Pressure Gas Pipelines Research Articles

‘More likely to be killed by a coconut’: varying professional perceptions of risk impacting residential development planning around pipelines

Best practice in land use planning linked to hazardous infrastructure requires that views of multiple stakeholders are considered. This study addresses the varying views of risk held by two groups of experts – pipeline sector engineers and land use planners – when it comes to decision making about residential development at the urban fringe near existing high pressure gas pipeline infrastructure. Given that third-party activities, particularly excavation, are the largest cause of pipeline failure, continuing urban expansion into historically rural areas poses a significant risk to high pressure pipelines. The serious fires or explosions that can result have the potential to impact any nearby communities. Consequently, land use planning decisions can have a direct impact on public safety near pipelines. Drawing on interviews with land use planners and pipeline sector engineers in Australia, the comparative analysis highlights the different perceptions of risk of these groups driven by differing views about how to frame the issue of new housing near existing pipelines. Current institutional structures foster a lack of trust. Better risk governance would result in less conflict between the various parties and hence better community outcomes for both safety and amenity. The study also demonstrates that risk research findings focused on hazardous facility siting does not translate directly into the converse case of residential development siting near industrial facilities. This case provides evidence of a broader need for risk research and land use planning to better address ‘hazard creep’ – where residential development moves into areas potentially impacted by existing hazardous facilities such as pipelines but also including dams and other kinds of infrastructure.

Effect of linear investment on agricultural uses on the basis of validity of estimated compensation

Purpose. The work takes up topic with the impact of gas pipeline investments in the agricultural space. The reduction in the productivity of agricultural areas is felt by farmers already at the stage of investment construction (loss of benefits, reduction of property value, additional costs for biological reclamation). The purpose of the article is to determine the impact of the high-pressure gas pipeline by open trench method on agricultural land on the basis of estimated compensation. Estimating the value of compensations for field crops and reducing yield and biological reclamation as an issue that raises many doubts. Determining the appropriate compensation for losses incurred in field crops, due to temporary partial occupation of the area is often a matter definitely resolved in civil proceedings by the court.
 Methodology / approach. The research was supposed to answer the question whether the unit cost of biological reclamation after the installation of the high pressure gas pipeline depends on the type of use and the type of crops being cultivated. Assumed, among others that the decrease in the value of benefits (yielding of plants) is higher, the higher the soil quality class and that the decrease in the value of the property depends on the type of soil valuation class. Determination of the gas pipeline impact of the high-pressure line investment is presented on the example of the 34 km section of the gas pipeline, running through the villages of Zawonia and Długołęka communes, ie Budczyce, Byków, Cielętnik, Czeszów, Kamieniec, Krakowiany, Michałowice, Pęciszów, Piecowice, Tarnowiec, Zaprężyn, and Zawonia (areas located in the Lower Silesia Voivodship).
 Results. As a result of the conducted research, it was established on the basis of the estimated compensations that the cost of biological reclamation after building the high pressure gas infrastructure does not depend on the type of use and the type of crops being cultivated. It was also found that the decrease in the value of benefits (yielding of plants) is all the greater, the higher the soil quality class.
 Originality / scientific novelty. The study looked for the answer to the question: Does the unit cost of biological reclamation after the implementation of the high-pressure gas pipeline depend on the type of use and type of crop being cultivated. It was assumed that the decrease in the value of benefits (yielding of plants) is all the greater, the higher the soil quality class and that the decrease in value of benefits (yielding of plants) depends on the type of cultivation per 1 m2. It was also assumed that the decrease in the value of the property depends on the type of soil valuation class. For the purposes of the study, the authors collected data indicating the value of compensation, including to the size of the surface.
 
 Practical value / implications. Determination of the impact of high pressure gas pipeline construction using the open trench method on agricultural land on the basis of compensation paid indicates that the reduction in the value of benefits depends on the type of crops.

