scholarly journals Pipeline Performances under Earthquake-Induced Soil Liquefaction: State of the Art on Real Observations, Model Tests, and Numerical Simulations

2020 ◽  
Vol 2020 ◽  
pp. 1-20
Author(s):  
Massimina Castiglia ◽  
Tony Fierro ◽  
Filippo Santucci de Magistris

The design and the manufacture of the oil and gas pipelines are being improved over the years in response to the observed damages and related disastrous effects. The improvements are possible, thanks to the increasing knowledge about pipeline performances in specific contexts. The seismic hazard on buried pipelines has always been of major concern, and the earthquake-induced soil liquefaction effects are among the most important issues to be accounted for in the design. Experiences based on case histories, experimental modelling, and numerical simulations represent the source of understanding of the involved mechanisms, the affecting parameters, and the structure response. Recently, all these aspects are becoming more accurate, thanks to the use of monitoring systems. The protection of pipelines from the seismic hazard is a crucial and challenging issue. This paper provides an overview of the research that has been conducted over the years in the specific framework of soil liquefaction phenomenon. Case histories on pipeline performances, commonly adopted analytical methods, and results of model tests and numerical simulations are summarized with main focus on the level of knowledge achieved up to date and the existing limitations that represent open issues for further development of the research. This study represents a useful background to be adopted from academics and practitioners in order to enhance the methods of analyses of the pipelines, thus improving their performances in the applications of the oil and gas industry.

Author(s):  
Warren Brown ◽  
Geoff Evans ◽  
Lorna Carpenter

Over the course of the past 20 years, methods have been developed for assessing the probability and root cause of bolted joint leakage based on sound engineering assessment techniques. Those methods were incorporated, in part, into ASME PCC-1-2010 Appendix O [7] and provide the only published standard method for establishing bolted joint assembly bolt load. As detailed in previous papers, the method can also be used for troubleshooting joint leakage. This paper addresses a series of actual joint leakage cases, outlines the analysis performed to determine root cause of failure and the actions taken to successfully eliminate future incidents of failure (lessons learned).


Author(s):  
Are Johan Berstad ◽  
Jan Vidar Aarsnes

This paper presents a case study of a structure of a novel fish farm cage. The “AquaTraz” cage is more similar to structures known to the the oil and gas industry. The cage has the same shape as the normal cages used in the aquaculture industry and can be introduced to existing grid-moorings. Model testing has been carried out and results from the model test are compared with results from numerical simulations using the tool AquaSim. The response deviating from classic fish farms is shown and what extra considerations that should be carried out for this type of systems compared to classic fish farms is discussed.


Author(s):  
S. N. A. Tuhaijan ◽  
C. Y. Ng ◽  
V. J. Kurian

In South East Asia, Malaysia is one of the leading countries in the oil and gas industry. Today, Malaysia has expanded the explorations into the deeper water region. Before the installation of the Malaysia first deepwater platform, the Kikeh Spar, spar platforms can only be found in the Gulf of Mexico. Malaysian offshore regions are subjected to significant water current. From the literature review carried out, it was found that the current would change the behavior of the sea waves. This is contributing significantly to the environmental loading and affect the dynamic responses of the offshore structures. Hence, the study that focused on the effects of the current together with the wave on the structural dynamic response is necessary. In this study, the effect of the current coexisting with the wave on the dynamic responses of a truss spar model was experimentally investigated and quantified. The model tests were performed in the wave tank of the Offshore Laboratory in Universiti Teknologi PETRONAS with a scaling factor of 1:100. Two sets of environmental conditions were considered in the model tests i.e. wave only and wave-current condition. The dynamic responses of the truss spar model subjected to these conditions were measured. In order to quantify the effect of current, the measured results for the condition with and without current were compared among and presented here. From this investigation, it was found that the existence of the current in the water body has increased the truss spar motions, whereby the higher current velocity, give the higher response.


Author(s):  
Edwin Kreuzer ◽  
Ludwig Krumm ◽  
Marc-André Pick

Drill strings are used in the oil and gas industry to search for oil, gas, and geothermal resources and form extremely slender structures which makes them very sensitive to torsional and other vibrations. In order to immensely reduce torsional vibrations along the whole string, a wave based control method was developed at our institute. Numerical simulations and tests at an experimental setup showed very good results, but the implementation in a real drilling rig has not yet been taken place. One apparent difference in a real drill string will be the assembly of many rather short drill pipes, which is unregarded in conventional models and our small test rig. This might lead to improper behavior of our wave based control mechanism and shall be investigated is this paper. We present a model that accounts for a discontinuously built drill string and show the consequences for our advanced control method via numerical simulations.


Author(s):  
X. D. Liu ◽  
J. Sun ◽  
J. T. Yi ◽  
F. H. Lee ◽  
H. Gu ◽  
...  

Depletion of shallow-water hydrocarbons is increasingly forcing the oil and gas industry to explore in deeper water. Dynamically installed anchors (i.e. torpedo anchors and deep penetrating anchor) are increasingly used as a cost-effective solution for floating offshore structures in deep water environments because their installation cost is largely independent of water depth. In addition, dynamically installed anchors can be deployed accurately, and their performance is less dependent on accurate assessment of the soil shear strength since lower seabed strengths permit greater penetration depths. Despite of the economic advantages afforded by dynamically installed anchors, there remain significant uncertainties in the prediction of the embedment depth and verticality, which is likely to affect their long-term holding capacity. Currently, the holding capacity of the dynamically installed anchors is assessed using conventional pile capacity techniques, which neglect discrepancies in the rate of installation and failure mechanism between them. This paper presents a series of model tests simulating dynamic installation and monotonic pull-out of dynamically installed anchors in normally consolidated clay. The model tests are carried out in a beam centrifuge at 100g, with varying penetration angles, extraction angles and model masses. A special designed apparatus allows model anchors to be penetrated and extracted with different penetration angles. The test results show that for models without fins, no matter by which angle the model penetrated the soil, the smallest value of holding capacity is obtained when the pullout and penetration directions are the same. Results also indicate that the penetration depth linearly increases with the anchor mass. This study also reported the results from finite element (FE) analyses. The Coupled Eulerian-Lagrangian (CEL) approach in the commercial FE package Abaqus/Explicit is carried out to simulate dynamic anchor installation. The findings of this study points to a method of assessing the minimum holding capacity of the anchor and its depth of penetration. Further study is now on-going to study the behavior of finned anchors.


2020 ◽  
Vol 78 (7) ◽  
pp. 861-868
Author(s):  
Casper Wassink ◽  
Marc Grenier ◽  
Oliver Roy ◽  
Neil Pearson

2004 ◽  
pp. 51-69 ◽  
Author(s):  
E. Sharipova ◽  
I. Tcherkashin

Federal tax revenues from the main sectors of the Russian economy after the 1998 crisis are examined in the article. Authors present the structure of revenues from these sectors by main taxes for 1999-2003 and prospects for 2004. Emphasis is given to an increasing dependence of budget on revenues from oil and gas industries. The share of proceeds from these sectors has reached 1/3 of total federal revenues. To explain this fact world oil prices dynamics and changes in tax legislation in Russia are considered. Empirical results show strong dependence of budget revenues on oil prices. The analysis of changes in tax legislation in oil and gas industry shows that the government has managed to redistribute resource rent in favor of the state.


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