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1
Kharionovskiy, V. V. "Offshore Pipeline Safety". Occupational Safety in Industry, n. 5 (maggio 2022): 7–14. http://dx.doi.org/10.24000/0409-2961-2022-5-7-14.
Testo completoAbstract (sommario):
Due to the nature of the development of gas transmission network, the problem of ensuring reliability and safety of the underwater gas pipelines was practically exhausted by the calculation of underwater crossings through the rivers, lakes, and other water barriers. However, in recent years in connection with the development of oil and gas fields on the shelf, and the globalization of the gas transmission network, the question came up related to designing, building, and subsequently ensuring the stable operation of the offshore deep-water pipelines. Individual information about the accident rate of the offshore pipelines is given. They mainly concern the coastal pipelines transporting raw materials from the offshore production platforms to the onshore terminal. The largest number of accidents is typical for the pipelines of small diameters (2–6 inches) — 59 % of their total number. A group of medium-diameter pipelines (8–16 inches) accounts for 32 % of accidents. Pipelines of large diameter (18–36 inches) are the least susceptible to damage — about 3 % of accidents. In recent decades, the offshore main gas pipelines were widely used and are considered as the most promising way of transporting gas due to higher reliability, safety, and environmental friendliness, as well as the advantages of direct Analysis is presented in the article concerning the accident rate and features of failures of the offshore gas pipelines. The criteria of limit states and the algorithm for calculating the stress-strain state of the offshore pipeline, which are the main part of the safety assessment, are given. Methodology for the safety of the offshore gas pipelines was developed, based on which the example of the safety assessment of the Blue Stream gas pipeline is given. The materials of the article were used in the development of the projects for the offshore gas pipelines and are also included in the industry regulatory document.
2
Ervina Efzan, Mohd Noor, e S. Kesahvanveraragu. "Review on Pipelines in Offshore Platform Processing System". Applied Mechanics and Materials 695 (novembre 2014): 684–87. http://dx.doi.org/10.4028/www.scientific.net/amm.695.684.
Testo completoAbstract (sommario):
Pipelines are essential for transporting energy utilities such as oil, natural gas and coal for the nation. Similarly, pipelines are the only medium installed at offshore region to convey oil, gas, chemicals and water. Currently, corrosion is being a major problem for offshore pipeline occurrences around the world. Hence, this paper discussed on the pipelines in offshore platform and the corrosion of corresponding pipeline materials.
3
Liu, Peng, Shi Yuan Wu e Le Kang. "Upheaval Buckling Analysis of Buried Offshore Pipelines under High Temperature and High Pressure". Advanced Materials Research 919-921 (aprile 2014): 292–95. http://dx.doi.org/10.4028/www.scientific.net/amr.919-921.292.
Testo completoAbstract (sommario):
Nonlinear finite element upheaval buckling model of buried offshore pipelines under HT/HP is built using ABAQUS. The petroleum is defined as uniform flow; temperature field of offshore pipelines produced in the process of petroleum transportation is obtained by heat transfer analysis; offshore pipelines are buried in trench of sandy seabed, interaction between seabed and offshore pipelines is defined as friction, seabed interaction with offshore pipelines will limit the movement of offshore pipelines; coupled fluid-structure analysis for three phase model of oil-pipe-soil is conducted to obtain stress under HT/HP. Initial imperfection of pipeline is introduced to calculate upheaval buckling of buried offshore pipeline under HT/HP. Through numerical analysis, the axial force of pipelines under HT/HP is obtained and thus resulted in upheaval buckling.
4
Seth, Debtanu, Bappaditya Manna, Jagdish Telangrao Shahu, Tiago Fazeres-Ferradosa, Francisco Taveira Pinto e Paulo Jorge Rosa-Santos. "Buckling Mechanism of Offshore Pipelines: A State of the Art". Journal of Marine Science and Engineering 9, n. 10 (1 ottobre 2021): 1074. http://dx.doi.org/10.3390/jmse9101074.
Testo completoAbstract (sommario):
The buckling analysis of an offshore pipeline refers to the analysis of temperature-induced uplift and lateral buckling of pipelines by analytical, numerical, and experimental means. Thus, the current study discusses different research performed on thermal pipe-buckling and the different factors affecting the pipeline’s buckling behaviour. The current study consists of the dependency of the pipe-buckling direction on the seabed features and burial condition; the pre-buckling and post-buckling load-displacement behaviour of the pipeline; the effect of soil weight, burial depth, axial resistance, imperfection amplitude, temperature difference, interface tensile capacity, and diameter-to-thickness ratio on the uplift and lateral resistance; and the failure mechanism of the pipeline. Moreover, the effect of external hydrostatic pressure, bending moment, initial imperfection, sectional rigidity, and diameter-to-thickness ratio of the pipeline on collapse load of the pipeline during buckling were also included in the study. This work highlights the existing knowledge on the topic along with the main findings performed up to recent research. In addition, the reference literature on the topic is given and analysed to contribute to a broad perspective on buckling analysis of offshore pipelines. This work provides a starting point to identify further innovation and development guidelines for professionals and researchers dealing with offshore pipelines, which are key infrastructures for numerous maritime applications.
5
Jas, Eric, Allison Selman e Valerie Linton. "Out of sight out of mind – subsea pipeline decommissioning". APPEA Journal 57, n. 1 (2017): 79. http://dx.doi.org/10.1071/aj16215.
Testo completoAbstract (sommario):
Existing legislation, regulation and documentation dealing with decommissioning of offshore oil and gas infrastructure has traditionally been derived from experience gained in the North Sea and the Gulf of Mexico. The Australian operating environments are very different and, consequently, there is no Australian industry-wide engineering standard dedicated to the decommissioning of offshore pipelines. Decommissioning of Australian offshore pipelines is currently handled on a case-by-case basis. The efficiency and effectiveness of any given decommissioning project is variable, and highly dependent upon the experience of the pipeline operator. Given the maturity stage of the Australian offshore oil and gas industry, it is foreseen that in the coming years many operators will approach the task of decommissioning offshore pipelines for the first time. In 2014 the Energy Pipelines Cooperative Research Centre (EPCRC) formed an offshore users group, comprising pipeline experts from several offshore oil and gas operators and engineering consultancies that are members of the Australian Pipelines and Gas Association’s Research and Standards Committee (APGA RSC). This group is developing an engineering guideline for the decommissioning of offshore pipelines. It is being developed in close communication with the Australian Petroleum Production and Exploration Association (APPEA), which has formed a decommissioning committee in relation to offshore facilities. This ensures the guideline is being developed by and with input from a broad spectrum of the Australian offshore oil and gas industry, with the aim of capturing best practice in the Australian context.
6
Najafzadeh, Mohammad, Giuseppe Oliveto e Farshad Saberi-Movahed. "Estimation of Scour Propagation Rates around Pipelines While Considering Simultaneous Effects of Waves and Currents Conditions". Water 14, n. 10 (16 maggio 2022): 1589. http://dx.doi.org/10.3390/w14101589.
Testo completoAbstract (sommario):
Seabed offshore pipelines are widely applied to carry fluid over long distances of the seafloor. The design of offshore pipelines is conducted to bear quite a few environmental loading circumstances in order to provide a well-guarded and reliable fluid transition. Fluid leakage and pipeline vibration due to a failure of the pipeline are the prime causes of accidental catastrophes. Scour phenomena occur around offshore pipelines due to currents and/or wave conditions, consequently causing the susceptibility to pipeline failure. Then, scouring propagation rates require to be studied in three dimensions, namely beneath and normal to the offshore pipeline and the longitudinal direction of itself. In this research, Artificial Intelligent (AI) models are used to derive new regression equations based on the laboratory data for the estimation of 3D scour propagation patterns while seafloor offshore pipelines are exposed to simultaneous impacts of currents and waves. In this way, chiefly based on the experimental investigations conducted by Cheng and colleagues, seven sets of dimensional parameters were given in terms of the Shields’ parameter due to currents and waves, the Keulegan–Carpenter number, the ratio of embedment depth to pipeline diameter, the ratio of orbital velocity to current velocity, and the wave/current angle of attack. Dimensionless parameters were used to provide regression-based equations to evaluate scour propagation rates in three dimensions. The performance of AI models was evaluated by various statistical measures. The model based on our proposed equations performed better than the reported models in the literature. Even more importantly, we indicated that our model inherently has a reliable physical consistency for variations of dimensionless parameters against the scour propagation patterns.
