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H2 and H2 Blends with Natural Gas Transportation in Offshore Pipelines: An Overview from Flow Assurance Perspective
Felice, A. Di (Saipem, Fano, Italy) | David, D. (Saipem, Jakarta, Indonesia) | Mosci, E. (Saipem, Fano, Italy) | Canestrari, A. (Saipem, Fano, Italy) | Masi, O. (Saipem, Fano, Italy) | Arcangeletti, G. (Saipem, Fano, Italy)
Abstract The use of offshore existing or new pipeline is a solution to deliver the blue / green hydrogen at reduced transport cost and in proximity of final users. Pipeline design and repurposing for hydrogen transportation require the use of commercial design tools, originally developed for hydrocarbons. The applicability of available design tools shall be assessed versus. available experimental data and academic studies findings to understand the current applicability range of the design tools and the areas of further improvements of commercial software to model green H2 and H2 + Natural Gas blends, with focus on thermophysical properties relevant to transport and hydrate estimation capabilities in the identified operating ranges. Thermodynamic tools are used to evaluate the phase behavior, thermodynamic data, and potential operational issue (like hydrate formation risk). Fluid dynamic tools are needed for the assessment of hydraulic performance and to generate inputs for mechanical sizing. The combination of both tools to develop models is the first step for the pipeline design. This work will present the results obtained for multiple case studies of H2 and H2 blends transportation in offshore pipelines. Sensitivities have been performed with available EOSs considering different H2 rich mixture compositions and up to date available software. The results obtained with the models and typically used for the design, like pressure, temperature, density, velocity profiles, are compared and discussed. The outcome of this work is to present the status of available tools in the industry and open the discussion with interested parties about areas of improvement and the future development to cover the design requirements for H2 and H2 blends pipelines.
- Reservoir Description and Dynamics > Fluid Characterization > Fluid modeling, equations of state (1.00)
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ABSTRACT This paper described a hybrid method to assess large diameter spool VIV and FIV, and applied it to a 36" complex-shape spool study. The hybrid method employs empirical lift coefficients, and imposes the lift force to spool structural beam model to obtain the time domain dynamic response, and extracts results for design criteria check. Spool boundary conditions at the PLEM end was modeled separately in FEA software to give the equivalent bending stiffness. Internal slug flow induced force was assessed and converted to time history using an equivalent work technique, which enabled the superposition of the slug force and lift force. The hybrid method was validated on a straight pipeline span, with comparison to Shear7 results. It is then further used to assess the 36" spool vibrations under both installation and operation conditions. For all external current induced vibrations (VIV), severe resonance vibrations have been observed, and the results are in good agreements with Shear7 results. For internal slug flow induced vibrations (FIV), the vibration amplitudes are small, and has negligible effect on spool dynamics. Based on the assessment results, FIV is not a concern for the spool system, however, additional free span supports are required to alleviate the risks of VIV. It concluded that the hybrid method is valid for large diameter 3D spool VIV and FIV analysis, and it is also applicable to other similar pipeline and spool free span analysis. INTRODUCTION In a recent project offshore Bengal, large diameter (36") pipelines have been designed and installed, for crude oil and high-speed diesel transportation between an offshore single point mooring buoy and onshore facility, and a 36" pipeline spool was used to connect the pipeline and PLEM, as shown in Fig. 1. The spool end flanges have an elevation difference of approximately 5m, with lower end flange connecting to pipeline, and higher end flange connecting to pipeline end manifold (PLEM) pipe. Middle segment of the spool is coated with concrete coating. Spool total dry weight is about 40Te.
