Oil Transmission Pipelines Research Articles

Evaluation the Effect of Velocity and Temperature on the Corrosion Rate of Crude Oil Pipeline in the Presence of CO2/H2S Dissolved Gases

In this paper investigate the influences of dissolved CO2/H2S gases, crude oil velocity and temperature on the rate of corrosion of crude oil transmission pipelines of Maysan oil fields southern Iraq. The Potentiostatic corrosion test technique was conducted into two types of carbon steel pipeline (materials API 5L X60 and API 5L X80). The computer software ECE electronic corrosion engineer was used to predict the influences of CO2 partial pressure, the composition of crude oil, flow velocity of crude oil and percentage of material elements of carbon steel on the rate of corrosion. As a result, the carbon steel API 5L X80 indicates good and appropriate resistance to corrosion compared to carbon steel API 5L X60. The rate of corrosion acquired from the test in flow conditions is most significant than that in static conditions. The crude oil from Noor field has the largest value of corrosion rate, while the crude oil from Halfaya field has the lower value; other crude oils have moderate values. The dissolved CO2/H2S gases contribute by a low degree in internal pipeline corrosion because of the small concentrations.

Anisotropy in Mechanical Properties and Corrosion of X-52 Pipeline Steel at Different Pipe Angles

Non-uniform corrosion and cracking could occur at different pipe angles (different clocks) on oil and gas transmission pipelines. While this could be due to different environmental conditions surrounding the pipeline or nonuniformity in microstructure, mechanical and corrosion properties at different pipe angles. This study investigates corrosion and mechanical properties of X-52 pipeline steel at different pipe angles. In this regard, microscopic characterization, weight loss corrosion tests, electrochemical corrosion tests, and also mechanical characterizations tests (hardness, tensile and fracture toughness) were performed. Results showed that corrosion and mechanical properties of the X-52 pipeline steel was not uniform at different pipe angles and 180 degree (6 o’clock) position had the most corrosion rate and fracture toughness. Nonuniformity in grain orientations and microstructure of pipeline steel is considered to be the reason for anisotropy observed in corrosion and mechanical properties.

Modelling and Simulation of Multiphase Flow Applicable to Processes in Oil and Gas Industry

Abstract Solid particle erosion is a mechanical process of destroying a wall surface material due to the impacts of solid particles entrained with a fluid. It is a frequent phenomenon encountered within various industries such as chemical processes, oil and gas, and hydraulic transportation. Erosion problem has led to enormous consequences such as oil spills caused by equipment failure of oil transmission pipelines, chokes valves, pipe fittings etc; resulting in considerable economic loss as well as safety and environmental concerns. In this study, a 3-D simulations are performed using CFD code ANSYS FLUENT to predict sand erosion rates under different engine-oil viscosity conditions for multiphase liquid, in a 90-degree standard (R/D = 1.5) elbow pipe. The CFD utilizes Eulerian-Lagrangian method to model the multiphase flow oil-water-sand in elbow. The realizable k-ε model is adopted for the fluid turbulence effects. The velocity and pressure distributions are analysed as contours for the fluid flow. In order to understand the dynamics of the erosion process, the motion of the solid particles are also investigated based on Stokes number as well as the effect of secondary flows. The results indicated that erosion rates decrease with the increase in oil viscosity. Additionally, erosion mainly occurs in two locations; at the extrados near the bend exit and also on the side walls of the downstream straight pipe. The unusual distribution of erosion on the side walls occurred as a result of the effect of secondary flows due to centrifugal force. The numerical results are in qualitative good agreement with the experimental data available in the literature for elbows in order to validate the presented modelling approach.

Concept of the FMEA method-based model supporting proactive and preventive maintenance activities

Proper planning of preventive maintenance (PM) is crucial in many industries such as oil transmission pipelines, automotive and food industries. A critical decision in the PM plans is to determine frequencies and types of maintenance actions in order to achieve a certain level of system availability with a minimum total cost. For any given interval, a decision must be made to perform one of the three actions on each component; inspection, preventive repair and preventive replacement. Any of these activities has different effects on the reliability of the components and the corresponding distinct costs based on the required recourses. The intention of the authors is to develop a concept of supporting the process of planning and scheduling of preventive and proactive activities using the FMEA method for failure analysis. According to the concept of sustainable production, the failure will be assessed from different perspectives, not only in terms of production, but also considering operators and process safety as well as threats to the environment. The concept developed and presented in the paper in combination with IT support is the basis for risk assessment and establishment of cause and effect relationships to prevent failures and / or minimize their consequences.

