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Collaborating Authors
Results
The Selection of Corrosion Inhibitors under Oil/Water/Gas Flow Conditions in Deep Offshore Catenary Risers
Kang, Cheolho (Det Norske Veritas USA, Incorporated) | Tummala, Kavitha (Det Norske Veritas USA, Incorporated) | Rhodes, Jesse (Det Norske Veritas USA, Incorporated) | Magalhae, Alvaro Augusto Oliveira (Petrobras)
ABSTRACT Multiphase flow characteristics can be altered with the change of pipeline topography in deep offshore oil and gas production. The increase of corrosion rate and decrease of inhibitor performance in the risers can occur due to the change of multiphase flow characteristics (e.g. severe slugging). For the simulation of offshore flow lines and risers, the experiments were carried out in a 44 m long industrial scale multiphase flow loop equipped with three different pipeline inclinations of 0, 3 and 45 degrees. The effectiveness of three commercial corrosion inhibitors were analyzed using 25 cP oil at 20% water cut with three different gas velocities (0.7 m/s, 3 m/s, and 6 m/s). All tests were carried out at a liquid velocity of 1.5 m/s, a system pressure of 6 bar (76 psig) using carbon dioxide gas as the gas phase, and a temperature of 50°C. Also, the effect of inclination on the flow characteristics (e.g. flow pattern) and their subsequent effect on corrosion rates are described. The results indicated that severe pitting corrosion was noticed in the 3 and 45° weight loss coupons for baseline testing. Severe slugging and high slug frequency were seen in 45 degree upward flowing conditions. The tests differentiated between three corrosion inhibitors. In most of testing conditions, high inhibitor concentration was required to achieve the target corrosion rate.
- Well Completion > Well Integrity > Subsurface corrosion (tubing, casing, completion equipment, conductor) (1.00)
- Production and Well Operations > Well & Reservoir Surveillance and Monitoring > Production logging (1.00)
- Production and Well Operations > Production Chemistry, Metallurgy and Biology > Corrosion inhibition and management (including H2S and CO2) (1.00)
- Facilities Design, Construction and Operation > Pipelines, Flowlines and Risers > Materials and corrosion (1.00)
Development of Continuous Application Based Corrosion Inhibitors to Mitigate the Problems Caused by Top of the Line Corrosion in Upstream Oil and Gas Industry
Narasaiah, Vijaya Kumar (Nalco Water India Limited) | Gangar, Mitesh Laxmichand (Nalco Water India Limited) | Garg, Gaurav (Nalco Water India Limited) | Monk, Keith (Nalco Energy Services)
ABSTRACT In multiphase wet gas systems with stratified flow, condensation of water and/or hydrocarbon occurs at the top of the line because of a temperature gradient between the internal and external environments of the pipeline. Acidic gases such as carbon dioxide, hydrogen sulfide, and even organic acids may be present in such systems, and they cause a reduction of pH because of their dissolution in the condensed water. In the absence of any buffering agents, this condensed water can cause significant corrosion between the 10 o?clock to 2 o?clock positions, and this deterioration is formally described as top of the line corrosion (TLC). Conventional corrosion inhibitors are transported to the pipeline surface through the produced fluids, and in the absence of turbulence in the pipeline, the effectiveness of conventional continuous inhibitors at the top of the line is drastically reduced. The metal remains unprotected and exposed to these corrosive species resulting in severe damage. Corrosion at the top of the line can severely hamper the safe operation of assets as well as decrease their life of operation, and hence, there is a need for effective chemistries which will mitigate the corrosion issues at the top of the line. This paper describes the development of new, continuous application based, top of the line corrosion inhibitors utilizing an in-house condensation rig for screening applicable candidates. Progress on the development and understanding of applicable chemistries for several generations of TLC inhibitor products will be discussed.