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- Facilities Design, Construction and Operation > Pipelines, Flowlines and Risers > Offshore pipelines (1.00)
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- Facilities Design, Construction and Operation > Pipelines, Flowlines and Risers > Piping design and simulation (0.68)
Abstract It is globally recognized that a transition in energy generation, transportation and utilization is required to meet climate change goals. There are a considerable number of rival technologies that are contesting for inclusion in this energy transition, but this paper focusses on the opportunities that hydrogen presents. Hydrogen offers an opportunity that can benefit from the significant infrastructure that is already in place as part of the fossil fuel industry, but there are risks. Hydrogen embrittlement poses a significant risk to high-pressure steel transmission pipelines, putting them in danger of cracking, blistering and weakness. Hydrogen embrittlement occurs when the hydrogen diffuses with the pipeline material resulting in the deterioration of the steel pipe, valves, and fittings. With existing pipeline infrastructure, the costs of incorporating specialty steels to counteract these risks may not be economically viable and as such diluting the hydrogen concentration within a natural gas compound is one of the few viable methods for managing the risks. This paper provides two case studies to discuss the challenges and benefits of a real-time system for the simulation of hydrogen pipelines. Using a currently operational pure hydrogen pipeline the accuracies of different equations of state will be investigated. These equations will then be compared against different hydrogen blends and hydrogen synthetic fuels to determine their suitability. The benefits of the real-time system will then be examined including the benefits of gas quality mixing, the challenges of hydrogen to operational planning and how to use pipeline models to manage demands. A brief discussion on DOT requirements for the transportation of hydrogen will also be provided.
Design for preventing or minimizing the effects of accidents is termed accidental limit states (ALS) design and is characterized by preventing/minimizing loss of life, environmental damage, and loss of the structure. Collision, grounding, dropped objects, explosion, and fire are traditional accident categories.
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"In offshore and coastal engineering, metocean refers to the syllabic abbreviation of meteorology and (physical) oceanography" (Wikipedia). Metocean research covers dynamics of the oceaninterface environments: the air-sea surface, atmospheric boundary layer, upper ocean, the sea bed within the wavelength proximity (~100 m for wind-generated waves), and coastal areas. Metocean disciplines broadly comprise maritime engineering, marine meteorology, wave forecast, operational oceanography, oceanic climate, sediment transport, coastal morphology, and specialised technological disciplines for in-situ and remote sensing observations. Metocean applications incorporate offshore, coastal and Arctic engineering; navigation, shipping and naval architecture; marine search and rescue; environmental instrumentation, among others. Often, both for design and operational purposes the ISSC community is interested in Metocean Extremes which include extreme conditions (such as extreme tropical or extra-tropical cyclones), extreme events (such as rogue waves) and extreme environments (such as Marginal Ice Zone, MIZ). Certain Metocean conditions appear extreme, depending on applications (e.g.
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Consequences on Buoyancy Loss in Case of Subsea Gas Dispersion
Pierro, Alessio (Techfem S.p.A. โ Human and Sustainable Engineering) | Cassano, Katia (Techfem S.p.A. โ Human and Sustainable Engineering) | Farinelli, Paolo (Techfem S.p.A. โ Human and Sustainable Engineering) | Perini, Raffaella (Techfem S.p.A. โ Human and Sustainable Engineering) | Ferrini, Francesco (Techfem S.p.A. โ Human and Sustainable Engineering)
Abstract Hydrocarbon releases are events originated from pipeline leaks ruptures, that could occur for accidental events during operating life, maintenance phase or in case of subsea tie-in installation. Subsea release is one of the main events to be accounted for offshore risk assessment. The accidents caused by pipeline hydrocarbons leak lead to explosions, fire and buoyancy loss. When a subsea pipeline is ruptured, the pressurized gas rise at sea surface in bubbles form. Due to significant drag forces, the bubbles break and the plume will begin to disperse in atmosphere. The buoyant bubble plume rises to the surface, spreading radially and entrains water, introducing a recirculation. The gas presence changes the local density, mainly at sea surface where this variation could induce a buoyancy loss, important aspect for ships and other floating structures. Several approach can be used to analyze the problem. Empirical and integral models provide a good representation of the phenomena but they are based on simplifications, moreover they are not able to model the sea surface behavior, crucial since is the zone where interactions with offshore structures, vessels and floating installations occur. In this work a Computational Fluid Dynamic approach is proposed, carried out with the freeware software OpenFOAM, simulating the multiphase system with dispersed gas, seawater and air, in order to study in detail the subsea gas bubbles cone and the surface interactions, with the aim of analyze the possible consequences in terms of buoyancy loss. The adoption of CFD approach gives to the safety engineer a powerful tool to investigate the problem, also including the environmental effects like wind and sea currents. Introduction Hydrocarbon releases are events originated from pipeline leaks ruptures. In particular, subsea release events are part of accidental scenarios included in the risk assessment of offshore installations. The accidents caused by pipeline hydrocarbons leak are countless and a considerable number of these leaks lead to explosions, fire or other hazardous scenario as loss of buoyancy [1]. In case of break of a subsea pipeline, the pressurized gas rises up to the sea surface in in form of bubbles. Due to the significant drag forces, the sea plume scatters in the atmosphere because of the bubbles break up. At the same time, the buoyant bubble plume rises to the sea surface by spreading radially, entraining water and inducing recirculation [2]. The plume behaviour depends on a number of factors, like release rate, release phase and environmental conditions [3].
