Corrosion Testing of Reinforcement in Simulated Annulus Environments of Flexible Pipelines

2002 ◽  
Author(s):  
N. J. Underwood
Keyword(s):  
Weight Loss ◽  
Carbon Steel ◽  
Small Scale ◽  
General Corrosion ◽  
Flexible Pipe ◽  
Operational Conditions ◽  
Simulated Environments ◽  
Scale Test ◽  
Test Cells ◽  
Internal Volume

The multi-layered unbonded structure of a flexible pipe creates an inherent internal volume known as an annulus. This annulus envelops the hoop pressure and tensile reinforcements of the pipe. This presents very specific corrosion conditions if seawater intrudes or water condenses in the annulus and no protection system operates to prevent corrosion. This paper describes an investigation into the effect on general corrosion as a result of this environment utilising small-scale test cells. This was undertaken as an attempt to simulate the corrosion conditions that may occur in differing zones of a flexible pipeline. The cell environment was varied by use of both de-ionised water and seawater. The system was saturated with CO2 and CH4 to simulate permeation of this gas through the polymer pressure sheath. Electrochemical and weight loss measurements were undertaken in order to quantify the corrosion rate in these simulated environments. This approach attempts to give useful information regarding the nature of carbon steel tensile reinforcements used in flexible pipeline under operational conditions.

Corrosion Testing of Armour Wire in Simulated Annulus Environments of Flexible Pipelines: An Update

2003 ◽  
Author(s):  
Richard Clements ◽  
Andrew D. Ethridge
Keyword(s):  
Deionized Water ◽  
Small Scale ◽  
General Corrosion ◽  
Flexible Pipe ◽  
Scale Test ◽  
Condensed Water ◽  
Test Cells ◽  
Sour Service ◽  
First Time ◽  
Permeation Models

This paper describes further investigations, utilising small scale test cells, into the general corrosion which can occur on wires within the inherent annulus space in a flexible pipe, particularly, and for the first time, in a sour service (H2S containing) environment. The work enhances data presented previously in 2002. Tests have been performed in cells specifically designed to simulate, as closely as possible, the environment and confines of a flexible pipe annulus, using solutions of both deionized water and seawater (to represent seawater flooding and condensed water). The systems were saturated with CO2 and H2S to simulate permeation of gases through the polymer pressure sheath (as predicted by validated permeation models). Weight loss measurements were undertaken in order to quantify the corrosion rate in these simulated annulus environments and metallography was undertaken to characterise the corrosion and check for HIC/SOHIC.

Advanced Finite-Element Modeling for Creep Simulation on Flexible Pipe Pressure Sheath

2016 ◽  
Author(s):  
Jérôme Naturel ◽  
Thomas Epsztein ◽  
Thierry Gavouyère
Keyword(s):  
Finite Element ◽  
Full Range ◽  
Sensitivity Study ◽  
Small Scale ◽  
Main Function ◽  
Flexible Pipe ◽  
Creep Tests ◽  
Additional Information ◽  
Fea Model ◽  
Scale Test

Unbounded Flexible pipe used for offshore fields development are usually composed of different layers of polymer and steel, each layer having a specific function during the product service life. This multi-layer characteristic enables to tailor the cross-section of the pipe to meet project-specific requirement, and optimize the cost of the product for each application. In particular, the main function of the thermoplastic pressure sheath is to guaranty the sealing of the product. The material and the thickness of this pressure sheath mainly depend on the pressure and temperature of the bore, and the design choice is driven by the creeping of the sheath in the interstices of the pressure vault: it must be limited with regard to sheath thickness reduction, as per API17J design requirement. Consequently, when developing new material for pressure sheath application, the early prediction of the creep performance over the full range of the targeted application is crucial. For this reason, before any full-scale test, a test campaign is required to evaluate the creeping of the material on small-scale material sample. In this development context, the use of advanced finite-element simulation for predicting the creeping behavior is quite useful to amplify the benefit of tests campaign results, and to give additional information on material performances. As far as the modelling is validated by correlation with small-scale tests, the numerical tool is used to multiply virtual creep tests configurations. This paper will focus on the numerical challenges for developing such creeping simulation, based on ABAQUS commercial software. Firstly, the identification of the viscoelastoplastic parameters for polymer material law will be presented. This material law is a nonlinear viscoelastoplastic model consisting of multiple networks connected in parallel. The number of parameters of such law is not limited, but a compromise between law precision and identification robustness must be found. Then, the correlation process between small-scale test and finite-element results will be detailed. In particular, the influence of the experimental protocol has to be determined. Finally, a sensitivity study of the most influent parameters, based on parametric FEA model, will be presented to highlight the benefice of such model. The benefice of such model does not only consist on correlation with small-scale test. As the material modeling is intrinsic, it is also possible to use the same law for studying the creep behavior on very different geometrical configurations.