7
Xu, Pu, Zhixin Du e Shunfeng Gong. "Numerical Investigation into Freak Wave Effects on Deepwater Pipeline Installation". Journal of Marine Science and Engineering 8, n. 2 (14 febbraio 2020): 119. http://dx.doi.org/10.3390/jmse8020119.
Testo completoAbstract (sommario):
Freak waves are an extreme marine environment factor in offshore structure design and become a potential risk, particularly for laying oil-gas pipelines in deep waters. The objective of this study was to reveal the freak wave effects on dynamic behaviors of offshore pipelines for deepwater installation. Thus, a dedicated finite element model (FEM) for deepwater pipeline installation by the S-lay method was developed with special consideration of freak waves. The FEM also took pipelay vessel motions, pipe–stinger roller interactions, and the cyclic contacts between the pipeline and seabed soil into account. Real vessel and stinger data from an actual engineering project in the South China Sea were collected to obtain an accurate simulation. Moreover, an effective superposition approach of combined transient wave trains and random wave trains was introduced, and various types of freak wave trains were simulated. Extensive numerical analyses of a 12 inch gas pipeline being installed into a water depth of 1500 m were implemented under various freak wave conditions. The noticeable influences of freak waves on the pipeline and seabed responses were identified, which provides significant awareness of offshore pipelines for deepwater installation design and field operation monitoring.
8
Herbich, John B. "Hydromechanics of submarine pipelines: design problems". Canadian Journal of Civil Engineering 12, n. 4 (1 dicembre 1985): 863–74. http://dx.doi.org/10.1139/l85-099.
Testo completoAbstract (sommario):
In recent years, the size, number, and applications of offshore pipelines have been steadily increasing. The design and construction of pipelines in offshore cold regions calls for special measures (such as deep burial) because of seabed scouring caused by ice.Various societies and associations have pointed out the deficiencies in the state-of-the-art areas of environmental, design, and construction factors, particularly those dealing with structural, external pressure effects, and depth of burial. It has also been recommended that more data be obtained in order to fully evaluate pipeline–soil interaction. Also, field measurements of velocities, accelerations, and forces causing scour around pipelines would greatly enhance our understanding of offshore pipeline behavior.Offshore pipelines fail in many different ways, and each mode of failure should be examined individually. Because of the complexity of the ocean environment it is quite difficult to evaluate pipeline failures in detail.Environmental factors such as hydrodynamic wave forces and currents, buoyancy forces due to liquefaction of sediment, and scouring potential are presented. The dynamics of scour, incipient sediment motion, depth of scour, and scour patterns around pipelines are also reviewed as well as the maximum scour depths as a function of bottom current velocity.Methods for scour protection in shallow and deep water are described as well as the need for inspection and maintenance to prevent failures. Key words: pipelines, offshore, hydrodynamic forces, cover, scour.
9
Jujuly, M. M., Mohammad Azizur Rahman, Aaron Maynard e Matthew Adey. "Hydrate-Induced Vibration in an Offshore Pipeline". SPE Journal 25, n. 02 (31 dicembre 2019): 732–43. http://dx.doi.org/10.2118/187378-pa.
Testo completoAbstract (sommario):
Summary Gas-hydrate plugging poses an operational challenge to offshore petroleum production and transportation. In this study, a computational-fluid-dynamics (CFD) model that uses ANSYS Fluent (ANSYS 2019) multiphase-flow-modeling techniques to simulate and analyze the effect of gas-hydrate flow in pipelines is proposed. For this purpose, the study attempted to integrate the ANSYS Fluent model with an existing commercial subsea-pipeline-visualization tool. To validate the simulation results, two case studies were conducted. The first study was about a pipeline whose dimensions are based on the specifications in existing literature (Balakin et al. 2010a). The second study was about a pipeline with more-complex geometry (M-shaped jumper with six elbows). The Eulerian/Eulerian method was used to model the multiphase hydrate flow. The population-balance method (PBM) was then used to model hydrate agglomeration and its breakup mechanism in the flow. A parametric study of the stresses in the pipelines resulting from flow-induced vibration (FIV) was conducted to identify the regions that underwent the maximum stresses and deformations under various flow conditions. The tool can be used in the petroleum industry to identify the operational hazards in offshore structures and to take necessary safety measures to avoid any potential catastrophic events.
10
Song, Shangfei, Di Fan, Yijia Fan, Bing Yan, Bohui Shi, Shengnan Zhang, Xiaofang Lv, Haiyuan Yao, Qingping Li e Jing Gong. "Research on transient composition tracking in natural gas condensate pipeline networks". Physics of Fluids 35, n. 2 (febbraio 2023): 026102. http://dx.doi.org/10.1063/5.0138237.
Testo completoAbstract (sommario):
Offshore pipelines are hailed as the “lifeline” of an offshore oil and gas production system and are essential for offshore oil and gas development. Component tracing technologies for the oil and gas multiphase transmission pipeline networks need to be urgently developed to predict the fluid composition changes in pipeline networks. Instead of assuming the fluid components are constant, we consider they varied with flow. The component conservation equations and a phase change model are established. The equation of state of the fluid is adopted to determine the equilibrium state of each component in real time. Considering the macroscopic flow calculation, microscopic fluid components, and phase equilibrium, the component tracking algorithm is established for natural gas condensate pipeline networks, which can dynamically track the fluid composition in pipeline networks and calculate the phase exchange amount and related flow parameters in real time. Three case studies are performed to verify the effectiveness of the algorithm. These findings are of great practical significance for understanding the gas–liquid two-phase flow in pipeline networks, promoting further engineering applications of component tracking on pipeline networks.
11
Gulare Imanova, Gulare Imanova, e Elshan Mammadli Elshan Mammadli. "LAYING OF PIPELINES IN SUBSEA TAKING INTO ACCOUNT THE PROTECTION OF THE ENVIRONMENT". PAHTEI-Procedings of Azerbaijan High Technical Educational Institutions 15, n. 04 (15 aprile 2022): 23–27. http://dx.doi.org/10.36962/pahtei15042022-23.
Testo completoAbstract (sommario):
This article is devoted to the construction of offshore pipelines, taking into account the protection of the environment. Initially, information was provided on the conditions of the pipelines. Then there was a discussion about the methods of laying pipelines, their pros and cons, and therefore the choice of method, which is economically viable and takes into account the environment. We know that the main factor in choosing any method of laying a submarine pipeline is economic and environmental factors. Underwater pipelines are invaluable for offshore oil and gas transportation and water supply to the islands. The construction method is very important for the installation of an expensive and time-consuming offshore pipeline and should be selected after a general consideration of equipment, capital and time. In addition, the environmental impact and safety of construction and its impact on surrounding marine operations are also determining factors. Decks, pipelines and cables, valves and switches, pumps, cleaning and all equipment must work without hindrance and must be tested repeatedly to avoid endangering people and the environment. At present, submarine gas pipelines continue to develop, accounting for 45% of natural gas exports to the west. Therefore, before the submarine is laid, the entire route along the seabed must be carefully studied, and all potential obstacles, including the sunken ship, large rocks must be identified, eliminated or bypassed. Subsea pipelines are the safest, most cost-effective, and most environmentally friendly route. Keywords: subsea pipelines, construction technologies, submarine pipeline installation, environment supervision, management and control of industrial waste, prevention of pollution, pipeline laying.
12
Humphreys, Brian, e Wacek Lipski. "Late life management of onshore and offshore pipelines". APPEA Journal 55, n. 2 (2015): 414. http://dx.doi.org/10.1071/aj14049.
