Justification of a Novel Pipe in Tunnel Approach to a River Crossing

Author(s):  
Chas Jandu ◽  
Mike Taylor ◽  
Stephen Humphrey

As part of a major pipeline construction project, Laing O’Rourke had a requirement to install a section of pipeline beneath a river estuary. Due to a number of reasons it was not possible to negotiate the crossing using conventional techniques such as horizontal directional drilling (HDD) and an alternate method had to be sought. A feasibility study was undertaken and it was decided that a pipe-in-tunnel approach was the most viable. Due to constraints at the points of entry and exit it was necessary to cut two vertical shafts, one on each river bank. Linepipe sections were to be welded together, in the entry shaft, and pulled through the 2.44m diameter tunnel on plastic rollers, which were later to become the permanent supports during operation. On completion of the installation within the tunnel, two vertical sections of pipeline were to be installed in the shafts for connection to the main pipeline system. Due to the length of the crossing it was decided that back filling the void between the pipe and the tunnel wall with a suitable grout was not viable. A particular consideration was the likely occurrence of voids which would reduce the effectiveness of the CP system. For this reason, following installation, the tunnel was to be sealed with a concrete plug and flooded with water, and the shafts are to be backfilled with soil. This unique design arrangement presented a number of challenges and hence a requirement for the use of more complex modelling techniques than would normally be required. Models of the pipeline in various stages of installation were produced using the finite element software ABAQUS, with a variety of element types. Sets of rollers and their contact with the linepipe were also modelled. Soil loading, pressure, weight, buoyancy and temperature were applied to simulate a range of construction, commissioning and operational conditions. These were analysed, and the results were assessed for compliance with appropriate standards. Based on the results of the study it was possible to show that with a number of modifications to the original proposed design configuration, the crossing would be fit-for-purpose.

2021 ◽  
Author(s):  
Javad Iskandarov ◽  
George Fanourgakis ◽  
Waleed Alameri ◽  
George Froudakis ◽  
Georgios Karanikolos

Abstract Conventional foam modelling techniques require tuning of too many parameters and long computational time in order to provide accurate predictions. Therefore, there is a need for alternative methodologies for the efficient and reliable prediction of the foams’ performance. Foams are susceptible to various operational conditions and reservoir parameters. This research aims to apply machine learning (ML) algorithms to experimental data in order to correlate important affecting parameters to foam rheology. In this way, optimum operational conditions for CO2 foam enhanced oil recovery (EOR) can be determined. In order to achieve that, five different ML algorithms were applied to experimental rheology data from various experimental studies. It was concluded that the Gradient Boosting (GB) algorithm could successfully fit the training data and give the most accurate predictions for unknown cases.


Author(s):  
John Martin

The pilger process is a cold-worked mechanical process that combines the elements of extrusion, rolling, and upsetting for the formation of thin-walled tubes. This complex manufacturing process relies on the results of trial and error testing programs, experimental parameter sensitivity studies, and prototypical applications to advance the technology. This finite element modelling effort describes the methods, models, and assumptions used to assess the process parameters used to manufacture thin-walled tubing. The modelling technique breaks down the manufacturing process into smaller computer generated models representing fundamental process functions. Each of these models is linked with the overall process simulation. Simplified assumptions are identified and supporting justifications provided. This work represents proof of principle modelling techniques, using large deformation, large strain, finite element software. These modelling techniques can be extended to more extensive parameter studies evaluating the effects of pilger process parameter changes on final tube stress and strain states and their relationship to defect formation/propagation. Sensitivity studies on input variables and the process parameters associated with one pass of the pilger process are also included. The modelling techniques have been extended to parameter studies evaluating the effects of pilger process parameter changes on tube stress and strain states and their relationship to defect formation. Eventually a complex qualified 3-D model will provide more accurate results for process evaluation purposes. However, the trends and results reported are judged adequate for examining process trends and parameter variability.


2005 ◽  
Vol 45 (1) ◽  
pp. 551
Author(s):  
E.P. Jas ◽  
A.T. McPhee

An insight is provided into the design and construction of the shore crossing of the export pipeline system for the Otway Gas Project in Western Victoria. The development of the Otway Gas Project, which is now underway, requires the installation of a 20-inch gas pipeline and a 4-inch glycol service line across the shoreline in the Port Campbell National Park along the Great Ocean Road, one of the major tourist attractions in Australia. An account is given of the landfall site selection process, the collection of required site data, the identification of geo-hazards, the development of a unique construction method based on a combination of retractable micro-tunnelling and horizontal directional drilling, and an outline of the construction challenges. These include the complex geo-technical conditions, the ever present high-energy Southern Ocean swell, and the environmental significance of the site. The design and construction work performed demonstrates that trenchless technology can successfully be applied for the installation of pipelines across shorelines provided detailed attention is paid to a number of design and construction aspects; bearing in mind that horizontal directional drilling design guidelines are generally limited with respect to these crossings.


