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Picture for Investigating the Effect of Temperature in the Community Structure of an Oilfield Microbial Consortium and Its Impact on Corrosion of Carbon Steel
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Investigating the Effect of Temperature in the Community Structure of an Oilfield Microbial Consortium and Its Impact on Corrosion of Carbon Steel

Product Number: 51319-13343-SG
Author: Silvia Salgar Chaparro
Publication Date: 2019
$20.00

Crude oil and formation water in oil reservoirs hosts a variety of microorganisms. The community structure of these microbial populations depends on the environmental conditions. Regularly oil reservoirs present high temperatures favouring the activity of thermophiles microbes. Nonetheless temperature decreases after the oil-water extraction along the oil production facilities. The effect of this temperature fluctuation from thermophilic (60°C) conditions to mesophilic (40°C) conditions on the microbial composition has been investigated in a microbial consortium recovered from a Western Australian oilfield. NGS sequencing of 16S rRNA gene was implemented for the diversity profiling of total and active community under both thermal conditions. Additionally carbon steel coupons were exposed for studying the impact of the microbial structure changes in the corrosivity of the consortium. Results showed noticeable differences in the relative abundance of the species and likewise their corrosive behaviour. Sulphide producing prokaryotes and methanogens were the predominant microbial groups at a higher temperature whereas acid producing and iron-related bacteria also played a role in the mesophilic consortium. Both consortia caused weight losses to the metal coupons exposed however corrosion rates were dissimilar from which thermophile community was the most corrosive. This analysis suggests that microbiologically influenced corrosion rates and mechanisms may differ along the oil facilities according to the variation of abundant species due to temperature changes.

Picture for Investigating the Effect of Trace O2 Concentrations on CO2 Corrosion Mechanisms
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Investigating the Effect of Trace O2 Concentrations on CO2 Corrosion Mechanisms

Product Number: 51324-20996-SG
Author: Shrirang Deshmukh; Bruce Brown; David Young
Publication Date: 2024
$40.00
CO2 co-produced in brine with crude oil is the governing corrodent in upstream oil and gas systems. A potential additional corrosive species that can be introduced through ingress is O2. Consequently, strict guidelines exist within the oil and gas industry to limit O2 levels in production environments, emphasizing the significance of understanding any associated corrosion risks. These guidelines require O2 concentrations to be as low as 20 ppb, however, there is little to no experimental evidence to support this limit. The aim of the research described herein was to advance the understanding of how trace O2 concentrations can influence CO2 corrosion mechanisms of bare steel at the acidic pH of 4. Elucidating these underlying mechanisms would enable more effective corrosion prediction, thereby enabling development of effective mitigation strategies, as well as establishing validity of the aforementioned “20 ppb” guideline related to O2 ingress. To accomplish these goals, controlled experiments were performed to test aqueous O2 concentrations up to 100 ppb on pipeline steel in a CO2 saturated 1 wt% NaCl brine at 1 bar total pressure. Various electrochemical analytical techniques, including LPR, EIS, and potentiodynamic polarization measurements were employed. The research reported herein is foundational for characterizing the impact of oxygen in CO2 corrosion environments, an ongoing research activity. This will contribute to the development of more reliable and sustainable corrosion control practices for industries experiencing CO2 corrosion which can be extendable to carbon capture and transmission systems.
Picture for Investigating the Interaction of Brine Solutions and Diluted Inhibited HCl Acid on Coiled Tubing Steel Corrosion
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Investigating the Interaction of Brine Solutions and Diluted Inhibited HCl Acid on Coiled Tubing Steel Corrosion

Product Number: 51320-14596-SG
Author: N. Chkolny, J. Burns, D. Maley, C. Wiggins
Publication Date: 2020
$20.00

Coiled tubing is defined as a continuous tubular product that is used for oil and gas well interventions. Its popularity continues to grow due to its versatility and speed of operation. Though superior grades of metal alloys exist in terms of corrosion resistance, coiled tubing operations primarily employ high-strength low-alloy steels because of their availability, lower cost and weldability. The low-alloy steel can also be thermo-mechanically controlled to elicit specific material properties, such as yield strength and ductility. These coiled tubing steels are often introduced into potentially corrosive downhole conditions, therefore proper testing must be completed to ensure adequate corrosion protection prior to job execution. Downhole corrosive conditions often encountered include; oxygen saturated fluids, elevated temperatures, exposure to oxidizing agents, hydrochloric acid and highly concentrated brines. Often these fluids will be recirculated in a closed loop system, consistently re-exposing equipment to potentially damaging conditions. Frequently, these challenging conditions faced are tested individually with pressurized mass loss coupon testing at bottom hole conditions. However, due to a recent coiled tubing incident in which the coiled tubing pipe had completely parted downhole, the post-job incident investigation involving SEM and metallographic analysis revealed pitting corrosion throughout the tubing, despite the pre-job testing performed indicating adequate acid corrosion protection for the entirety of the job. A literature review indicated very little research was available involving the possible interaction of brine solutions and diluted acid on coiled tubing carbon steels. This paper aims to investigate the possible corrosive interactions between salt brines and inhibited acid blends at elevated temperatures on high grade coiled tubing coupon samples through metallographic examinations and mass loss tests in pressurized heated cells. Coiled tubing coupons will be exposed to a variety of acid blends diluted with a 10% brine (8% wt NaCl and 2% wt CaCl2) or fresh water to investigate the possibility of corrosion enhancement between saline fluids in a diluted acid system. 