An experimental investigation of the nature of longitudinal cracks in oil and gas transmission pipelines

Oil and gas pipeline maintenance and monitoring are of utmost importance. Therefore, being aware of the pipeline conditions, predicting their failure, planning to manage emergencies and evaluating their conditions are essential. In this study, Magnetic Particle test inspection was performed on a 52-year-old, 6 inch steel pipeline, which was primarily used as an oil transmission pipeline but was repurposed to a gas transmission pipeline later. Longitudinal cracks were found on the pipes during the inspection. Several tests were conducted aiming to clarify the nature of these cracks. The tests included chemical analysis, tensile test, impact test, hardness measurement to determine the type of steel, soil tests to specify the elements present in the soil and to evaluate corrosion conditions of the soil, SEM imaging, optical microscopy, and Energy-Dispersive X-ray Spectroscopy (EDS). The steel was found to be of X46 grade and the tests did not suggest the presence of aerobic as well as anaerobic bacteria in the environment. Moreover, the EDS results did not show any signs of corrosion in the samples. The depth of cracks was measured to be 80μm. No evidence of hydrogen induced cracking (HIC) and stress corrosion cracking (SCC) which are the main cracking mechanisms of steel transmission pipelines was appeared in the present study. Overall, it is safe to conclude that the longitudinal cracks were formed during fabrication.

Estudo do efeito da tensão sobre a permeação por Hidrogênio em Aços API 5L X60 e API 5L X65

<p>Under operating conditions, the oil and gas transmission pipelines can be subjected to high pressures and, at the same time, suffer the effect of acidic substances in the transported hydrocarbons such as H2S, whose action alone or combined with stresses acting in the structure can cause degradation processes of the mechanical properties of the material. Given the importance of the phenomenon, this work has as main objective the realization of hydrogen electrochemical permeation tests in API 5L X60 and API 5L X65 steels under mechanical loading conditions. A device for performing electrochemical permeation tests of hydrogen in the specimens subjected to stress was used for the tests. Thus, it was possible to observe experimentally the influence of stress on the diffusion properties during the experiment. By applying stress on the order of 20% of the yield strength, it was possible to verify the increase of diffusivity of API 5L X60 steel. Furthermore, there was a strong influence of the stress level of permeability, because a large increase of permeability of API 5L X65 steel. The results indicate that the lattice deformation due to imposed mechanical stress has a great influence on the diffusion properties of materials</p>

Influence of surface modified ilmenite/melamine formaldehyde composite on the anti-corrosion and mechanical properties of conventional polyamine cured epoxy for internal coating of gas and oil transmission pipelines

Abstract To support the corrosion protection behavior and mechanical performance properties of conventional epoxy utilized for internal coating of gas and oil transmission pipelines, the present approach was performed to prepare different high build epoxy coating formulations modified using various amounts of processed ilmenite/melamine formaldehyde composite (IMFC) cured by poly amine hardener. X-ray diffraction (XRD) analysis was implemented to assure the phase identification of the crystalline ilmenite particles. Dynamic light scattering measurements were accomplished to measure the particle size distribution of micro-sized ilmenite particles. The lamellar shape of the prepared ilmenite pigment particles (FeTiO 3 ) was illustrated by transmission electron microscope (TEM) investigation. Flaky-like nature and the arrangement in overlapping plates of ilmenite particles were confirmed by scanning electron microscope (SEM) technique. Energy dispersive analysis of X-rays (EDX) was performed to ensure the elemental composition of ilmenite pigment particles. FTIR characteristic spectra for melamine formaldehyde resin, ilmenite/melamine formaldehyde composite (IMFC), conventional polyamine cured epoxy and polyamine cured ilmenite/melamine formaldehyde epoxy composite were done. The anti-corrosion performance properties of the considered IMFC epoxy coating formulations against unmodified blank conventional epoxy were studied by accelerated corrosion experiment (salt spray chamber) after 500 h exposure in 5% NaCl solution. The obtained results revealed a significant improvement in the rust grade, blistering size, color tolerance and adhesion strength of IMFC modified epoxy coated steel films with increasing the loading level (%) by weight of the nanocomposite modifier in the coating film. To confirm the previous concept, mass loss method was performed. The mechanical performance properties of these films were investigated by adhesion pull-off, bend, impact and abrasion coating tests to confirm their application efficiency. From the recorded results, the adhesion properties, elongation character, resistance to rapid deformation and film stiffness of these coatings increased significantly with increasing the amount of IMFC modifier.