Gas and Water Permeation in Flexible Pipes

2002 ◽  
Author(s):  
Tore Roberg Andersen ◽  
Jan Ivar Skar
Keyword(s):  
Large Scale ◽  
Cold Water ◽  
Small Scale ◽  
Test Results ◽  
Test Program ◽  
Flexible Pipe ◽  
Water Permeation ◽  
Flexible Pipes ◽  
Scale Test ◽  
Temperature And Pressure

A test program has been performed to obtain the permeation coefficients for methane, carbon dioxide and water in PVDF. Small-scale tests showed that water is transported through the PVDF inner sheath of the flexible pipes, and into the annulus. A large-scale test was carried out to verify the small-scale test results. It was performed in a 2″ flexible pipe with length 3 m. The bore temperature and pressure were 100°C and 50 bar, respectively. The pipe was submerged in cold water in order to get a correct temperature gradient in the pipe. The test showed that the annulus of flexible pipe with PVDF inner sheath would become water wet due to permeation, depending upon the bore and annulus conditions.

scholarly journals Evaluation of the Impact of Corrosion Attack in Carbon Steel C-1040 Marine Piping System in Two Media

2019 ◽  
pp. 1-10
Author(s):  
Onoriode K. Idiapho ◽  
William E. Odinikuku ◽  
Onomine M. Akusu
Keyword(s):  
Weight Loss ◽  
Carbon Steel ◽  
Piping System ◽  
General Corrosion ◽  
Corrosion Attack ◽  
Freshwater Environment ◽  
Before And After ◽  
Weight Loss Method ◽  
Loss Method ◽  
The Impact

The focus of this study was to investigate the impact of corrosion attack in carbon steel C-1040 marine piping system using weight loss method. Two carbon steel specimens (coupons) of cylindrical shape were selected and weighed before they were exposed to two different test solutions (corrosion media) at a concentration of 0.2M and 0.04M in seawater and freshwater respectively at room temperature for eight weeks. The weight loss was taken as the difference in the weight of the coupons before and after immersion in the two different test solutions. The corrosion rates of the coupons were calculated from the weight loss obtained. The experimental result from weight loss method was calculated using engineering equation solver (EES). The weight loss and rate of corrosion of the two coupons varied as higher corrosion rate and weight losses were observed in coupon 2. The weight loss and corrosion rate in 0.2M concentration of coupon 2 in seawater environment increased from 0.04 g to 0.53 g, 0.007133 mmpy to 0.0181 mmpy while coupon 1 showed an increase from 0.01 g to 0.25 g, 0.0035 mmpy to 0.005573 mmpy was observed in 0.04M concentration in freshwater environment. This shows that carbon steel metal was more susceptible to corrosion attack in seawater environment than in the freshwater environment. The micrograph results of coupon 2 before and after immersion in 0.2M of seawater for about 1344 hrs showed evidence of uniform (general) corrosion as the coupon surface was rough and jarring. The grain boundaries of the surface morphology also revealed general corrosion effects on the coupon after immersion as the film present on the surface was cracked as a result of corrosion impact.

Qualification of High Strength Carbon Steel Wires for Use in Specific Annulus Environment of Flexible Pipes Containing CO2 and H2S

2006 ◽  
Author(s):  
Carol Taravel-Condat ◽  
Nicolas Desamais
Keyword(s):  
Carbon Steel ◽  
Corrosion Fatigue ◽  
High Strength ◽  
Full Scale ◽  
Small Scale ◽  
Annular Space ◽  
Flexible Pipe ◽  
Corrosion Rates ◽  
Steel Wires ◽  
Flexible Pipes

Flexible pipes have been used for many years in offshore applications for the transportation of crude oil, gas and water. Such structures are subjected to mechanical loads due to tension, high internal pressure and dynamic motions which are sustained by the use of high strength carbon steel wires. The steel wires are located in the annular space that may contain water and acid gas (CO2, H2S) which can be detrimental for steels. For that reason, risks of Sulfide Stress Corrosion Cracking (SSCC) and Hydrogen Induced Cracking (HIC) shall be considered. Moreover, for dynamic conditions, presence of corrosive environment in the annulus could significantly reduce the fatigue performance of flexible pipe compared to air environment. The annulus composition is calculated using a permeability model that has been validated with medium scale tests, full scale tests and field cases [1]. In parallel, corrosion and corrosion fatigue studies have shown that the annulus of a flexible pipe is a very confined space with over-saturation in iron and no renewal of oxygen. This results in a higher pH, much lower corrosion rates and less HIC and SSCC than one would expect based on normal environments. This paper presents, in a first part, the different results obtained during small scale corrosion and corrosion fatigue tests demonstrating the beneficial specificity of the annular space. In a second part, the paper presents the results of pH measurements and corrosion rates obtained during a full scale dynamic corrosion fatigue test in CO2/H2S environment validating the previous results. This test was conducted on a 6” pipe between 1999 and 2003. In a third part, the paper describes how the annulus specificities should be used today to determine the suitability of carbon steel wires for use in flexible flowlines and risers considering SSCC, HIC, corrosion and corrosion fatigue.

