Landslides are one of the key problems for stability analysis of pipelines in the western region of China where the geological conditions are extremely complicated. In order to offer a theoretical basis for the pipe-s...Landslides are one of the key problems for stability analysis of pipelines in the western region of China where the geological conditions are extremely complicated. In order to offer a theoretical basis for the pipe-soil interaction, the general finite element program ABAQUS is used to analyze the distribution of pipe strain caused by landslide through which the pipeline passes. In this paper the Ramberg-Osgood constitutive equation is used to study the strain-based mechanical characteristics of pipelines. Different calculation schemas are designed by considering the change of spatial relationship between pipeline and landslide, and the change of D/t, diameter-thickness ratio of pipeline. The results indicate that the pipeline is primarily subjected to tension stress when the landslide crosses the pipeline perpendicularly, the pipe strain is a maximum along the central axis of the landslide, and reverse bending occurs on pipeline at both edges of the landslide. The pipeline is primarily subjected to friction force caused by the downward movement of the landslide, and the friction force is relatively small when the landslide is parallel to the pipeline. The pipe strain is in proportional to D/t, and this means decreasing D/t can help to improve security of pipelines subjected to the landslide.展开更多
Many years experience of the operation of high stress (>72% specified minimum yield strength, SMYS) gas pipelines and statistical analysis results of pipeline incidents showed that the operating pipelines at stress...Many years experience of the operation of high stress (>72% specified minimum yield strength, SMYS) gas pipelines and statistical analysis results of pipeline incidents showed that the operating pipelines at stress levels over 72% SMYS have not presented problems in USA and Canada, and design factor does not control incidents or the safety of pipelines. Enhancing pipeline safety management level is most important for decreasing incident rate. The application history of higher design factors in the U.S and Canada was reviewed. And the effect of higher factors to the critical flaw size, puncture resistance, change of reliability with time, risk level and the arrest toughness requirements of pipeline were analyzed here. The comparison of pipeline failure rates and risk levels between two design factors (0.72 and 0.8) has shown that a change in design factor from 0.72 to 0.8 would bring little effect on failure rates and risk levels. On the basis of the analysis result, the application feasibility of design factor of 0.8 in China was discussed and the related suggestions were proposed. When an operator wishes to apply design factor 0.8 to gas pipeline, the following process is recommended: stress level of line pipe hydro test should be up to 100% SMYS, reliability and risk assessment at the design feasibility or conceptual stage should be conducted, Charpy impact energy should meet the need of pipeline crack arrest; and establish and execute risk based integrity management plan. The technology of pipeline steel metallurgy, line pipe fabrication and pipeline construction, and line pipe quality control level in China achieved tremendous progresses, and line pipe product standards and property indexes have come up to international advanced level. Furthermore, pipeline safety management has improved greatly in China. Consequently, the research for the feasibility of application of design factor of 0.8 in China has fundamental basis.展开更多
A mathematical model for optlmization design of the hot waxy crude oil transmission IZipelineis studied. The dimension-reducing method is selected to solve problems raised from multivariable,restricted and non-linear ...A mathematical model for optlmization design of the hot waxy crude oil transmission IZipelineis studied. The dimension-reducing method is selected to solve problems raised from multivariable,restricted and non-linear planning. And the optimization design model is applied to the practical design ofHejian Shijiazhuang oil transmission pipeline. outstanding economic and social benefits have beengained.展开更多
s: Regarding the influencing factors in an optimal selection of pipeline design alternative as fuzzy variables with different weights, a fuzzy comprehensive assessment was applied to an optimal selection of the design...s: Regarding the influencing factors in an optimal selection of pipeline design alternative as fuzzy variables with different weights, a fuzzy comprehensive assessment was applied to an optimal selection of the design alternative. Giving the Lanzhou-Chengdu pipeline as an example to explain the process, the result shows that this method is acceptable.展开更多
Underground natural gas storage(UNGS)is an important part of the natural gas supply system to ensure a balanced energy supply.The surface system,as an important part of the gas storage,undertakes the functions of gas ...Underground natural gas storage(UNGS)is an important part of the natural gas supply system to ensure a balanced energy supply.The surface system,as an important part of the gas storage,undertakes the functions of gas injection and gas production of the gas storage,and its investment economy is of vital importance.In fact,the UNGS surface pipeline network has two-way injection and production characteristics,which is different from the one-way production characteristics of conventional oil&gas gathering and transportation systems.This paper takes the minimum investment of the pipeline network as the objective function,considers the gas injection and gas withdrawal flow conditions and esablishes a mixed integer non-linear programming model(MINLP)for the surface pipeline network of the UNGS to optimize its pipeline layout and diameter parameters.Constraints including the well affiliation,the number of stations,the gathering radius,the processing capacity and the flow/pressure equilibrium equations,are also taken into consideration.Taking an UNGS in China as an example,the results of the optimal structure and diameter of the pipeline network,as well as the pipe flow,node pressure,and maximum/minimum flowrate during gas injection and gas withdrawal are obtained.Finally,the effects of constraints such as processing capacity and radius on the structure layout and investment of the UNGS are analyzed,verifying the reliability and effectiveness of the model.展开更多
基金supported by the National Natural Science Foundation of China (Grant No. 50774090)
文摘Landslides are one of the key problems for stability analysis of pipelines in the western region of China where the geological conditions are extremely complicated. In order to offer a theoretical basis for the pipe-soil interaction, the general finite element program ABAQUS is used to analyze the distribution of pipe strain caused by landslide through which the pipeline passes. In this paper the Ramberg-Osgood constitutive equation is used to study the strain-based mechanical characteristics of pipelines. Different calculation schemas are designed by considering the change of spatial relationship between pipeline and landslide, and the change of D/t, diameter-thickness ratio of pipeline. The results indicate that the pipeline is primarily subjected to tension stress when the landslide crosses the pipeline perpendicularly, the pipe strain is a maximum along the central axis of the landslide, and reverse bending occurs on pipeline at both edges of the landslide. The pipeline is primarily subjected to friction force caused by the downward movement of the landslide, and the friction force is relatively small when the landslide is parallel to the pipeline. The pipe strain is in proportional to D/t, and this means decreasing D/t can help to improve security of pipelines subjected to the landslide.
