scholarly journals INFLUENCE OF THE CORROSION AND ENSURING INTEGRITY THE FLUIDS TRANSPORT PIPELINES, ON BASED OF THE ROUTINE DIAGNOSIS

Neft i gaz ◽  
2020 ◽  
Vol 6 (120) ◽  
pp. 93-108
Author(s):  
V.P. TUDORACHE ◽  
◽  
N.N. ANTONESCU ◽  
N. ILIAS ◽  
◽  
...  
Keyword(s):  
Mechanical Damage ◽  
Intervention Programs ◽  
Time To Failure ◽  
Stress Cracking ◽  
Defect Rate ◽  
Rate Versus ◽  
Pressure Pipeline ◽  
Oil And Natural Gas ◽  
Pipeline Failure ◽  
High Pressure Pipeline

Pipelines represent a very important part of the energy infrastructure. They ensure an economical, safe and continuous transport of fluids, in generally of oil crudes and natural gases. As time goes, pipelines of transporting oil and natural gas (more, buried and high-pressure pipeline) are subjected to loads and environmental effects which may cause them to become degraded with. Pipelines may suffer degradation from a variety of causes, as: corrosion, mechanical damage, stress cracking etc. As pipelines age and the degradation mechanisms become more problematic, it is recognised that the integrity of those pipelines must be proactively managed. All pipeline operators are well aware of this, and at this problem. Evident, the prudent operators have active programs, - timely intervention programs to assure continuing pipeline transporting fluids -, more, to mitigate deterioration and to repair defective pipes. Another important aspect is forecasting corrosion over a period of time in order to predict the possibility of pipeline failure (in other words, defect rate versus time to failure). A variety of techniques are used depending on the nature of the pipeline and the perceived problems. Some of the basic techniques are described in this article.

Improved Diffuser/Volute Combinations for Centrifugal Compressors

2008 ◽  
Vol 130 (1) ◽  
Author(s):  
T. Steglich ◽  
J. Kitzinger ◽  
J. R. Seume ◽  
R. A. Van den Braembussche ◽  
J. Prinsier
Keyword(s):  
Cross Sections ◽  
Pressure Ratio ◽  
Pressure Rise ◽  
Outer Radius ◽  
Inner Radius ◽  
Pressure Pipeline ◽  
The Cross ◽  
Improved Performance ◽  
High Pressure Pipeline ◽  
Original Configuration

Internal volutes have a constant outer radius, slightly larger than the diffuser exit radius, and the circumferential increase of the cross section is accommodated by a decrease of the inner radius. They allow the design of compact radial compressors and hence are very attractive for turbochargers and high-pressure pipeline compressors, where small housing diameters have a favorable impact on weight and cost. Internal volutes, however, have higher losses and lower pressure rise than external ones, in which the center of the cross sections is located at a larger radius than the diffuser exit. This paper focuses on the improvement of the internal volute performance by taking into account the interaction between the diffuser and the volute. Two alternative configurations with enhanced aerodynamic performance are presented. The first one features a novel, nonaxisymmetric diffuser̸internal volute combination. It demonstrates an increased pressure ratio and lower loss over most of the operating range at all rotational speeds compared with a symmetric diffuser̸internal volute combination. The circumferential pressure distortion at off design operation is slightly larger than in the original configuration with a concentric vaneless diffuser. Alternatively, a parallel-walled diffuser with low-solidity vanes and an internal volute allows a reduction of the unsteady load on the impeller and an improved performance, approaching that of a vaneless concentric diffuser with a large external volute.

Welding Stress Numerical Simulation and Analysis of High-Pressure Pipeline

2014 ◽  
Vol 912-914 ◽  
pp. 890-894
Author(s):  
Lei Zhang ◽  
Jin Zhou Zhang ◽  
Xiao Ming Li
Keyword(s):  
High Pressure ◽  
Welding Process ◽  
Source Model ◽  
Heat Source Model ◽  
Welding Stress ◽  
Welding Temperature ◽  
Welding Arc ◽  
Pressure Pipeline ◽  
Pipeline Welding ◽  
High Pressure Pipeline

Welded stress has an important impact on quality and life of of high-pressure pipeline. Based on pipeline material performance, considered welding arc force and its mining action, selected double ellipsoidal heat source model, simulated welding process of of high-pressure pipeline, analysised welding temperature field and stress field, determined the distribution disciplines of welding stress, provides useful help on exploring the disciplines of pipeline welding.

Geotechincal Assessment for Mitigation of a High-Pressure Pipeline Across Active Landslides: Design of a Directional Bore in Southern California

2008 ◽  
Author(s):  
Christopher S. Hitchcock ◽  
Richard W. Gailing ◽  
Scott C. Lindvall
Keyword(s):  
High Pressure ◽  
Slope Failure ◽  
Sufficient Information ◽  
Directional Drilling ◽  
Mitigation Options ◽  
Active Portion ◽  
Pressure Pipeline ◽  
Efficient Alternative ◽  
High Pressure Pipeline ◽  
Alternative Routes

Landslides are often a hazard to high-pressure gas transmission pipelines operating in hilly and mountainous terrain. Typical mitigation options include pipeline rerouting or removing the landslide from the pipeline, if possible. When rerouting or hazard removal is not a viable option due to terrain conditions or the size of the landslide loading the pipeline, directional bores can be used to place the pipeline beneath the active portion of the slope failure. As part of our study of the geotechnical viability of mitigation options for a pipeline impacted by coastal landslides, rerouting and landslide mitigation alternatives were fully investigated. Geologic interpretation of high-resolution, publicly available IfSAR and privately-flown LiDAR data were used to evaluate alternative routes around active and potentially active landslides. Geotechnical borings through the landslides ultimately provided sufficient information supporting directional drilling beneath the active landslides as the most efficient alternative, returning the pipeline to full service.