Testo completoAbstract (sommario):
The Australian oil and gas boom of the 1960s and 1970s lead to production commencing in the Gippsland, Surat, Cooper and Carnarvon basins and so many pipeline assets around Australia are approaching operating lives of 40-50 years and the end of their design lives. With unconventional field development and the Australian gas markets opening up to international customers through LNG, there will be an increasing requirement to extend the life of pipelines while maintaining safety and integrity. The management of pipeline assets late in their design life is a challenge for operators both onshore and offshore, with pipelines requiring higher levels of inspection and maintenance, while revenues can be fixed or regulated for downstream assets or potentially declining for upstream assets. To operate pipelines beyond their specified design life, there are requirements that must be fulfilled—for offshore, a design re-qualification in accordance with DNV-OS-F101 and for onshore, a remaining life review in accordance with AS2885.3. In addition, for onshore pipelines, AS2885.3 requires the remaining life review process to be undertaken every 10 years, rather than just at the end of the design life. This extended abstract discusses the requirements of the DNV-OS-F101 and AS2885.3 and the approaches required to meet these requirements. It also discusses key lessons that have been learned and makes recommendations to pipeline operators preparing for end-of-design-life reviews and executing them as cost effectively as possible.
13
Namazi-Saleh, Fatemeh, V. John Kurian e Mustaffa Bt Zahiraniza. "Investigation of Vortex Induced Vibration of Offshore Pipelines near Seabed". Applied Mechanics and Materials 567 (giugno 2014): 265–70. http://dx.doi.org/10.4028/www.scientific.net/amm.567.265.
Testo completoAbstract (sommario):
Recently, dynamic interaction between pipelines, seabed and the ocean currents has received wide concern from marine pipeline designers and researchers. The analysis of dynamic responses of subsea pipeline, in vicinity of the seabed in severe ocean environments, is very important. In this regard, this study reviews and sums up recent researches and investigations performed on vortex induced vibration of pipelines near seabed for analysis and design. In addition, the preliminary results of a developed model around a pipe subjected to steady current have been presented. Future trends and challenges in this research are also identified.
14
Henzell, Steve, e Fiona Read. "Casino pipeline: novel pipeline integrity inspection". APPEA Journal 57, n. 2 (2017): 603. http://dx.doi.org/10.1071/aj16049.
Testo completoAbstract (sommario):
The Casino offshore pipeline required inspection to demonstrate the integrity of the pipeline and allow the operating life of the pipeline to be extended. There were numerous challenges in performing a conventional internal pipeline inspection which would have required diver operations to install and operate subsea pig launchers. Two alternative inspection methods were used to inspect the high priority sections of the pipeline, at the pipeline tees and in the horizontal directionally drilled (HDD) section of pipeline at the coastline crossing.The pipeline tees and well flowlines were inspected using an external magnetic flux inspection tool deployed by remotely operated vehicle (ROV), to test for top-of-line corrosion. Bi-directional pigging from the onshore valve station, offshore for 30 km using gas from the host gas plant and then return to the shore using gas from the offshore wells allowed for inspection of the HDD pipeline with a total of 10 bi-direction pig runs completed. The pig position was accurately predicted by monitoring the operating conditions of the pipeline and confirmed by displacement past the subsea well closest to shore (Casino 5). The novel pigging methods brought significant benefits for cost, schedule and reduced EHS exposure by avoiding diver operations. The cost of the overall inspection program was less than 25% of the conventional inspection methods and was achieved a year earlier than if a dive support vessel (DSV) had been mobilised. The bi-directional pigging campaign proved to be highly successful.
15
Wang, Xiao, Dong-Sheng Jeng e Chia-Cheng Tsai. "Meshfree Model for Wave-Seabed Interactions Around Offshore Pipelines". Journal of Marine Science and Engineering 7, n. 4 (28 marzo 2019): 87. http://dx.doi.org/10.3390/jmse7040087.
Testo completoAbstract (sommario):
The evaluation of the wave-induced seabed instability around a submarine pipeline is particularly important for coastal engineers involved in the design of pipelines protection. Unlike previous studies, a meshfree model is developed to investigate the wave-induced soil response in the vicinity of a submarine pipeline. In the present model, Reynolds-Averaged Navier-Stokes (RANS) equations are employed to simulate the wave loading, while Biot’s consolidation equations are adopted to investigate the wave-induced soil response. Momentary liquefaction around an offshore pipeline in a trench is examined. Validation of the present seabed model was conducted by comparing with the analytical solution, experimental data, and numerical models available in the literature, which demonstrates the capacity of the present model. Based on the newly proposed model, a parametric study is carried out to investigate the influence of soil properties and wave characteristics for the soil response around the pipeline. The numerical results conclude that the liquefaction depth at the bottom of the pipeline increases with increasing water period (T) and wave height (H), but decreases as backfilled depth ( H b ), degree of saturation ( S r ) and soil permeability (K) increase.
16
Muraveva, L. V., e I. G. Ovchinnikov. "AN ENGINEERING APPROACH TO ASSESSING THE CONSEQUENCES OF AN UNDERWATER EXPLOSION AND EVALUATING THE STRUCTURAL INTEGRITY OF AN UNDERWATER BURIED PIPELINE IS PRESENTED". EurasianUnionScientists 1, n. 3(72) (15 aprile 2020): 53–67. http://dx.doi.org/10.31618/esu.2413-9335.2020.1.72.617.
Testo completoAbstract (sommario):
Introduction: The performance of oil and gas pipeline systems under operational and natural loads is an important engineering indicator. In the new century, energy resources and methods of transportation have improved. We have abundant supplies of natural gas and oil; nuclear power plants. Renewable energy sources are being introduced, which increase production efficiency and improve the country's energy portfolio. Achievements in the field of energy efficiency allow to reduce energy costs of producers. Our energy infrastructure needs largescale investments, construction, but developers face new challenges. The structural integrity of an underwater pipeline exposed to an underwater explosion is an important task. The simulation of a submerged underwater pipeline as a pipeline-water-ground system is considered, taking into account the influence of the water environment, the soil base and the explosion of the transported medium. The work was carried out to ensure and develop security requirements for existing and future offshore projects. The purpose of this work is to present an engineering approach to the assessment of the consequences of an underwater explosion and to assess the structural integrity of an offshore buried pipeline. Materials and methods: The existing approaches are based on the applied mathematical models for assessing the integrity of the structure under explosive influences, taking into account the internal energy of the structure. Results: Proposals to the requirements for ensuring the safety of buried subsea pipelines with the water medium under the influence of the explosion of the transported medium and the elastic energy of the pipeline. The proposals are submitted for consideration to the Russian Maritime Register of Shipping. Studies have been carried out to determine the safe distance between two underwater pipelines. Conclusions: The results were obtained empirically using finite element models of the pipeline-water-soil system to assess the safety of the offshore buried pipeline taking into account the elastic energy of the structure.
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Zhang, Shi-fu, Chang Chen, Qi-xin Zhang, Dong-mei Zhang e Fan Zhang. "Wave Loads Computation for Offshore Floating Hose Based on Partially Immersed Cylinder Model of Improved Morison Formula". Open Petroleum Engineering Journal 8, n. 1 (26 marzo 2015): 130–37. http://dx.doi.org/10.2174/1874834101508010130.
Testo completoAbstract (sommario):
Aimed at wave load computation of floating hose, the paper analyzes the morphologic and mechanical characteristics of offshore hose by establishing the partially immersed cylender model, and points out that the results of existing Morison equation to calculate the wave loads of floating hose is not precise enough. Consequently, the improved Morison equation has been put forward based on its principle. Classical series offshore pipeline has been taken as example which applied in the water area of different depth. The wave loads of pipeline by using the improved Morison equation and compared the calculation results with the existing Morison equation. Calculations for wave loads on pipelines in different depth were accomplished and compared by the improved Morison equation and the existing Morison equation. Results show that the improved Morison equation optimizes the accuracy of the computation of wave load on floating hose. Thus it is more suitable for analyzing the effects of wave loads on floating hose and useful for mechanic analysis of offshore pipeline.
