Physical and Numerical Modeling of the Performance of Dynamically Installed Anchors in Clay

2014 ◽  
Author(s):  
X. D. Liu ◽  
J. Sun ◽  
J. T. Yi ◽  
F. H. Lee ◽  
H. Gu ◽  
...  
Keyword(s):  
Oil And Gas ◽  
Cost Effective ◽  
Oil And Gas Industry ◽  
Offshore Structures ◽  
Model Tests ◽  
Embedment Depth ◽  
Depth Of Penetration ◽  
Pile Capacity ◽  
Gas Industry ◽  
Pull Out

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.

The Effect of Current on the Dynamic Responses of Truss Spar in Malaysia Water

2016 ◽  
Author(s):  
S. N. A. Tuhaijan ◽  
C. Y. Ng ◽  
V. J. Kurian
Keyword(s):  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Offshore Structures ◽  
Model Tests ◽  
Dynamic Responses ◽  
Water Current ◽  
Sea Waves ◽  
Structural Dynamic ◽  
Gas Industry ◽  
Truss Spar

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.

scholarly journals ON STANDARDIZATION OF LABORATORY SOIL TESTING IN OFFSHORE GEOTECHNICAL SURVEY

Gruntovedenie ◽  
2021 ◽  
Vol 1 (16) ◽  
pp. 16-52
Author(s):  
E.A. Voznesensky ◽  
◽  
A.S. Loktev ◽  
M.S. Nikitin ◽  
◽  
...  
Keyword(s):  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Offshore Structures ◽  
Soil Testing ◽  
National Standard ◽  
Gas Industry ◽  
Code Of Practice ◽  
Complete Section ◽  
Testing Practice ◽  
Russian Soil

Issues of laboratory soil studies standardization in offshore geotechnical survey are discussed in connection with the end of expertise of two new regulative documents – new edition of the Code of practice and Russian national standard developed on the basis of international ISO standard. Since these documents of different level belong also to different categories (geotechnical survey and oil and gas industry), the authors analyze their interrelation and consistency, from one hand, and the preparedness of Russian soil testing practice to implementation of the new standard which results from harmonization with international ones, from the other. Complete section of the standard draft related to soil laboratory testing is presented, preceded by commentary on some important issues regarding the implementation of its specific methodic statements. It is concluded that the new national GOST draft «Petroleum and natural gas industries. Specific requirements for offshore structures. Marine soil investigations» developed on ISO basis will be a useful document supported in general by Russian normative base but expanding a possible range of voluntary methods into well time-tested foreign approaches. This documents can be considered to be a toolkit annex to the Code of practice describing testing approaches beyond the scope of typical tasks

Stress Concentration Factors Calculation: Analytical and Numerical Approaches for Welded Tubular Joints

2020 ◽  
Author(s):  
Nathalia Paruolo ◽  
Thalita Mello ◽  
Paula Teixeira ◽  
Marco Pérez
Keyword(s):  
Stress Concentration ◽  
Oil And Gas ◽  
Hot Spot ◽  
Experimental Tests ◽  
Oil And Gas Industry ◽  
Offshore Structures ◽  
Gas Industry ◽  
Tubular Joints ◽  
Concentration Factors ◽  
Stress Concentration Factors

Abstract In the oil and gas industry, fixed platforms are commonly applied in shallow water production. In-place environmental conditions generates cyclic loads on the structure that might lead to structural degradation due to fatigue damage. Fatigue is one of the most common failure modes of offshore structures and is typically estimated when dimensioning of the structure during design phase. However, in times when life extension of existing offshore structures is being a topic in high demand by industry, mature fields may represent an interesting investment, especially for small companies. Concerning fixed platforms, composed mainly by welded tubular joints, the assessment of hot spot stresses is considered to predict structure fatigue. The estimation of welded joint hot spot stresses is based on the stress concentration factors (SCFs), which are given by parametric formulae, finite element analysis (FEA) or experimental tests. Parametric formulae may be defined as a fast and low-cost method, meanwhile finite elements analysis may be time consuming and experimental tests associated with higher costs. Given these different characteristics, each method is applied according to the study case, which will rely on the joint geometry and associated loads. Considering simple joint geometries several sets of parametric equations found in the literature may be applied. On the other hand, the SCFs calculation of non-studied yet complex joints consider known formulae adapted according to the under load joint behavior and geometry. Previous analysis shows that this adaptation may furnish different results compared to those obtained by FEA. Furthermore, it is observed that even for simple joints the results derived from the different methods may differ. Given their importance for the oil and gas industry, since they are the basis for the assessment of the fatigue life of welded tubular joints which may impact on additional costs related to maintenance and inspection campaigns, the estimation of SCFs must be the most accurate as possible. Therefore, this paper intends to investigate the differences between results derived from parametric formulae and different FEA studies.

