Corrosion inhibition effect of biocides on carbon steel pipelines at different service stages

This paper embarks on an extensive investigation into the corrosion behavior of carbon steel pipelines across aqueous environments. It aims to evaluate the effectiveness of bio-corrosion inhibitors, specifically focusing on beetroot powder doped with NaNO2, in bolstering the durability of these pipelines. The study encompasses a multifaceted analysis, including quantification of corrosion rates, and assessment of the inhibitor's impact on pipelines in various sub-sea fluid conditions. The combination of beetroot with NaNO2 presents a promising avenue for corrosion inhibition, aligning with sustainability goals and offering a potential solution to enhance pipeline longevity. The research methodology employs immersion experiments with carbon steel samples to scrutinize their response across seawater environments. Bio-corrosion inhibitors are rigorously tested in aqueous samples using a wet immersion technique, wherein a solution of beetroot powder doped with NaNO2 is prepared. Experiments are meticulously conducted utilizing a 4 wt./volume % NaCl solution, with the churned beetroot powder doped with NaNO2 at varying loadings, typically ranging between 18% to 64%. The resulting inhibitor doped samples were tested through FTIR analysis and microscopic analysis, in order to understand the changes in the corrosion environment, and finally the corrosion measurement calculations, corrosion rate calculations and inhibition efficiencies were calculated. The experimental findings unveil a substantial reduction in corrosion rates, particularly notable in seawater conditions (NaCl solution), where the combination of beetroot powder and NaNO2 demonstrates superior effectiveness. Visual observations compliments the significant decrease in corrosion by 47.2 wt.% with the utilization of the bio-corrosion inhibitor blend. This innovative approach not only offers a practical and environmentally friendly strategy for corrosion prevention in pipelines but also underscores the potential of organic inhibitors in mitigating corrosion challenges. This study contributes novel insights into the efficacy of bio-corrosion inhibitors, shedding light on the synergistic effects of beetroot powder with NaNO2 in combating corrosion in carbon steel pipelines. The presence of organic compounds in beetroot, coupled with the corrosion inhibition properties of NaNO2, enhances the protective capabilities against corrosion, thus showcasing the potential of natural substances in corrosion management. Understanding the performance of bio-corrosion inhibitors across diverse environmental conditions is pivotal in devising tailored strategies to optimize pipeline durability and ensure reliable operation in varying contexts.

The paper shows a comparison between two intervention methods for interconnecting two gas transmission pipelines within a natural gas transmission system. One intervention implies shutdown of pipelines, while the other one in-service pipelines. Each method is described in detail along with the main technological issues, as well as the related advantages and disadvantages. The technological procedures imply special working techniques such as welding or hot tapping in service pipelines.

A critical step in proving a pipeline is fit for operational use is the hydrostatic test, in which it is filled with water and pressurized to 125% of its Maximum Allowable Operating Pressure (MAOP). The water that is used in this testing can cause corrosion of the pipe, potentially leading to failure early in its operating life. Failures have occasionally been reported even before a pipeline enters service. The most common mechanisms by which carbon steel pipelines may undergo corrosion on exposure to hydrotest water are Microbially Induced Corrosion (MIC), oxygen-related corrosion, galvanic corrosion and under-deposit corrosion. An overview of these mechanisms is presented, along with a discussion of the influence of different environmental factors on them. Factors considered include water source, degree of filtration, exposure period and temperature, air pockets, presence of internal pipe coatings and future pipeline service conditions. Maintaining the risk of pipe corrosion from hydrotest water within acceptable limits is discussed. Factors considered are: How long the untreated water may be allowed to be present in the pipeline.Should water treatment be required, what must be used?Disposal requirements for the treated water, including chemical treatments.

The integrity of pipelines transporting wet gas has been a concern to oil and gas industry in recent times. Top of the line corrosion (TLC) in particular is important because of the inability to protect the upper wall of pipelines (i.e. in the vapour space) with conventional corrosion inhibitors. Organic acids, such as acetic, are volatile components in oil and gas reservoirs and play significant roles in determining the corrosion process that occurs at the 10-2 o'clock position of the pipelines. TLC of a typical carbon steel pipeline containing 1% NaCl (containing acetic acid) saturated with CO2 gas at 60°C for a period of 100hrs was investigated by applying electrochemical techniques such as electrochemical impedance spectroscopy (EIS) and linear polarisation resistance to mild steel samples exposed to these conditions. Both CO2 and acetic acid are transported in the gas phase and condensed with water thereby contributed to corrosion processes at the top of the line. Preliminary results demonstrated a progressive reduction in corrosion rate with time in the CO2 environment indicated by an increase in the polarisation resistance. However, with the introduction of acetic acid the corrosion rates increased significantly. The results of this study will form the basis of an understanding of the corrosion experienced at the top of the line and determining the amount of corrosion inhibitors to be injected using V-Jet™ pig in similar field environment to prevent carbon steel pipeline failure, and subsequent oil spillage.

