Influence of Ocean Transport on the Design of Onshore and Offshore Constructions, Modules, Topsides, Jackets and Towage on FPSO Design

2013 ◽  
Author(s):  
A. J. Bos ◽  
T. M. Ligterink
Keyword(s):  
Fatigue Damage ◽  
Proper Motion ◽  
Oil And Gas ◽  
Offshore Structures ◽  
General Purpose ◽  
Design Phase ◽  
Floating Structures ◽  
Final Destination ◽  
Rules Of Thumb ◽  
Negative Effect

Oil and gas installations both onshore as well as offshore are often built in modules and components on a different location than where those facilities are commissioned. Although stress and fatigue damage have proven to be significant on these structures during ocean transport, ocean transportation is often not adequately accounted for during design. Prior to arrival on its final destination, constructions are exposed to severe motions when carried on a modules carrier, a general purpose vessel or towed by 1 or more ocean tugs. The authors argue that calculations on the significance and effect of these motions should be based on proper motion response calculations instead of currently used ‘rules of thumb’. Especially regarding the continuing growth of the size of these carriers and the weight of the structures which both increase the negative effect of sea behavior and affects the loads on the constructions. This article aims to explain the importance of design for transport during the design-phase of these onshore and offshore structures. A distinction is made between structures transported aboard a barge, semi-submersible or general purpose vessel and floating structures transported through a ‘wet-tow’ operation.

Hull Structure Integrity Management in Floating Structures–FSO Puteri Dulang Case

2014 ◽  
Vol 69 (7) ◽  
Author(s):  
Ajith Kumar Thankappan ◽  
M. Fazli B. M. Yusof
Keyword(s):  
Fatigue Life ◽  
Structural Integrity ◽  
Structural Response ◽  
Offshore Structures ◽  
Design Phase ◽  
Floating Structures ◽  
Offshore Installations ◽  
Hull Structure ◽  
Integrity Management ◽  
New Buildings

This paper highlights the key differences in practices employed in managing hull structure integrity of permanently moored floating offshore structures as against sailing vessels which are subject to periodic dry docking. During the design phase, the structural integrity management over the life of a sailing vessel is primarily taken into account by means of Class prescribed Nominal Design Corrosion Values which are added to minimum scantling requirements calculated based on strength and fatigue criteria. In contrast, for permanently moored offshore installations like FPSOs, FSOs etc. the hull structure integrity over the entire design life of the asset is a key design consideration both for new buildings and conversions. Analytic methods and tools (primarily those developed by Class Societies) are available to evaluate the strength requirements (based on yielding, buckling and ultimate strength criteria) and fatigue life of the hull structure. Typically three levels of analysis with increasing degree of complexity and analysis time are used to predict the structural response and fatigue life of the Hull during design phase. The degree of detailed analysis required needs to be determined in light of the expected optimization in terms of savings in scantlings for new building or for steel renewal requirements in case of conversions.

Fatigue Analysis of Subsea Jumpers due to Slug Flow

2014 ◽  
Author(s):  
Bob (H. E. J. ) van der Heijden ◽  
Henk Smienk ◽  
Andrei V. Metrikine
Keyword(s):  
Pressure Drop ◽  
Static Analysis ◽  
Fatigue Damage ◽  
Slug Flow ◽  
Oil And Gas ◽  
Operating Conditions ◽  
Design Phase ◽  
Line System ◽  
Excitation Mechanisms ◽  
The Difference