scholarly journals Characterization and Treatment Technologies Applied for Produced Water in Qatar

Water ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 3573
Author(s):  
Hana D. Dawoud ◽  
Haleema Saleem ◽  
Nasser Abdullah Alnuaimi ◽  
Syed Javaid Zaidi
Keyword(s):  
Natural Gas ◽  
Oil And Gas ◽  
Produced Water ◽  
Cost Effective ◽  
Oil And Gas Industry ◽  
Gas Industry ◽  
Treatment Techniques ◽  
Treatment Technologies ◽  
Oil Gas

Qatar is one of the major natural gas (NG) producing countries, which has the world’s third-largest NG reserves besides the largest supplier of liquefied natural gas (LNG). Since the produced water (PW) generated in the oil and gas industry is considered as the largest waste stream, cost-effective PW management becomes fundamentally essential. The oil/gas industries in Qatar produce large amounts of PW daily, hence the key challenges facing these industries reducing the volume of PW injected in disposal wells by a level of 50% for ensuring the long-term sustainability of the reservoir. Moreover, it is important to study the characteristics of PW to determine the appropriate method to treat it and then use it for various applications such as irrigation, or dispose of it without harming the environment. This review paper targets to highlight the generation of PW in Qatar, as well as discuss the characteristics of chemical, physical, and biological treatment techniques in detail. These processes and methods discussed are not only applied by Qatari companies, but also by other companies associated or in collaboration with those in Qatar. Finally, case studies from different companies in Qatar and the challenges of treating the PW are discussed. From the different studies analyzed, various techniques as well as sequencing of different techniques were noted to be employed for the effective treatment of PW.

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
Keyword(s):  
Seismic Hazard ◽  
Numerical Simulations ◽  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Model Tests ◽  
Soil Liquefaction ◽  
Case Histories ◽  
Gas Industry ◽  
Experimental Modelling ◽  
Level Of Knowledge

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.

Rationale for load specifications and load factors in the new CSA code for fixed offshore structures

1991 ◽  
Vol 18 (3) ◽  
pp. 454-464 ◽  
Author(s):  
Ian J. Jordaan ◽  
Marc A. Maes
Keyword(s):  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Offshore Structures ◽  
Limit States ◽  
Gas Industry ◽  
Offshore Installations ◽  
Load Factors ◽  
Annual Probability ◽  
Acceptable Risks ◽  
Economic Analyses

The Canadian Standards Association (CSA) initiated effort in 1984 aimed at the development of an offshore code for production structures in the oil and gas industry. The present paper summarizes the rationale behind the development of design load specifications in the preliminary standard S.471 "General requirements, design criteria, the environment, and loads." As part of this development, background calibration studies were conducted in tandem with the work of various committees. Selected results from these studies are also discussed in this paper. The basic objectives and tools for developing load criteria for the design of offshore installations are discussed. The use of economic analyses of cost versus safety of structures does not provide clear guidance, and the perspective taken is that of acceptable risks to an individual. This is used in the context of limit states design, which, in S.471, incorporates two safety classes. In order to provide consistent safety levels, the environmental loads are divided into categories based on frequent and rare occurrence, examples being waves and earthquakes, respectively. The role of the annual probability of failure in setting target levels of reliability as well as in the calibration process is emphasized. Various aspects of calibration are summarized, including the background to the rare-frequent separation of loads, the objective function used to optimize the results, as well as the method of handling model uncertainty. Key words: environment, limit states, loads, offshore, reliability, resistance, safety, structures.

ISO Offshore Structures Standards

2011 ◽  
Author(s):  
Philip Smedley ◽  
Pat O’Connor ◽  
Richard Snell
Keyword(s):  
Oil And Gas ◽  
Steel Structures ◽  
Oil And Gas Industry ◽  
Offshore Structures ◽  
National Standards ◽  
Gas Industry ◽  
Technical Content ◽  
Technical Advances ◽  
Integrity Management ◽  
Specific Assessment