Influence factors of X80 pipeline steel girth welding with self-shielded flux-cored wire

For girth weld of high-pressure oil and gas transmission pipeline, there is impact toughness values deviation phenomenon with self-shielded flux-cored semi-automatic welding technology. The macro-images, microstructure and mechanical performance of girth welding joint have been investigated by OM, SEM, TEM. The results show that there are several factors of impact toughness unqualified values of weld joints, such as welding heat input, coarse grain zone and a chain of M–A organisations, Al2O3 and Zr Precipitates particle sizes and distribution et al., which are the main unqualified reasons of welding impact toughness of the semi-automatic self-shielded core butt welding process of X80 pipeline steel.

Numerical investigation of the erosion behavior in elbows of petroleum pipelines

Oil spill caused by the erosion in elbows is widely encountered in long-distance crude oil transmission pipelines and will lead to a considerable economic loss and potential safety hazards. In order to prevent the equipment failure and evaluate the campaign life of piping systems, there exists an urgent need to identify the positions suffering severe erosion damage and predict the erosion rate in pipelines for multiphase flow. In this study, a mathematical model is established to predict the solid particle erosion in the elbows of petroleum pipelines, in which the particle-fluid interaction is taken into account. The effects of bend orientation and particle properties on the erosion process are investigated in details. In order to understand the erosion mechanism related with the dynamic behavior of flow fluid and entrained particles, the relationship between the secondary flows and the particle trajectories is analyzed emphatically. The results indicate that erosion mainly occurs in the regions near the elbow exit, especially the side walls of the downstream straight pipe and extrados of the bend section. However, erosion on the side walls could not always happen when the effect of the secondary flows is not remarkable. It is also found that the erosion behavior depends upon both the centrifugal effect of pipe flow and the forces acting on particles. Finally, an erosion pattern based on Stokes number is developed to quantify the complex coupled effects of the flow field and particle properties.

Improving crack resistivity in Al alloy pressure vessels by FSW

Purpose: Fuel or oil transmission pipelines are made with light metal alloys to preventcorrosion and to provide a better safety record. This is achieved by the combinationof perfect design, selection of materials and functioning practices. However, like anyengineering structure, these lines also fail occasionally. Major cases of such failure it inducesdue to external interference or corrosion or due to manufacturing defects; so such of defectsif they were detected before failure and that can be treated to avoid failure or the life timecan be improved.Design/methodology/approach: In this study an aluminum alloy sample with microcrack was treated with FSW process with ZN powder. And studies were carried out againstboth treated and untreated samples with cracks.Findings: From the studies it is clear that FSW treatment over surfaces will reduces thecrack initiation in light metal alloy structures. The process can be done before or afterinstallation.Research limitations/implications: The results were recorded and suggested FSW as abest process for crack treatment in Al alloys. Especially in pressure lines or pressure vessels.Originality/value: Friction stir welding (FSW) is a solid-state metal joining process. Thisis energy efficient, ecofriendly, and versatile light metal joining technique. In particular,high-strength aerospace aluminum alloys can be welded by using this technique. This willproduces high harden joints in light metals as just like conventional arc welding techniques.It is considered as the most significant research development in light metal joining.

Challenges in applying AS 2885 to aging oil and gas pipelines

Oil and gas transmission pipelines in Australia are licensed under state-based pipeline acts and regulations, or a safety case regime for offshore pipelines. Both approaches deal with requirements for the design, construction and operation of a pipeline. A core requirement of a licensee’s pipeline management system—as required by AS 2885.3 (Operation and Maintenance)— is to maintain a live view of the failure threats to a pipeline. AS 2885 also requires licensees to undertake a regular review of the pipeline safety management study (SMS), to examine the effectiveness of existing threat controls, and to ensure existing and any new threats to the pipeline are being managed to ALARP using the prescribed risk assessment process and societal risk appetite defined in AS 2885.1. The SMS review is complemented with a similar periodic review of the location class of the pipeline route, often challenged by ever-changing urban development and encroachment. The location class determines design requirements for pipeline wall thickness, external interference protection measures, depth of cover, fracture control, isolation valve spacing and field signage, and is often difficult to comply with or retrofit to existing operational pipelines. Retrospective requirements also require assessment of highconsequence areas for no-rupture and maximum energy discharge rates. This paper explores the application of the SMS process and the challenges faced by licensees of ageing existing onshore pipelines in complying with AS 2885, and illustrates an array of pragmatic lessons, and the approach taken by the author—in the SMS facilitator role—in assisting licensees to undertake SMS and location class reviews.