ABSTRACT Over the last decade, significant advances in chemical inhibition have enabled operators to use carbon steel pipework in oil and gas facilities where sand production is a concern. The ability of these chemicals to reduce both the electrochemical corrosion reactions and the mechanical damage attributed to particle impingement is well documented but the underlying mechanisms have been the subject of less attention. This paper presents a review of three commercially available oilfield corrosion inhibitors (two standard corrosion inhibitors and one high shear resistant inhibitor) in an effort to establish their performance in erosion-corrosion environments. Experiments were conducted at 45°C using a submerged impinging jet (SW) in CO2-saturated conditions with a fluid velocity of 14 m/s and sand loading of 500 mg/L. A combination of gravimetric measurements, in-situ electrochemistry and surface profilometry allowed the inhibitors to be assessed based on a number of different parameters (i.e. reduction in weight loss, in-situ corrosion rate behavior and total penetration depth). The results demonstrated the importance of surface analysis techniques when evaluating the performance of chemicals, indicating that weight loss and in-situ electrochemical techniques alone can sometimes provide misleading information on inhibitor performance in laboratory tests. This evaluation is conducted in erosion-corrosion environments where no semi-protective corrosion product formation occurs. AC impedance measurements have also been incorporated into the analysis to assist in interpreting inhibition mechanisms and determine how chemicals can reduce both the erosion and corrosion components of damage.
ABSTRACT The present study describes the impact of mineral deposits (SiO2, Al2O3 and CaCO3) on CO2 corrosion of 1030 carbon steel in a chloride-containing environment. The corrosion process was investigated using electrochemical and weight loss measurements, followed by surface analysis of the corroded steels conducted by visible-light and scanning electron microscopy. It was found that the extent of the corrosion damage is directly related to the nature of the mineral deposits and significant differences were observed in the morphology of the surfaces corroded in the presence/absence of different deposits. The susceptibility of the deposit-covered steels to localized corrosion and the influence of deposits on corrosion inhibition are also discussed and related to the properties of the deposits. The inhibitor performance at deposit-covered steels varied according to the chemical composition of the inhibitor and the nature of the deposit. The study serves to improve the understanding of CO2 corrosion process in the presence of solid deposits and the findings can be applied to address the under-deposit corrosion in oilfield operations.
- Europe (0.46)
- North America > United States > Texas > Harris County > Houston (0.16)
- Well Completion > Well Integrity > Subsurface corrosion (tubing, casing, completion equipment, conductor) (1.00)
- Production and Well Operations > Production Chemistry, Metallurgy and Biology > Corrosion inhibition and management (including H2S and CO2) (1.00)
- Facilities Design, Construction and Operation > Pipelines, Flowlines and Risers > Materials and corrosion (1.00)
ABSTRACT This paper seeks to increase the understanding of under-deposit corrosion with sand and the development of better inhibitors to mitigate this type of corrosion under sweet (carbon dioxide) conditions. In these tests an electrode exposed to the bulk solution and an electrode under the sand were galvanically coupled. This method represents the under-deposit corrosion condition within oil and gas pipelines, mimicking how the pipe surface can be covered by solids such as sand. The corrosion rates of both electrodes were monitored simultaneously using the linear polarization resistance technique. Zero resistance ammetry was used to measure the coupling current between the electrodes underneath the sand and in the bulk solution. After injection of inhibitors, the under-deposit electrode acted as the local anode and a dramatic acceleration of its corrosion was observed. The linear polarization resistance corrosion rate, the potential of the coupled electrodes, and the galvanic current density before and after the injection of inhibitors were used to characterize the corrosion inhibitor performance. Factors that affect the under-deposit corrosion measurement, such as the sand thickness, inhibitor concentration and temperature, were investigated and utilized in order to assist in the future development of higher performing corrosion inhibitors for this environment.
