Structural Integrity Assurance for Corroded Conductors in Offshore Shallow-Water Wells

2018 ◽  
Author(s):  
Oleksandr Spuskanyuk ◽  
Saad Mumtaz ◽  
Amr Mahmoud ◽  
Chee Lam Gan ◽  
Walid M. Abdulhai ◽  
...  
Keyword(s):  
Shallow Water ◽  
Structural Integrity ◽  
Water Wells ◽  
Integrity Assurance

scholarly journals A probabilistic method for structural integrity assurance based on damage detection structural health monitoring data

2021 ◽  
pp. 147592172110388
Author(s):  
Michael Siu Hey Leung ◽  
Joseph Corcoran
Keyword(s):  
Damage Detection ◽  
Particle Filtering ◽  
Structural Integrity ◽  
Probabilistic Method ◽  
Probability Of Detection ◽  
Monitoring Systems ◽  
Negative Results ◽  
Systematic Effects ◽  
Detection Capabilities ◽  
Integrity Assurance

The value of using permanently installed monitoring systems for managing the life of an engineering asset is determined by the confidence in its damage detection capabilities. A framework is proposed that integrates detection data from permanently installed monitoring systems with probabilistic structural integrity assessments. Probability of detection (POD) curves are used in combination with particle filtering methods to recursively update a distribution of postulated defect size given a series of negative results (i.e. no defects detected). The negative monitoring results continuously filter out possible cases of severe damage, which in turn updates the estimated probability of failure. An implementation of the particle filtering method that takes into account the effect of systematic uncertainty in the detection capabilities of a monitoring system is also proposed, addressing the problem of whether negative measurements are simply a consequence of defects occurring outside the sensors field of view. A simulated example of fatigue crack growth is used to demonstrate the proposed framework. The results demonstrate that permanently installed sensors with low susceptibility to systematic effects may be used to maintain confidence in fitness-for-service while relying on fewer inspections. The framework provides a method for using permanently installed sensors to achieve continuous assessments of fitness-for-service for improved integrity management.

scholarly journals Modelling and variability of selected chemical properties of shallow water wells using GIS in Wasit and Dhi Qar provinces/Iraq

2020 ◽  
Vol 39 (1) ◽  
pp. 13-26
Author(s):  
Basima Abbas Jabir Al-humairi ◽  
◽  
Nadhum Shamkhi Rahal ◽  
Ahmed Kareem Jebur ◽  
◽  
...  
Keyword(s):  
Shallow Water ◽  
Chemical Properties ◽  
Water Wells

Optimisation of Conductor System Design to Minimise Wellhead Fatigue Issues

2013 ◽  
Author(s):  
Dara Williams ◽  
Kevin Purcell
Keyword(s):  
System Design ◽  
Shallow Water ◽  
Water Depth ◽  
Fatigue Loading ◽  
Recent Experience ◽  
Water Wells ◽  
Increased Risk ◽  
Main Driver ◽  
Drilling Rigs ◽  
Water Depths

Current market trends in the construction of newbuild drilling rigs indicate that the market is driven by demand for ultra-deepwater capacity semi-submersible rigs and drillships. These drilling vessels have capacity to drill in water depths of up to 12,000ft and possibly beyond in the near future. With increase in water depth capacity, more complex and heavier BOP stacks are required. Many modern drilling vessels are now incorporating BOPs with capacities of 20ksi pressure and up to 7 shear/seal rams incorporated. This leads to increased height and weight in the BOP. Whilst newbuild drilling vessels will be required to operate in water depths from 1,500ft to 12,000ft whilst on DP mode, deepwater semi-submersible drilling rigs will also have capability for operation in water depths <1,500ft using conventional mooring. Recent experience with modern deepwater rigs with large BOP stacks in water depth of 1,500ft or less suggests increased risk of fatigue when compared to 3rd generation rigs. If future trends continue with larger BOP stacks being designed then the problem of wellhead fatigue with modern deepwater drilling vessels is likely to become more acute. As noted in previous studies the water depth at drillsite has a major impact on the level of fatigue accumulated in the wellhead system. The main driver for this has been found to be the height and weight of the BOP. With requirements for newbuild drilling rigs for 12,000ft water depth capacity being the industry norm, and with increased requirements for BOP functionality, the gap between wellhead loading from 3rd generation and 6th generation rigs is widening. Given that many 3rd generation rigs will likely be decommissioned in the coming years then the usage of 6th generation rigs for shallow water operations will only become more commonplace due to rig availability. Thus, unless market conditions dictate the construction of smaller and lighter BOP stacks, the design of shallow water wells will be critical to ensure fatigue loading on the wellhead and conductor is kept to a minimum. This paper presents a summary of the results of a series of parameter studies carried out to assess a range of options for optimisation of casing and conductor design for 6th generation rigs in shallow water. Various recommendations are made as part of this study as to the addition of supplemental casing and conductor strings of varying sizes and wall thickness to ensure a robust conductor system design for fatigue performance.