Slurry Erosion of Pipeline Steel: Effect of Velocity and Microstructure

Pipelines are the most flexible, economic, and convenient way for oil and gas transportation. Material degradation by slurry erosion is a common feature in oil transmission pipeline. In the present work, slurry erosion of AISI 1018, AISI 1080, API X42, and API X70 steels is investigated in terms of slurry velocity and target material microstructure. The slurry velocity and impact angle employed were 0.2, 0.29, 0.36, and 0.43 m s−1 and 90 deg, respectively. It is found that erosion rate increases with increasing slurry velocity. Scanning electron microscopy was employed to investigate the eroded surface and subsurface of the steels. Plastic deformation, microcutting, and fracture are identified as dominant erosion mechanisms. Pearlitic microstructure exhibits superior erosion resistance compared to ferrite depending upon slurry velocity and microstructural orientation.

Impact of Model Errors of Burst Capacity Models on the Reliability Evaluation of Corroding Pipelines

AbstractThis paper quantifies the impact of model error associated with the burst capacity model on the probability of burst of corroding oil and gas pipelines due to the internal pressure. Three burst pressure models that are widely used in the pipeline industry, namely the B31G Modified, det norske veritas (DNV), and pipeline corrosion failure criterion (PCORRC) models, are considered in the analyses. The time-dependent probabilities of burst of three hypothetical examples, which are representative of the oil and gas transmission pipelines in the United States, are evaluated by using the first-order reliability method (FORM) to carry out the comparative study. The analysis results indicate that the model error has a substantial effect on the burst probability evaluated. The probabilities of burst evaluated by considering the model error can be several orders of magnitude higher than those evaluated by ignoring the model error. The results underscore the critical importance of including the model error a...

Parametric Modeling Studies for Sediment Deposition as Sites for Under-Deposit Corrosion in Oil Transmission Pipelines

Transmission heavy crude oil carries water-wetted solid particles. Studies have shown that these particles can accumulate on the pipe floor and cause under-deposit corrosion and that the incidence of accumulation is strongly correlated to locations downstream of overbends. Computational fluid dynamics (CFD) analysis of light and heavy crude oil flows in a representative segment of a real transmission pipeline suggested that the deposition patterns in heavy oil flow are a result of low near-wall velocity, especially downstream of overbends, which prevents the flow from sweeping particles along the pipe floor, not the tendency of particles to fall to the pipe floor. The objective of the present study was to provide information that would help establish mitigation strategies. The present parametric study used the CFD model to predict the decrease in near-wall velocity at the pipe floor downstream of overbends for different pipe diameters and oil flow rates and properties. This information provided the basis for mapping the transition from light oil behavior to heavy oil behavior. The results were condensed to a chart that provides the reduction in near-wall velocity downstream of overbends as a function of the Reynolds number. It indicated a sharp overbend effect as the Reynolds number decreased below 30,000.

Optimisation of PM scheduling for multi-component systems – a simulated annealing approach

Proper planning of preventive maintenance (PM) is crucial in many industries such as oil transmission pipelines, automotive and food industries. A critical decision in the PM plans is to determine frequencies and types of maintenance actions in order to achieve a certain level of system availability with a minimum total cost. In this paper, we consider the problem of obtaining availability-based non-periodic optimal PM planning for systems with deteriorating components. The objective is to sustain a certain level of availability with the minimal total maintenance-related costs. In the proposed approach, the planning horizon is divided into some inspection periods of equal intervals. For any given interval, a decision must be made to perform one of the three actions on each component; inspection, preventive repair and preventive replacement. Any of these activities has different effects on the reliability of the components and the corresponding distinct costs based on the required recourses. The cost function includes the cost for repair, replacement, system downtime and random failures. System availability and PM resources are the main constraints considered. Since the proposed model is combinatorial in nature involving non-linear decision variables, a simulated annealing algorithm is employed to provide good solutions within a reasonable time.