Risk Analysis for High Pressure Gas Pipeline Construction Schedule

In article authors focus on preparation of construction works schedule for high pressure gas pipeline in urbanized area and implementation of risk analysis in estimation of realistic completion date. In the first step, the pipeline was divided into couple of sections with different construction methods. During evaluation open cut methods, HDD and microtunneling methods were verified and for every approach specific types of risk were identified. Since number of potential risks was significant authors decided to apply the method for ranking the risks and introducing most important potential complications in the construction schedule. After risk identification authors prepared set of impact categories, varying for negligible few days delays to disastrous three months or more delays. Moreover for potential risks a list of probabilities were elaborated to described risk is plausible to happen several times during project execution or is rather likely to occur every couple of similar projects. Combination of sets of possible impacts and sets of probabilities resulted in a project specific risk matrix. Risk matrix was the first tool used for ranking of all risks, especially when regions of intolerable risks and risks requiring mitigation plan were drawn in the matrix. Based on professional literature, and their own experience for every potential risk, authors estimated the risk level. Knowing this in the next step all risks were sorted according to decreasing value of risk level and for risks within intolerable area or within area requiring emergency back-up plan. Authors verified if those plausible risks indeed require a schedule reserve or some other solution may be applied. If schedule reserve was a reasonable solution the relevant additional construction time was estimated, having in mind the schedule impact level of reviewed risk. In the end construction schedule was prepared, which includes the risk analysis for all construction methods.

Experimental study of growth kinetics of CO2 hydrates and multiphase flow properties of slurries in high pressure flow systems.

The formation and accumulation of hydrates in high pressure oil and gas pipelines bring great risks to field development and deep-water transportation. In this paper, a high pressure flow loop equipped with visual window was used to study the growth process of hydrates in a pipe flow system and slurry flow characteristics. Deionized water, industrial white oil and CO2 were selected as the experiment medium. A series of experiments with different initial pressures (2.5–3 MPa), liquid loads (7–9 L), flow rates (25–35 kg min−1) and water cuts (60–100%) were designed and carried out. Specifically, hydrate formation and slurry flow characteristics in two different systems, pure water and oil–water emulsion system, were compared. Both of the systems experienced an induction stage, slurry flow stage and followed by a plugging stage. Although hydrate growth gradually ceased in the slurry flow stage, plugging still occurred due to the continuous agglomeration of hydrates. Visual observation showed that there were obvious stratification of the oil–water emulsion systems at the later time of slurry flow stage, which directly resulted in pipe blockage. The hydrate induction time of the flow systems gradually decreased with the increasing initial pressure, initial flow rate and water content. And the induction time tended to decrease first and then slowly increase with the increasing liquid loading. For emulsion systems, the apparent viscosity and friction coefficient of the hydrate slurry increased with the increasing water content, indicating that there were higher plugging risks compared to the pure water systems. Moreover, the results of sensitivity analysis showed that the water content was the main factor affecting the hydrate induction time, followed by the influence of liquid carrying capacity and flow rate, and the initial pressure had the least influence on the induction time. Conclusions obtained in this paper can provide some reference not only for the prevention and management of hydrates in pipelines, but also for the application of CO2 hydrate as a refrigerant.

A note on Nash equilibrium with wave dynamics and boundary control: controllability, observability and stabilizability considerations

ABSTRACTIn this paper, the gas dynamics within the pipelines is written as a wave repetitive process, and modified in a way that the dynamics is driven by the boundary conditions. We study controllability of the system through boundary control and every agent, as well as observability of the system being steered by initial and boundary data. Next, we obtain sufficient criteria for the existence and uniqueness of boundary equilibrium controls. From the point of view of some applications, e.g. in high pressure gas pipeline management, it seems to make sense to consider boundary data controls. The same problem is then extended to its infinite counterpart since it may run infinitely and, in this case, we become interested in studying its stabilisation.

Corroboration of sparse failure data through Bayesian estimation for natural gas cross country pipelines: A case study with reference to the Indian scenario

The rising demand for Natural Gas (NG) in India, a developing country, necessitates adequate, uninterrupted and safe transmission and distribution of the gas to consumers at various points within the country. Though pipelines are considered as the safest mode of transportation, the failure of a flammable and highly pressurized natural gas pipeline can cause fatalities and extensive damage to properties. A reliable estimation of occurrence probabilities of ‘actual’ natural gas pipeline incident scenarios helps to evaluate the safety management and control system existing in the country. Unfortunately, India does not maintain any quantitative failure data base of the natural gas pipeline incidents due to lack of operational history. This paper outlines the use of Bayesian logic for corroborating the existing sparse and imprecise occurrence proportion of natural gas pipeline incident scenarios obtained from the incident analysis reports. This is done by incorporating the specific unreported Piped Natural Gas (PNG) incident scenario frequency per year. Posterior occurrence probability estimates of the incident scenarios lie between the sparse prior proportions obtained from the published incident analysis reports and the likelihood proportion of specific PNG incidents happening in India per year. The newly generated data through the Bayesian estimation therefore can be considered more reliable and sensible and are also validated like such data available in the developed countries. The posterior estimates also necessitate more improved safety management and control system in each City Gas Distribution (CGD) entity within the country to reduce specific failure cause-consequences.