18
Ansari, Yousef, George P. Kouretzis e Dai Chao Sheng. "Coupled Finite Element Analysis of Partially Embedded Offshore Pipelines during Vertical Penetration". Applied Mechanics and Materials 553 (maggio 2014): 428–33. http://dx.doi.org/10.4028/www.scientific.net/amm.553.428.
Testo completoAbstract (sommario):
Diverse vertical embedment response is observed for partially embedded pipelines when experimentally tested under similar initial and boundary conditions. Although vertical resistance of pipelines is presented through simple analytical solutions, a number of factors contribute to complications in implementing these theories into practice. The objectives of this research is to provide a more detailed investigation on the vertical embedment for the partially-embedded pipelines (PEPs) using a coupled large deformation finite element (CLDFE) analysis with contact. A modified Cam Clay (MCC) model represents the elastoplastic response of the soil. The model of pipeline embedment investigates the effect of drainage condition on heave forming with respect to rate of penetration. Besides, effect of frictional contact on the heave development and wedging effect is investigated and design-related considerations are proposed. It is shown that depending on the rate of pipeline penetration and soil consolidation rate, the pipeline penetration response can be categorised as undrained, partially drained or fully drained.
19
Zhang, Bo, Rui Gong, Tao Wang e Zhuo Wang. "Causes and Treatment Measures of Submarine Pipeline Free-Spanning". Journal of Marine Science and Engineering 8, n. 5 (8 maggio 2020): 329. http://dx.doi.org/10.3390/jmse8050329.
Testo completoAbstract (sommario):
Submarine pipelines, as arteries for offshore oil and gas transportation, play a particularly important role in the exploitation of offshore oil and gas resources. Since the world’s first submarine pipelines were laid in the Gulf of Mexico, numerous failures have been caused by pipeline free-spanning. This paper provides a review of the causes and treatment measures for the free span of submarine pipeline. Various factors cause the free span of submarine pipelines, including wave flow scouring, fluctuations in seabed topography, residual stress or thermal stress of pipelines, and human activities. The scour of the wave current is the main factor affecting free span; the research on sediment starting and equilibrium depth during scour is reviewed in-depth. For the span treatment of submarine pipelines, the main measures available at present include the re-digging trench burying, structural support, covering bionic water plants, and choke plate self-burying. For each, the principle, advantages, disadvantages, and research are discussed. This review provides a convenient resource for understanding the causes of submarine free-spanning pipelines and choosing suitable treatment measures.
20
Veselov, Vitaly A., Vladimir V. Probotyuk, Maksim V. Kitaev e Oleg E. Surov. "METHOD FOR DETECTING DEFECTS IN MARINE PIPELINES BY WAVELET ANALYSIS OF REMOTE MAGNETOMETRY SIGNAL". Russian Journal of Water Transport, n. 65 (23 novembre 2020): 133–42. http://dx.doi.org/10.37890/jwt.vi65.135.
Testo completoAbstract (sommario):
The paper considers a method for detecting offshore pipelines defects using a wavelet transform of a remote magnetometry signal. This method makes it easier and faster to process large amounts of information obtained as the measuremens result. According to statistics, 40% to 50% of accidents with offshore pipelines occur due to the pipe walls corrosion. Thus, the research aimed to development the methods for offshore pipelines inspection and diagnostics is very important. For the testing of the suggested method for detecting pipeline defects, on the engineering analysis software ELCUT base a numerical model describing the magnetic field distribution in the area of corrosion spot located on the pipe wall was developed. It is shown that the suggested method can be used for detecting the defects and evaluating the offshore pipelines technical condition.
21
Gulin, D. A., E. D. Kvitsinskaya e A. S. Glazkov. "DEFECTS OF OFFSHORE PIPELINE SYSTEMS". Petroleum Engineering 18, n. 5 (novembre 2020): 95. http://dx.doi.org/10.17122/ngdelo-2020-5-95-103.
Testo completo
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Shikhiyeva, L. M. "The analysis of pipeline damages and diagnostics of oil spills in environment". Azerbaijan Oil Industry, n. 12 (15 dicembre 2021): 54–59. http://dx.doi.org/10.37474/0365-8554/2021-12-54-59.
Testo completoAbstract (sommario):
The paper deals with the study and diagnostics of negative effect of complications in the operation of oil pipelines, as well as the impact of oil spills on environment. The main purpose of the study is the development of the methods for the specification of damage and spill sites due to the failures in main pipelines and the amount of spill in environment. The complications in the pipeline operation have been analyzed, the major reasons for pipeline damages and oil spills presented as well. The oil spills during the failures in the offshore pipelines in the Caspian Sea, and their reasons have been studied, a method for the diagnostics to specify the site and amount of the spill developed as well. The reports on the various operation regimes in the offshore pipelines in the Caspian Sea for transportation systems have been made. The developed method is recommended for the implementation.
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Najafzadeh, Mohammad, e Giuseppe Oliveto. "Scour Propagation Rates around Offshore Pipelines Exposed to Currents by Applying Data-Driven Models". Water 14, n. 3 (7 febbraio 2022): 493. http://dx.doi.org/10.3390/w14030493.
Testo completoAbstract (sommario):
Offshore pipelines are occasionally exposed to scouring processes; detrimental impacts on their safety are inevitable. The process of scouring propagation around offshore pipelines is naturally complex and is mainly due to currents and/or waves. There is a considerable demand for the safe design of offshore pipelines exposed to scouring phenomena. Therefore, scouring propagation patterns must be focused on. In the present research, machine learning (ML) models are applied to achieve equations for the prediction of the scouring propagation rate around pipelines due to currents. The approaching flow Froude number, the ratio of embedment depth to pipeline diameter, the Shields parameter, and the current angle of attack to the pipeline were considered the main dimensionless factors from the reliable literature. ML models were developed based on various setting parameters and optimization strategies coming from evolutionary and classification contents. Moreover, the explicit equations yielded from ML models were used to demonstrate how the proposed approaches are in harmony with experimental observations. The performance of ML models was assessed utilizing statistical benchmarks. The results revealed that the equations given by ML models provided reliable and physically consistent predictions of scouring propagation rates regarding their comparison with scouring tests.
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Sulaima, Mohamad Fani, F. Abdullah, Wan Mohd Bukhari, Fara Ashikin Ali, M. N. M. Nasir e Abu Bakar Yahya. "Oil and Gas Offshore Pipeline Leak Detection System: A Feasibility Study". Applied Mechanics and Materials 699 (novembre 2014): 891–96. http://dx.doi.org/10.4028/www.scientific.net/amm.699.891.
Testo completoAbstract (sommario):
Pipelines leaks normally begin at poor joints, corrosions and cracks, and slowly progress to a major leakage. Accidents, terror, sabotage, or theft are some of human factor of pipeline leak. The primary purpose of Pipeline leak detection systems (PLDS) is to assist pipeline operators in detecting and locating leaks earlier. PLDS systems provide an alarm and display other related data to the pipeline operators for their decision-making. It is also beneficial because PLDS can enhance their productivity by reduced downtime and inspection time. PLDS can be divided into internally based or computational modeling PLDS Systems and external hardware based PLDS. The purpose of this paper is to study the various types of leak detection systems based on internally systemtodefine a set of key criteria for evaluating the characteristics of this system and provide an evaluation method of leak detection technology as a guideline of choosing the appropriate system.
25
Zhang, Yu, Zhongtao Wang e Huafu Pei. "Development of a novel lateral resistance measurement penetrometer for pipe–soil interaction centrifuge model test". International Journal of Distributed Sensor Networks 14, n. 11 (novembre 2018): 155014771881564. http://dx.doi.org/10.1177/1550147718815647.