Reliability Based Design Optimisation of a “No Burst” High Pressure Pipeline

2002 ◽  
Author(s):  
Graham Stewart ◽  
Caroline Roberts ◽  
Ian Matheson ◽  
Malcolm Carr
Keyword(s):  
High Pressure ◽  
Structural Reliability ◽  
Design Stage ◽  
Design Parameters ◽  
Extreme Value Distributions ◽  
Reliability Based Design ◽  
Pressure Pipeline ◽  
Pipeline Wall ◽  
High Pressure Pipeline ◽  
Pipeline Design

The design philosophy of a pressure-protected subsea pipeline is intimately linked to the reliability of the Pressure Protection System (PPS) and to the probability of burst of the pipeline if it is exposed to full wellhead shut-in pressure. A reliability based design approach is presented that allows the pipeline wall thickness (and cost) to be reduced under the philosophy that the pipeline will “not burst” in the event of PPS failure. This paper describes how uncertainties in the pipeline design parameters may be initially modelled statistically to allow structural reliability techniques to be adopted at the design stage (before the pipe is manufactured). It further addresses how correlation of these parameters can be included and their extreme value distributions developed, which is particularly relevant as the length of the tieback increases. A method to incorporate inspection inaccuracy is also presented. The initial estimates of the design parameters necessarily err on the conservative side. These can be later updated when manufacturing data is available.

Modelling of Fluid Dynamics Interacting With Ductile Fraction Propagation in High Pressure Pipeline

2008 ◽  
Author(s):  
M. Popescu ◽  
W. Shyy
Keyword(s):  
Fluid Dynamics ◽  
High Pressure ◽  
Gas Flow ◽  
Flow Analysis ◽  
Time Discretization ◽  
Pressure Profile ◽  
Choked Flow ◽  
Pressure Pipeline ◽  
Crack Dynamics ◽  
High Pressure Pipeline

This paper presents a computational model for describing the behavior of the fluid dynamics in a fractured ductile pipe under high pressure. The pressure profile in front of the crack tip, which is the main source of the crack driving source, is computed by using nonlinear wave equation. The solution is coupled with one dimensional gas flow analysis behind the crack, choked flow. The simulation utilizes a high order optimized prefactored compact–finite volume method for space discretization, and low dispersion and dissipation Runge-Kutta for time discretization. As the pipe fractures the rapid depressurization take place inside the pipe and the propagation of the crack induce waves which strongly influence the nature of the outflow dynamics. Consistent with the experimental observation, the model predicts the expansion wave inside the pipe, and the reflection and outflow of the wave. The model also helps characterize the propagation of the crack dynamics and fluid flows around the tip of the crack.

scholarly journals Fracture Behaviour and Defect Evaluation of Large Diameter, HSLA Steels, Very High Pressure Linepipes

2000 ◽  
Author(s):  
G. Demofonti ◽  
G. Mannucci ◽  
L. Barsanti ◽  
C. M. Spinelli ◽  
H. G. Hillenbrand
Keyword(s):  
High Pressure ◽  
Natural Gas ◽  
Fracture Behaviour ◽  
Large Diameter ◽  
Transportation Cost ◽  
Current Status ◽  
Pressure Pipeline ◽  
On Line ◽  
High Pressure Pipeline ◽  
Very High

Actually, the increase in natural gas needs in the European market, foreseen for the beginning of the next century, compels to develop new solutions for the exploitation of gas fields in remote areas. For natural gas transportation over long distances the hypothesis of a large diameter high-pressure pipeline, up to 150 bar (doubling of the actual one) has been found economically attractive, resulting in significant reduction of the transportation cost of the hydrocarbon. In this contest the interest amongst gas companies in the possible applications of high-grade steels (up to API X100) is growing. A research program, partially financed by E.C.S.C. (European Community for Coal and Steel), by a joint co-operation among Centro Sviluppo Materiali (CSM), S.N.A.M. and Europipe in order to investigate the fracture behaviour of large diameter, API X100 grade pipes at very high pressure (up to 150 bar) has been carried out. This paper presents: the current status of technology of API X100 steel with respect to the combination of chemical composition, rolling variables and mechanical properties the results obtained from West Jefferson tests, in order to confirm the ductile-brittle transition behaviour stated from laboratory tests (DWTT), the results obtained concerning the control of long shear propagating fracture and in particular the results of a full scale crack propagation test on line operating at very high hoop stress (470 MPa). Besides, in order to investigate the defect tolerance behaviour of the pipe with respect to axial surface defect, burst tests with water as pressurising medium have been carried out and the relative results are presented and discussed.

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