Uplift Resistance of Buried Pipelines in Partially Saturated Sands

High Pressure and High Temperature (HPHT) oil and gas pipelines are commonly buried subsurface and the depth of burial is determined by upheaval buckling mitigation requirement or legislation requirement. The upheaval buckling mitigation design requires evaluation of uplift resistance of soil in which pipeline is buried. Conventional design guidelines and current analytical models for predicting the soil uplift resistance are based on either dry soil or fully saturated soil. However, onshore pipeline are buried in soils which are often partially saturated. Therefore, current analytical models do not capture the effects of soil saturation on the uplift resistance of buried pipeline. In partially saturated soils, the uplift resistance is greater than that under fully saturated conditions. This is because the water meniscus between soil particles creates an additional normal force due to suction, which in turn makes the soil behaviour stiffer and stronger. This paper presents full scale pipe-soil tests results and finite-element parametric studies conducted to investigate the effects of soil moisture content, dimensionless cover heights (soil cover height to diameter ratio) and soil relative density on the peak uplift resistance of pipes. The results demonstrate that the current available analytical models under-predict the soil peak uplift resistance in partially saturated conditions. Further, the analyzed results are presented as dimensionless design charts and non-linear regression models which can be used to quantify the partial saturation effect on uplift resistance of buried pipes.

Dynamic measurement of CTOA of unstable ductile fracture of high pressure gas pipelines

Demand for natural gas is increasing worldwide and pressure and diameter of gas pipelines are increasing. In such high-pressure gas pipelines, prevention of unstable ductile fracture is an important issue. Crack tip opening angle (CTOA) is widely used for fracture criterion of unstable ductile fracture, and measured by Drop Weight Tear Test (DWTT). But, measuring CTOA during dynamic crack propagation in pipe burst is very limited. Therefore, in this study, we measured CTOA in a pipe burst test. The crack propagation was photographed by high-speed camera. The CTOA values by the DWTT and the burst tests were found somewhat different. A care should be taken when using CTOA value obtained by DWTT for analyzing dynamic crack propagation behavior in pipelines.

Structural Reliability Analysis of Corroded Pipeline made in X60 Steel Based on M5 Model Tree Algorithm and Monte Carlo Simulation

Accurate determination of the failure probability of oil and gas pipeline is very important in integrity assessment and work conditions of such structure. In this paper, the failure probability of the corroded pipelines which is made by X60 steel grade is evaluated. The burst corroded performance function is developed using the M5 model tree for this complex real engineering failure problem. The structural reliability of a the pressurized gas pipeline containing external corrosion defects has been evaluated using hybrid reliability method combined by the M5 model tree and Monte Carlo simulation. The results indicated that increasing the defects depth are strongly reduced the safety levels of this problem.

Influence of Repairing Using Welded Steel Patches on Structural Integrity of a High Pressure Gas Pipeline

The present paper deals with complex material properties of DN 300 pipeline from the section Olesna - Barchov. The work was aimed at experimental verification of the effect of welded-on cover patches on the pipeline integrity. Two types of welded-on cover patches were evaluated. In the first case, just a single patch - steel plate was welded into the pipeline wall, replacing the damaged area. A lack of root fusion was found by means of the NDT. In the second case, the primary patch welded into the wall was covered by an auxiliary patch welded over the first one. No imperfection of the weld integrity was shown in the second case. The experimental programme contained an evaluation of the resistance of the repaired section to 10 000 pressure cycles induced by the inner water pressure at R = 0 cycle load asymmetry and maximum pressure of 6.3 MPa. The effect of these repairs on the limit state of the pipeline was verified by means of hydrostatic burst test. The tests comprised the evaluation of fracture surface morphology.

