Pipeline Orientation Research Articles

Intelligent recognition and automatic localization of pipeline welds based on multi-vision system

Abstract Currently, the leakage detection of spacecraft pipeline welds relies on manual point-by-point inspection using a detection gun, which is inefficient and inadequate for the automation needs of spacecraft production. However, the accurate recognition and precise localization of widely distributed and small pipeline welds are crucial for automated detection. Therefore, this paper proposes a multi-vision detection and localization system that integrates global and local information, considering both comprehensive global 3D search and high-precision local 3D measurement. The improved YOLOv8 model is employed for pipeline weld recognition, which improves the recognition rate of welds. Based on the deep learning recognized and segmented welds, this paper proposes stereo matching and segmentation extraction methods for 3D localization and pipeline orientation determination. Additionally, the system integrates a robot to perform automated point-by-point inspection of welds within the area without collisions. The experimental results demonstrate the effectiveness of the improved YOLOv8 and the proposed methods for 3D weld localization and pipeline orientation determination. The maximum deviation of the spatial distance of fine weld positioning is 0.20 mm, and the repeatability of the 3D coordinates is around 0.1 mm. The system can perform precise localization and detection, meeting the requirements for automatic weld recognition and localization.

Influence of slug flow on sand dune transport in a 3.6° upward inclined pipeline

AbstractThis study presents an experimental investigation of sand conveying from a stationary flatbed through two‐phase liquid–gas flows as a function of the fluids flow rates and pipeline orientation (α = 0°, and α = +3.6°). The characteristics of sand particle transportation by saltation, sand dune formation process and morphologies are visualized using a transparent cylindrical acrylic pipeline and digital photography. It was observed that slug flow regime was the dominant mechanism to lift the sand particles for both horizontal and upward inclinations. It was also found that sand dunes deconstructed more quickly at an upward inclination than horizontal position. For the upward inclination, the conveying phenomenon is characterized by sand bed lifting, suspension, and backward entrainment below the air bubble in the water film. Due to the increased liquid flow rates, higher dune velocity is recorded for the inclined condition. The dune pitch length grew for the horizontal configuration after the transient phase, as a result of the gravitational force effect, while it remained constant for the inclined orientation. In both conditions the slip face angle decreased with time; however, for the inclined configuration, this angle was lower because of the higher upstream liquid flow rate. These results provide important insights into the effect of pipe inclination on bed‐load mode solid transport by two‐phase flow inside a closed circular conduit. The obtained experimental data can be used to validate future numerical investigations.

Particle-Transport Mechanism in Liquid/Liquid/Solid Multiphase Pipeline Flow of High-Viscosity Oil/Water/Sand

Summary In this study, an investigation of sand transport in heavy-oil/water multiphase flow is performed. The study is conducted in three multiphase-flow pipeline-test facilities with internal diameters (IDs) of 1, 1, and 3 in. The pipeline orientations relative to the horizontal in the facilities are 0, +30, and 0°, respectively. Oil viscosity of 3.5 and 10.0 Pa·s with sand volume fractions from 0.010 to 0.100 vol% were used in the study. The effects of oil viscosity, upward inclination, sand volume fraction, pipe ID, and water cut on the sand-transport mechanism in pipelines are investigated. In the horizontal test section, flow patterns—namely, dispersed flow (DF), plug flow (PF), plug flow with moving sand bed (PFM), and plug flow with stationary sand bed (PFS)—were identified through flow visualization. In addition to the aforementioned, two flow patterns—stratified wavy flow with moving sand bed (SWM) and stratified wavy flow with dunes (SWD)—were observed in the inclined pipeline orientation. The pressure gradient measured decreased with a decrease in water cut until a minimum value was reached. Beyond the minimum pressure gradient, further reduction in water cut led to an increase in pressure gradient. The sand minimum transport condition (MTC) in the oil/water/sand test was largely the same for the 1-in. 30° upward inclined and the 1-in. horizontal test section. In contrast, that of the 3-in. horizontal test section was considerably higher. An improved MTC predictive correlation is proposed for multiphase heavy-oil/water/sand flow. The proposed correlation outperforms the existing models when tested on the heavy-oil/water/sand data set.