- Well Completion > Well Integrity > Subsurface corrosion (tubing, casing, completion equipment, conductor) (1.00)
- Production and Well Operations > Production Chemistry, Metallurgy and Biology > Corrosion inhibition and management (including H2S and CO2) (1.00)
- Facilities Design, Construction and Operation > Pipelines, Flowlines and Risers > Materials and corrosion (1.00)
ABSTRACT US EPA reports that there are over 240,000 water main breaks and up to 75,000 sanitary sewer overflows per year in the United States (EPA, 2009). The number of failures has also been increasing as the systems approaching their service life. Effective management is required to extend the lives of the pipelines, and to ensure the public health and safety. An effective assets management plan, in turn, requires proper pipe condition assessment. About two thirds of the installed municipal pipelines consist of various forms of ferrous pipes (EPA, 2005). Methods are very limited to assess the corrosion condition of metal pipelines buried underground without interrupting services or excavating. This paper presents a synergistic non-destructive method to assess the condition of underground metal pipelines by discussing a case study of 140,000 ft of sewer force mains (Cast Iron, Ductile Iron). This non-destructive method synthesizes the environmental condition with the pipe-to-soil potential data. The environmental information includes soil condition and stray currents. In this method, soil resistivity and soil pH are regarded as surrogate parameters for the corrosivity of the soil environment. High level of stray current is regarded as an indicator of corrosion activities. Environmental information (i.e., the soil and stray current information) is supplemented by the pipe-to-soil potential data. Pipe-to-soil potentials are measured with two Cu-CuSO4 half cells by following a cell-to-cell protocol. By comparing the readings of the two half cells, actively corroding areas (anodic) can be identified. This synergistic assessment method was shown to accurately locate corroding pipes in 140,000 ft of the subject sewer force mains. Actively corroding areas selected by this method was excavated and it is confirmed that these areas have very high corrosion rate (shown by Tafel curve developed in-situ). Severe wall thinning and even pipe bursts were recorded at these actively corroding areas as well.
- North America > United States > Colorado (0.28)
- North America > United States > California (0.28)
- Materials (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- Government > Regional Government > North America Government > United States Government (0.91)
- Law > Environmental Law (0.77)
- Well Completion > Well Integrity > Subsurface corrosion (tubing, casing, completion equipment, conductor) (1.00)
- Production and Well Operations > Production Chemistry, Metallurgy and Biology > Corrosion inhibition and management (including H2S and CO2) (1.00)
- Health, Safety, Environment & Sustainability > HSSE & Social Responsibility Management > HSSE standards, regulations and codes (1.00)
- Facilities Design, Construction and Operation > Pipelines, Flowlines and Risers > Materials and corrosion (1.00)
Corrosion Kinetics of Ductile Iron in Remineralized RO Desalinated Seawater
Liang, Juan (National University of Singapore) | Deng, Anqi (National University of Singapore) | Hu, Jiangyong (National University of Singapore) | Zhang, Jufang (National University of Singapore) | Ong, Choon Nam (National University of Singapore) | Adin, Avner (National University of Singapore) | Xie, Rongjing (the Public Utilities Board) | Gomez, Mylene (the Public Utilities Board)
ABSTRACT To understand the corrosion process better, corrosion kinetics of ductile iron coupons, which is a popular material for fabricating water distribution pipes, was investigated in a system using remineralized reverse osmosis membrane desalinated seawater under tropical conditions. Coupon corrosion rate and water quality were monitored during the test period up to 20 days. The corrosion rate decreased quickly during the first several days and slowly levelled off thereafter. Total hardness, total alkalinity and calcium concentration declined as the tests continued and approached to a stabilized value eventually. The passive behavior was observed because the rust layer formed during the test period has acted as a barrier of the corrosion process. Corroded products observed during the test included FeO(OH), Fe(OH)3, FeO, CaO, CaO2, CaCO3, etc. The knowledge gained in this study could be useful in operation and asset management such as monitoring water quality and projecting pipeline life-span.
