A Modified Matlock–Duffing Model for Two-Dimensional Ice-Induced Vibrations of Offshore Structures With Geometric Nonlinearities

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Hugh McQueen ◽  
Narakorn Srinil
Keyword(s):  
Oil And Gas ◽  
Numerical Models ◽  
Wedge Angle ◽  
Offshore Structures ◽  
Two Dimensional ◽  
Geometric Nonlinearities ◽  
Oil And Gas Exploration ◽  
Nonlinear Stress ◽  
Exploration And Production ◽  
Duffing Model

Oil and gas exploration and production have been expanding in Arctic waters. However, numerical models for predicting the ice-induced vibrations (IIV) of offshore structures are still lacking in the literature. This study aims to develop a mathematical reduced-order model for predicting the two-dimensional IIV of offshore structures with geometric coupling and nonlinearities. A cylindrical structure subject to a moving uniform ice sheet is analyzed using the well-known Matlock model, which, in the present study, is extended and modified to account for a new empirical nonlinear stress–strain rate relationship determining the maximum compressive stress (MCS) of the ice. The model is further developed through the incorporation of ice temperature, brine content, air volume, grain size, ice thickness, and ice wedge angle effects on the ice compressive strength. These allow the effect of multiple ice properties on the ice–structure interaction to be investigated. A further advancement is the inclusion of an equation allowing the length of failed ice at a point of failure to vary with time. A mixture of existing equations and newly proposed empirical relationships is used. Structural geometric nonlinearities are incorporated into the numerical model through the use of Duffing oscillators, a technique previously proposed in vortex-induced vibration studies. The model is validated against results from the literature and provides new insights into IIV responses including the quasi-static, randomlike chaotic, and locked-in motions, depending on the ice velocity and system nonlinearities. This numerical Matlock–Duffing model shows a potential to be used in future IIV analysis of Arctic cylindrical structures, particularly fixed offshore structures, such as lighthouses, gravity bases, and wind turbine monopiles.

Modelling Two-Dimensional Ice-Induced Vibrations of Offshore Structures With Geometric Nonlinearities

2015 ◽  
Author(s):  
Hugh McQueen ◽  
Narakorn Srinil
Keyword(s):  
Numerical Model ◽  
Oil And Gas ◽  
Numerical Models ◽  
Wedge Angle ◽  
Offshore Structures ◽  
Degree Of Freedom ◽  
Two Dimensional ◽  
Structural Dynamic ◽  
Geometric Nonlinearities ◽  
Nonlinear Stress

Oil and gas exploration and production has been expanding in Arctic waters. However, numerical models for predicting the ice-induced vibrations (IIV) of offshore structures are still lacking in literature. This study aims to develop a mathematical reduced-order model for predicting the two-dimensional IIV of offshore structures with geometric coupling and nonlinearities. A cylindrical structure subject to a moving uniform ice sheet is analysed using the well-known Matlock model which, in the present study, is extended and modified to account for a new empirical nonlinear stress-strain rate relationship determining the maximum compressive stress of the ice. The model is further developed through the incorporation of ice temperature, brine content, air volume, grain size, ice thickness and ice wedge angle effects on the ice compressive strength. These allow the effect of multiple ice properties on the ice-structure interaction to be investigated. A further advancement is the inclusion of an equation allowing the length of failed ice at a point of failure to vary with time. A mixture of existing equations and newly proposed empirical relationships are used. Structural geometric nonlinearities are incorporated into the numerical model through the use of Duffing oscillators, a technique previously proposed in vortex-induced vibration studies. A one-degree-of-freedom (DOF) model is successfully validated against experimental results from the literature whilst the extended two-degree-of-freedom model produces new insights. Parametric studies highlight the effect of asymmetric geometric nonlinearities and ice velocity on the structural dynamic response. Results were compared to Palmer et al. (2010) which identified quasi-static, random-like or chaotic and locked-in motions. This numerical model has advanced the original Matlock model, showing a potential to be used in future IIV analysis of arctic cylindrical structures, particularly fixed offshore structures such as lighthouses, gravity bases and wind turbine monopiles.

