Iterative tomography of pipes during operation

The pipe wall thickness was estimated based on three-dimensional images of the pipe recovered from several X-ray projections, which were made in a limited angle of view. Since the effects of scattered radiation and beam hardening are up to 50 % of the main radiation, ignoring them leads to blur of the image and inaccuracy in determining dimensions. To restore pipe images from projections, a volume and/or shell representation of the pipe is used, as well as iterative Bayesian methods. Using these methods, the error in estimating the pipe wall thickness from the projection data can be equal to or less than 300 μm. It has been shown that standard X-ray projections on the film or imaging plates used to obtain data can be used to restore pipe wall thickness profiles in factory conditions.

Analysis of Ultimate Bearing Capacity and Parameters of Steel Support Cutting Pipe Roofing Structure

A new pipe-roof construction method, the steel support cutting pipe method (SSCP), was proposed to improve the construction security and accuracy of pipe jacking as well as underground space usage. The pipe-roof method is one of the underground excavation methods which push multiple steel pipes into the soil, then connect the steel pipes horizontally to form a whole. The proposed structure’s failure mode and force characteristics were determined through theoretical analysis, and then its ultimate bearing capacity and influencing parameters were analyzed through laboratory experiments and numerical simulation. The research results show that the structure’s bearing capacity depends on the steel pipe’s buckling load; the structure’s failure mode is a result of the steel pipe’s buckling. The ultimate bearing capacity of the pipe-roof structure first increases and then decreases with the increase of the steel pipe chord height ratio. The ultimate bearing capacity reaches the maximum when the ratio is 0.33. In addition, the structure’s ultimate bearing capacity is positively related to the steel pipe wall thickness and the pipe section’s length. This can be obtained from the relationship curve showing that the steel pipe wall thickness should be selected according to the engineering requirements and that the pipe section’s length is preferably 2.3 times the diameter of the steel pipe in the construction design.

Sectorial Scanning Electromagnetic Defectoscope: The Next Stage in Well Integrity Diagnostics

The paper presents a new technology for the oil and gas industry for azimuthal electromagnetic scanning of the first tubular wall defects, the basis of which is a small-sized sector scanning tool that measures the pipe wall thickness. The paper presents the results of laboratoryand well tests, as well as the early field surveys using this technology. These constitute thebasis on which the actual sensitivity of the technology and its prospects in diagnosing well integrity are determined.

Design Adequacy for Change in Pipeline Service: A Case Study

Pipelines have proven to be the most reliable and efficient means of transportation of hydrocarbons. Different fluids from numerous sources have different physical, chemical and operational properties, thereby separate pipelines were laid for most of the fluids. However, laying of new pipelines is becoming more and more challenging with vast and complex network of existing pipelines and topographies being faced in both onshore as well as offshore. Moreover considering the huge laying costs and risks of damaging the delicate balance of flora and fauna by entering the unchartered territories, a point does arise to optimally utilize already existing massive pipeline infrastructure. In this technical paper a method has been formulated to achieve such a cause. A case study from an existing subsea pipeline project of M/s ADOC (Japan) has been presented. Existing 8 inch subsea pipeline of M/s ADOC (Japan) from Hail Site Terminal (HST) to Mubarraz Island in UAE was originally designed for gas service. However, the client intended to use the same for treated sea water service. A thorough design adequacy check was performed to convert the existing subsea gas pipeline into a liquid pipeline. In such a case it is mandatory to check the adequacy of the pipeline for the intended service and design parameters which includes checking for suitability of already selected pipe wall thickness, on-bottom stability and free spans under the action of hydrostatic and hydrodynamic forces. The methodology adopted for this project can be generalized in order to create a framework to establish a basis to use an existing pipeline for different services.

Leak Testing

While the exercise of pressurizing a piping system and checking for leaks is sometimes called pressure testing, the Code refers to it as leak testing. The main purpose of the test is to demonstrate that the piping can confine fluid without leaking. When the piping is leak tested at pressures above the design pressure, the test also demonstrates that the piping is strong enough to withstand the pressure. For large bore piping where the pipe wall thickness is close to the minimum required by the Code, being strong enough to withstand the pressure is an important test. For small bore piping that typically has a significant amount of extra pipe wall thickness, being strong enough is not in question. Making sure that the piping is leak free is important for all piping systems.

Design Conditions and Criteria

Design conditions in ASME B31.3 are specifically intended for pressure design. The design pressure and temperature are the most severe coincident conditions, defined as the conditions that result in the greatest pipe wall thickness or highest required pressure class or other component rating. Design conditions are not intended to be a combination of the highest potential pressure and the highest potential temperature, unless such conditions occur at the same time.

Exhaust system piping made by hydroforming: relations between stresses, microstructure, mechanical properties and surface

The subject of research is car exhaust system piping made of chromium–nickel steel of grade AISI304L with a unique, complex shape that was obtained by hydroforming technology. The purpose of the research was to determine the relation between the microstructure features, surface condition, hardness and the stresses on the external surface as determined by the sin2ψ X-ray method. We found that the stresses were tensile and correlated with the steel hardness, i.e. they were greater where the hardness was higher. Moreover, longitudinal stresses showed a relationship with pipe wall thickness, while circumferential stresses did so only partially. According to our data, the greatest value of stress determined in the pipe amounted to 290 MPa, and was close to the yield point of the strain hardened 304L steel. As depicted via XRD and SEM examination, the pipe stress level and hardness were influenced by the transition γ→α’. Furthermore, in the region of higher stress and hardness, the amount of martensite was 10 vol.%. We also noted that the pipe’s outer surface when subjected to friction against the die shows lesser roughness compared to its inner surface upon exposure to water under pressure.