Testo completoAbstract (sommario):
Offshore pipelines are exposed to potential submarine landslides. It is difficult to measure the impact forces exerted on a pipeline induced by submarine landslides because the upper seabed is very soft and an impact angle exists in practice. Current laboratory experiments are limited on measuring the normal force exerted on pipeline by the slides. This article describes the feasibility and performance of a novel penetrometer, which is designed to measure impact forces of submarine landslides on offshore pipeline including both the normal and frictional forces from variable impact angle in centrifuge test, termed as the lateral resistance measurement penetrometer. The calibration procedure for this particular version is illustrated in detail and the reliability and feasibility of the lateral resistance measurement penetrometer are preliminarily confirmed by an experimental study. Pipe–soil interaction centrifuge tests were subsequently performed on a normally consolidated kaolin sample with 40 g level conducted in Dalian University of Technology drum centrifuge to investigate the effect of incident angles on the impact forces exerted by submarine landslides on a pipeline. The impact forces deduced from the lateral resistance measurement penetrometer are analysed in comparison with published results. The lateral resistance measurement penetrometer is a potentially valuable device to measure the interaction force between submarine landslides and offshore pipeline, cables and other subsea facilities in small-scale centrifuge models.
26
Zhai, Hualing, Dong-Sheng Jeng e Zhen Guo. "The Role of 2D Seepage on Sediment Incipient Motion around a Pipeline". Journal of Marine Science and Engineering 9, n. 6 (27 maggio 2021): 580. http://dx.doi.org/10.3390/jmse9060580.
Testo completoAbstract (sommario):
Pipelines have been used as one of the main transportation methods for the offshore industry, with increasing activities in marine resources recently. Prediction of seabed instability is one of key factors that must be taken into consideration for an offshore pipeline project. As the first step of the scour process, sediment incipient motion has been intensively studied in the past. Most previous investigations didn’t consider the wave-induced seepage in the elevation of sediment motion. In this paper, two-dimensional seepage was considered to modify the conventional Shields number and its associated impact on sediment incipient motion around the trenched pipeline was investigated. Both flat and sloping seabeds are considered. The numerical results indicated that a peak or valley of the modified Shields number was formed below the pipeline and horizontal seepage flow tremendously impact the sediment motion in the vicinity of the pipeline. Parametric analysis concludes: the influence of the seepage around the pipeline becomes more significant in a large wave, shallow water in a seabed with large shear modulus and permeability, and larger pipeline diameter and smaller flow gap ratio. This will make soil particles be more easily dragged away from the seabed.
27
Hong, Zhaohui, Dengfeng Fu, Wenbin Liu, Zefeng Zhou, Yue Yan e Shuwang Yan. "Effect of Gain in Soil Friction on the Walking Rate of Subsea Pipelines". Journal of Marine Science and Engineering 7, n. 11 (8 novembre 2019): 401. http://dx.doi.org/10.3390/jmse7110401.
Testo completoAbstract (sommario):
Subsea pipelines are commonly employed in the offshore oil and gas industry to transport high-pressure and high-temperature (HPHT) hydrocarbons. The phenomenon of pipeline walking is a topic that has drawn a great deal of attention, and is related to the on-bottom stability of the pipeline, such as directional accumulation with respect to axial movement, which can threaten the security of the entire pipeline system. An accurate assessment of pipeline walking is therefore necessary for offshore pipeline design. This paper reports a comprehensive suite of numerical analyses investigating the performance of pipeline walking, with a focus on the effect of increasing axial soil resistance on walking rates. Three walking-driven modes (steel catenary riser (SCR) tension, downslope, and thermal transient) are considered, covering a wide range of influential parameters. The variation in walking rate with respect to the effect of increased soil friction is well reflected in the development of the effective axial force (EAF) profile. A method based on the previous analytical solution is proposed for predicting the accumulated walking rates throughout the entire service life, where the concept of equivalent soil friction is adopted.
28
Do, Hoa Xuan, e Lan Cao Mai. "Numerical modeling of Slug flows in multiphase pipeline system of lion offshore oil fields". Science and Technology Development Journal 19, n. 1 (31 marzo 2016): 16–26. http://dx.doi.org/10.32508/stdj.v19i1.501.
Testo completoAbstract (sommario):
Oil and gas transportation by the pipelines among different production wells from one or more reservoirs is one primary part of an oil field development plan. When multiple pipelines transporting oil and gas from different fields are collected on the same Central Processing Platform (CPP) or Floating Production Storage Offloading (FPSO), however, the fluid behavior in multiphase flow pipelines become more complicated and often cause slugging problems that badly impact on downstream facility performance. It is, therefore, necessary to investigate the slug flow to control and/or improve flow stability in the pipeline systems. In this paper, the workflow for building and calibrating a multiphase flow model are described. The numerical model is then applied for the pipeline system of Lion oilfields in Cuu Long Basin, Southern Vietnam. Sensitivity analysis have been performed to investigate the influences of various factors on the slug flow in the pipeline system. The results from this work would be useful for tracking and controlling the slugging effect on the separator performance.
29
Summers, P. B., e D. J. Nyman. "An Approximate Procedure for Assessing the Effects of Mudslides on Offshore Pipelines". Journal of Energy Resources Technology 107, n. 4 (1 dicembre 1985): 426–32. http://dx.doi.org/10.1115/1.3231214.
Testo completoAbstract (sommario):
The theoretical basis of an approximate procedure for assessing the effects of mudslides on buried marine pipelines is presented. The procedure has the capability to account for geometric nonlinearities (i.e., large-displacement “cablelike” behavior of the pipeline), nonlinear longitudinal soil restraint against pipeline pull-out, and a limited degree of nonlinear pipe material behavior. The analytical approach is based upon a variational work method known as the Theorem of Stationary Total Potential and is simpler and easier to employ than a nonlinear finite element code, while generally yielding good approximations to pipeline stresses and strains. The validity of the procedure is demonstrated for a typical mudslide situation through comparison with results of nonlinear finite element analyses.
30
Iskenderov, E. Kh, e S. A. Baghirov. "The analytical method for the specification of the beginning of hydrating in the offshore gas main pipelines". Azerbaijan Oil Industry, n. 05 (15 maggio 2022): 31–36. http://dx.doi.org/10.37474/0365-8554/2022-05-31-36.
Testo completoAbstract (sommario):
The paper is dedicated to the analysis of hydrating conditions in the process of the transportation of the natural gas by subsea pipeline, to the mechanism of formation of hydrate plugs, to the localization and elimination by means of an immediate definition of hydrates as well. As a result of the analysis, it was marked that one of the complicated issues in the transportation of the natural gas, particularly via the sea, is the hydrating. Gas hydrates are crystal compounds formed from the water and gas in the specific temperature and pressure parameters. The necessity of the implementation of such a complicated and labor-intensive process as the weighting and separation of hydrates from the subsea gas pipelines as a result of hydrating is noted. According to the results of the observation of subsea gas pipelines, it was specified that the hydrates and partial or full choking of gas pipeline occur due to two various scenarios. The first case arises from the deposition of the hydrate in the inner surface of gas pipeline, and the second one – from the accumulation of a great deal of water and condensate within the pipeline, as well as from the decrease of pipeline flow in the section of fluid collection, from the increase of gas charge and its temperature. Unlike the onshore gas pipelines, the number of technological parameters for an accurate estimation of the moment of hydrating in the offshore gas pipelines is quite limited. The paper presents an analytical method for the specification of the hydrating moment within a subsea gas main in the limited parameters. The reports on an actual gas pipeline justified the efficiency and information value of the method. Suggested method is characterized with the simplicity, perspective of an immediate employment and comfort of usage by the staff.
31
Dzikowski, Remigiusz, e Krzysztof Marcjan. "Analysis of Ship Traffic Over Subsea Pipeline in the Gdańsk Bay Area". Annual of Navigation 24, n. 1 (1 dicembre 2017): 207–20. http://dx.doi.org/10.1515/aon-2017-0015.