Abstract The successful implementation of a crude oil custody transfer sampling system is a key component to achieving a desired measurement uncertainty for a crude oil metering station or loading/unloading point. Our analysis of thousands of installations worldwide provides practical examples of how operators can be confident that when they install a sampling system, it will deliver the uncertainty that they need to meet the overall custody transfer requirements. Crude oil sampling for custody transfer becomes more challenging as production flow rates decline, oil fields mature, and water cut content increases. It is therefore important that the performance of a sampling system is evaluated on a regular basis and that any limitations are identified. Any risk of change in performance or measurement uncertainty can then be prioritized or minimized. International standards and contracts determine the allowable uncertainty for net oil (oil minus water) for custody transfer/allocation. For accurate allocation of the sources of crude oil or the application of tax tariffs, fluids must be measured prior to being comingled. Automatic crude oil sampling can be challenging because it can require high-energy mixing with low power consumption and negligible pressure loss to overcome stratification and allow representative sampling. The certification, or "proving", of the sampling system provides a basis for establishing and verifying the system's true uncertainty at worst case conditions. There is an abundance of computational fluid dynamics (CFD) simulations and studies on crude oil (and water) mixing. However, these are abstract because of the uncertainty in where the water is located and how it may be dispersed at the boundary conditions of any simulation. To provide more robust simulations, we expanded on the established methods by combining simulation data with known theoretical calculations and engineering laboratory test data as well as hundreds of certifications (proving) results from around the world. Automatic sampling systems using dynamic mixing technology delivers a unique solution that enables operators to minimize the quality measurement uncertainty, improve overall balance, and reduce financial loss (and unaccounted for) in custody transfer quality measurements.
- Data Science & Engineering Analytics > Information Management and Systems (0.89)
- Facilities Design, Construction and Operation > Pipelines, Flowlines and Risers > Offshore pipelines (0.46)
- Production and Well Operations > Well & Reservoir Surveillance and Monitoring > Production logging (0.35)
- Reservoir Description and Dynamics > Improved and Enhanced Recovery > Conformance improvement (0.35)
Study on Marine Pipelines Forced Vibration and Vortex-Induced Vibration in Uniform flow and Combined Flow at Different Reynolds Number
Deng, Yue (National Marine Data and Information Service / Shandong University) | Li, Jin (National Marine Data and Information Service) | Meng, Jie (National Marine Data and Information Service) | Cao, Yingzhi (National Marine Data and Information Service) | Zhao, Lixi (National Marine Data and Information Service) | Zhao, Jingli (National Marine Data and Information Service / Shandong Marine Resource and Environment Research Institute)
Abstract In this paper, the forced vibration and vortex induced vibration of a cylinder under the combined action of uniform flow and oscillatory flow were numerically simulated by using dynamic grid technology. The effects of the distance between the cylinder and the wall and the number of model grids on the numerical simulation results were analyzed. The drag force and inertial force were separated by programming with C++, and the inertial force, drag force, velocity and acceleration curves were analyzed. The variation of drag force coefficient and inertia force coefficient under different frequency ratio was studied. The wake shedding of cylinder in superimposed flow field was investigated. It is found that the wake shedding of cylinder in superimposed flow field is different from that of uniform flow and oscillatory flow. The oscillating flow was added from the inlet through C++ programming. INTRODUCTION Marine pipelines and risers are affected by the complex marine current. More and more cylindrical structures are used in marine engineering equipment to stand the test of the ocean. At present, many researches are focused on the hydrodynamics of cylinder in different flow fields. Gu et al. (1994) found that vortex from one side of the cylinder to the other reach to a high degree of concentration of vorticity next to cylinder when the frequency ratio (ฦโฦs ) increased ( ฦ is the oscillating frequency of cylinder, ฦsis the shedding frequency for the fixed cylinder). Lu and Dalton (1996) studied the vortex shedding from a transversely oscillating circular cylinder in a uniform flow by numerical simulations. The effect of