Study of Multiaspect and Multistatic Sonar Systems Using a Small-Scale Test Bed

2010 ◽  
Author(s):  
Jon La Follett ◽  
John Stroud ◽  
Pat Malvoso ◽  
Joseph Lopes ◽  
Raymond Lim ◽  
...  
Keyword(s):  
Small Scale ◽  
Test Bed ◽  
Sonar Systems ◽  
Scale Test

scholarly journals A Novel Niosome-Encapsulated Essential Oil Formulation to Prevent Aspergillus flavus Growth and Aflatoxin Contamination of Maize Grains During Storage

Toxins ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 646 ◽  
Author(s):  
García-Díaz ◽  
Patiño ◽  
Vázquez ◽  
Gil-Serna
Keyword(s):  
Aspergillus Flavus ◽  
Fungal Growth ◽  
Storage Conditions ◽  
Aflatoxin Contamination ◽  
Small Scale ◽  
Low Concentrations ◽  
Oil Formulation ◽  
Scale Test ◽  
Encapsulation Method

Aflatoxin (AF) contamination of maize is a major concern for food safety. The use of chemical fungicides is controversial, and it is necessary to develop new effective methods to control Aspergillus flavus growth and, therefore, to avoid the presence of AFs in grains. In this work, we tested in vitro the effect of six essential oils (EOs) extracted from aromatic plants. We selected those from Satureja montana and Origanum virens because they show high levels of antifungal and antitoxigenic activity at low concentrations against A. flavus. EOs are highly volatile compounds and we have developed a new niosome-based encapsulation method to extend their shelf life and activity. These new formulations have been successfully applied to reduce fungal growth and AF accumulation in maize grains in a small-scale test, as well as placing the maize into polypropylene woven bags to simulate common storage conditions. In this latter case, the antifungal properties lasted up to 75 days after the first application.

BLISS@CNR-Pisa: a flexible laser for small scale test experiments on fusion oriented physics

2010 ◽  
Author(s):  
O. Ciricosta ◽  
L. Labate ◽  
S. Atzeni ◽  
A. Barbini ◽  
D. Batani ◽  
...  
Keyword(s):  
Small Scale ◽  
Scale Test

Limitations of Corrosion Resistant Alloy in High CO2 Gas Production Systems: A Case Study

2021 ◽  
Author(s):  
Jorge Rodriguez ◽  
Susana Gómez ◽  
Ngoc Tran Dinh ◽  
Giovanni Ortuño ◽  
Narendra Borole
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
High Pressure ◽  
Stainless Steel ◽  
Carbon Steel ◽  
Material Selection ◽  
Dynamic Modelling ◽  
General Corrosion ◽  
High Co2

Abstract The paper presents the application of a holistic approach to corrosion prediction that overcomes classical pitfalls in corrosion testing and modelling at high pressure, high temperature and high CO2 conditions. Thermodynamic modelling of field and lab conditions allows for more accurate predictions by a novel CO2/H2S general corrosion model validated by laboratory tests. In the proposed workflow, autoclave tests at high pressure and temperature are designed after modeling corrosion in a rigorous thermodynamic framework including fluid-dynamic modelling; the modeled steps include preparation, gas loading and heating of fluid samples at high CO2 concentration, and high flow velocities. An autoclave setup is proposed and validated to simultaneously test different conditions. Corrosion rates are extrapolated to compute service life of the materials and guide material selection. The results from the model and tests extend the application of selected stainless steel grade beyond the threshold conditions calculated by simplistic models and guidelines. Consideration of fugacities and true aqueous compositions allows for accurate thermodynamic representation of field conditions. Computation by rigorous fluid dynamics of shear stress, multiphase flow and heat transfer effects inside completion geometry lead to a proper interpretation of corrosion mechanisms and models to apply. In the case study used to showcase the workflow, conventional stainless steel is validated for most of the tubing. It is observed that some sections of the system in static condition are not exposed to liquid water, allowing for safe use of carbon steel, while as for other critical parts, more noble materials are deemed necessary. Harsh environments pose a challenge to the application of conventional steel materials. The workflow applied to the case study allows accurate representation and application of materials in its application limit region, allowing for safe use of carbon steel or less noble stainless steels in those areas of the completion where corrosion is limited by multiphase fluid-dynamics, heat transfer or the both. The approximation is validated for real case study under high CO2 content, and is considered also valid in the transportation of higher amounts of CO2, for example, in CCUS activities.

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