Numerical Analysis of Impact Loads on Subsea Structures During Water Entry in Presence of Waves

Author(s):  
Gustavo Garcia Momm ◽  
Ivan Fábio Mota de Menezes

Abstract Subsea structures employed on offshore oil and gas production systems are likely to be subject to severe loads during deployment. Lowering these structures through the wave zone is a critical operation and the prediction of the loads associated is complex as it involves accelerations of these bodies induced by the vessel motion and the sea surface displacements. This work presents a numerical approach to assessment of the effect of waves on the impact loads that subsea structures are subject to during water entry. A 2D one degree of freedom model using the SPH method was developed to estimate slamming loads on rigid bodies during water entry considering both calm and wavy surfaces. Initially the model was employed to simulate the water entry of wedge considering both free fall and constant velocity cases, obtaining loads profile similar to experiments and numerical simulations from the literature. Later, the constant velocity model was configured to a flat bottom surface rigid body in order to represent a subsea manifold. A regular waves generator provided different wavelength, height and phase enabling slamming load assessment in various situations.

Author(s):  
Trond G. Gru¨ner ◽  
Lars E. Bakken

The development of wet gas compressors will enable increased oil and gas production rates and enhanced profitable operation by subsea well-stream boosting. A more fundamental knowledge of the impact of liquid is essential with regard to the understanding of thermodynamic and fluid dynamic compressor behavior. An open-loop impeller test facility was designed to investigate the wet gas performance, aerodynamic stability, and operation range. The facility was made adaptable for different impeller and diffuser geometries. In this paper, the wet gas test facility and experimental work concerning the impact of wet gas on a representative full-scale industrial impeller are presented. The centrifugal compressor performance was examined at high gas volume fractions and atmospheric inlet conditions. Air and water were used as experimental fluids. Dry and wet gas performance was experimentally verified and analyzed. The results were in accordance with previous test data and indicated a stringent influence of the liquid phase. Air/water tests at atmospheric conditions were capable of reproducing the general performance trend of hydrocarbon wet gas compressor tests at high pressure.


2013 ◽  
Vol 688 ◽  
pp. 213-221 ◽  
Author(s):  
Juraj Králik

This paper presents a optimal design of a damping devices for the protection of the reinforced concrete structure of a nuclear power plant (NPP) against the impact loads from a container of nuclear fuel of the type TK C30 drop. The finite element idealization of the building structure is used in space. The interaction of the soil-structure, as well as the fluid-structure of the deactivated basin is considered in space. A steel pipe damper system is proposed for the dissipation of the kinetic energy of the container is free fall. The Newmark’s integration method is used for the solution of the dynamic equations.


Author(s):  
Kumarswamy Karpanan ◽  
Craig Hamilton-Smith

Subsea oil and gas production involves assemblies such as trees, manifolds, and pipelines that are installed on sea floor. Each of these components is exposed to severe working conditions throughout its operational life and is difficult and expensive to repair or retrieve installed. During installation and operation, a rig/platform and several supply vessels are stationed on the waterline directly above the well and installed equipment below. If any object is to be dropped overboard, it presents a hazard to the installed equipment. A subsea tree comprises of a number of critical components such as valves and hydraulic actuators, in addition to several electrical components such as the subsea control module and pressure/temperature gauges. Their ability to operate correctly is vital to the safe production of oil and gas. If an object were to impact and damage these components, resulting in their inability to operate as intended, the consequences could be severe. In this paper, a typical subsea tree frame is analyzed to ensure its ability to withstand the impact from an object accidentally dropped overboard. This was accomplished using nonlinear dynamic Finite Element Analysis (FEA). In this study, the framework was struck by a rigid body at terminal velocity, resulting in a given impact energy. Displacements and resultant strain values at critical locations were then compared to allowable limits to ensure compliance to the design requirements.


Author(s):  
Uwe Zencker ◽  
Linan Qiao ◽  
Holger Völzke

Drop test scenarios with cubic containers without impact limiters at interim storage sites or in a final repository have been investigated by numerical simulations. An ideally flat drop is impossible to conduct as a free fall of a container even under laboratory conditions. Dynamic stresses and strains inside the container structure are sensitive to the impact angle. Even very small impact angles cause remarkable changes in the experimental or numerical results when a flat bottom or wall of a container hits a flat target. For drop tests with transport packages the International Atomic Energy Agency (IAEA) regulations define an essentially unyielding target. In contrast, potential accident scenarios for storage containers are derived from site-specific safety analyses or acceptance criteria in Germany. Each interim storage site or repository has a yielding or so-called real target with individual structural and material properties. The real target acts as a kind of impact limiter. A more conservative container design is required if the impact limiting effect of the target is not considered.