The ISO 19900 series of Standards address the design, construction, transportation, installation, integrity management and assessment of offshore structures. Offshore structural types covered by ISO include: bottom-founded ‘fixed’ steel structures; fixed concrete structures; floating structures such as monohull FPSOs, semi-submersibles and spar platforms; arctic structures; and site-specific assessment of jack-up platforms. All the fundamental ISO Offshore Structural Standards have now been published representing a major achievement for the Oil and Gas Industry and representative National Standards Organizations. A summary of the background to achieving this milestone is presented in this paper. In parallel, other Codes and Standards bodies such as API, CEN, CSA, Norsok and the Classification Societies are looking to harmonize some, or all, of their Offshore Structures Standards in-line with ISO, wherever this is desirable and practical. API, in particular, have been pro-active in reviewing and revising their Offshore Recommended Practices (RPs) to maximize consistency with ISO, including revising the scope and content of a number of existing API RPs, adopting ISO language, and embracing technical content. Given API’s long heritage of Offshore Standards it is not surprising that this remains very much a mutual effort between ISO and API with much in ISO Standards building on existing API design practice. Now published, those involved in developing and maintaining the ISO 19900 series of Standards have to deal with both new and existing challenges, including encouraging wider awareness and adoption of these Standards, enhancing the harmonization effort, ensuring technical advances are captured in timely revisions to these Standards, and most pressing to ensure that the next generation of offshore engineers are encouraged to participate in the long-term development of the Standards that they will be using and questioning. This paper is one of a series of papers at this OMAE Conference that outline the technical content and future strategy of the ISO Offshore Structures Standards.

POTENTIAL IMPACTS OF GAS-TO-LIQUIDS ON THE OIL AND GAS INDUSTRY

2002 ◽  
Vol 42 (1) ◽  
pp. 47
Author(s):  
P.D. Patterson ◽  
R. Payne ◽  
S.S. Tam
Keyword(s):  
Production Rate ◽  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Depth Of Penetration ◽  
Consumer Market ◽  
Potential Growth ◽  
Gas Industry ◽  
Cost Reductions ◽  
Current Production ◽  
Gas To Liquids

Over the past decade interest in gas-to-liquids (GTL) technology within the oil and gas industry has been on the rise. Depending on the level of cost reductions obtained, this technology has the potential to create a significant change in the oil and gas industry. In an effort to consider these changes, this paper will address the following issues:Can GTL technology redefine the energy industry’s present structure and give rise to a broad range of new competitors and/or products? If so, how and when is it likely to happen?Our answer to the first part of the question is, simply, yes. GTL technology certainly has the potential. However, the depth and breadth and timing of GTL’s penetration into the industry will be driven by forces of cost, price and environmental regulations. The depth of penetration depends on the answers to the following questions: Can GTL plants be built for US$25,000/bpd or less? What impact will scale and learning curve have on cost reductions? What premium will the consumer market give for GTL products? Is the peak production for conventional oil production on the horizon?If the development of the LNG industry is representative of the potential growth in the GTL industry, we could project a GTL production rate of 1,000,000 bpd in 2025, or about 1.3% of the world’s current production rate.

The impact of oil and gas infrastructure in marine ecosystems: a global vision for informing decommissioning decisions

2020 ◽  
Vol 60 (2) ◽  
pp. 476
Author(s):  
D. L. McLean ◽  
T. Bond ◽  
J. C. Partridge ◽  
S. Rouse ◽  
M. Love
Keyword(s):  
Oil And Gas ◽  
Research Priorities ◽  
Cost Effective ◽  
Oil And Gas Industry ◽  
Environmental Data ◽  
Research Network ◽  
Gas Industry ◽  
Marine Research ◽  
Geographical Regions ◽  
The Impact

The offshore hydrocarbon basins of the world and their neighbouring countries are faced with an immense decommissioning challenge. Uncertainties in regulation and costs, coupled with limited environmental data, stifle consideration and support for alternative options to full removal. In separate regions, scientists and industry are forming partnerships and commencing research that advances understanding of regional and ecosystem-scale processes, including the habitat value of oil and gas infrastructure. With similar decommissioning-related marine research priorities being identified globally, a more coordinated approach to such research is needed: a global decommissioning marine research network and taskforce. This taskforce would not only be highly cost-effective, but it would also enable consistent approaches to science and management of the marine environment and secure protection and conservation of global marine resources. This network and taskforce would bring together leading scientists and experts in the oil and gas industry to develop an international research program that will significantly advance our understanding of the consequences to ecosystems as a result of decommissioning, as well as identify the differences and commonalities in environment–infrastructure interactions across different geographical regions. The outcomes would support sustainable installation and decommissioning practices worldwide and ensure that policies adhere to international agreements on environmental protection.

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