Buried Oil Pipeline Research Articles

Numerical Simulation of Multiphase Flow Pollutants during Migration Process in Buried Oil Pipeline Leakage

Considered influence of buried pipeline leakage of crude oil pollutants multiphase flow migration phenomenon effects, numerical model was established to buried pipeline road multiphase leak process simplified for two-dimension problem, numerical simulation was used with the CFD software FLUENT on buried pipeline leakage of crude oil pollutants migration process caused pollution problem, calculation simulation was carried out in the two species workers condition of one phase flow and multiphase flow buried pipeline leakage of pollutants around earth temperature field, the speed field and the distributions of oil/water phase in the soil porous media. Analysis the comparison of results indicated that: 1) the affected region of temperatures spread above the buried oil pipeline was more slowly than either side of the rate of diffusion;2) During the buried pipeline leakage early, except the maximum of velocity near the leakage mouth, the other penetration regional velocity of leakage crude oil are very low.

Implementation of the Variable Center Frequency Band-Pass Filter Based on FPGA

Digital band-pass filters play a very important role in instrument design. For some special applications, such as corrosion inspection of buried oil or gas pipeline, more than one band-pass filter with different center frequencies are needed to process different frequency signals. FPGA (Field-Programmable Gate Array) are widely used in these applications because of its high compute velocity and flexibility. For low cost and high reliability purposes, it is expected that one digital filter with a fixed configuration parameters can serve as multi different center frequency digital filter. In this paper a design method is proposed to realize two different center frequency band-pass filters which have the same filtering effect. Through analysis of design process for FIR band-pass filter, it’s easy to find that if the ratios (filter’ sample rate of input data to its cut-off frequency) of two filters keep equal, the normalized frequency will also equal. Thus according to this, two band-pass filters can have the same coefficients only if they have the same ratio of sample rate to cut-off frequency. This relationship is discussed here and MATLAB experiment is used to prove its effectiveness. This method is already used to design filters in pipeline current mapper instrument to inspect pipeline corrosion.

The Impact Analysis on Crude Oil Phase Change to the Migration of Buried Oil Pipelines Leakage Pollution

This paper established mathematic and physic model of buried oil pipelines leaking in porous media of soil. Make use of FLUENT software to simulate crude oil phase change and non-phase change in the soil of cold regions. The result shows that: The temperature over the leakage hole of phase change diffusion process is higher than not considering phase change. The oil phase diffuse to the earth’s surface needs more time. And the speed diffusing to the underground is basically same. The earth surface temperature’s variation of leakage process without crude oil phase change lags behind the process considering phase change.

The Analysis of Crude Oil Nature’s Impact on Oil Pipeline Underground Divulging Pollutant Migration

The oil pipeline burying divulging pollutant was taken as the object of study in this paper, the heat transfer and mass transfer process of which in the soil porous medium were carried by the numerical analysis. The oil phase change for multiphase flow leakage process for buried pipelines for oil, gas and water in the low temperature was considered, and the impact on multiphase leakage process of high and low viscosity of the oil phase viscosity properties was analyzed. It cited multiphase pipeline leak by using Fluent at different times during the course of the earth temperature field , the oil / water phase distribution , surface temperature, and the results showed that : there existed a big difference between the multiphase flow leakage process surface temperature changes and porous medium heat and mass transfer processes with the conditions of high viscosity and low viscosity conditions . Therefore, the impact of the physical properties on buried oil pipeline leak process at low temperatures is great.

Study on the water-heat coupled phenomena in thawing frozen soil around a buried oil pipeline

Buried pipelines are one of the most economical and efficient methods for long distance transportation of crude oils, but when a pipeline goes through the cold regions, it may suffer serious threats caused by the freezing and thawing problems of frozen soil. In this study, the water-heat coupled problem of frozen soil around buried hot oil pipeline in cold regions is systematically studied by means of numerical simulation. The temperature field, water content field and unfrozen water migration of frozen soil under different pipeline operation periods are obtained by pure heat conduction model and water-heat coupled model respectively to illustrate the influence of water content field on temperature distribution of frozen soil and oil temperature along the pipeline. It can be concluded from the simulation results that it is the coupled interactions of temperature distribution and water migration that determine the ultimate status of transport phenomena in frozen soil. The most obvious water migration occurs in the soil area close to the buried oil pipeline where there is the largest gradient of temperature. And the change of thermal properties caused by the water migration turns out to be one of the most important factors affecting the temperature field of frozen soil.

Numerical Simulation of Frost Heave in Soils around the Buried Oil Pipeline in Island Talik Permafrost Region

A systematic method to obtain the freezing characteristics and the amounts of frost heave in the soils around a buried oil pipeline in island talik permafrost region is presented on the basis of the simulation of soil temperature fields and a classic segregated potential frost heave model. The finite thermal effect domain and the equivalent heat capacity method were adopted to analyze the heat transfer process with phase change. The calculation parameters were derived from the China-Russia Crude Oil Pipeline engineering. The developments of the annual maximum freezing circles and frost penetrations emerging in typical years within the pipeline operation life cycle under different oil temperature, different thickness of thermal insulation layer, and different water content of soils were investigated. The maximum frost heaves in four typical sections of island talik were predicted. The results can be used to further mechanical calculation and can provide references for risk evaluation and site management of the buried pipelines in island talik permafrost regions.