Offshore structure design and development

1982 ◽  
Vol 307 (1499) ◽  
pp. 263-277
Keyword(s):  
Deep Water ◽  
Oil And Gas ◽  
Offshore Structures ◽  
Structure Design ◽  
Offshore Structure ◽  
Oil And Gas Exploration ◽  
Exploration And Production ◽  
Offshore Oil And Gas ◽  
Offshore Structure Design ◽  
Offshore Oil

The kinds of technology currently being applied to the design, construction, installation and operation of offshore structures for oil and gas exploration and production are quite sophisticated and include many examples of innovative configurations and approaches. The decade of the 1990s should see further evolution, reinterpretation and improvements of concepts that are already in service or being readied for service. The importance of offshore oil and gas may be judged by the projection that over half of overall exploration investments will go to offshore prospects in future years. This paper surveys some expected evolutions, with particular emphasis on the challenging area of deep-water applications. Some features of a tension leg platform design are discussed as an example of a deep-water oil production system. An attempt is made to recognize the problems of applying advanced engineering and analytical capabilities, when many specialists must interact, to producing a thoroughly engineered design, which is also balanced and economical, for such innovative systems.

Accelerating oil and gas investment and reserves by design

2018 ◽  
Vol 58 (2) ◽  
pp. 557
Author(s):  
Barry A. Goldstein
Keyword(s):  
Natural Gas ◽  
Fossil Fuels ◽  
Oil And Gas ◽  
South Australia ◽  
Land Access ◽  
Oil And Gas Exploration ◽  
Oil And Gas Producers ◽  
Crude Oil Prices ◽  
Exploration And Production ◽  
Oil And Gas Operations

Facts are stubborn things; and whatever may be our wishes, our inclinations, or the dictates of our passion, they cannot alter the state of facts and evidence (Adams 1770). Some people unfamiliar with upstream petroleum operations, some enterprises keen to sustain uncontested land use, and some people against the use of fossil fuels have and will voice opposition to land access for oil and gas exploration and production. Social and economic concerns have also arisen with Australian domestic gas prices tending towards parity with netbacks from liquefied natural gas (LNG) exports. No doubt, natural gas, LNG and crude-oil prices will vary with local-to-international supply-side and demand-side competition. Hence, well run Australian oil and gas producers deploy stress-tested exploration, delineation and development budgets. With these challenges in mind, successive governments in South Australia have implemented leading-practice legislation, regulation, policies and programs to simultaneously gain and sustain trust with the public and investors with regard to land access for trustworthy oil and gas operations. South Australia’s most recent initiatives to foster reserve growth through welcomed investment in responsible oil and gas operations include the following: a Roundtable for Oil and Gas; evergreen answers to frequently asked questions, grouped retention licences that accelerate investment in the best of play trends; the Plan for ACcelerating Exploration (PACE) Gas Program; and the Oil and Gas Royalty Return Program. Intended and actual outcomes from these initiatives are addressed in this extended abstract.

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.

Mathematical Modeling and Analysis of Riser Gas Unloading Problem

2018 ◽  
Author(s):  
Raj Kiran ◽  
Saeed Salehi
Keyword(s):  
Oil And Gas ◽  
Numerical Models ◽  
Drilling Fluid ◽  
Extensive Study ◽  
Integrated System ◽  
Modeling And Analysis ◽  
Oil And Gas Exploration ◽  
Water Based ◽  
Point Pressure ◽  
Comparative Results