increasing the amplitude of an oscillating cylinder and the Reynolds number value were shown to lower the value of ฦโฦsat which vortex switching. Meneghini and Bearman (1995) obtained the boundary of lockโin for small amplitudes of oscillations. ฦโฦs varied from 0.7 to 1.15 and AโD from 0.025 to 0.6 in their simulations. Anagnostopoulos and Bearman (1992) conducted experiments about the vortex induced transverse oscillations of a circular cylinder at low Reynolds number ranging between 90 and 150. The amplitude of the lift force in phase with the circular cylinder velocity was maximum at the lower limit of the lockโin region. Zhao and Chen (2006) reproduced these results with an Arbitrary LagrangianโEulerian (ALE) method. Zhao et al. ( 2010 ) investigated Combined steady and oscillatory flow past a circular cylinder by three-dimensional Direct Numerical Simulation. Raghavan and Bernitsas (2011) found that the Reynolds number has significant effects on the response of an elastically mounted cylinder in crossโflow, but didn't involve combination of uniform and oscillating flow. Low et al. (2016) studied VIV fatigue reliability analysis of marine risers with uncertainties in the wake oscillator model. Navrose et al. (2017) explored the existence of multiple responses in vortexโinduced vibration of a circular cylinder in the laminar flow regime by carrying out computations with different initial conditions for several mass ratios. In addition to primary and secondary hysteresis near the ends of the lockโin regime, multiple states of the fluid-structure system existed in the middle of the lockโin regime as well. Deng et al. (2019) carried out numerical simulations on VIV of a cylinder experiencing an oscillatory flow by the inโhouse VIVโFOAMโSJTU solver. Results showed that the oscillatory period is relevant to the width of โlockโinโ in half period. Vibration features such as โintermittent VIVโ, mode transition and the VIV developing process of โbuildingโupโ, โlockโinโ and โdyingโoutโ were observed. Zhang et al. (2020) tested a pipe under coupled uniform and shear oscillatory flow, with Reynolds number ranging from 2000 to 24000. When combined with uniform flow, the identification of timeโvarying frequency and amplitude modulation was significantly enhanced by uniform flow with lower velocities while the topโend surge mainly affects the vibration instability in higherโvelocity uniform flow. Wang et al.(2021)numerically investigated the crossflow VIV of a cylinder in oscillatory flow.
- Reservoir Description and Dynamics > Reservoir Simulation (1.00)
- Data Science & Engineering Analytics > Information Management and Systems (1.00)
- Facilities Design, Construction and Operation > Pipelines, Flowlines and Risers > Offshore pipelines (0.62)
- Production and Well Operations > Well & Reservoir Surveillance and Monitoring > Production logging (0.54)
Abstract Free spans exist in subsea multiphase pipelines laid over undulating seabed profiles or across continental scarps for offshore field developments. Slug flow induced fatigue damage on the free spans can potentially lead to pipeline re-sizing, more restrictive installation and welding requirements, and limits on life-of-field operational flexibility; these, in turn, have a significant impact on project economics. Slug flow assessments are typically associated with large uncertainties (e.g. flow conditions and span arrangement) and therefore require comprehensive sensitivity analysis to confirm robustness; this can prove time-consuming. This presents opportunities for significant optimisation in workflows to target governing operating scenarios. This paper describes an integrated iterative approach between the Flow Assurance and Pipeline engineering disciplines to streamline the workflow based on the value or cost associated with changes in input parameters that impact pipeline fatigue assessment outcomes. Case studies on two multiphase pipelines (one with multiple long spans introduced by undulating seabed profile and another featuring a very long span across a continental scarp) are presented to illustrate this design approach. The results show that early identification of the key pipeline profile features and dominating spans for pipeline slugging fatigue assessments facilitated the Flow Assurance slug flow modelling optimisation and reduced the computational time. Early engagement and alignment regarding pipeline assessment methods and desired slugging data requirements were very valuable for optimising the Flow Assurance slug flow modelling fidelity and also to minimise data processing requirements for both Flow Assurance and Pipeline disciplines. Timely feedback from the Pipeline discipline regarding fatigue accumulation based on screening work performed using an initial slugging data set with a wide flow rate range helped narrow down additional slug flow scenarios to be modelled by Flow Assurance.