Heat Effect Analysis of Buried Oil Pipeline in the Qinghai-Tibet Plateau

The Geermu-Lasa oil pipeline was located in the Qinghai-Tibet Plateau permafrost regions. The building and operating of pipeline will change the temperature field of soil around it, which can lead to changes of frozen soil mechanic properties, and this will induces deformation or even fracture of pipeline. These phenomena will affect the normal transportation of oil. In this paper, temperature field around the pipelines were analyzed due to different pipe diameters and different insulation layer thicknesses in the way of finite element method. The rule of thawing and freezing of soil around the pipeline in an annual cycle was obtained. Artificial permafrost table variations under the pipeline were also obtained due to different operating conditions. For 30cm diameter pipeline with 7cm insulation layer, its artificial permafrost table depth change value is just 0.48m after 30-year running. These analysis results can provide references to the construction of the new Geermu-Lasa oil pipeline.

Transient response of buried oil pipelines fiber optic leak detector based on the distributed temperature measurement

Oil leakage of transportation pipelines causes a change in its environmental temperature. This effect is employed to detect the leakage and its positions. The Raman Optical Time Domain Reflectometer (ROTDR) and Brillouin Optical Time Domain Amplifier (BOTDA) sensors are two of the most precise oil pipeline leak detector systems operate based on this effect. The position of leakage is determined by the time difference between the sending and backscattered laser pulses. In this paper, the transient response of BOTDA and ROTDR sensors are obtained through solution of the mass, energy and heat transfer in soil and fiber cable. It is shown that the mechanical rise time is of the order of a few minutes, which is in agreement with the experimental results of BOTDA and ROTDR sensors. Ultimately, on the basis of the heat transfer results, a method for leak flow rate measurement by the optical fiber leak sensors is proposed.

Failure of Pressurized Corroded Pipeline Subject to Axial Compression: A Parametric Study

Onshore buried steel pipelines are used for transporting oil and gas to various cities and locations. These pipelines can be subjected to various loading, such as axial, bending, shear, and other complex loading from the geotechnical movements and temperature variations. For example, a buried pipeline situated on an unstable slope can be subjected to axial load and axial deformation. In addition, this pipe experiences pressure loading from the fluids that it transports. The buried pipelines also need to endure corrosive environmental and as a result, corrosion occurs in these pipelines. Corrosion is the primary cause for structural failure of buried oil and gas pipelines and corrosion may lead to a catastrophic rupture failure causing environmental damage, injuries to human and animals, and loss of production and revenue. Hence, understanding the structural behavior and failure conditions of corroded pipelines is important for the pipeline operators. Therefore, this project was undertaken to determine the conditions required for failures of corroded steel pipes when subjected to axial deformation and internal pressures. Then the effect of internal pressure, dimensions of the corrosion, and depth of corrosion on the failure condition and failure mode was studied. It was found that the increasing value of these parameters is beneficial for achieving a favorable failure mode, however it can reduce the axial load carrying capacity significantly.

Fast Calculation of the Soil Temperature Field around a Buried Oil Pipeline using a Body-Fitted Coordinates-Based POD-Galerkin Reduced-Order Model

In order to calculate the soil temperature field around a buried oil pipeline of different geometric parameters and boundary conditions fast and accurately, the POD-Galerkin reduced-order model is established based on body-fitted coordinates (BFC). The most exciting feature of the established BFC-based reduced-order model is that it is independent of not only boundary conditions but also geometrical shape; that is, the reduced-order model can accurately calculate the specific physical problems which have different boundary conditions or different geometrical shapes from those of the sample cases. To some extent, this study expands the application scope of the POD reduced-order model.

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.

Failure analysis and mechanical performance of an oil pipeline

This paper presents a work scheme for failure analysis of buried oil pipelines. The scheme provides answers for two main questions at least: what were the causes that made the system fail and why the system failed in the way it did. The scheme is based on five stages and the results of these stages are related to each other and consistent with the type of failure, thereby providing objective conclusions. The proposed scheme was successfully applied to a case of a buried oil pipeline whose failure was a result of external corrosion. We established the occurrence of accelerated corrosion characterized by two corrosion mechanisms: one involving iron oxides and the other, iron sulfides. Furthermore, the ductile type failure has proved to be due to leakage, which is consistent with the reported evidence.

Leakage of Long-Distance Pipeline by FIOEFD Simulation and Indoor Experiment

Based on the established indoor experimental platform for the leakage of buried oil pipeline, the characteristics of leakage under varied transfer pressure have been studied and simulated according to the experimental model by using FLOEFD—an analysis software of fluid & heat transfer. By comparing and analyzing the result of simulation, experiment and applying correlate theory of fluid dynamics，the theoretical model is established.