Author(s):  
G. Arthur Kanzaki ◽  
Stephen L. Grant ◽  
Jarrod R. MacKenzie

This paper will discuss how the project team planned, designed and constructed a unique and innovative casing sleeve as one of the key solutions to overcome a major threat to the completion of a horizontal directional drilling (“HDD”) project (“Fraser River South Arm Crossing Upgrade Project” or “Fraser River Crossing”). In 2009 FortisBC Energy Inc. (“FortisBC”) started construction to upgrade its NPS 20 and NPS 24 pipeline crossings of the Fraser River, the largest river in the province of BC, Canada via HDD. Due to the poor surface geology at this location on the Fraser River, temporary surface casings were required on both sides of the crossing to get drilling activities into a formation suitable for conducting an HDD crossing. As a result, the Fraser River Crossing required an HDD rig to drill concurrently from either side of the crossing in order to create a continuous borehole (also known as an intersect crossing). During the pullback of the NPS 24 - 1.35 km crossing section, a major mechanical failure occurred when over 95% of the length had been pulled through. After multiple attempts to resume pullback by the HDD rigs and other onsite equipment were unsuccessful, the project team was left with the major challenge(s) of determining how else the crossing could be completed and the pipeline tied in on both sides of the river without incurring major business interruption in a busy industrial section of Richmond, BC. Moreover, FortisBC was faced with the possibility of having to abandon the project and the millions spent up to that point in time with no value. This paper will focus on how the project team overcame the challenge and mitigated long term operational issues that included maintaining adequate cathodic protection. Learn how the combined efforts of a multi-disciplined project team planned, designed, fabricated and ultimately successfully inserted an innovative casing sleeve, although unproven at the time and with its share of additional risks, after reviewing an extensive assessment of numerous alternatives as the optimum solution in order for FortisBC to finally complete the upgrade of its pipeline system.


Author(s):  
Antonio Borges Rodriguez ◽  
Vishal Dantal ◽  
Victor Bjorn Smith ◽  
Roselyn Carroll

Deep-water developments rely on pipeline and riser systems to transfer hydrocarbon products to floating facilities or potentially longer tie-back pipelines to shallow water platforms/onshore facilities. Depending on the nature of the product and operational conditions, the pipeline and riser system design may need to consider a range of dynamic processes during operation such as (i) controlled lateral buckling of the pipeline in order to relieve excessive constrained axial forces induced by temperature and pressure changes in the system; (ii) the accumulation of pipeline axial displacement or ‘walking’; and (iii) evolution of the pipe-soil interaction at the riser seabed touchdown point due to the dynamic behaviour of the riser. Under these conditions, the reliable structural assessment of the pipeline system relies upon accurate assessment of the pipeline-soil interaction (PSI), from the initial lay embedment of the pipeline to the evolution of the lateral and axial response over the lifetime of the facilities. Accurate assessment of these PSI parameters requires adequate characterisation of the seabed topography, seabed processes (e.g. geohazards) and the soil properties. This paper proposes ways for efficient planning of the geophysical and geotechnical site investigation activities and subsequent soil element and physical model testing for the assessment of relevant PSI parameters in deep-water.


2013 ◽  
Vol 300-301 ◽  
pp. 1381-1384
Author(s):  
Cheng Di Dong ◽  
Yao Ting Tu ◽  
Chiu Wen Chen ◽  
Chih Ming Kao ◽  
Chih Feng Chen

Major objectives of this study are to evaluation the enrichment, accumulation, and potential biological effects of copper (Cu) in the surface sediments of Jen-Gen River estuary, Taiwan. Eleven sampling locations were installed near the mouth of Jen-Gen River to collect sediment samples for analyzing Cu. Results of laboratory analyses show that concentrations of Cu in the sediments are between 67 and 278 mg/kg with an average of 181±61 mg/kg. The spatial distribution of Cu reveals that the Cu concentration is relatively high in the boundary of the river estuary. This indicates that upstream industrial and municipal wastewater discharges along the river bank are major sources of pollution. Results from the enrichment factor (EF) analysis imply that the sediments can be characterized as minor to moderately severe degree of Cu enrichment. Results of geo-accumulation index (Igeo) analysis indicate that the sediments can be characterized as none to moderate degree of Cu accumulation. Base on the comparison with sediment quality guidelines (SQGs), the concentrations of Cu in Jen-Gen River mouth sediments may cause acute biological damage.