Pushing the boundaries of oil and gas exploration and development to new frontiers have led to exposure and more significant uncertainties, which necessitates robust strategies and techniques. With the increasing water depth, longer risers, and harsh pressure and temperature conditions; the risk of riser gas getting undetected get bigger. The lack of an integrated system to anticipate the controlling parameters at the choke below the BOP constrains the tackling operations and exacerbate the side effects of oil and gas well blowouts. This leads to an urgent need for an extensive study to address the riser gas unloading (RGU) events. This study encompasses the development of a robust model that can characterize the effect of different parameters such as temperature, mud types, back pressure, and solubility in RGU events. It also presents comparative results of oil-based and water-based mud systems, using a novel tool based on analytical and numerical models. The analytical model is constructed using combined gas law, heat transfer mechanism, and gas solubility and bubble point pressure concepts. Results suggest that the oil-based mud (OBM) takes more time for gas unloading in comparison to the water-based mud. Also, a significant deviation was observed in unloading patterns while considering temperature effect. For the drilling fluid without temperature consideration, the gas unloading occur in a smaller span of time and at a higher depth. Overall, this paper will demonstrate the effect of different parameters affecting the gas unloading in the riser, and present a comparative study of different parameters using an analytical which can be used in the field to get an idea of gas prior to any response for abnormality.

scholarly journals Analisis Curse Theory pada Sumber Daya Alam Migas Bagi Warga Madura

2018 ◽  
Vol 14 (1) ◽  
pp. 12
Author(s):  
Mohammad Hidayaturrahman
Keyword(s):  
Oil And Gas ◽  
Gas Production ◽  
Community Empowerment ◽  
Government Programs ◽  
Oil And Gas Production ◽  
Oil And Gas Exploration ◽  
Exploration And Production ◽  
State Income ◽  
The Government ◽  
Oil And Gas Sector

Government policies in natural resource management, especially in the oil and gas sector face a lot of problems. However, the government also has a responsibility to improve the life of people affected from oil and gas exploration and production activities. This research was aimed at investigating how the implementation of policies run by the central and local government toward the oil and gas management and community empowerment, especially the community located closely  to oil and gas exploration and production activity in Madura, East Java. This research method is phenomenological research using descriptive qualitative approach. Therefore, this study is conducted through direct observation on the object during the research time. The data collection is done through observation and interview. The results of this study revealed that it is needed an integrated step done by the government, vertically, whether central, provincial, district, and village to synchronize oil and gas management and community empowerment programs. By doing so, the ideas and desires to improve the welfare and increase the state income will be realized, especially in focusing corporate and government programs improving citizen’ economic and education, whose area becomes the location of oil and gas production.

scholarly journals Fluid pressure waves trigger earthquakes

2015 ◽  
Vol 200 (3) ◽  
pp. 1279-1283 ◽  
Author(s):  
Francesco Mulargia ◽  
Andrea Bizzarri
Keyword(s):  
Oil And Gas ◽  
Nonlinear Partial Differential Equation ◽  
Active Faults ◽  
Fluid Pressure ◽  
Rock Joints ◽  
Pressure Waves ◽  
Earthquake Triggering ◽  
Oil And Gas Exploration ◽  
Exploration And Production ◽  
Von Mises

Abstract Fluids—essentially meteoric water—are present everywhere in the Earth's crust, occasionally also with pressures higher than hydrostatic due to the tectonic strain imposed on impermeable undrained layers, to the impoundment of artificial lakes or to the forced injections required by oil and gas exploration and production. Experimental evidence suggests that such fluids flow along preferred paths of high diffusivity, provided by rock joints and faults. Studying the coupled poroelastic problem, we find that such flow is ruled by a nonlinear partial differential equation amenable to a Barenblatt-type solution, implying that it takes place in form of solitary pressure waves propagating at a velocity which decreases with time as v ∝ t [1/(n − 1) − 1] with n ≳ 7. According to Tresca-Von Mises criterion, these waves appear to play a major role in earthquake triggering, being also capable to account for aftershock delay without any further assumption. The measure of stress and fluid pressure inside active faults may therefore provide direct information about fault potential instability.

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