Rigid steel jumpers are used in a subsea flow line system to connect subsea components. They provide a certain flexibility with respect to installation and operating conditions. This flexibility makes the jumper susceptible to slug flow induced vibrations. Slug flow can be described as an alternating flow of long oil and gas bubbles which flow at the gas velocity. The alternation between oil and gas density causes loads on the jumper which causes the jumper to vibrate. Two excitation mechanisms can be identified; 1) The variation in weight along the straight sections and 2) the difference in impact loads on the bends. Due to the cyclic nature of these loads fatigue can cause the jumper to fail. As a main contractor of SURF-projects (Subsea Umbilicals Risers and Flowlines) Heerema Marine Contractors (HMC) is responsible for the engineering, procurement, construction and installation (EPCI) of the entire project scope, including the design of the subsea jumpers. Hence this paper has been set up by HMC and the Delft University of Technology to study slug flow induced fatigue in subsea jumpers and in order to find new design considerations. In the early design phase of a subsea jumper the offshore industry commonly uses, to authors knowledge, a static analysis to predict the fatigue damage caused by slug flow. Since the vibrations caused by slug flow are not incorporated in a static analysis an accurate tradeoff between flexibility and fatigue lifetime cannot be made during the design phase. As this tradeoff during the design phase is desirable, a new dynamic and more accurate analysis method has been developed which takes these vibrations into account. A comparison between this new methodology and the common industry method is made in order to quantify the difference in analyzed fatigue damage due to slug flow induced vibration. Additionally the effects of a pressure drop over a passing slug is also investigated to determine if a pressure drop should be incorporated as a design factor for slug flow induced fatigue. The new dynamic method will also be used to investigate the relation between jumper configuration and high slug flow velocity. It will show what excitation mechanisms are dominant and how this affects the fatigue behavior. Since is be the first time, to authors knowledge, such an extensive analysis of geometries and velocities is undertaken it will provide new insights into slug flow induced fatigue in subsea jumpers in general. The newly found amplification and attenuation of the vibration by the successive impacts on the bends of a subsea jumper are investigated.

Life Extension of Ageing Offshore Structures: A Framework for Remaining Life Estimation

2017 ◽  
Author(s):  
Ashish Aeran ◽  
Sudath C. Siriwardane ◽  
Ove Mikkelsen ◽  
Ivar Langen
Keyword(s):  
Fatigue Damage ◽  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Offshore Structures ◽  
Assessment Process ◽  
Localized Corrosion ◽  
Life Extension ◽  
Remaining Life ◽  
Structural Degradation ◽  
Life Estimation

The remaining life estimation of ageing structures has been identified as a growing challenge in the oil and gas industry. Although the available guidelines provide a general fatigue assessment process, it is necessary to have more detailed guidelines by adding relevant theories and models which can capture the time-dependent structural degradation more precisely. To address this, a new framework is proposed in this paper. The proposed framework provides recommendations on various issues such as simulation of structural degradation, loading history, effect of localized corrosion, selection of a suitable fatigue strength curve and fatigue damage theories. Recently developed precise fatigue damage theory is also included in the proposed framework.

Identification of the Possible Negative Effect of the Brucite Drilling Reagent on the Employees Involved in the Wells Construction

2021 ◽  
pp. 75-80
Author(s):  
K.B. Tagirova ◽  
◽  
V.B. Barakhnina ◽  
I.R. Kireev ◽  
Ya.A. Konnov ◽  
...  
Keyword(s):  
Oil And Gas ◽  
Incidence Rates ◽  
General Purpose ◽  
The Body ◽  
Dust Particles ◽  
Chemical Reagents ◽  
Negative Effect ◽  
Inorganic Chemical ◽  
Harmful Effects ◽  
Macrophage Reaction

In the technological processes of oil and gas wells construction, a variety of general-purpose inorganic chemical reagents are used. The ingress of these reagents into the body of drilling enterprises employees together with the inhaled air, ingested food (through the pores and mucous membrane) is currently not sufficiently studied. The work investigated the effect of the Brucite drilling reagent on the lung tissue of rats of the non-linear albino line. With the inhalation of the Brucite drilling reagent to rats, the dystrophic processes were observed in their lungs, which were accompanied by the development of chronic inflammation and an acute macrophage reaction. There was a significant increase in the size of perivascular infiltrates compared to the control (13370 ± 248.6) μm2) with 14-day administration of particles of the Brucite drilling reagent — (14867.21 ± 369.29) μm2, with 30-day administration — 15853, 87 ± 126.57. Also, morphometric analysis showed a significant decrease in the area of alveolar space, and the area of medium-caliber bronchus. In the lungs, the formation of many airless areas was noted, alternating with emphysematous — altered, the severity of which increased with the duration of exposure to the drilling reagent. The consequence of work with Brucite drilling reagent of the drilling enterprises employees can be professional, acute, and chronic diseases of the lungs, as well as specific sensitization of the body caused by the exposure to dust particles. In the future, it is planned to conduct a statistical analysis of the incidence rates with temporary disability, occupational diseases, and occupational poisoning among the employees in contact with the Brucite drilling reagent, and the development of efficient measures to reduce the harmful effects of the Brucite drilling reagent on the certain categories of specialists at the drilling enterprises.