- Research Report > New Finding (0.34)
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- Production and Well Operations > Well & Reservoir Surveillance and Monitoring > Production logging (1.00)
- Facilities Design, Construction and Operation > Pipelines, Flowlines and Risers > Piping design and simulation (1.00)
- Facilities Design, Construction and Operation > Pipelines, Flowlines and Risers > Offshore pipelines (1.00)
ABSTRACT In this study, an unresolved CFD-DEM was used to investigate a fluid flow and a behavior of sediment particles around a monopile. In order to consider the interaction between particles on the seabed and a current, an improved CFD-DEM solver was implemented within the OpenFOAM framework by proposing a void fraction method based on the kernel function. To validate computational methods, a settling velocity of a single particle, an angle of repose and an incipient motion of particles were simulated and compared with the existing experimental data. Finally, a scour around the monopole was predicted and discussed. INTRODUCTION In relatively shallow water, most offshore wind turbines are based on monopile foundations as bottom-fixed structures. Theses bottom-fixed foundations installed on an erodible seabed are exposed to scour, which may lead to structural failure. Therefore, it is essential to understand how the hydrodynamic environments affects the foundation and the interaction between flow, structure and seabed (Sumer, 2014). In particular, the scour can be defined as the phenomenon that the seabed particles around the foundation structure are transported due to the interaction of the fluid flow and the structure. The scour is a threat to the stability of the structure exposed to currents and waves. In order to alleviate the scour problem, many studies have been conducted experimentally (Dargahi, 1989, Whitehouse, 1998; Sumer and Fredsoe, 2002). In particular, most of the work has been done on scour phenomenon with monopile foundations. It led to various empirical formulas and methods to predict scouring depth and extension (Matutano et al., 2013). On the other hand, the computation can be employed as an alternative tool to study the scour process around structure (Pang et al., 2016). Recently, several computational methods have been developed to estimate the equilibrium scour depth. The scour depth and extent were estimated based on the bed shear stress exerted by the flow field in the Eulerian-based approach (Park et al., 2017). However, the single-phase model usually was not able to consider interparticle interactions in the scour around structures. To deal with this problem, many studies have adopted a two-phase model (Yeganeh-Bakhtiary et al., 2011; Hajivalie et al., 2012). These models can be divided into two types, depending on the method used. One is the so-called Euler-Euler two phase model, which treats the fluid and sediment phases as separate continuous mediums. The other calculate the particle motion individually using a discrete element method (DEM). The advantage of this method is that it can analyze a large amount of particles based on a simple collision model and analyze the exact behavior of the particles. Thus, to consider the interaction between the fluid flow and the seabed soil, a CFD and DEM coupling method is needed. Recently, studies on the sediment transport using the CFD-DEM coupling method have been carried out (Schmeeckle, 2014; Sun and Xiao, 2016), and even the scouring around a submarine pipeline was performed to investigate the flow behavior and particle motions (Yeganeh-Bakhtiary et al., 2013; Zhang et al., 2015). However, there have been only a few studies to realize the scour phenomenon around the monopile using CFD-DEM coupling method.
- Reservoir Description and Dynamics > Reservoir Simulation (1.00)
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