Analyses and verifications of magnetic shielding of long pipelines aiming for pipeline orientation measurements

So far, none of conventional magnetic shielding models can model a field long pipeline consisting of many welded short sections with different permeabilities. This paper demonstrates the magnetic shielding model of long pipelines via simulation analyses based on the finite element method (FEM) and experimental verifications of the magnetic shielding of short pipes, torus pipes, and field long pipelines. The radial and axial shielding factors of a finite pipe can be accurately calculated by the FEM. As the pipe length increases, the axial factor rapidly converges to a value less than 1, and the convergence value is independent of the pipe length because of the magnetic charges at the two ends. For a long pipeline consisting of many short sections, the averaged shielding factors over a couple of adjacent sections are equal to that of an ideal infinite pipeline, and the axial factor is always equal to 1. An “average” strategy for field pipeline orientations that employs the averaged magnetic fields and shielding factors over several sections is then proposed and demonstrated. As the geomagnetic field is taken as the absolute reference, this orientation measurement method has no risk of divergence over a long time and distance. Index Terms—cylindrical magnetic shield, magnetic fields, pipeline orientation.

Burst capacity due to corrosion acting at radial orientation of pipeline

Carbon steel pipeline is known as the safest method to transfer a large volume of oil and gas from sources to the consumers. Carbon steel has higher tendency to fail after long time because of major hazard such as corrosion. Corrosion develops at both sides of pipeline wall; internally and externally thus the strength and integrity are affected caused by such metal deterioration. This paper emphasizes on defects interaction between external and internal walls in the radial orientation towards failure burst pressure. To date, there are no standards, codes or guidelines on radial corrosion defect to explain such behaviour. Seven types of corrosion arrangement retrieved from literature were modelled in finite element software for a pipeline in the grade API 5L X42. Von Mises distribution curve was plotted to determine the pipeline pressure limit at different corrosion arrangement. The maximum radial interaction with the lowest failure pressure was determined from the values obtained.

Tunnelling-induced response of buried pipelines and their effects on ground settlements

In urban areas, it is common to construct new tunnels beneath existing buried pipelines. The accurate estimation of the response of pipelines and the overlying ground is of great importance as it is essential for the protection of the pipelines and other facilities. However, this problem is quite difficult as it involves complicated soil-pipeline interaction. In this paper, analytical solutions incorporating the tensionless Pasternak model, which takes full account of the gap formation and the pipeline orientation, have been formulated to estimate the response of the pipeline and the overlying ground. The analytical solutions have been validated by observations from field and model tests, followed by parametric studies to investigate the effects of the gap formation and pipeline orientations. It is found that the formation of a gap beneath the pipeline lowers its deflection and bending moment generated by tunnelling, and a pipeline with a larger intersection angle with respect to the tunnel alignment is anticipated to bear larger bending moment.

Toward Automatic Subsurface Pipeline Mapping by Fusing a Ground-Penetrating Radar and a Camera

We propose a novel subsurface pipeline mapping and 3D reconstruction method by fusing ground-penetrating radar (GPR) scans and camera images. To facilitate the simultaneous detection of multiple pipelines, we model the GPR sensing process and prove hyperbola response for general scanning with nonperpendicular angles. Furthermore, we fuse visual simultaneous localization and mapping outputs, encoder readings with GPR scans to classify hyperbolas into different pipeline groups. We extensively apply the J-linkage method and maximum likelihood estimation with error analysis to improve algorithm robustness and accuracy. As a result, we optimally estimate the radii and locations of all pipelines. We have implemented our method and tested it in physical experiments with representative pipeline configurations. Two different kinds of 3-m-long pipes are used, with radii being 4.62 and 3.02 cm, respectively. The results show that our method successfully reconstructs all subsurface pipes. Moreover, the average estimation errors for two orientation angles of pipelines are 1.73° and 0.73°, respectively. The average localization error is 4.47 cm. Note to Practitioners —Automatic and accurate underground pipeline mapping technology is very important in civil construction projects. Lack of 3D utility pipeline maps may lead to accidental damage in civil construction and maintenance. Although ground-penetrating radar (GPR-based pipeline mapping methods have been studied for several years, these methods require the perpendicular scanning with respect to the pipe, which is impossible to guarantee in practice since the orientations of pipelines are unknown. Furthermore, these traditional methods can only estimate one pipeline at a time in a survey area and require prior knowledge of pipe diameter. We propose a robotic subsurface pipeline mapping method with a GPR and a camera to handle difficult factors such as multiple pipes, unknown pipeline orientation, and unknown pipeline diameters. Hence, we can perform GPR scanning along any generic linear trajectories. Our method has been tested in physical experiments with representative pipeline configurations. The results are sufficiently accurate, and it proves that our method can be an effective technology to reconstruct the underground pipelines.