基金supported by China National Petroleum Corporation Application Fundamental Research Foundation (Grant No. 07A40401)
文摘Many years experience of the operation of high stress (>72% specified minimum yield strength, SMYS) gas pipelines and statistical analysis results of pipeline incidents showed that the operating pipelines at stress levels over 72% SMYS have not presented problems in USA and Canada, and design factor does not control incidents or the safety of pipelines. Enhancing pipeline safety management level is most important for decreasing incident rate. The application history of higher design factors in the U.S and Canada was reviewed. And the effect of higher factors to the critical flaw size, puncture resistance, change of reliability with time, risk level and the arrest toughness requirements of pipeline were analyzed here. The comparison of pipeline failure rates and risk levels between two design factors (0.72 and 0.8) has shown that a change in design factor from 0.72 to 0.8 would bring little effect on failure rates and risk levels. On the basis of the analysis result, the application feasibility of design factor of 0.8 in China was discussed and the related suggestions were proposed. When an operator wishes to apply design factor 0.8 to gas pipeline, the following process is recommended: stress level of line pipe hydro test should be up to 100% SMYS, reliability and risk assessment at the design feasibility or conceptual stage should be conducted, Charpy impact energy should meet the need of pipeline crack arrest; and establish and execute risk based integrity management plan. The technology of pipeline steel metallurgy, line pipe fabrication and pipeline construction, and line pipe quality control level in China achieved tremendous progresses, and line pipe product standards and property indexes have come up to international advanced level. Furthermore, pipeline safety management has improved greatly in China. Consequently, the research for the feasibility of application of design factor of 0.8 in China has fundamental basis.
文摘A mathematical model for optlmization design of the hot waxy crude oil transmission IZipelineis studied. The dimension-reducing method is selected to solve problems raised from multivariable,restricted and non-linear planning. And the optimization design model is applied to the practical design ofHejian Shijiazhuang oil transmission pipeline. outstanding economic and social benefits have beengained.
文摘s: Regarding the influencing factors in an optimal selection of pipeline design alternative as fuzzy variables with different weights, a fuzzy comprehensive assessment was applied to an optimal selection of the design alternative. Giving the Lanzhou-Chengdu pipeline as an example to explain the process, the result shows that this method is acceptable.
基金This work was part of the program“Study on the optimization method and architecture of oil and gas pipeline network design in discrete space and network space”,funded by the National Natural Science Foundation of China,grant number 51704253.The authors are grateful to all study participants.
文摘Underground natural gas storage(UNGS)is an important part of the natural gas supply system to ensure a balanced energy supply.The surface system,as an important part of the gas storage,undertakes the functions of gas injection and gas production of the gas storage,and its investment economy is of vital importance.In fact,the UNGS surface pipeline network has two-way injection and production characteristics,which is different from the one-way production characteristics of conventional oil&gas gathering and transportation systems.This paper takes the minimum investment of the pipeline network as the objective function,considers the gas injection and gas withdrawal flow conditions and esablishes a mixed integer non-linear programming model(MINLP)for the surface pipeline network of the UNGS to optimize its pipeline layout and diameter parameters.Constraints including the well affiliation,the number of stations,the gathering radius,the processing capacity and the flow/pressure equilibrium equations,are also taken into consideration.Taking an UNGS in China as an example,the results of the optimal structure and diameter of the pipeline network,as well as the pipe flow,node pressure,and maximum/minimum flowrate during gas injection and gas withdrawal are obtained.Finally,the effects of constraints such as processing capacity and radius on the structure layout and investment of the UNGS are analyzed,verifying the reliability and effectiveness of the model.
