validates the factors and attributes that may impact the installation and maintenance strategy of subsea components. The factors are ranked according to importance and as practiced in the industry.

The research is based on a case study in the Norwegian O&G industry, but the approach and results could be adapted to other industries as well.

The identified factors can be used by decision makers in the development of offshore projects.

The purpose of this paper is to identify and discuss maintenance challenges and maintenance practices for subsea petroleum production systems.

Maintenance challenges, current practices and factors that influence the maintenance and support practices were identified by a literature review and by using a case study conducted in the Norwegian oil and gas industry. The case study was based on semi‐structured face‐to‐face interviews with a number of experts working in the subsea systems’ design, installation and support services in the Norwegian oil and gas industry.

The paper identifies and discusses subsea petroleum production system failures, maintenance, inspection, modification and support practices. Findings from literature are validated, and new challenges are identified and discussed.

The research is based on a case study in the Norwegian petroleum industry, but may be applicable in other countries as well. The subsea production systems are critical production systems, and failures may result in long downtime and costly maintenance, inspection and support services. Hence, inspection, maintenance and modification intervention support services requires careful project planning, implementation and execution, taking into account all influencing factors.

The identified challenges can be used by decision makers in offshore maintenance projects.

The purpose of this paper is to propose a multi-variable analysis (MVA) model for predicting potential delays in the delivery of subsea inspection, maintenance and repair (IMR) services.

Based on data from 351 subsea IMR service jobs executed between 2006 and 2008, a MVA model is proposed for predicting the potential delays in the delivery of IMR services in different plausible scenarios.

A model for predicting the delays in IMR service delivery, based on four practical variables that are readily available during the planning phase, was developed and tested. The factors contributing to delays in petroleum subsea IMR services based on importance are: water depth, weather, job complexity, job uncertainty as well as job complexity mix.

The MVA model is developed based on analyzing subsea IMR service jobs performed in the petroleum industry from 2006-2008. The model can be used in the planning stage to predict potential delays in service delivery based on practical variables available.

The research proposes a MVA model for predicting delays in service delivery. The model is useful for predicting potential delays in service delivery and for improving the plan based on model analysis results.

The purpose of this paper is to focus on developing a knowledge-based engineering (KBE) approach to recycle the knowledge accrued in an industrial organization for the mitigation of unwanted events due to human error. The recycling of the accrued knowledge is vital in mitigating the variance present at different levels of engineering applications, evaluations and assessments in assuring systems’ safety. The approach is illustrated in relation to subsea systems’ functional failure risk (FFR) analysis.

A fuzzy expert system (FES)-based approach has been proposed to facilitate FFR assessment and to make knowledge recycling possible via a rule base and membership functions (MFs). The MFs have been developed based on the experts’ knowledge, data, information, and on their insights into the selected subsea system. The rule base has been developed to fulfill requirements and guidelines specified in DNV standard DNV-RP-F116 and NORSOK standard Z-008.

It is possible to use the FES-based KBE approach to make FFR assessments of the equipment installed in a subsea system, focussing on potential functional failures and related consequences. It is possible to integrate the aforementioned approach in an engineering service provider’s existing structured information management system or in the computerized maintenance management system (CMMS) available in an asset owner’s industrial organization.

The FES-based KBE approach provides a consistent way to incorporate actual circumstances at the boundary of the input ranges or at the levels of linguistic data and risk categories. It minimizes the variations present in the assessments.

The FES-based KBE approach has been demonstrated in relation to the requirements and guidelines specified in DNV standard DNV-RP-F116 and NORSOK standard Z-008. The suggested KBE-based FES that has been utilized for FFR assessment allows the relevant quantitative and qualitative data (or information) related to equipment installed in subsea systems to be employed in a coherent manner with less variability, while improving the quality of inspection and maintenance recommendations.

A substantial number of production assets in the offshore oil and gas industry are facing operation beyond their anticipated design life, thus necessitating a service life extension program in the future. Selection of the most suitable strategy among a wide range of potential options to extend the lifetime of equipment (e.g. re-using, reconditioning, remanufacturing, refurbishing and adding on safety/process control measures) remains a challenging task that involves several technical, economic and organizational complexities. In order to tackle this challenge, it is crucial to develop analytical tools and methods capable of evaluating and prioritizing end-of-life strategies with respect to their associated costs and quantifiable benefits. The paper aims to discuss these issues.

This paper presents a life-cycle cost-benefit analysis approach to identify the most suitable life extension strategy for ageing offshore assets by taking into account all the capital, installation, operational, maintenance and risk expenditures during the extended phase of operation. The potential of the proposed methodology is demonstrated through a case study involving a three-phase separator vessel which was constructed in the mid-1970s.