Failure analysis and simulation model of pinhole corrosion of the refined oil pipeline

A new approach has been developed to conduct failure analysis of pinhole corrosion in pipelines using the normal material failure method and corrosion environment simulations during a full life cycle of the pipeline. A 277 km long DN 355.6 underground pipeline used for the transportation of diesel and gasoline leaked 3 times within 4 years of service. The pipeline had been operating at a 30% permissible capacity with one-third of operation and two-third of shutdown every month. Failure occurred due to internal corrosion at the 3, 4, and6 o'clock positions with respect to the pipeline orientation, resulting in pinholes within 3–4 years of commission. Chemical analysis and metallography were carried out on one of the failed pipeline segments. Various sections of the corrosion products were metallurgically evaluated using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy. The corrosion product was identified using photometric and potentiometric analyses combined with X-ray diffraction. Diesel, gasoline, and water samples obtained from the pipeline were also analyzed. The material of the pipeline was identified to be X60 with inclusions and manufactured pores. The experimental results indicate that the failure was caused by general corrosion, the activities of sulfate reducing bacteria (SRB), inclusion and/or manufactured pores of pipe body in the environment of chloride, sulfur, and oxygen in water wet at the internal of the pipeline. It is concluded that before the commission, due to the existence of hydrostatic test water, it is easy to cause corrosion of the pipeline. After the commission, along with lower flow velocity and long time shutdown of operation, water deposited to the bottom of pipeline and it is also likely to cause corrosion. The presence of inclusions or small holes in the pipe body accelerates the penetration speed. Series of a pinhole failure caused simulation model and equation of pinhole length were built. The calculation based on the parameters of the failed pinhole is more consistent with the proposed model.

An accurate localization method for subsea pipelines by using external magnetic fields

Accurate localization of subsea pipeline is the prerequisite of pipeline maintenance, reinforcement and tracking inspection. Via finite element simulations and experiments, this paper reveals the distribution characterizations of the total magnetic flux density (MFD) and the reduced MFD near the steel pipeline, and demonstrates a method for accurately positioning subsea pipeline by using the external magnetic field. The characteristic peak position of the total and reduced MFDs’ components are all susceptible to the radial magnetization direction, except for the reduced MFD’s norm whose peak always overlaps the projection of the pipeline axis on the magnetic measurement plane. The norms of the total and reduced MFDs are used to determine the pipeline orientation and axis position, respectively. For an 8 m long steel pipe with diameter of 8 in., when the measurement plane is 1.5 times the diameter away from the pipe, the positioning error is around 2 cm.

Pipeline Inclination Measurements Based on a Spherical Detector With Magnetic Proximity Switches

Spherical detector (SD) is a novel and promising magnetic shielding-based approach for long subsea pipeline orientation and localization with low risk of blockage. As not all the shielding factors can be accurately obtained, large errors of inclination measurements can be caused. This paper proposes a new inclination measurement method without utilizing the magnetic shielding model of the pipeline. A tiny magnet and a Hall sensor is installed on the SD to form a magnetic proximity switch (MPS) to determine the moment when the sensitive axis of the accelerometer perpendicularly points to the pipe wall. The acceleration value at that moment and the phase difference between the acceleration and magnetic signals are used to calculate the pipeline inclination. Numerical simulations are carried out to analyze and design reasonable structural parameters of the carrier for fixing the MPS and the accelerometer. The carrier can be driven to roll inside the pipe to mimic the rolling of the SD. Through measuring a couple of pipe inclinations both upward and downward, it is demonstrated that the proposed method can distinguish the rising and descending pipe sections, and most of the measurement errors are less than 0.5° over the range of 0°–90°. In case if the MPS is not on the middle circle plane of the SD, a circumferential MPS array can be deployed in field applications to cover a large range and obtain a small liftoff value, so that the proximity moment can still be captured by at least one MPS.

A 3D Localization Approach for Subsea Pipelines Using a Spherical Detector

A 3D localization approach for subsea pipelines is proposed using an internal mobile spherical detector without any external auxiliary location measurements. The process of solving for the pipeline orientation using the magnetic field and acceleration measured simultaneously by the spherical detector is formulated in the rotating sensor frame. Specifically, when the frames of the accelerometer and magnetometer are identical, the measured acceleration can be used to construct the rotation matrix to map the rotating sensor frame to the stationary pipe frame. This transformation by the rotation matrix can be applied to the measured rotating magnetic field to solve the orientation equations. The rolling frequency of the detector is used to calculate the spherical detector’s velocity and mileage within the pipeline. The approach and the system have been successfully applied in a 30-km long oil pipeline. After calibration by aligning the calculated and actual pipeline ends through 3D rotation, an absolute localization error of 1.2 km is achieved. This result is promising as an initial model for future use with external measurements.