A method of technical diagnostics for offshore structures

1994 ◽  
Vol 16 (2) ◽  
pp. 43-48
Author(s):  
Do Son
Keyword(s):  
Diagnostic Method ◽  
Joint Venture ◽  
Oil And Gas ◽  
Residual Life ◽  
Life Time ◽  
Offshore Structures ◽  
Technical Diagnostics ◽  
Offshore Platforms ◽  
South Vietnam ◽  
Local Destruction

This paper describes the results of measurements and analysis of the parameters, characterizing technical state of offshore platforms in Vietnam Sea. Based on decreasing in time material characteristics because of corrosion and local destruction assessment on residual life time of platforms is given and variants for its repair are recommended. The results allowed to confirm advantage of proposed technical diagnostic method in comparison with others and have been used for oil and gas platform of Joint Venture "Vietsovpetro" in South Vietnam.

Sand Free Production Success Through Proven Technology Enabler from An Untapped Heterogeneous Reservoir Zone Utilizing Gravel Pack Replacement Methodology

2020 ◽  
Author(s):  
Y. Anggoro
Keyword(s):  
Oil And Gas ◽  
Erosion Resistance ◽  
Cost Effective ◽  
High Rate ◽  
Screen Design ◽  
Sand Control ◽  
Rules Of Thumb ◽  
Production Success ◽  
Control Technologies ◽  
Gravel Pack

The Belida field is an offshore field located in Block B of Indonesia’s South Natuna Sea. This field was discovered in 1989. Both oil and gas bearing reservoirs are present in the Belida field in the Miocene Arang, Udang and Intra Barat Formations. Within the middle Arang Formation, there are three gas pay zones informally referred to as Beta, Gamma and Delta. These sand zones are thin pay zones which need to be carefully planned and economically exploited. Due to the nature of the reservoir, sand production is a challenge and requires downhole sand control. A key challenge for sand control equipment in this application is erosion resistance without inhibiting productivity as high gas rates and associated high flow velocity is expected from the zones, which is known to have caused sand control failure. To help achieve a cost-effective and easily planned deployment solution to produce hydrocarbons, a rigless deployment is the preferred method to deploy downhole sand control. PSD analysis from the reservoir zone suggested from ‘Industry Rules of Thumb’ a conventional gravel pack deployment as a means of downhole sand control. However, based on review of newer globally proven sand control technologies since adoption of these ‘Industry Rules of Thumb’, a cost-effective solution could be considered and implemented utilizing Ceramic Sand Screen technology. This paper will discuss the successful application at Block B, Natuna Sea using Ceramic Sand Screens as a rigless intervention solution addressing the erosion / hot spotting challenges in these high rate production zones. The erosion resistance of the Ceramic Sand Screen design allows a deployment methodology directly adjacent to the perforated interval to resist against premature loss of sand control. The robust ceramic screen design gave the flexibility required to develop a cost-effective lower completion deployment methodology both from a challenging make up in the well due to a restrictive lubricator length to the tractor conveyancing in the well to land out at the desired set depth covering the producing zone. The paper will overview the success of multi-service and product supply co-operation adopting technology enablers to challenge ‘Industry Rules of Thumb’ replaced by rigless reasoning as a standard well intervention downhole sand control solution where Medco E&P Natuna Ltd. (Medco E&P) faces sand control challenges in their high deviation, sidetracked well stock. The paper draws final attention to the hydrocarbon performance gain resulting due to the ability for choke free production to allow drawing down the well at higher rates than initially expected from this zone.

A Phenomenological Model for Vortex-Induced Motions of the Monocolumn Platform and Comparison With Experiments

2009 ◽  
Author(s):  
Guilherme F. Rosetti ◽  
Rodolfo T. Gonc¸alves ◽  
Andre´ L. C. Fujarra ◽  
Kazuo Nishimoto ◽  
Marcos D. Ferreira
Keyword(s):  
Time Domain ◽  
Phenomenological Model ◽  
Structural Model ◽  
Design Phase ◽  
Van Der Pol ◽  
Floating Structures ◽  
Towing Tank ◽  
Wake Oscillator ◽  
Two Degree Of Freedom ◽  
Comparison With Experiments

Vortex-Induced Motions (VIM) of floating structures is a very relevant subject for the design of mooring and riser systems. In the design phase, Spar VIM behavior as well as Semi Submersible and Tension Leg Platform (TLP) flow-induced motions are studied and evaluated. This paper discusses flow-induced behavior on the Monocolumn concept by presenting a phenomenological model and comparing its results with a set of experiments that took place in the IPT Towing Tank - Brazil (September 2008). The experimental results have shown some fundamental differences from previous VIM tests on other units such as Spars. This numerical model attempts to identify these disparities in order to better understand the mechanics of this phenomenon. The model is based on a time-domain, two degree-of-freedom structural model coupled with a van der Pol type wake oscillator. The comparison was performed in order to calibrate the model, to study and better understand the tests results, and finally to identify important aspects to investigate in further experiments.