Ferrite Evolution During Isothermal Process in a High Deformability Pipeline Steel

In order to ensure the safety of long-distance oil and natural gas transmission pipeline installed in seismic and/or permafrost region, high strength pipeline steel with excellent deformability has been developed. The ferrite and bainite dual phase pipeline steel is a very important kind of high deformability pipeline steel. Polygonal ferrite is a key microstructure in ferrite and bainite dual phase deformability pipeline steel. Ferrite evolution during isothermal process at 700 °C after 50% deformation at 800 °C was conducted by using a Gleeble-3800 thermal simulator, and microstructure was characterized by using an optical microscope, a scanning electron microscope and a transmission electron microscope. There are two types of ferrite, ferrite with high density dislocation and ferrite with a little dislocation. There is about 7% (volume percent) deformation induced ferrite (DIF) for compression of 50% at 800 °C and strain rate of 1 s−1. During the isothermal process at 700 °C, with the holding time increasing, ferrite volume percent, ferrite grain number and average ferrite grain size increase. As the holding time is prolonged, dislocation recovery occurs in DIF. There are secondary phases in ferrite when the holding time is too long, and secondary phases and dislocation formation in dislocation pinning.

First steps in developing an automated aerial surveillance approach

Partners in emerging risk representative application (ERRA) A3 ‘Emerging risks related to the industrial use of automated and un-manned surveillance of industrial infrastructure’ develop a set of new technologies to automate aerial surveillance by collecting images with a drone and automatically processing them to identify threats to buried oil and gas transmission pipelines. Progress on two aspects is presented, on one hand, technology development, and on the other hand, dealing with the emerging risks associated with these new technologies. Technology development covers three functions assembled in a workflow: • Image collection via a light drone with an autonomous navigation system and image geographical positioning system (GPS) referencing capabilities. • Image automated pre-processing: image assembly and georeferencing. • Threat detection: image analysis by change detection is performed using Definiens software for identifying external interferences like construction work and excavations threatening the pipeline. This set of technologies is perceived as an emerging risk that is appraised from several points of view: • Technology: unmanned aerial vehicle (UAV), image georeferencing and assembly, change detection for threat identification. • Human and Organisational and Communication: investigate the acceptance of this technology by the population and local authorities. • Regulatory: check conditions that will ensure acceptance of operational use of light drones in some European countries. • This general approach is needed to ensure both technology optimisation and the shortest path to reliable practical applications.

Fundamentals of the design of welding sealing structures of transmission oil pipelines. Welded connectors and T-bends

Investigations were carried out to determine the stress state of a cylindrical, connector, connectors with unloading rings, used for restoring the load-carrying capacity of sections of transmission oil pipelines with metal losses of different origins, and also a sheltering branch pipe, a branch pipe with a circular strap and a split T-bent, used as repair jackets preventing the unsealing of non-working technological fittings.

Oil Transmission Pipelines Condition Monitoring Using Wavelet Analysis and Ultrasonic Techniques

In this paper, a reliable and sensitive diagnostic method for oil pipelines based on wavelet analysis and ultrasonic technique. This will be achieved by the use of 3-D finite element modeling software (Abaqus CAE 6.10) combined with a power full wavelet based signal processing technique will be used to collect the empirical ultrasonic data to validate the developed diagnostic method. The affect known seeded faults i.e., 1 mmhole at 25%, 50%, 75% and 100% depth in pipe wall were investigated using FEM techniques. A developed acoustic transceiver (Air Ultrasonic Ceramic Transducer 235AC130) will be used to collect the empirical ultrasonic data to validate the developed diagnostic method. The amplitudes and frequency spectra of the ultrasonic signals were measured and the predicted results were found to be in good agreement with the measured data, and that to confirm that this method can provide important information on pipe defects.

Effects of Repair Weld on Residual Stress Distributions in Offshore Pipelines

Subjects related to strength and durability of structures such as oil and gas transmission pipelines areof great importance. Considering the special characteristics of these structures including their construction and harsh working environment, they are especially prone to different types of damages. Repair welding is a viable optiontomitigatesuch damages and for restoration of the strength and resistance of these structures. In this paper, anumerical coupled thermo-mechanical finite element modelling approachis conducted tosimulatethewelding and the repair welding process. The results of the studyshow that repair weldsmay wellhave adverseeffects on the residual stress magnitudeand on its distribution. This might in turnpotentially put the integrity of the pipeline at risk.