Crack Arrest Toughness of High Grade Gas Pipeline

Pipeline transportation is the most economical and reasonable way to transport natural gas. However, there are still some technical problems in high grade gas pipeline, in which fracture control is one of the key problems. The ductile fracture for long-range expansion is the most destructive failure mode of high pressure gas pipeline. In this study, the determination and prediction methods of crack arrest toughness of high grade (X80 and above) pipe line steels were introduced. Their application range, advantages and disadvantages were analyzed. The results showed that the toughness of X80 pipe line steel can meet the needs of the pipeline crack arrest requirements. It is difficult for the ultra-high-grade (X90 and above) pipe line steel to arrest crack by their own toughness. Therefore, the crack arrester should be installed. This paper introduced the crack arrest principle, advantages and disadvantages of various kinds of crack arresters.

Membrane-Based Electrochemical Sensor for Corrosion Monitoring in Natural Gas Pipelines

Although electrochemical sensors are widely used in many aqueous systems, their applications have been limited in environments where water is distributed within a bulk non-aqueous phase. One example is in transmission pipelines such as for natural gas. In these environments, the bulk phase is often not conductive enough to perform electrochemical measurements. We have investigated the use of ion conducting membranes of the type found in polymer electrolyte membrane fuel cells for preparing sensors to be used in high pressure gas pipelines. The membrane provides an electrolyte whose conductivity depends on the partial pressure of water vapor in the gas stream. Commercial Nafion™ 117 was used for the prototypes, and conductivity and corrosion measurements in gas streams up to 75 °C and 6.9 MPa (1000 psig) were conducted to determine the effectiveness of the sensor. Membrane conductivity data is reported for a range of water contents representative of gas transmission at 0.69 and 6.9 MPa (100 and 1000 psig) in nitrogen, methane, and a methane/carbon dioxide blend. Corrosion data collected from linear polarization resistance and electrochemical impedance spectroscopy measurements for carbon steel in simulated pipeline conditions are also presented.

Safety framing and compliance in relation to standards: Experience from the Australian gas pipeline industry

Safety is conceptualized in different ways across hazardous industries, but it is often expressed in terms of compliance. Compliance is about rules in various forms, including standards. Standards are core reference points that guide the design, construction and management of hazardous infrastructure such as high pressure gas pipelines. While standards are critical, we argue that neither their application nor their relationship to safety should be taken for granted. In this article, we investigate the ways in which safety as compliance in relation to standards manifests, the ways it is contested, its strategic use and implications for major accident risk management. Building on the framing literature, this article reveals where these frames reside and their interactions. We use qualitative methods to examine the framings of safety present in accounts of Australian pipeline industry members. We argue that the frames (compliance as expert judgment and compliance as process) are contested, which leads to the creation of a hybrid or compromise frame – one which integrates the underlying concerns of both frames. Best case, a dialogue between people using both frames results in a hybrid frame involving expert use of standards, with consideration of industry context. Worst case, standards are thoughtlessly applied, or are used as a way to displace organizational responsibility for safety that may be in conflict with business pressures.

Stress-strain assessment of dents in wall of high pressure gas pipeline

The aim of this work was experimental study of the dents effect on structural integrity of a high-pressure gas pipeline with nominal diameter 300 mm after long-terme operation. Stress-strain behaviour of two dents was evaluated by strain gauge chains oriented in hoop direction. Dent profiles were measured by digital slide caliper in circumferential and longitudinal direction in points distant 10 mm from each other. Residual deformations were detected after internal pressure loading by water to the operating level. Negative and positive values of residual deformation were found wuth the help of strain gauges. Fatigue resistance was tested by 10 000 pressures cycles with load asymmetry R = 0 and maximum internal pressure pmax = 6,3 MPa (nominal operating level). Internal pressure cyclic loading caused an increase of residual deformation values. By means of subsequent pressure burst test, the limit state of this type defect was found. Two dwells were realized in 66% and 100% yield stress. Negative values of strain were observed at strain gauges placed on edge of dents. Positive values of strain were found at strain gauges placed inside the dents. The increase of internal pressure led to the changes of dent shape. Dent depth decreased and the original circular tube profile was reached again. The pipe fracture occurred at the internal pressure of 19 MPa. Tensile properties and Charpy absorbed energy were measured on standartized specimens of the pipe material.