Testo completoAbstract (sommario):
Abstract The paper discusses issues of the impact of traffic density of the vessels on the sea surface to offshore underwater pipelines. The risk includes vessel foundering, sinking, grounding, dropping and dragging anchors, trawling fishing gear. The density of merchant, offshore field support vessels and fishing vessels presented by this paper is base for build risk model for underwater infrastructures. As an example it has been analyzed ships traffic over underwater gas pipeline between platform Baltic Beta and Wladyslawowo power plant.
32
Lin, Yi Zhou, Jiang Hong Xue e Ming Qiao Tang. "Finite-Element Analysis of Buckle Propagation in Offshore Pipelines". Applied Mechanics and Materials 488-489 (gennaio 2014): 1039–42. http://dx.doi.org/10.4028/www.scientific.net/amm.488-489.1039.
Testo completoAbstract (sommario):
The buckle propagation phenomenon in offshore pipelines is an important subject of ocean engineering. The local buckling will easily propagate along the pipeline if the external hydrostatic pressure is high enough. The buckle propagation will seriously hinder the transmission of the oil. This paper focuses on the numerical calculation of buckle propagation pressure using ABAQUS software.
33
Kurbatova, G. I., V. A. Klemeshev e V. B. Filippov. "Calculation of depressurization coordinate in underground and offshore gas pipelines". Journal of Physics: Conference Series 2162, n. 1 (1 gennaio 2022): 012023. http://dx.doi.org/10.1088/1742-6596/2162/1/012023.
Testo completoAbstract (sommario):
Abstract The paper introduces a method for calculating the depressurization coordinate of an extended ultra-high pressure gas pipeline from the data measurements of pressure and flow rate at the outlet. The method is based on a mathematical model of a non-isothermal steady single-phase gas mixture flow through a pipeline of constant section on the quasi-linearization method. It allows to calculate the depressurization coordinate for extended underground and offshore ultra-high pressure gas pipelines with high accuracy, while considering varying leakage size and location. Examples of solving problems of practical interest are given. The influence of the flow rate and pressure settings error on the coordinate of depressurization calculating error has been demonstrated.
34
Marshall, G. Robert. "Cleaning the Valhall Offshore Oil Pipeline". SPE Production Engineering 5, n. 03 (1 agosto 1990): 275–78. http://dx.doi.org/10.2118/17880-pa.
Testo completo
35
Rouse, Sally, Peter Hayes, Ian M. Davies e Thomas A. Wilding. "Offshore pipeline decommissioning: Scale and context". Marine Pollution Bulletin 129, n. 1 (aprile 2018): 241–44. http://dx.doi.org/10.1016/j.marpolbul.2018.02.041.
Testo completo
36
Westgate, Z. J., D. J. White e M. F. Randolph. "Modelling the embedment process during offshore pipe-laying on fine-grained soils". Canadian Geotechnical Journal 50, n. 1 (gennaio 2013): 15–27. http://dx.doi.org/10.1139/cgj-2012-0185.
Testo completoAbstract (sommario):
Subsea pipelines are becoming an increasingly significant element of offshore hydrocarbon developments as exploration moves into deep-water environments further from shore. During the lay process, pipelines are subject to small amplitude vertical and horizontal oscillations, driven by the sea state and lay vessel motions. Centrifuge model tests have been used to simulate these small-amplitude lay effects, with varying degrees of idealization relative to the real lay process. In the soft soils found in deep water, pipe embedment can exceed a diameter or more, thus significantly affecting the lateral pipe–soil interaction, axial resistance, and thermal insulation. In this paper, results from centrifuge model tests are used to calibrate a model for calculating the dynamic embedment of a subsea pipeline. The model uses elements of plasticity theory to capture the effects of combined vertical and horizontal loading, and incorporates the softening of the surrounding soil as it is remoulded due to the pipeline motions. Influences from the lay rate, lay geometry, and sea state are included in the calculation process. The model is compared with observed as-laid pipeline embedment data from field surveys at three different offshore sites. Using site-specific soil parameters obtained from in situ testing and idealized pipe loads and motions to represent the load and displacement patterns during offshore pipe-laying, respectively, the model is shown to capture well the final as-laid embedment measured in the field surveys.
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Pavlou, Dimitrios. "FRP pipeline performance in tensional and torsional S-lay installation loads". IOP Conference Series: Materials Science and Engineering 1201, n. 1 (1 novembre 2021): 012044. http://dx.doi.org/10.1088/1757-899x/1201/1/012044.
Testo completoAbstract (sommario):
Abstract The loading conditions of a composite pipeline is the main factor for its dimensioning. During S-lay offshore installation of multilayered FRP pipelines, severe tensional and torsional loads take place in the above sea part of the pipeline. Since the wall pipe is multilayered and the material properties of the laminae and the laminate is anisotropic, the maximum stresses depend on the stacking sequence. In the present work, an analytical model is proposed for calculating the capacity of multilayered FRP pipelines to carry axial and torsional loads. Numerical results for typical multilayered filament wound E-Glass/Epoxy pipelines under axial tension and torsion are provided and discussed.
38
Xu, Pu, Shun Feng Gong, Ting Zhang e Cheng Chen. "Parametric Study on Dynamic Tension Behaviour of Offshore Pipeline for Deepwater S-lay Operation". E3S Web of Conferences 38 (2018): 03014. http://dx.doi.org/10.1051/e3sconf/20183803014.
Testo completoAbstract (sommario):
In recent years, higher demands for offshore pipeline design of deepwater installation are put forward. This paper mainly aims to investigate the influence of pipelay parameters on dynamic tension behaviour of deepwater S-lay pipeline to optimize the design of pipe structure and tensioner. A full finite element model for deepwater S-lay systems is developed to simulate the dynamic response of offshore pipeline from the pipelay vessel via stinger to the seabed. The influences of water depth, outer diameter and submerged self-weight of the pipe, and stinger length on the dynamic tension behaviour of the pipeline have been quantitatively studied. A strong relevance between the axial tension of offshore pipeline and pipelay parameters is observed, which offers very intuitive evidences for the design of pipe structure and tensioners.
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Liang, Dongfang, Jie Huang, Jingxin Zhang, Shujing Shi, Nichenggong Zhu e Jun Chen. "Three-Dimensional Simulations of Scour around Pipelines of Finite Lengths". Journal of Marine Science and Engineering 10, n. 1 (14 gennaio 2022): 106. http://dx.doi.org/10.3390/jmse10010106.
Testo completoAbstract (sommario):
In the past few decades, there have been many numerical studies on the scour around offshore pipelines, most of which concern two-dimensional setups, with the pipeline infinitely long and the flow perpendicular to the pipeline. Based on the Ansys FLUENT flow solver, this study establishes a numerical tool to study the three-dimensional scour around pipelines of finite lengths. The user-defined functions are written to calculate the sediment transport rate, update the bed elevation, and adapt the computational mesh to the new boundary. The correctness of the model has been verified against the measurements of the conventional two-dimensional scour around a long pipe and the three-dimensional scour around a sphere. A series of computations are subsequently carried out to discover how the scour hole is dependent on the pipeline length. It is found that the equilibrium scour depth increases with the pipeline length until the pipeline length exceeds four times the pipe diameter.
40
Ju, G. T., e S. Kyriakides. "Thermal Buckling of Offshore Pipelines". Journal of Offshore Mechanics and Arctic Engineering 110, n. 4 (1 novembre 1988): 355–64. http://dx.doi.org/10.1115/1.3257073.
Testo completoAbstract (sommario):
The vertical buckling of offshore pipelines caused by thermal loads is analyzed by modeling the pipeline as a long heavy beam resting on a rigid foundation. The axial restraint provided to the line by the surrounding soil is modeled as Coulomb friction. The study is concerned with the effect of localized, small initial geometric imperfections on the response and stability of the structure. In the presence of initial imperfections, the response is characterized by the temperature rise required to cause initial uplift and by a limit temperature rise beyond which the structure becomes unstable. Both of these critical values are shown to be sensitive to the form and magnitude of the imperfections as well as by the pipe material inelastic characteristics.