The switch from oil to gas production will dramatically change the operation conditions in the producing wells, topside facilities, and transportation pipelines. Besides the changes in gas/liquid compositions, operating pressure and temperature, multiphase flow in the pipeline will also shift from a high-liquid load pattern to a low-liquid load pattern. Typically, the demarcation point between the two patterns could be considered as GOR of 1000 SCF/BBL. Forecast of the field studied in the paper indicates that the transition might happen after a few years and GOR will increase gradually with the aging of the wells. The changes will have a great impact on internal pipeline corrosion and corrosion inhibition and thus require a systematical study to identify the keys parameters and strategize a suitable corrosion management plan. In this paper, the experiences gained from current corrosion monitoring and corrosion inhibition programs were reviewed first. Corrosion scenarios were also analyzed for future operational conditions by conducting both fluid- dynamic analysis and corrosion risk prediction along the pipeline for a wet gas environment. In order to study the impact of flow on the corrosion inhibitor application, laboratory tests were carried out to evaluate the incumbent corrosion inhibitor for future wet gas environment. The lab study focused on testing the partitioning capability of the corrosion inhibitor at different water cuts (10% – 100% water cut) and the localized corrosion risk due to the high shear stress using both rotating cylinder electrode (RCE) apparatus and rotating cage type of autoclave. The study showed that, though the corrosion risk of the system was determined to be relatively low, the option of applying corrosion inhibitor by batch treatment should be ruled out due to the possible breakdown of inhibitor film in a turbulent flow, which is associated with high shear stress and subject to gas bubble impingement. Lab tests also indicated that continuous treatment of 25 to 50 ppm corrosion inhibitor could minimize the localized corrosion risk of carbon steel pipeline in a 150-Pa shear stress flow.

In the oil and gas industry top-of-the-line corrosion (TLC) has been the cause of numerous pipeline failures and continues to be one of the more challenging corrosion mechanisms to mitigate. Historically, attempts to mitigate top-of-the line corrosion in carbon steel pipelines using chemicals has relied on batch inhibitors (BIs). However, the batching process comes with several drawbacks including a large draw on operator field personnel resources, safety aspects of in-situ pre-diluting with solvents, deferred production, etc., whilst some facilities are not amenable to pigging and batch chemical treatment. Continuously applied corrosion inhibitors (CIs) are an attractive alternative since they don’t incur these problems whilst reducing or eliminating the need for BI by using a CI helps to lessen chemical handling and logistics with associated safety and environmental, social, and governance (ESG) benefits. Nonetheless, the efficacy of traditional CIs at mitigating TLC has often been limited. This paper presents data from a focused research and development laboratory program on the development of a versatile continuous CI product, formulated with a unique backbone of chemistries, to mitigate both sweet and sour top-of-the-line corrosion under laminar, low flow conditions whilst also having demonstrated effectiveness under aggressive elevated shear stress conditions which may occur at different locations of the same system at the bottom-of-the-line. Furthermore, the newly developed CI also demonstrates very good secondary properties having good stability along with low foaming and emulsification tendency.

Corrosion at the slug front at the bottom of a pipeline is identified as one of the worst cases of corrosion occurring in the pipeline which carries unprocessed multiphase production with a high level of CO2 gas. One objective of our study in recommending a subsea completion to shore was to determine if commercial corrosion inhibitors can control this type of corrosion using carbon steel pipeline. Thus, inhibitors which showed excellent performance in the lab using the Rotating Cylinder Electrode system (RCE) were further evaluated to confirm their performance in a flow loop simulating the test conditions predicted from the flow modeling for the proposed pipeline. The performance profile of two commercial inhibitors were determined in a 4” flow loop at 70°C, 100 psig CO2 partial pressure in corrosive brines with or without ethylene glycol and/or light hydrocarbon. Results showed that the carbon steel pipeline could be adequately protected at low temperature using a commercial corrosion inhibitor to meet the designed life of the pipeline. Ethylene glycol, which is used in the pipeline to prevent hydrate formation, reduces the corrosivity of the brine and gives no effect on inhibitor performance under the slug flow conditions. A good agreement in inhibitor performance was observed between the flow loop and the RCE testing. The uninhibited corrosion rate of the test brine in this study is in good agreement with the predicted value using deWaard and Milliams correlation for CO2 corrosion.

