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This research aims to investigate the influence of soil engineering properties on the corrosion dynamic and to classify these properties according to the power law constants k and v. Fieldwork and laboratory tests were carried out to measure the metal loss influenced by soil properties. Results from fieldwork indicated moisture content as the most influential factor on metal loss. Principal component analysis classified moisture content into constant k, while plasticity index and particle size are grouped into constant v. Similar findings were also observed for laboratory tests. As a conclusion, this research has identified moisture content as the most significant governing factor on constant k, while other soil properties have strong to modest influence on constant v. This research also reveals the existence of an optimum value of soil properties that influence the highest measured corrosion rate. This finding is significant and may change the way researcher model corrosion behaviour.

For offshore structures, especially jacket supported structure such as fixed platform and offshore wind turbine, the underwater area provides an ideal site for corrosion formation and marine fouling. In this marine environment, the structures are exposed to particularly aggressive corrosion and colonized by marine organisms involving a diversity of species. In this paper, a number of cases are conducted where an existing fixed platform is subjected to uniform corrosion. Furthermore, the platform is also subjected to marine fouling. The platform is assessed to investigate the effects of corrosion and marine fouling on its structural strength by determining the Reserve Strength Ratio (RSR) value. It is found the platform is limited to at least 50 years of service life when subjected to average corrosion. However, the platform is no longer considered as safe after 37 years when subjected to severe corrosion. Moreover, there is an RSR loss of 38% when marine fouling is introduced at the first 5 years which is detrimental to the overall safety of the platform. On the other hand, there is minimum RSR loss of only 5% for most cases when marine fouling is introduced but still detrimental to the overall safety of the platform. The obtained outcomes were documented and will be useful information to conduct condition assessment (or structural health monitoring) of aged fixed jacket structures.

Subsea pipelines used for oil and gas production in deepwater are exposed to harsh environment involving corrosion, high internal pressure, high temperature, and bending moment. Failure of subsea pipelines can cause serious problems, including oil/gas spill, hydrocarbon explosion and fires, production downtime, and maintenance and repair. Hence, it is of paramount importance to prevent failure of subsea pipelines. The aim of the present study is to investigate the residual strength characteristics of corroded subsea pipelines under combined internal pressure and bending moment. ANSYS non-linear finite element method was applied to examine the residual strength characteristics of subsea pipelines by varying the corrosion damage and the loading ratio of internal pressure and bending moment, where the size of the corrosion damage was also varied. The ultimate strength interaction relationships of subsea pipelines between the internal pressure and bending moment with various corrosion damages were also develo...

Accurately assessing the reliability of ageing structures is essential, especially in the oil and gas industry where inaccurate predictions of structural performance may have significant hazardous consequences. This study aims to develop a time-dependent pit depth corrosion model for subsea gas pipelines. This model is formulated with the parameters as function of age using the 3-parameter Weibull distribution function. The developed model gives the prediction of the pit depth of a gas pipeline at any given age by changing the scale, shape and location parameters. Measurement data for gas pipeline corrosion pit depth were collected and the statistical characteristics were quantified by statistical analysis in terms of gas pipeline age. The results and outcomes of the present study will be useful for predicting the corrosion pit depth of gas pipeline structures and can be used in the design stage of a new gas pipeline structure.

Precisely evaluation of the reliability of aging structure is essential, particularly in the oil gas industry where inaccurate predictions of structural performance may have significant hazardous consequences. Related to this issue, it is important to predict the corrosion behavior of the gas pipeline structure used in the production of gas in subsea area. As corrosion is concerned, the effects of pipeline failure due to significant reduction of burst strength will make it hard for the pipeline operator to maintain the serviceability of pipelines. Therefore related to this problem, the resistance service of the pipeline is assessed by means of burst strength capacity. In this study, the critical part of the corrosion along 2.4 km pipeline is assessed using two approaches; empirical design codes formula and ANSYS numerical analysis. The future integrity of the pipeline is then assessed to predict the remaining year in service for the aging pipeline. The results and outcomes of the present study will be useful for evaluating the pipeline integrity as well as the prediction of the remaining life of in service aging pipeline structures.Copyright © 2013 by ASME