Inversion of magnetic fields inside pipelines: Modeling, validations, and applications

Spherical detector is a novel and promising approach for pipeline inspections with high signal-to-noise ratio and low risk of blockage. As the magnetic signals are recorded in a rotating frame by the rolling spherical detector, it is difficult to directly deploy the raw periodic signals for magnetic inspections, such as pipeline orientation calculations and the identifications of girth welds, turning points, and other pipe features. Against this backdrop, a magnetic inversion approach for transforming the measured magnetic signals from the rotating sensor frame into the stationary pipe frame is developed and demonstrated both analytically and experimentally. By comparing the transformed values with that measured by a sensor moving on a straight route, the inversion approach is proven to hold for an arbitrary fixed rotation axis, with the average and maximum errors mostly less than 1 and 2 µT, respectively. Field experiments demonstrate that the magnetic inversion can expose and enhance hidden or imperceptible magnetic anomalies and pipeline turning points and improve pipeline route calculation accuracy via secondary alignments. The results will promote the spherical detector to play a greater role in pipeline inspections.

Forward modeling of total magnetic anomaly over a pseudo-2D underground ferromagnetic pipeline

Magnetic anomalies are formed by the superposition of earth's magnetic field and the induced field of an underground ferromagnetic pipeline. To analyze the influence of all factors on the detected magnetic anomalies, a forward model is established in this paper. A numerical integration method, magnetic dipole reconstruction (MDR), for magnetic anomaly forward modeling is proposed, and a series of calculations is performed between model parameters of the pipeline, the geomagnetic field, the measuring trace, and total magnetic anomaly (TMA). The influence of model parameters on the shape, amplitude, and magnetic width is then analyzed. Results show that the shape of TMA curve is primarily influenced by the magnetic inclination and relative azimuth of the pipeline. The amplitude is linearly related to geomagnetic intensity and pipeline parameters including diameter, thickness, and susceptibility, and decreases in inverse proportion to increase in distance between the pipeline's axis and measurement plane; it decreases in a cosine manner with decrease in inclination and relative azimuth. The magnetic width is less affected by the geomagnetic intensity and pipeline parameters, but does increase with increase in distance between the pipeline's axis and measurement plane, and decreases with decreasing inclination and relative azimuth. The MDR method effectively simulates the distributions of TMA caused by various models of pseudo-2D underground ferrous pipeline. Magnetic anomaly detection (MAD) does not effectively estimate existence or orientation of pipeline that are deeply-buried, slender or with axes parallel to the earth's magnetic field in the low magnetic latitude area. Rough measurement of magnetic anomaly is necessary before the orientation of the underground pipeline is identified, followed by exact measurements along the perpendicular direction of the axis of pipeline to accurately locate underground pipeline.

Numerical modeling of tunneling effect on buried pipelines

The underground space in urban areas is frequently congested with utilities, including pipelines and conduits, that are affected by underground construction, e.g., tunneling. This paper carries out finite element (FE) analyses to investigate the effects of tunneling-induced ground movement on pipelines, with special attention to the different soil responses to uplift and downward pipe–soil relative movements. A series of numerical parametric studies with 900 FE simulation runs in total is performed to encompass various combinations of ground settlement profiles, pipe dimensions, material properties, pipe burial depth, and soil properties that are typical for utility pipelines and tunnel construction in urban areas. The results are summarized in a dimensionless plot of relative pipe–soil stiffness versus ratio of maximum pipe curvature to maximum ground curvature, which can be used to directly estimate the maximum pipe bending strain and (or) to directly assess the tunneling-induced risk to pipelines. The FE results and dimensionless plot are validated against field and centrifuge test results reported in the literature. Effect of pipeline orientation with respect to the tunnel centerline is explored. It might be unconservative if design analysis only considers the case that the pipeline is perpendicular to the tunnel centerline.

The Charpy Notch Impact Test of X70 Pipeline Steel with Delamination Cracks

The effects of thickness, notch orientation and delamination cracks on the impact toughness of X70 pipeline steel are investigated experimentally by use of the instrumented Charpy impact tests at different temperatures. The couple effect of delamination cracks, thickness, notch orientation and temperature is discovered. The delamination cracks have certain direction, and their amount and size are related to the temperature and the specimen thickness. Though the delaminating orientations of T-S and T-L specimen are not same, the reasons for both T-S and T-L specimen delaminating are that the weak interfaces in the specimens are pulled apart by the stress perpendicular to them. The delamination cracks can improve the actual impact toughness of X70 pipeline steel both T-L and T-S specimens. The effect of delamination cracks on the actual impact toughness changes with the thickness and the temperature. The couple effect of wall thickness, defect orientation and working temperature of pipeline must be taken into account in safe assessment of pipeline.