One of the main challenges in Petroleum and gas companies facilities is corrosive fluid due to high sour, water cut and CO2. Corrosion inhibitors are typically injected in Carbon Steel pipeline in oil and gas production to mitigate corrosion caused by the presence of water, H2S/CO2, chloride, and acidic gas. This paper will cover latest experience in corrosion inhibitors tender qualification for all fields. The qualified corrosion inhibitor must be compatible with production fluid, and not affect the performance of other process chemicals or non-metallic seals. Testing procedures for the qualification and selection of corrosion inhibitors vary in efficiency to the pipeline's fluid chemistry, temperature, velocity, and pressure. The procedures also change because of the different specifications and implementation approaches employed by chemical suppliers and end users. The latest tender covers all client fields in Oman which classified in five cases and six chemical suppliers participated in the tender. The tender included all series of laboratory testing and field trial in the field. The paper also describes the results of laboratory testing (pre-qualifications and performance tests) and field trial results. Furthermore, lab testing was done to qualify corrosion inhibitor for sour fluid with high velocity and shear stress 60 Pa. All stages of the tender from starting till announcing the qualified chemical supplier and all the difficulties and challenges which was in tender will be described in detail in this paper.

The detrimental effects of corrosion in transportation pipelines have been a primary issue for the oil and gas industry for many years. Every year, millions of dollars are invested into corrosion inhibitors in order to minimise corrosions implication on flow assurance. Imidazoline and its derivatives have been a prevalent corrosion inhibitor owing to its good adsorption characteristics and film forming capabilities; however, there remains some uncertainty in literature pertaining to the effect of temperature on its performance. GULP simulation software was used to study the effect of temperature on the thermodynamic properties of imidazoline in carbon steel pipelines. Entropy, heat capacity, Helmholtz free energy, entropy and Gibbs free energy were influenced by changes in temperature. An optimal operating range was found to exist between 298K and 333K. Within this range, spontaneous chemisorption was occurring and the imidazoline molecules possessed enough kinetic energy to displace any bound water on the metal surface to permit the preferential adsorption of the imidazoline head group. However, beyond 333K, the kinetic energy of the system hindered the steady formation of the protective barrier, reducing its inhibitive potential. This study agrees with previous literature on the effect of temperature on the ability of imidazoline as a corrosion inhibitor, however further studies into the effect of pipeline conditions and imidazoline molecular structure are needed in order to affirm the optimal applicability of imidazoline as a corrosion inhibitor.

The objective of developing effective triazine-based corrosion inhibitors aims to mitigate the significant issue of corrosion in carbon steel pipelines within oil and gas field environments. In the present study, we synthesised a corrosion inhibitor designated as ST-2 through a two-step process utilising melamine, octylamine, diethylenetriamine and ethanedioic acid as precursor materials. The structural characterisation of ST-2 was conducted using Fourier transform infra-red spectroscopy and proton nuclear magnetic resonance spectroscopy. The performance of ST-2 in inhibiting corrosion at a temperature of 90°C was evaluated through static weight loss and electrochemical techniques, which demonstrated a corrosion inhibition efficiency of 92.14% at a concentration of 200 mg/L. The structure–activity relationship and film-forming mechanism of ST-2 were investigated through the application of functional theory and molecular dynamics simulations. The results revealed that the heteroatoms present in the molecule exhibited significant interactions with the metal substrate. At a corrosion inhibitor concentration of 200 mg/L, the absolute value of the adsorption energy was determined to be 1084.74 kcal/mol. Under these experimental conditions, the resulting corrosion inhibitor film exhibited maximum thickness, optimal densification and enhanced corrosion inhibition performance.