Launching of Ships and Floating Structures from Horizontal Berth by Tipping Table

1998 ◽  
Vol 14 (04) ◽  
pp. 265-276
Author(s):  
Ivo Senjanovic
Keyword(s):  
Structural Dynamics ◽  
Review Paper ◽  
Offshore Structures ◽  
Model Tests ◽  
Full Scale ◽  
Strength Analysis ◽  
Test Results ◽  
Floating Structures ◽  
Measurement Results

This review paper covers extensive investigations which were undertaken in order to verify the idea of launching of ships and other floating structures from a horizontal berth by a set of turning pads. This includes structural dynamics during launching, model tests and strength analysis of the structure and the launching system. The most important results, which were used for the design of the launching system, are presented. The preparation of a barge for side launching is described, and the full-scale measurement results are compared with the test results. The advantages of building ships and offshore structures on a horizontal berth are pointed out in the conclusion.

Stability of offshore structures in shallow water depth

2011 ◽  
Vol 2 (2) ◽  
pp. 320-333
Author(s):  
F. Van den Abeele ◽  
J. Vande Voorde
Keyword(s):  
Shallow Water ◽  
Water Depth ◽  
Fossil Fuels ◽  
Oil And Gas ◽  
Structural Response ◽  
Offshore Structures ◽  
Exploration And Production ◽  
Subsea Pipelines ◽  
Wave Induced ◽  
Shallow Water Depth

The worldwide demand for energy, and in particular fossil fuels, keeps pushing the boundaries of offshoreengineering. Oil and gas majors are conducting their exploration and production activities in remotelocations and water depths exceeding 3000 meters. Such challenging conditions call for enhancedengineering techniques to cope with the risks of collapse, fatigue and pressure containment.On the other hand, offshore structures in shallow water depth (up to 100 meter) require a different anddedicated approach. Such structures are less prone to unstable collapse, but are often subjected to higherflow velocities, induced by both tides and waves. In this paper, numerical tools and utilities to study thestability of offshore structures in shallow water depth are reviewed, and three case studies are provided.First, the Coupled Eulerian Lagrangian (CEL) approach is demonstrated to combine the effects of fluid flowon the structural response of offshore structures. This approach is used to predict fluid flow aroundsubmersible platforms and jack-up rigs.Then, a Computational Fluid Dynamics (CFD) analysis is performed to calculate the turbulent Von Karmanstreet in the wake of subsea structures. At higher Reynolds numbers, this turbulent flow can give rise tovortex shedding and hence cyclic loading. Fluid structure interaction is applied to investigate the dynamicsof submarine risers, and evaluate the susceptibility of vortex induced vibrations.As a third case study, a hydrodynamic analysis is conducted to assess the combined effects of steadycurrent and oscillatory wave-induced flow on submerged structures. At the end of this paper, such ananalysis is performed to calculate drag, lift and inertia forces on partially buried subsea pipelines.

scholarly journals Integrity Management of Marine Structures; With Emphasis on Design for Structural Robustness

2018 ◽  
Author(s):  
Torgeir Moan
Keyword(s):  
Structural Damage ◽  
Structural Integrity ◽  
Oil And Gas ◽  
Offshore Structures ◽  
Design Standards ◽  
Limit States ◽  
Fabrication Errors ◽  
Integrity Management ◽  
Operational Errors ◽  
And Control

Based on relevant accident experiences with oil and gas platforms, a brief overview of structural integrity management of offshore structures is given; including an account of adequate design criteria, inspection, repair and maintenance as well as quality assurance and control of the engineering processes. The focus is on developing research based design standards for Accidental Collapse Limit States to ensure robustness or damage tolerance in view damage caused by accidental loads due to operational errors and to some extent abnormal structural damage due to fabrication errors. Moreover, it is suggested to provide robustness in cases where the structural performance is sensitive to uncertain parameters. The use of risk assessment to aid decisions in lieu of uncertainties affecting the performance of novel and existing offshore structures, is briefly addressed.

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