41
Schmidt, Zelimir, Dale R. Doty e Kunal Dutta-Roy. "Severe Slugging in Offshore Pipeline Riser-Pipe Systems". Society of Petroleum Engineers Journal 25, n. 01 (1 febbraio 1985): 27–38. http://dx.doi.org/10.2118/12334-pa.
Testo completoAbstract (sommario):
Abstract Severe slug flow (i.e., terrain-dominated slug flow) was studied in a simulated offshore pipeline riser-pipe system. Severe slug flow is characterized by extremely long liquid slugs generated at the base of the vertical riser. This phenomenon occurs at low gas and liquid flow rates and for negative pipeline inclinations. Slugging in some offshore platforms has required the use of operating procedures that drastically curtail production. Losses in flow capacity up to 50% have been reported. production. Losses in flow capacity up to 50% have been reported. A hydrodynamic model has been developed for severe slug flow. The model's predictions agree with experimental data. The model can be used to design predictions agree with experimental data. The model can be used to design new pipeline riser-pipe systems or to adjust the operation of existing systems to prevent the occurrence of severe slug flow. Also, a flow-regime map is presented for predicting the severe slug flow regime, where the boundaries are determined analytically. Finally, additional methods are proposed to prevent the flooding of separation facilities by riser-pipe proposed to prevent the flooding of separation facilities by riser-pipe generated slugs. This study is an extension of Ref. 1, in which severe slug flow was introduced and was only partially modeled. Introduction Two-phase flow in pipelines frequently involves the formation of liquid slugs. Processing of these slugs with separators can be extremely difficult if the size of the slugs becomes abnormally long. When a long liquid slug reaches a separator, it is possible for the liquid level in the separator to rise faster than the separator can purge the liquid, resulting in possible liquid carry-over into the gas stream. A technique often used for possible liquid carry-over into the gas stream. A technique often used for protecting separators from liquid slugs is to install an additional vessel protecting separators from liquid slugs is to install an additional vessel ahead of the separator, which usually is called a "slug catcher." The combined cost of the two smaller vessels is usually lower than the cost of a single large separator, which must be designed to process liquid slugs. However, the size of the slug catcher and/or separator must increase with increasing expected liquid slug sizes. The cost of installation of large separators and slug catchers, especially in the hostile environments found in Alaska, in swamps, or on offshore platforms, may be prohibitive. Therefore, it is desirable to have a technique that can predict and control both the occurrence and magnitude of liquid slugs so that separation facilities can be designed properly and their size decreased. Recently, studies have been performed that have increased dramatically the accuracy of both slug size and frequency predictions. Earlier studies, performed under laboratory conditions, indicated that slug lengths would performed under laboratory conditions, indicated that slug lengths would be no more than 100 ft [30.48 m]. However, recent studies performed on full-scale pipelines have indicated that slug lengths of more than 2,000 ft [609.6 m] are possible. In addition, it has been discovered that slug flow can be generated by several different mechanisms, each producing liquid slugs with different physical properties. Schmidt et al., in studying slug flow in a simulated offshore pipeline riser-pipe system, found two distinct slug flow patterns: normal (e.g., hydrodynamic) and severe (e.g., terrain-dominated) slug flow. Severe slug flow is characterized by the generation of liquid slugs at the base of the riser pipe, with the remainder of the pipeline in stratified flow. Normal slug flow is characterized by many liquid slugs being generated along the length of the pipeline and occurs at higher gas and liquid flow rates. The liquid slugs generated during severe slug flow were found to range in length from one to several riser-pipe heights, which, at the time this study was performed, generally exceeded the slug lengths associated with normal slug flow. Therefore, riser-pipe-generated slug flow was designated "severe" slug flow, in comparison to "normal" pipeline-generated slug flow. Severe slug flow was found to depend on the geometry of the pipeline riser-pipe system. The pipeline must be in stratified flow, as well as inclined negatively for the liquid slug to be generated at the base of the riser. Also, because of the mechanism by which severe slugs are generated, it was found that the degree of slug aeration for severe slugs was much lower than that associated with normal slug flow. Also, the study showed that the phenomena of severe and normal slug flow are mutually exclusive because normal pipeline slugs and bubbles will flow through the riser pipe nearly unchanged, excluding the possibility of a riser-generated slug. Finally, a hydrodynamic model was developed for severe slug flow. The model was formulated on basic physical principles and was limited to a description of how the liquid slug is generated at the base of the riser pipe. No attempt was made to model the full behavior of the severe slug pipe. No attempt was made to model the full behavior of the severe slug flow cycle. Bendiksen et al. developed a dynamic one-dimensional two-phase flow model for the Norwegian state oil company, Statoil. They gave the mass and momentum conservation equations for each phase, and solved them numerically by using finite difference techniques. SPEJ P. 27
42
Asfar, Mhd Ibkar Yusran, Johny Wahyuadi Soedarsono, Arie Wijaya, Taufik Aditiyawarman, Dony Soelistiyono e Romal Ramadhan. "Quantitative Risk-Based Inspection on Gas Riser Pipelines at Offshore Facilities". Teknomekanik 4, n. 2 (1 novembre 2021): 78–84. http://dx.doi.org/10.24036/teknomekanik.v4i2.11172.
Testo completoAbstract (sommario):
Numerous pipeline failures have occurred due to the drastic increase in oil and gas product distribution pipelines over the last three decades. Corrosion is a significant factor in the failure of offshore gas pipelines. It is necessary to maintain the integrity of the offshore transmission system, one of which is the riser, for the product to be adequately distributed. The purpose of this study is to ensure the riser's reliability by conducting a risk assessment of the probability and consequences of equipment failure, mitigating the impact of failure risk, and developing a more optimal inspection plan. The API 5L Grade X60 gas riser pipe is the subject of this study. The quantitative Risk-Based Inspection (RBI) technique was used in 2016 following the API 581 standard. This quantitative approach is founded on a numerical value model constructed using validated operational data and inspection results. The risk assessment indicates that the gas riser pipelines will have a high-risk level (5D) for the splash zone segment and a medium-risk level (2D) for the above-and below-water segments. The recommended inspection plan for the gas riser pipeline is one year after the risk-based inspection assessment.
43
Mustaffa, Zahiraniza, Mohammed Badri Taufiq e Thar M. Badri Albarody. "Wounding Composite Pipeline with Internally Pressurized Conditions". Applied Mechanics and Materials 353-356 (agosto 2013): 3280–83. http://dx.doi.org/10.4028/www.scientific.net/amm.353-356.3280.
Testo completoAbstract (sommario):
Although installing offshore pipelines by reel-laying method is eases and cost-effective, still conceal some of plastic deformation into the pipeline which may, in combination with ageing, affect strength and ductility of the pipe material. Therefore, reeling pipelines that internally pressurized is addressed in this study sifting parametrically pipelines stiffness to prevent the ovalization and bifurcation produces during spooling of (initially straight) or laying of (initially bent) pipe. A combination of composite materials is examined and number of bending cases at the limit of ovalization and bifurcation is investigated. It is demonstrated that composite pipeline exhibit more bending stability than Steel. Results on the strain energy release in the reel lay system are presented, extending the findings of previous works on the methods of spooling and laying mechanism.
44
Albarody, Thar M. Badri, Mustaffa Bt Zahiraniza e Mohammed Badri Taufiq. "Pipeline Reeling". Applied Mechanics and Materials 376 (agosto 2013): 185–89. http://dx.doi.org/10.4028/www.scientific.net/amm.376.185.
Testo completoAbstract (sommario):
The reel laying offshore pipeline installation method is known to be easier and cost effective, but the method may induce some plastic deformation into the pipe, thus affecting the strength and ductility of the pipe material. However, the design and modeling of applied bending loads to the pipe during spooling of (initially straight) or laying of (initially bent) pipe has become a great challenge and are addressed in this study,sifting parametrically pipelines stiffness. It is demonstrated that rigid pipeline requires higher spooling loads, but indeed rigidity improves the laying effort without the need of applying tension, thus making it more tractable during the straighteningstage. The paper also emphasizes on pipe free-end deformations and offset of bending, which extends the findings of previous works on spooling or laying control.