Carbon steel pipelines, a means for crude oil transportation, occasionally experience highly localized perforation caused by microorganisms. While microorganisms grown in laboratory culture tend to corrode steel specimens unevenly, they rarely inflict a corrosion morphology consistent with that of pipelines, where centimetre-sized corrosion features are randomly distributed within vast stretches of otherwise pristine metal surface. In this study, we observed that corrosion inhibitors (CIs), widely used for the control of acid gas (H2 S, CO2 ) corrosion in oil fields, also affect microbial growth and activity. Inhibited carbon steel resisted biofilm formation and underwent negligible corrosion (<0.002mm Fe0 year-1 ), despite 15months of exposure to oil field waters harbouring a diverse microbiome. In contrast, physical scavenging of CI in these waters led to severe and highly localized corrosion (up to 0.93mm Fe0 year-1 ) underneath biofilms dominated by methanogenic archaea and sulfate-reducing bacteria. A sharp decline in CI concentration, as well as its active components, quaternary ammonium compounds (QACs), correlated with microbial sulfidogenesis. CIs are ubiquitously present in oil field waters and play an underappreciated role in microbial corrosion mitigation. Physical and biological scavenging of CIs may create local differences in steel inhibition effectiveness and thus result in highly localized corrosion.

The parsley extract (PLE) was prepared using absolute ethyl alcohol. The PLE and synergistic iodide were firstly utilized as efficacious corrosion inhibitors to slow down the corrosion rate of carbon steel-Q235 in 0.5 mol/L H2SO4 solution. The anti-corrosion performance was researched by weight loss method, electrochemical tests, surface analysis and quantum chemistry calculation. Results of electrochemical and weight loss tests show that the synergetic PLE and I− exhibit the optimal corrosion inhibition efficiency 99%. The combined inhibitor displays the favorable long-term corrosion inhibition effect, and the inhibition efficiency can maintain more than 90% after 144 h immersion. The introduction of I− makes carbon steel surface with higher negative charge amount, which could be beneficial to the interaction between corrosion inhibitor and Fe atoms. The adsorption behavior obeys the Langmuir isotherm adsorption, and involves chemical and physical adsorption. On the basis of electrochemical consequences and theoretical calculation, the adsorption process and anti-corrosion mechanisms are further explored.

Enhancing the corrosion inhibition performance of Mannich base on mild steel in lactic acid solution through synergistic effect of allicin: Experimental and theoretical study

Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Twitter Facebook Reddit LinkedIn Tools Icon Tools Reprints and Permissions Cite Icon Cite Search Site Citation Norman Vincent A. Pasasa, Bunbun Bundjali, Deana Wahyuningrum; The microwave assisted synthesis of 1-alkyl-3-methylimidazolium bromide as potential corrosion inhibitor toward carbon steel in 1 M HCl solution saturated with carbon dioxide. AIP Conf. Proc. 30 September 2015; 1677 (1): 070016. https://doi.org/10.1063/1.4930720 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAIP Publishing PortfolioAIP Conference Proceedings Search Advanced Search |Citation Search

Carbon steel pipelines used in the oil and gas industry can be susceptible to the combined presence of deposits and microorganisms, which can result in a complex phenomenon, recently termed under-deposit microbial corrosion (UDMC). UDMC and its inhibition in CO2 ambiance were investigated in real-time using a multi-electrode array (MEA) system and surface profilometry analysis. Maps from corrosion rates, galvanic currents, and corrosion potentials recorded at each microelectrode allowed the visualization of local corrosion events on the steel surface. A marine bacterium Enterobacter roggenkampii, an iron-oxidizing, nitrate-reducing microorganism, generated iron deposits on the surface that resulted in pitting corrosion under anaerobic conditions. Areas under deposits displayed anodic behavior, more negative potentials, higher corrosion rates, and pitting compared to areas outside deposits. In the presence of the organic film-forming corrosion inhibitor, 2-Mercaptopyrimidine, the marine bacterium induced local breakdown of the protective inhibitor film and subsequent pitting corrosion of carbon steel. The ability of the MEA system to locally measure self-corrosion processes, galvanic effects and, corrosion potentials across the surface demonstrated its suitability to detect, evaluate and monitor the UDMC process as well as the efficiency of corrosion inhibitors to prevent this corrosion phenomenon. This research highlights the importance of incorporating the microbial component to corrosion inhibitors evaluation to ensure chemical effectiveness in the likely scenario of deposit formation and microbial contamination in oil and gas production equipment.