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Investigating the Trends in Coating Degradation During Long Term Accelerated Testing

Product Number: 51324-21021-SG
Author: Anand H.S. Iyer; Andreas Løken; Anders W.B. Skilbred
Publication Date: 2024
$40.00
Accelerated corrosion testing has been an integral part of estimating the durability of protective coatings on metal substrates. Test methods such as salt spray and artificial ageing has been used extensively according to the requirements put forward by the ISO 12944 standards. The testing time depends on the corrosivity of the environment as well as the durability expected from the coatings. For the highest corrosion class, this can range up to 4200 hours (approx. 6 months). With the ongoing demand for coatings with higher durability (> 25 years), the testing time will be further increased. This in turn results in prolonged periods of testing requiring a huge number of resources. We therefore conducted a study to determine the presence of any trends in the corrosion creep observed in salt spray testing as well as artificial ageing. An epoxy with a polyurethane topcoat was chosen as the paint system, and salt spray tests according to ISO 9227 and artificial ageing according to ISO 12944-6 and 9 were conducted for various durations. Following the end of testing, the evaluation of degradation was performed using corrosion creep as a parameter. Visual examination was performed to observe any visible degradation. The barrier properties of the coating system were evaluated using Electrochemical Impedance Spectroscopy (EIS) according to ISO 16773-2. Supplementary data obtained from water condensation tests and adhesion pull-off tests shall as be presented as well. The identification of trends in such corrosion tests opens the possibilities of estimation of corrosion behaviour of paint systems based on a finite set of data.
Picture for Investigation into Possible AC Corrosion from a Cathodic Protection Groundbed
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Investigation into Possible AC Corrosion from a Cathodic Protection Groundbed

Product Number: 51319-13188-SG
Author: Wolfgang Fieltsch
Publication Date: 2019
$20.00

This case study involves an investigation into corrosion anomalies on an NPS 6 approximately 4 km long Yellow Jacket coated pipeline that interconnects two terminals. An in-line inspection (ILI) in 2017 identified 70 external corrosion anomalies with two of them exceeding 55% wall loss. An additional five corrosion anomalies had been previously repaired.Recent annual cathodic protection (CP) surveys and a close-interval potential survey conducted in 2015 all indicate good cathodic protection levels along the line.AC voltages as high as 6 V were measured along the pipeline which was unexpected as there are no high voltage powerlines in this area. A distribution powerline that parallels the pipeline for approximately 0.6 km was identified near the location with the elevated AC voltages.More surprisingly AC current densities of up to 1400 A/m2 and DC current densities of 2100 A/m2 were recorded on AC coupons in this area indicating a severe AC corrosion risk.Waveforms indicated that very little of the AC voltage was related to the fundamental 60 Hz powerline frequency. The majority of the AC voltage was 120 Hz frequency indicating that the AC is likely from an unfiltered single-phase rectifier. There are several CP rectifiers that influence this pipeline and one of these is associated with a ground bed installed in the area of concern.This paper discusses the testing performed to confirm the source of the elevated AC current densities and quantify the associated corrosion risk. The mitigation strategy employed to address this risk is provided.Keywords:AC Corrosion AC Interference AC Mitigation Cathodic Protection CP Ground Bed Rectifier Interference Unfiltered Rectifier Corrosion Investigation Pipeline.

Picture for Investigation of Acid Corrosion Inhibition Using N,N′-(1,4-phenylenebis(methyl))bis(N,N-dimethylalkan-1-aminium) Chloride Corrosion Inhibitors
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Investigation of Acid Corrosion Inhibition Using N,N′-(1,4-phenylenebis(methyl))bis(N,N-dimethylalkan-1-aminium) Chloride Corrosion Inhibitors

Product Number: 51320-14723-SG
Author: Norah Aljeaban, Nurudeen A. Odewunmi, Bader Alharbi, Mohammad A. Jafar Mazumde, Salem Balharth, Shaikh A. Ali
Publication Date: 2020
$20.00

The application of corrosion inhibitors (CI) to producing oil and gas field systems is one of the most common practices of corrosion control. Acid stimulation fluids such as hydrochloric acid (HCl) and organic acids has high calcite and dolomite dissolving power; however, pumping HCl downhole during acid stimulation process particularly at elevated temperatures can cause severe corrosion. Therefore, the addition of corrosion inhibitors is indispensable to protect the metal from corrosion. More inhibitors that are efficacious are still needed to provide better protection against the corrosion.
Two new bisquaternary ammonium salts; 1,4-Benzenedimethanaminium, N,N'-didodecyl-N,N,N',N'-tetramethyl-, dichloride (CI-1) and 1,4-Benzenedimethanaminium, N,N'-dihexadecyl-N,N,N',N'-tetramethyl-, dichloride (CI-2) as corrosion inhibitors were successfully synthesized, characterized and electrochemically evaluated for their corrosion inhibition efficiency in 1 M hydrochloric acid (HCl) solution on API 5L X60 low carbon steel. Potentiodynamic polarization measurement revealed mixed type inhibition mechanisms of the synthesized inhibitors. Inhibition efficiency of CI-1 increase with increase in concentration 2.0 to 20.0 ppm while CI-2 efficiency does not go beyond 2 ppm. Adsorption isotherm of CI-1 was found to deviate from Langmuir isotherm due to its interaction on low carbon steel and the interaction was approximated by Temkin isotherm. Analysis of the adsorption of CI-1 on API 5L X60 involve both physisorption and chemisorption.