The results from the application case indicate that the capital expenditure (CapEx) accounts for the largest portion of life cycle cost for the replacement strategy, while risk expenditure (RiskEx) is the major contributor to costs associated with life extension. A sensitivity analysis is also conducted to identify factors having the greatest impact on the optimum life extension solution, including oil price, production rate and money interest rate.

In the past, the decisions about life extension or replacement of in-service equipment were often made in a qualitative way based on experience and judgment of engineers and inspectors. This study presents a “quantitative” framework to evaluate and compare the costs, benefits and risks associated with life extension strategies and subsequently to select the best strategy based on benefit/cost ratios.

To the best of authors’ knowledge, no studies before have applied life cycle assessment and cost-benefit analysis methods to prioritize the potential life extension strategies in the oil and gas industry sector. The proposed approach not only assists decision makers in selecting the most suitable life extension strategy but also helps duty holders reduce the costs corresponding to life extension execution.

This paper aims to propose a diverless weld bead maintenance welding technology to prevent the leakage of subsea oil and gas pipeline and solve the key problems in the maintenance of subsea pipeline.

Based on the analysis of the cross-section of the fillet weld, the multi-layer and multi-pass welding path planning of the submarine pipeline sleeve fillet weld is studied, and thus a multi-layer and multi-pass welding path planning strategy is proposed. A welding seam filling method is designed, and the end position of the welding gun is planned, which provides a theoretical basis for the motion control of the maintenance system.

The trajectory planning and adjustment of multi-layer and multi-pass fillet welding and the motion stability control of the rotating mechanism are realized.

It provides the basis for the prototype design of the submarine pipeline maintenance and welding robot system, and also lays the foundation for the in-depth research on the intelligent maintenance system of submarine pipeline.

The maintenance of diverless subsea pipeline is a new type of maintenance method, which can solve the problem of large amount of subsea maintenance work with high efficiency.

Corrosion monitoring and inspection is commonly done in industry, for a wide range of applications:

Regular and repeatable surveys of submarine pipelines are necessary to give the designers of CP systems greater knowledge with which to design more efficient systems and so that maintenance can be more effectively planned. Mark Scorer, Subsea Survey Manager of Corrintec/UK, here describes the survey options available and goes on to explain the high level service and ease of operation of the Corrintec CPSS4 survey system, an enhanced version of the SS3 used extensively last year.

The offshore supply vessel (OSV) industry is critical to offshore oil and gas operations around the world and contributes to the economic and ecological impacts experienced by the local communities supporting the offshore oil and gas industries. The OSV industry has not been studied significantly and the economic and ecological impacts to local communities is generally unknown. This paper aims to address these issues.

In this paper, the authors review the activities and logistical requirements involved in offshore exploration and development with special attention paid to workflows and the manner in which service vessels are utilized in the Gulf of Mexico. The authors estimate the OSV needs per stage of activity for offshore operations based on data collected from company planning documents, fleet utilization data from oil and gas companies and service providers, interviews and surveys. The statistical data is synthesized and reconciled and despite large variances the data sources are in reasonable agreement. Empirical data on circuit factors are also provided. The applications and limitations of the analyses are discussed.

In the US GOM, a large variety of marine vessels transport goods and provide services to exploration, development and production activity. OSVs provide a vital link between offshore E&P activities and shore‐based facilities. Offshore oil and gas operations cannot function without them and their utilization and spatial distribution provide a way of understanding the impacts of the offshore oil and gas industry on coastal communities.

This is the first empirical analysis of any offshore service vessel industry. The data presented here can be used to predict the environmental, economic, public health, and infrastructural consequences of alternative offshore development policies.

The purpose of this paper is to propose a practical method of performing maintenance in the offshore industry where engineers have to manage problems such as the high cost of operations, assuring an high availability of the plant, safety on board and environmental protection. Indeed an efficient maintenance method it is necessary in order to offer methods and criteria to select the rights maintenance strategies keeping in to account the environmental, safety and production constrains.

The paper provides an overview of reliability centered maintenance (RCM) and reliability, availability, maintainability methodologies and an integration of the two methodologies in a particular case study in the oil and gas sector.

This paper suggests an improvement of the well-established RCM methodology applicable to industries with high priority level. It is proposed an integration between a reliability analysis and an availability analysis and an application on the offshore oil and gas industry.

The methodology provides an excellent tool that can be utilized in industries, where safety, regulations and the availability of the plant play a fundamental role.

The proposed methodology provides a practical method for selecting the best maintenance strategy considering the equipment redundancy and sparing, the asset’s performance over long time scales, and the system uptime, downtime and slowdowns.