Effect of pipe orientation on dense-phase transport I. Critical angle in inclined upflow

The dense-phase region of the Zenz-type phase diagram in the pneumatic transport of medium-sized glass beads with a diameter of 0.45 mm along a 26.6 mm i.d. pipeline oriented at different inclination angles from 5° to 80° has been predicted by modifying the earlier model of Hong and Tomita ( Int. J. Multiphase Flow, 21 (1995) 649–665) for inclined gas-particle stratified upflow. It is confirmed that the pressure gradient of inclined upward transport is consistently greater than that of horizontal transport and a maximum pressure gradient exists corresponding to the critical inclination angle around 65° as the pipeline orientation changes from the horizontal to nearly vertical. Lowering the solids mass flow rate and/or loading ratio leads to a higher critical inclination angle. These findings are in good agreement with the existing experimental results reported in the literature. For the first time, an expression for estimating the critical inclination angle is derived. In comparison with the phase diagram for horizontal transport, a similar contour in the dense-phase region in the Zenz-type phase diagram has been predicted for inclined upward transport under given operating parameters. Furthermore, regardless of the parameter (i.e. solids mass flow rate or loading ratio) employed in the phase diagram, the minimum pressure-gradient point is found to shift up to a higher gas velocity and also to be different from the theoretical saltation point.

Calculation of Pressure And Temperature Profiles In Multiphase Pipelines And Simpne Pipeline Networks

Abstract The structure and related theory for a computer program to perform detailed design calculations for pipelines and simple pipeline networks are presented and discussed. The sensitivity to calculated pressures, temperatures and total liquid holdups of parameters such as pipe-to-ground heat transfer coefficient, ground temperatures, pipeline orientation (horizontal, uphill and downhill) and total flow rate are examined and discussed in detail for a typical natural gas - condensate system. Some characteristics of several different design calculation procedures are noted. Introduction Multiphase flow in wells and gathering systems is of considerable interest to petroleum engineers as well as many working in other branches of engineering. Petroleum engineers arc particularly interested in the prediction of flow pattern, holdup and pressure drop in well tubings and gathering lines or networks. These calculations areusually rather involved and the problem is further complicated because:no single design method is "best" under all conditions:several design methods must be tried to get some appreciation for the possible range of answer andwhere reliable fluid property or other data are not available, sensitivity of results to variations of these data must be investigated. This makes hand calculations impractical. The calculations are, however, particularly amenable to computer programs and one such program is discussed in this paper. Applications of a previous version of the program are discussed elsewhere.(1,2) Program Structure For calculation purposes, the actual pipeline elevation profile is approximated by choosing a series of modal points on the profile for which x and z coordinates are available. The pipeline is assumed to have a constant slope, mass flow rate and diameter between nodal points; however, any or all of these parameters may change at the nodes. In the program, the distance between nodes is divided into a specified number of segments and, starting with the end where the pressure and temperature are known calculations are performed in a sequential fashion for one segment at a time until calculations are completed for the entire system. The segment size is selected so that the variation of fluid properties over its length is small and differential forms of the flow and energy equations can be used. The flow equation may be written as follows: There are many methods available in the literature for calculating the various terms in Equation (1). These are discussed in detail by Govier and Aziz(3) and compared with experimental data in a series of papers by the authors and Mandhane(4,3,6). In most cases of practical interest, ~PKE is negligible with respect to ΔPHH + ΔPr and can be neglected without significant error. The program contains fouf flow pattern prediction method(4), ten different holdup calculation methods(5) and fourteen different pressure- drop calculation methods(6). The energy equation is discussed in different forms in several references(7,8,9). In the energy equation the heat transfer term q may be estimated from (Equation Available In Full Paper) Estimation of the over-all heat transfer coefficient, U, is possible by a number of available method (10,11,12).

Effect of Pipeline Junctions on Water Hammer Surges

A study was carried out to determine the transmission and reflection characteristics of water hammer pressure surges at junction of pipes in a piping system. The effects of pipeline orientation, concentrated friction loss and motion of the piping system at the junctions were considered. The results were compared to the presently used relationships for surge reflection and transmission at junctions which do not consider these effects. It was shown that if the pipeline is completely restrained from motion the pipeline orientation and concentrated friction loss at the junction is free to undergo even slight movements, the reflection and transmission characteristic of pressure waves at such junctions may be significantly affected. In these cases a detailed transient flow analysis may be necessary to determine the effects.