Sankara Papavinasam

Comparison of Laboratory Methodologies to Evaluate Corrosion Inhibitors for Oil and Gas Pipelines

Abstract Experiments were carried out using a loop in three fields (gassy-oil, oily-gas, and oil-transmission pipes) under 17 operating conditions, using six inhibitors (three continuous and three ...

Kinetics of Corrosion Layer Formation. Part 2-Iron Sulfide and Mixed Iron Sulfide/Carbonate Layers in Carbon Dioxide/Hydrogen Sulfide Corrosion

Abstract Glass cell experiments were conducted to investigate kinetics of iron sulfide and mixed iron sulfide/carbonate layer formation in carbon dioxide/hydrogen sulfide (CO2/H2S) corrosion of mil...

Model to Predict Internal Pitting Corrosion of Oil and Gas Pipelines

Abstract A model has been developed to predict internal pitting corrosion of oil and gas pipelines. This model is based on experiments carried out in the laboratory at high pressure and high temperature under the operating conditions of the oil and gas pipelines. There are two kinds of inputs: construction (pipe diameter, pipe wall thickness, and pipe inclination) and operational (production rates of oil, water, gas, solid, temperature, total pressure, partial pressures of hydrogen sulfide [H2S] and carbon dioxide [CO2], concentrations of sulfate, bicarbonate, and chloride). The model accounts for the statistical nature of the pitting corrosion, predicts the growth of internal pits based on the readily available operational parameters from the field, includes the pit growth rate driven by variables not included in the model, considers the variation of the pitting corrosion rate as a function of time, and determines the error in the prediction. The validity of this model was checked using data obtained fro...

Effect of Hydrocarbons on the Internal Corrosion of Oil and Gas Pipelines

Abstract Under certain conditions, hydrocarbons may alter the internal corrosion conditions of oil and gas pipelines. In this paper, the effects of hydrocarbons on corrosion have been predicted bas...

Comparison of Techniques for Monitoring Corrosion Inhibitors in Oil and Gas Pipelines

Abstract Addition of corrosion inhibitors is one of the common methods to control both general and pitting corrosion of oil and gas pipelines. Development of an integrity management program to control internal corrosion of such pipelines depends on our ability to monitor the efficiency of the inhibitor performance. Monitoring in an oil and gas pipeline is a complex process due to the multitude of conditions that exist in such an environment. In this paper, the reliability of weight loss, linear polarization resistance (LPR), electrochemical impedance spectroscopy (EIS), electrochemical noise (EN), and externally mounted hydrogen probes for monitoring inhibitor performance in oil and gas pipelines is investigated.

Review of Models to Predict Internal Pitting Corrosion Of Oil and Gas Pipelines

Internal pit t ing corrosion is a significant factor in the degradat ion of pipel ines used for oil and gas production. The penetration of the pipe wall by pits is a process that consists of three stages: formation of a passive layer on the steel surface, initiation of pits at localized regions on the steel surface where film breakdown occurs, and pit propagat ion and eventual penetration of the pipe wall. This paper reviews the various models (based on corrosion science, electrochemical science, and corrosion engineer ing approach) that can be used to predict internal pitting corrosion of oil and gas pipelines. Models that have been developed based on laboratory exper iments are analysed to assess the ef fec ts of experimental duration, apparatus, and condi t ions on the results. Electrochemical react ions arc involved in all three stages. Applicabil i ty of electrochemical models to predict internal pitting corrosion of pipel ines is analysed. Analysis of t ime-series data f rom oil and gas fields indicated no significant d i f ferences in superficial oil, water, and gas velocit ies and watercut between pipelines that had failed and those that had not. Addit ionally, there is no correlation of other operat ing parameters , such as pipe inclination, operat ing pressure (both maximum and average) and hydrogen sulf ide (H2S), with pit growth rates. None of the three models cover all e lements of pitting corrosion, but each

Effect of Surface Layers on the Initiation of Internal Pitting Corrosion in Oil and Gas Pipelines

Abstract Experiments have been carried out in a high-temperature, high-pressure rotating electrode (HTHPRE) apparatus under 40 conditions to cover the spectrum of conditions found in oil and gas pr...

State-of-the-Art of Thermal Spray Coatings for Corrosion Protection

ABSTRACT Thermal-spray coatings are widely used in marine structures including offshore pipelines without external cathodic protection (CP). Al, Zn and Zn-Al thermal-spray coatings protect steel by acting both as barrier coatings and as sacrificial anodes at local defects where corrosion would otherwise occur. Zn provides better galvanic protection whereas Al is better as a less-reactive barrier layer. Zn-Al alloys appear to combine the protective properties of both Zn and Al. Although further research is required in order to specify the optimal alloy compositions for specific applications, 85% Zn-15% Al alloy is widely used. The best long-term protection is provided by suitably primed, sealed, and painted thermal-spray coatings. Thermal-spray coatings of acceptable structures and properties can be produced by flame spraying (wire or powder), arc spraying or plasma processing. However, due to economical reasons low melting point metals and their alloys are sprayed either by arc or flame. Surface preparation is considered to be a key factor in the production of uniform high quality coatings with maximum bond strength. Also of equal importance are the control of process facilities, equipment selection, and quality of consumable material for applying thermal-spray coatings. Well-bonded, relatively dense, sealed coatings have the ability to provide effective long term corrosion protection (10-20 years), with minimum periodic maintenance. Standards for evaluating thermal spray coatings have recently been developed.

Effect of Field Operational Variables on Internal Pitting Corrosion of Oil and Gas Pipelines

Abstract Experiments were conducted in six operating oil and gas production pipelines over four years to determine internal pitting corrosion rates under realistic operating conditions. —Pitting co...

The Oil and Gas Industry

This chapter provides a bird’s eye view of the oil and gas industry. It discusses the importance of energy from hydrocarbons, describes different types of hydrocarbons, indicates their sources, and provides a brief history of the industry. It then explains how the industry is regulated by various government agencies in North America, and finally presents the impact of corrosion on the industry.