- Asia (0.29)
- North America > United States (0.28)
- Water & Waste Management > Water Management > Water Supplies & Services (1.00)
- Materials > Metals & Mining (1.00)
- Energy > Oil & Gas > Upstream (1.00)
ABSTRACT Dry-cast Reinforced concrete pipes (RCP) are frequently used as drainage pipes by several state departments of transportation (DOTs) across the United States. Corrosion has been found on culverts at locations close to the ocean where they experience wet/drying cycles of chloride rich solution. However, modest or no corrosion of RCPs have been observed on RCPs placed in soils and exposed at sites with known high chloride concentration and high moisture content. It is frequently assumed that this good performance is due to oxygen concentration limitations at the reinforcement. Another factor contributing to this observation is that on those dry-cast RCPs in which corrosion had initiated the high porosity of dry-cast RCP allows the corrosion products to move through the pore structure without causing cracks or spalls. This paper presents preliminary results of an investigation being carried out to better understand and characterize on-going corrosion on RCP exposed to relevant conditions (concrete in a high moisture content state and/or exposed to low oxygen concentration at the rebar). The results presented here correspond to the methodology developed to accelerate chloride transport as to initiate corrosion within a short period of time (a few days to a few months instead of a several years).
- North America > United States > Florida (0.28)
- North America > United States > Texas (0.18)
- Materials > Construction Materials (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- Construction & Engineering (1.00)
- Government > Regional Government > North America Government > United States Government (0.34)
ABSTRACT Corrosion testing of various metal alloys was carried out down-hole in a high temperature sour geothermal well in Krafla. The tests were done following a failure analysis of a broken liner from the well. The failure analysis revealed that the liner was severely corroded and parts of it situated at 1600 m depth had experienced hydrogen damage in the form of hydrogen embrittlement. The specimens tested were exposed to the down-hole geothermal environment for 4 days and 14 days. Various stainless steels, nickel alloy and carbon steel casing materials were tested. A majority of the materials tested had a decrease in elongation on tensile testing both after 4 days and 14 days in the down-hole geothermal environment. The corrosion rates were above acceptable limits for the carbon steels and the 13Cr stainless steel. The highly alloyed austenitic and duplex stainless steels and the nickel alloy all had corrosion rates below the acceptable limits (0.1 mm/year). The results from the corrosion testing and analysis are described and discussed in this paper.
- Europe (0.86)
- North America > United States > Texas > Harris County > Houston (0.16)
- Materials > Metals & Mining > Steel (1.00)
- Energy > Renewable > Geothermal (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- Well Completion > Well Integrity > Subsurface corrosion (tubing, casing, completion equipment, conductor) (1.00)
- Reservoir Description and Dynamics > Non-Traditional Resources > Geothermal resources (1.00)
- Production and Well Operations > Production Chemistry, Metallurgy and Biology > Corrosion inhibition and management (including H2S and CO2) (1.00)
- Facilities Design, Construction and Operation > Pipelines, Flowlines and Risers > Materials and corrosion (1.00)
ABSTRACT Sulfuric acid alkylation (SAA), the conversion of olefins and butane to high-octane alkylate using highly concentrated sulfuric acid as a catalyst, is a very profitable refinery operation with powerful incentives to maximize throughput. However, until recently there were only minimal corrosion data available upon which to assess the possible equipment damage resulting from changes in SAA unit operating conditions. Thus, a joint industry program (JIP) entitled "Prediction of Corrosion in Sulfuric Acid Alkylation Units" was launched in January 2006 and completed in January 2010, to develop an empirical, predictive, data-based computer model for quantification/prediction of corrosion rates of carbon steel and selected stainless steels and nickel-base alloys under SAA conditions. This model encapsulates results of an extensive experimental corrosion program that generated hundreds of corrosion rate data points in sulfuric acid alkylation as a function of temperature, wall shear stress, and variation in sulfuric acid and acid soluble oil (ASO) concentrations. The experimental setup developed for generating corrosion rate data is described alongside important data / parametric insights from the JIP and the significant technical challenges encountered during the experimental simulation phase. An overview of the corrosion prediction software model is also given.
- Energy > Oil & Gas > Downstream (1.00)
- Materials > Chemicals > Commodity Chemicals > Petrochemicals (0.90)