Minerals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 545 ◽  
Author(s):  
Jinqing Liu ◽  
Ping Yin ◽  
Xiaoying Chen ◽  
Ke Cao

26 river bank sediments and 15 estuary seafloor sediments were sampled from the Dagu River and the estuary of Northwestern Jiaozhou Bay to determine contaminations of heavy metals and metalloids (Cu, Pb, Zn, Cr, Cd, Hg and As). The trace metal contents in sediment from the estuary area were much higher than those of the river. Correlation analysis showed that except for Pb, the metals were mainly controlled by the grain size, and enriched by adsorption of aluminosilicate minerals, Fe/Mn oxides and organic matter in river and estuary sediments. In addition to Cu in some stations, the metals met the requirements of the marine organism and humans for the quality of the marine environment. The concentrations of Cu, Pb, Cr, Hg and As were between the threshold effect level (TEL) and probable effect level (PEL), indicating those metals might have occasional adverse effects. Results of Enrichment Factor values revealed that the entire study area was enriched in Pb and Hg, at moderate environmental risk, but the estuary was more significant. Pb and Hg contaminations in this area were mainly from coal combustion and automobile emissions. River runoff and atmospheric deposition dominated the metals distribution and enrichment in the study area. Contaminants in sediments entering the estuary were further transported to the south and east under the river runoff and reciprocating current in the Jiaozhou Bay.


2013 ◽  
Vol 339 ◽  
pp. 717-720
Author(s):  
Cheng Di Dong ◽  
Chih Feng Chen ◽  
Yi Kuo Chang ◽  
Chiu Wen Chen

Major objectives of this study are to evaluation the pollution and potential ecological risk of chromium (Cr) in the sediments of Salt River estuary, Taiwan. Nine monitoring stations were installed near the estuary of Salt River to collect sediment samples for analyzing Cr. Results of laboratory analyses show that contents of Cr in the sediments are between 32 and 79 mg/kg with an average of 58±17 mg/kg. The spatial distribution of Cr reveals that the Cr concentration is relatively high near the boundary of the river estuary, and gradually diminishes toward the harbor region. This indicates that upstream industrial and municipal wastewater discharges along the river bank are major sources of pollution. Results from the enrichment factor analysis imply that the sediments can be characterized as minor to moderately severe degree of Cr enrichment. Results of geo-accumulation index analysis indicate that the sediments can be characterized as moderate degree of Cr accumulation. Results of potential ecological risk index indicate that the sediments at Salt River estuary have low ecological potential risk.


2005 ◽  
Vol 52 (12) ◽  
pp. 189-198 ◽  
Author(s):  
D. DeSilva ◽  
S. Burn ◽  
G. Tjandraatmadja ◽  
M. Moglia ◽  
P. Davis ◽  
...  

Wastewater pipeline leakage is an emerging concern in Europe, especially with regards to the potential effect of leaking effluent on groundwater contamination and the effects infiltration has on the management of sewer reticulation systems. This paper describes efforts by Australia, in association with several European partners, towards the development of decision support tools to prioritize proactive rehabilitation of wastewater pipe networks to account for leakage. In the fundamental models for the decision support system, leakage is viewed as a function of pipeline system deterioration. The models rely on soil type identification across the service area to determine the aggressiveness of the pipe environment and for division of the area into zones based on pipe properties and operational conditions. By understanding the interaction between pipe materials, operating conditions, and the pipe environment in the mechanisms leading to pipe deterioration, the models allow the prediction of leakage rates in different zones across a network. The decision support system utilizes these models to predict the condition of pipes in individual zones, and to optimize the utilization of rehabilitation resources by targeting the areas with the highest leakage rates.


2019 ◽  
Vol 11 (4) ◽  
pp. 491-502
Author(s):  
Abtin Baghdadi ◽  
Mahmoud Heristchian ◽  
Harald Kloft

Abstract Heinz Isler as the most famous contemporary shell designer has widely employed physical pre-modelling techniques for construction of many concrete shell structures. Through the physical approach to optimal form finding, Isler accomplished shell structures with robust performance. It would be interesting and beneficial to re-assess Isler’s shells, hence, this article attempts to study the structural performance of eight notable shells of Isler. Through reverse engineering and by the assistance of Rhino, MATLAB and Grasshopper, the precise geometry of Isler’s selected shells were modelled for the finite element analysis under their self-weight. The structural analysis was performed, with the parallel use of finite element software SAP2000 and Abaqus. The identical results of the two packages, further confirmed the accuracy of the analysis. The essential properties of various forms of the shells and their differences in behaviour were pinpointed and discussed within the calculations and the results were compared with the data of the genuine published references on Isler’s works. The internal forces, the amount of von Mises stresses, support reactions and the buckling loads of the shells are explored. The analyses revealed that, despite of their major membrane action, all the shells had negligible amount of bending moments, especially near the supports. However, in general, all the shells exhibited an appropriate performance under the applied actions. But, at the same time, they exhibited different buckling behaviour as a probable source of instability in them.


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