45
Peng, Deping, Buyan Wan, Yongping Jin, Likun Han, Jia Chen e Hongkun Liu. "The JCOE/JCOC manufacturing process and collapse resistance of submarine pipeline". Advances in Mechanical Engineering 15, n. 1 (gennaio 2023): 168781322211431. http://dx.doi.org/10.1177/16878132221143186.
Testo completoAbstract (sommario):
Submarine pipeline is an important part of deep-sea and ultra-deep-sea oil and gas development. In the cold forming process of longitudinal submerged arc welded (LSAW) pipe, the JCO manufacturing process is one of the key forming technologies for manufacturing submarine pipeline. The main problem encountered by submarine pipelines in offshore oil and gas transportation is insufficient pipeline collapse pressure, which leads to pipeline collapse and shortens the service life of the pipeline. Therefore, the analysis of the JCO manufacturing process is of great significance to improve the collapse resistance of pipelines. In this paper, the development and research status of the JCOE/JCOC manufacturing process are reviewed. The stress, contact, and deformation of the plate are symmetrical in the JCOE/JCOC manufacturing process. The effects of expanding and compression on pipe collapse performance in the JCO manufacturing process are summarized. The asymmetric factors can reduce the collapse performance of the pipeline. Compared with expanding, compression can effectively reduce the ovality of pipe and strengthen the compression performance of pipe, to improve the collapse performance of pipe; finally, the JCOE/JCOC manufacturing process and collapse resistance of submarine pipeline is summarized and prospected.
46
Zhang, Kang, Xiaoxiao Zhu, Shimin Zhang, Qingxin Ding e Zichen He. "Experimental research on frictional resistance of smart isolation tool during maintenance operation in offshore pipeline". Industrial Lubrication and Tribology 70, n. 7 (10 settembre 2018): 1145–50. http://dx.doi.org/10.1108/ilt-09-2017-0276.
Testo completoAbstract (sommario):
Purpose Pipeline maintenance technology using smart isolation tool is becoming more widely used in the global scope. This paper aims to investigate the effects of parameters on the frictional resistance between the slip and pipeline and the frictional characteristics under different lubrication films. Design/methodology/approach An experimental platform consisting of slip, pipeline and data acquisition system was developed, wherein the slip slips on the pipeline under different normal forces and velocities. In addition, three lubrication conditions, namely, dry wall, oil liquid and black powder on the wall, were investigated to study the effects of lubrications on the frictional coefficient and characteristics. Findings Research results indicate that the frictional force and coefficient were sensitive to normal force. The crude oil affected the frictional coefficient within a certain range of normal force, and the black powder enhanced the surface roughness in the natural gas pipeline. However, velocity had no effect on them. In addition, different contact behaviors could be observed from the frictional coefficient curves. Originality/value In this paper, the effects of normal force and velocity on frictional resistance of sliding slip during decelerating process in pipeline were investigated, and the effects of lubrication films on frictional characteristics were also revealed. The research results are of great value to improve the prediction accuracy of smart isolation tool, and also provide a guiding significance for the development of maintenance operation in pipelines.
47
Anderson, David A. "Natural Gas Transmission Pipelines: Risks and Remedies for Host Communities". Energies 13, n. 8 (12 aprile 2020): 1873. http://dx.doi.org/10.3390/en13081873.
Testo completoAbstract (sommario):
Transmission pipelines deliver natural gas to consumers around the world for the production of heat, electricity, and organic chemicals. In the United States, 2.56 million miles (4.12 million km) of pipelines carry natural gas to more than 75 million customers. With the benefits of pipelines come the risks to health and property posed by leaks and explosions. Proposals for new and recommissioned pipelines challenge host communities with uncertainty and difficult decisions about risk management. The appropriate community response depends on the risk level, the potential cost, and the prospect for compensation in the event of an incident. This article provides information on the risks and expected costs of pipeline leaks and explosions in the United States, including the incident rates, risk factors, and magnitude of harm. Although aggregated data on pipeline incidents are available, broadly inclusive data do not serve the needs of communities that must make critical decisions about hosting a pipeline for natural gas transmission. This article breaks down the data relevant to such communities and omits incidents that occurred offshore or as part of gas gathering or local distribution. The article then explains possible approaches to risk management relevant to communities, pipeline companies, and policymakers.
48
Olamide, Ayodeji, Abdeldjalil Bennecer e Stefan Kaczmarczyk. "Finite Element Analysis of Fatigue in Offshore Pipelines with Internal and External Circumferential Cracks". Applied Mechanics 1, n. 4 (24 novembre 2020): 193–223. http://dx.doi.org/10.3390/applmech1040013.
Testo completoAbstract (sommario):
Fatigue lifetime of offshore pipelines with semi-elliptical circumferential surface cracks is often underestimated. An accurate prediction of the pipeline structural integrity is nevertheless important in order to prevent unnecessary and expensive downtime, failures leading to leakage or spillage of pipeline contents to the surrounding environment, and ultimately improve the reliability of the pipeline. The estimation of crack growth in pipelines under varying loads is highly dependent on the calculation of crack driving parameters, such as the stress intensity factor and the crack tip opening displacement (CTOD) using the 3D J-integral or its equivalent. This paper presents a numerical study to predict the fatigue lifetime of cracks in pipes, determining the J-integral that includes first and second derivatives of the displacement field for pipes containing a range of circumferential surface cracks. A pipe segment is structurally loaded and stress intensity factors (SIF) evaluated using the finite element method (FEM). Based on the results, a number-of-cycles to failure curve shows a longer lifetime than previously predicted by about 5% for a pipe with semi-elliptical external surface cracks. In addition, they indicate that the external short cracks are more dangerous than the internal long surface crack hereby requiring earlier assessment.
49
Hinwood, J. B., e L. R. Denis. "ENVIRONMENTAL ISSUES IN PIPELINE FACILITY ABANDONMENT". APPEA Journal 38, n. 2 (1998): 172. http://dx.doi.org/10.1071/aj97090.
Testo completoAbstract (sommario):
A condition of offshore production licences in Australia, as in most countries, is that the operator undertakes to remove all facilities including pipelines. Frequently, when decommissioning an offshore facility, the operator will seek to leave the pipelines in place to avoid the costs of removal. In order to obtain approval for in-situ abandonment, however, the operator must satisfy regulatory authorities that the pipelines pose no hazards to the environment or to recognised beneficial uses of the offshore zone. Potential hazards to be considered include mechanical or physical effects of the pipe on the seabed, chemical and water quality effects due both to release of residues of the contents of the pipe and to the degradation of the pipe walls and coatings by mechanical and chemical action, and ecological effects.In reaching a recommendation in a particular case the above factors must be addressed, and it must be shown with reasonable certainty that recognised beneficial uses will not be disadvantaged. A strategy for reaching this position is outlined.
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de Medeiros, José Luiz, e Ofélia Queiroz Fernandes de Araújo. "CO2 Pipelines: A Thermodynamic Modeling with Pre-Salt Applications". Applied Mechanics and Materials 830 (marzo 2016): 57–64. http://dx.doi.org/10.4028/www.scientific.net/amm.830.57.
Testo completoAbstract (sommario):
This paper approaches CO2 pipelines operating with high dense compressible flow for Enhanced Oil Recovery (EOR) and/or Carbon Capture & Geological Storage (CCGS). The idiosyncrasies of high pressure CO2 flow are discussed and an appropriate and rigorous steady-state compressible flow pipeline model is disclosed. The model gives three Ordinary Differential Equations (ODE) which result from one-dimensional, one-phase, Mass, Momentum & Energy Balances along the pipeline axial direction. This ODE set is numerically integrated leading to profiles of temperature, pressure and inventory along the pipeline, which are basic for design. An example is explored in the context of a hypothetical EOR CO2 pipeline aligned to the production of CO2 rich natural gas in the Pre-Salt offshore oil and gas fields on the southeast coast of Brazil.