Integrity Monitoring of Offshore Arctic Pipelines

2021 ◽  
Author(s):  
Todd G. Cowin ◽  
Glenn A. Lanan ◽  
Mike Paulin ◽  
Duane DeGeer
Keyword(s):  
Structural Integrity ◽  
Management Program ◽  
Economic Consequences ◽  
The Arctic ◽  
Integrity Monitoring ◽  
Warm Up ◽  
Upheaval Buckling ◽  
Ground Deformations ◽  
Integrity Assurance ◽  
Pipeline Design

Abstract For safe and cost-efficient operations of new and existing offshore Arctic pipelines, monitoring of pipeline structural integrity is imperative. A well-founded pipeline integrity management program can optimize production output, extend the life of the pipeline, and serve as a tool for providing preventative maintenance information. Without the implementation of a routine integrity monitoring campaign, pipeline integrity degradation may go undetected until the point of failure. Arctic-specific offshore pipeline design and operational challenges, such as strudel scour, seabed ice gouge, pipeline upheaval buckling, permafrost thaw settlement, and remote location increase the risk and severity of a loss of pipeline integrity. These design cases can create abnormal conditions and ground deformations along sections of the pipeline which can be difficult to immediately detect through standard integrity monitoring systems and schedules. Many of the existing offshore pipelines in the Arctic are buried in remote locations under seasonal ice cover and the failure to detect pipeline damage in a timely manner could have severe safety, environmental, and economic consequences. An Arctic pipeline integrity monitoring philosophy can be implemented to provide further mitigation against loss of pipeline structural integrity by means of regular bathymetry surveys, In-Line Inspection (ILI) campaigns and Fiber Optic Cable (FOC) monitoring. This paper provides a guideline for buried offshore Arctic pipeline integrity monitoring. The guideline covers pipeline integrity assurance incorporated into the pipeline design, the surveys to be completed during installation, as-built assessment of the pipeline profile, the warm-up assessment/implementation needed before start-up, and the integrity inspections to be completed during operations.

Ice Loading of Jack-Up Platforms

2005 ◽  
Author(s):  
Alexandra Weihrauch ◽  
Joachim Berger ◽  
Marc Bartels
Keyword(s):  
Shallow Water ◽  
Structural Integrity ◽  
High Mobility ◽  
The North ◽  
Detail Design ◽  
Broken Ice ◽  
The Stability ◽  
Jack Up ◽  
The Impact ◽  
Analytical Approaches

The use of drilling platforms for exploration drillings in ice-covered shallow water is expected to increase in the future. Jack-up platforms (JU) are regarded to be most suitable for exploration drillings due to their high mobility, their facile transportation and installation. Although having proved their capability for harsh environments, e.g. in the North Sea, jack-ups have neither been especially designed for nor have been operated frequently in icy waters. The problems associated with the operation of jack-ups in ice waters are related to structural integrity as well as to operational limitations. One objective of the research project MATRA-OSE was to check the design of JU for exploration and oil production in ice-covered, shallow-water areas. The global stability of JU as well as local and global loads acting on a three-legged jack-up drilling unit were investigated. The design loads were determined by analytical approaches. Different ice load cases were defined as the basis for the detail design. These load cases include local loads on single members of the platform legs like chords or braces as well as global loads, which may act on one individual leg or on several legs of the platform. Vertical forces, which result from a change of the water level (up-surge and down-surge) in case ice sheets are frozen to the platform legs were considered. Also the impact of ice being jammed between the platform legs was investigated. It has been found out that the most critical load case results from the ice being jammed between the platform legs. It should therefore be tried in practice to avoid the ice jamming by proper ice management, as the large ice loads calculated for this scenario may result in problems for the stability of a JU. Ice breakers could be used to pre break the ice and should try to clear the site from broken ice pieces before it starts to accumulate.

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