2019 ◽  
Vol 12 (3) ◽  
pp. 46-57 ◽  
Author(s):  
S. V. Kazantsev

The article presents the results of the author’s research of the impact of a wide range of restrictions and prohibitions applied to theRussian Federation, used by a number of countries for their geopolitical purposes and as a means of competition. The object of study was the impact of anti-Russian sanctions on the development of Oil & Gas industry and defence industry complex ofRussiain 2014–2016. The purpose of the analysis was to assess the impact of sanctions on the volume of oil and gas production, the dynamics of foreign earnings from the export of oil and gas, and of foreign earnings from the sale abroad of military and civilian products of the Russian defence industry complex (DIC). As the research method, the author used the economic analysis of the time series of statistical data presented in open statistics and literature. The author showed that some countries use the anti-Russian sanctions as a means of political, financial, economic, scientific, and technological struggle with the leadership ofRussiaand Russian economic entities. It is noteworthy that their introduction in 2014 coincided with the readiness of theUSto export gas and oil, which required a niche in the international energy market. The imposed sanctions have affected the volume of oil production inRussia, which was one of the factors of reduction of foreign earnings from the country’s oil and gas exports. However, the Russian defence industry complex has relatively well experienced the negative impact of sanctions and other non-market instruments of competition


2021 ◽  
Author(s):  
Omran Al-Kuwari ◽  
Dan Welsby ◽  
Baltazar Solano Rodriguez ◽  
Steve Pye ◽  
Paul Ekins

Abstract This report focuses on reviewing the types of carbon intensity metrics, and the use of such metrics across the oil and gas sector, to monitor progress towards transitioning away from fossil fuel production. Producers are under pressure to respond to challenging conditions resulting from increasing climate policy, tightening markets and a move away by investors. A number of commentators are suggesting that production may have peaked, given these emerging trends, and the ongoing Covid-19 pandemic.From a combination of review and modelling, this report provides some key insights on carbon intensity metrics and the impact of different carbon intensities on future production, which are pertinent to the future strategies of the oil and gas sector -·Narrow-scoped metrics that only include upstream emissions are insufficient for producers reporting on progress towards climate goals. The carbon intensity of the final product also needs to be considered, given that it is increasingly subject to increased demand-side policy e.g. in relation to carbon pricing, bans on the sale of internal combustion engines (ICEs) etc.·Given that climate targets are expressed in absolute terms, the relative measure of progress provided by carbon intensity metrics is insufficient to guide progress towards net-zero emissions. As shown by the modelling, there is a significant decline in the levels of production permitted under climate targets by 2050. ·Given the need for diversification, metrics that account for scope 3 emissions will be important, to help monitor the transformation away from oil and gas. As discussed in this report, a number of IOCs appear to be making small steps in this direction, although their key business focus very much remains on oil & gas. As the IEA (2020a) has reported, less than 1% of capital expenditure is being spent outside of core business areas.·However, cleaner operations are also important. Therefore, scope 1&2 metrics are still useful for minimising upstream emissions. The modelling highlights the impact for example of high carbon intensity gas resources (due to methane emissions) on their production levels. Unconventional resources, which tend to require more energy input per unit of extraction, and are more costly, appear unlikely to be exploited in our Paris-aligned case.·Any assertion that higher carbon intensity production upstream can be offset by lower emissions downstream (e.g. via higher vehicle efficiency standards) is not supported by the modelling. This is particularly the case where these oil products are exported abroad to regions with low efficiency forms of transportation/limited environmental regulation.·National oil companies (NOCs) have more potential to achieve emission reduction from operational emissions, although the incentives to do so might be lower (with far less scrutiny and reporting). Diversification is also likely to be more of a challenge for NOCs, due to the reliance of public budgets on revenues gained. However, a number of high-producing countries are vigorously exploring diversification strategies. Such strategies could include massively increasing support for renewable industries, and focusing on areas such as hydrogen production and CCS applications.·For the large NOC producers, with the lowest-cost conventional reserves, it is likely that they may be able to continue producing for the longest time, as climate policy stringency increases. However, given that NOCs hold the largest reserves, risks of stranding will be greater in absolute terms.


2019 ◽  
Vol 7 (5) ◽  
pp. 122
Author(s):  
Pengyao Yu ◽  
Cong Shen ◽  
Chunbo Zhen ◽  
Haoyun Tang ◽  
Tianlin Wang

Motivated by the application of water-entry problems in the air-drop deployment of a spherical oceanographic measuring device, the free-fall water entry of a sphere was numerically investigated by using the transient Reynolds-averaged Navier–Stokes (RANS) method. A convergence study was carried out, which accounts for the mesh density and time-step independence. The present model was validated by the comparison of non-dimensional impact force with previous experimental and numerical results. Effects of parameters, such as impact velocity, radius, and mass of the sphere on the impact force and the acceleration of the sphere, are discussed. It is found that the peak value of the non-dimensional impact force is independent of the impact velocity and the radius of the sphere, while it depends on the mass of the sphere. By fitting the relationship between the peak value of the non-dimensional impact force and the non-dimensional mass, simplified formulas for the prediction of peak values of the impact force and the acceleration were achieved, which will be useful in the design of the spherical oceanographic measuring device.


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