A parametric study on the effects of surface explosions on buried high pressure gas pipelines

A parametric study on the effects of surface explosions on buried high pressure gas pipelines

Gas transmission pipeline failure probability estimation and defect repairs activities based on in-line inspection data

Degradation of an underground pipeline during its service life leads to reduction of the pipe wall thickness. Periodic in-line inspections are performed by onshore pipelines operators to detect corrosion anomalies and size their depth and width. In the paper, a simple analytical method of burst pressure calculation for a straight pipeline repaired with a composite sleeve was investigated. Repair activities after an in-line inspection of a gas transmission pipeline were considered in this research to assess the pressure of a pipe with a flaw reinforced with a different number of layers of a fiber-based polymer sleeve. Det Norske Veritas criteria and formulation of a limit state function were applied to determine the burst pressure and corresponding failure probability of a pipeline with a large number of single and non-interacting part-wall defects. The Monte Carlo method was selected for estimation of pipeline failure probability and cumulative failure probability due to the external corrosion considering fluid pressure fluctuations in dynamic flow effects with respect to statistical distribution of input parameters were examined in this research. The proposed novel 3-step approach was validated on the real data collected from an onshore high pressure gas pipeline DN 700, MOP 5.5 MPa provided by two magnetic flux leakage inspections repeated at an interval of twelve years. A probabilistic methodology was applied to evaluate the part-wall external corrosion defects and their deterministic linear growth with time and repair activities on gas transmission pipelines were analyzed. The results of this study shall help maintenance engineers solve the problems of an optimal strategy in reliability-based high pressure gas pipelines management.

Experimental Assessment of Residual Fatigue Life of High Pressure Pipeline Section Containing Longitudinal Cracks

Non-destructive inspection of an operated section of DN 300 high pressure gas pipeline (internal diameter 300 mm) indicated a quite frequent occurrence of longitudinal cracks of depths up to 50 % of the pipe wall thickness. As such cracks would be very dangerous from the viewpoint of further pipeline operation, selected sections of the pipeline were taken from the ground for an experimental programme aimed at evaluation of residual fatigue life. The first part of the programme concerned (i) experimental calibration of direct current potential drop (DCPD) method of crack depth estimation, complicated by the longitudinal position of the cracks, (ii) estimation of actual depths of selected, most distinct cracks and (iii) metallographical evaluation of profiles and depths of selected cracks. The DCPD calibration confirmed that for the specific configuration of electrodes used and characteristic crack profile, analytical calibration using Johnson´s formula corresponds to the actual crack depth quite exactly provided that the cracks are of radial direction. However, metallographical analyses showed that analysed actual cracks, though quite long, even more than 2 mm in some cases, were quite inclined, in some cases almost parallel to the pipe surface. These cracks occurred obviously in production during rolling process, which was a good sign for a relative safety of the affected pipeline. Further theoretical considerations were made to enable estimations of the inclined crack depths using the DCPD method, necessary for crack growth measurement during internal pressure fatigue tests, which followed.

Corrosion of Underground Low Pressure Gas Pipelines under Alternate Current

Під час експлуатації підземних газових мереж низького тиску не приділяють уваги боротьбі з електрокорозією під дією змінного струму. При цьому інтенсивні корозійні руйнування проходять у місцях стікання постійного струму зі зовнішньої поверхні в електроліт (ґрунт або воду). Проведено моніторинг корозійних уражень розподільчих трубопроводів "Івано-Франківськгаз". Виявлено локальні корозійні ураження, які за формою і глибиною відповідають електрокорозійним. Показано, що електрокорозія розподільчих газопроводів може бути зумовлена помилковим або навмисно неправильним підключенням електроприладів. Зафіксовано натікаючі струми навіть на малопотужних побутових приладах силою близько 4 А, що залежно від фізико-хімічних властивостей ґрунту відповідає густині струму на дефекті від 8,9 до 310 А/м2 за максимального нормативного значення 10 А/м2.

Finite Element Modeling and Numerical Simulation of Welding at the Repair of Gas Pipelines with Steel Sleeve

This article deals with simulations of the welding process for applications of practice using SYSWELD software. Simulation of welding at the repair of high-pressure gas pipeline with steel sleeve with composite filling is presented in this paper. Two welds connecting the distance ring and gas pipe were simulated. Structure of programme SYSWELD and repair of high pressure gas pipeline with steel sleeve is described in theoretical part of article. Preparation of boundary conditions for numerical simulation on real sample and numerical simulation of welding is in experimental part. Thermal fields, residual stresses and hardness were simulated. The results of the numerical model, which are listed in article except for residual stresses are compared to real experiments. This article mainly describes the numerical simulation capabilities in welding simulation programme SYSWELD.

Development of technology of mechanized arc welding in repair of pressurized main gas pipeline

Development of technology of mechanized arc welding in repair of pressurized main gas pipeline