Characterization of Al-Zn-Sn as Sacrificial Anodes to Protect Underground Oil Pipelines in Al-Hilla Regional

Sacrificial anode cathodic protection is one of the most widely used methods in protecting buried oil pipe lines against the corrosion damages. In the present work, a series of Aluminum alloys have been prepared as sacrificial anodes candidates to be used in the protection of the oil pipelines that pass through the Al-Hilla region. These prepared alloys were microstructurally and electrochemically characterized to evaluate their performance as Al-sacrificial anodes for cathodic protection of oil pipes The relationships between the protection potential with time, sacrificial anode life, discharge currents, and capacity of sacrificial anodes were found, taking into consideration the distance between sacrificial anode and protected steel sample. According to the results obtained, the best selection of sacrificial anodes was (Al-4% Zn-0.5% Sn) alloy at 30cm in Al-Hilla region.

Analysis of the harmful effects to buried oil pipeline from power line short-circuit fault

Based on the transmission line theory of the buried metallic structures, the concerned harmful effects to the buried oil and natural gas pipelines caused by the power line short-circuit fault are further discussed. A closed-form expression of the induced voltage caused by the short-circuit fault of the ultra-high voltage power (UHVAC) transmission line is given. The transmission line model of the buried pipeline is set up and a set of formulas for calculating induced voltage on the pipeline and the parameters of the buried pipeline in actual environment condition are given. At last, the characteristic of the harmful effects on the buried pipeline from the power line short-circuit fault are discussed.

Unsteady-state thermal calculation of buried oil pipeline using a proper orthogonal decomposition reduced-order model

The POD-Galerkin reduced-order model is established for the thermal process of the buried oil pipeline, which carries complex and inhomogeneous boundary conditions, including Dirichlet (or first-type), Neumann (or second-type), and Robin (or third-type) boundary conditions. Especially, the treatment of different boundary conditions is given in detail. The implementation of POD-Galerkin reduced-order model on unstructured mesh is also introduced. Subsequently, the thermal processes of batching transportation and commissioning in an oil pipeline are calculated by the established reduced-order model, indicating that the reduced-order model is accurate and efficient. The application of this reduced-order model may provide a convenient and rapid approach for the design and ensuring safe and economic operation of the oil transportation pipeline.

Effects of Tin on Aluminum – Zinc Alloy as Sacrificial Anode to Protect Underground Oil Pipeline in Al-Mahawil Regional

Abstract Sacrificial anode cathodic protection is one of the most widely used methods in protecting buried oil pipe lines against the corrosion damages. In the present work, a series of Aluminum alloys have been prepared as sacrificial anodes candidates to be used in the protection of the oil pipelines that pass through the Al-Mahawil region. These prepared alloys were microstructurally and electrochemically characterized to evaluate their performance as Al-sacrificial anodes for cathodic protection of oil pipes The relationships between the protection potential with time, sacrificial anode life, discharge currents, and capacity of sacrificial anodes were found, taking into consideration the distance between sacrificial anode and protected steel sample. According to the results obtained, the best selection of sacrificial anodes was Al-4% Zn-0.4% Sn) alloy at 30cm in Al-Mahawil region.

Simulation of Operation Scheme of Su Cuo Buried Oil Pipeline

Aim at the actual operating condition of Su Cuo buried oil pipeline, the simulation model of this pipeline operation was built by the simulation software of TLNET to simulate the running states of pipeline in different operating conditions. With the target of saving energy and reducing consumption, the operating parameters of this pipeline with different throughput and different seasons were optimized, and the optimization results can be used to guide the pipeline operation.

Biodegradation of asphalt by Garciaella petrolearia TERIG02 for viscosity reduction of heavy oil

Petroleum hydrocarbon is an important energy resource, but it is difficult to exploit due to the presence of dominated heavy constituents such as asphaltenes. In this study, viscosity reduction of Jodhpur heavy oil (2,637 cP at 50°C) has been carried out by the biodegradation of asphalt using a bacterial strain TERIG02. TERIG02 was isolated from sea buried oil pipeline known as Mumbai Uran trunk line (MUT) located on western coast of India and identified as Garciaella petrolearia by 16S rRNA full gene sequencing. TERIG02 showed 42% viscosity reduction when asphalt along with molasses was used as a sole carbon source compared to only asphalt (37%). The viscosity reduction by asphaltene degradation has been structurally characterized by Fourier transform infrared spectroscopy (FTIR). This strain also shows an additional preference to degrade toxic asphalt and aromatics compounds first unlike the other known strains. All these characteristics makes TERIG02 a potential candidate for enhanced oil recovery and a solution to degrading toxic aromatic compounds.

Prediction of Residual Life for Oil and Gas Pipe With Local Corroded Defects

According to the corrosion failure characteristics of buried oil and gas pipelines, electrochemical corrosion rates of the local corrosion and pitting corrosion flaws were derived by Faraday's laws, and the limit size model of corrosion defects was established based upon ASME-B31G criteria. A new method of the residual life prediction for buried pipelines was finally developed based on the corrosion rate model and limit size model of corrosion defects, and the prediction method was validated with an example and the results showed that the method is reliable for pipelines with corroded defects.