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This paper presents a recently developed flood propagation model. In order to use graphics processing unit (GPU) acceleration,the domain shallow water equations are simplified by linearizing bottom friction and neglecting advection, and an appropriate vectorization method is implemented. The model solves the finite difference scheme for each pixel of large-scale raster maps (i.e., regional or national ones). It was initially tested against a well-known benchmark and was then applied to a coastal flooding event in the Caorle area, Venice, Italy, which occurred in December 2008. Introduction Many available studies (e.g., Hinkel et al., 2014; Weisse et al., 2014), including the most recent assessment by the IPCC (2015), show that European coasts are threatened by rising sea levels and climate change. Coastal areas are subject to the risks of both flooding and erosion. The vulnerability stemming from these hazards needs to be adequately investigated in order to mitigate the risk to human health, economic activities, cultural heritage, and the environment. Therefore, under the EU Floods Directive, stakeholders need to establish flood maps to determine the risk of present and future levels of inundation. This issue is particularly relevant to the Northern Adriatic coast, where local managers require tools, possibly integrated to geographic information system (GIS), to simulate the complex problem of a coastal flood caused by waves overtopping in an urban area at regional level. This gave impulse to major EU projects, such as THESEUS (Zanuttigh, 2011), MICORE (Ciavola et al., 2011), and RISC-KIT (Armaroli and Duo, 2017).
Summary The world's first bottom-founded offshore liquefied natural gas (LNG) storage and regasification terminal is under development by affiliates of Qatar Terminal Limited, ExxonMobil, and Edison for installation in the Northern Adriatic, 15 km east of Porto Levante, Italy. This paper will describe the unique challenges faced and effort undertaken to locate and transform a casting basin to a world-class construction and integration site, including removal of the earthen wall prior to tow-out of the terminal. The concrete gravity-based structure (GBS) terminal enclosing two 125,000-m LNG tanks and supporting 8 GSCM regasification facilities will measure 180 m by 88 m and be located in 29 m of water. These dimensions, as well as proximity to Porto Levante, led to selection of the casting basin in the Spanish Bay of Algeciras as the construction and integration site. The site is under development by the Algeciras Port Authority for use as a container port, and therefore did not have the infrastructure needed to build the terminal. This paper will provide the basis for how parameters such as size, depth, layout, water and electricity supply, accessibility, dredging requirements, lease requirements, availability of workforce, and capacity for growth were established to result in an effective construction and integration site. Some of the execution technologies used for this terminal, such as removal of the earthen wall, installation of regasification facilities, and installation of the LNG tanks will also be described. The conclusions drawn in this paper can be utilized for upgrading of an existing construction site, or development of a Greenfield site into an effective facility for future GBSs, floating structures, or large-scale construction and integration projects. Background Adriatic LNG Terminal, the world's first offshore liquefied natural gas (LNG) receiving, storage and regasification terminal, is under development by affiliates of Qatar Terminal Limited, ExxonMobil, and Edison for installation in the Northern Adriatic, 15 km offshore just east of Porto Levante, Italy in 29 m of water. The substructure of the terminal consists of a concrete GBS with dimensions of 180 m × 88 m × 47 m. Two 125,000-m modular LNG tanks are housed inside the GBS, while the topsides facilities with 8 GSCM/year send-out capacity are located on the top. The export pipeline has a 30-in. diameter with a metering station near Cavarzere, Italy, tying into the Italian grid at Minerbio through a 36-in. line. The terminal will provide a berthing facility for 65,000- to 152,000-m LNG carriers. Fig. 1 shows a rendering of the terminal. The major components of the Adriatic LNG (ALNG) Terminal built by Terminale GNL Adriatico srl are the GBS substructure constructed in the bay of Algeciras, Spain; the LNG tanks fabricated in South Korea; topsides modules being fabricated in Cadiz, Singapore, and Sweden; and the mooring dolphins being constructed in Venice, Italy. Figs. 2a through 2d show photos taken at various stages of construction of these major components. The execution plan for the ALNG terminal consists of building the GBS at the deep casting basin site in Algeciras Bay, Spain, transporting the LNG tanks from South Korea to install into the GBS, transporting all the topsides modules and installing them on top of the GBS, removing the existing levee that keeps the basin dry and towing the fully integrated terminal to offshore Venice, where the mooring dolphins will be installed as well. Construction and Integration Site Selection One of the most important decisions during the execution planning of the ALNG Terminal Project was selecting the construction and integration site. In order to select the most appropriate location, more than 15 sites from western Europe through the Mediterranean to the Black Sea were evaluated based on particular criteria. All of the evaluated sites presented some advantages and challenges. For example, some of the sites were not selected because of their limited size or lack of adequate skilled labor to support a project of this magnitude. Others that were large enough and provided access to adequate labor required extensive dredging works to obtain the draft required for the execution plan (all installation and construction activities to be completed onshore). While some of the sites met the space and infrastructure requirements, because of the tow-route to offshore Venice, the available tow window was considered too restrictive. Another important criterion that led to elimination of some of the sites was the difficulty in obtaining the necessary permits for the development of the project. Last, but not least, the lease fee and availability of the site were other criteria that were evaluated before making the final decision to select the Algeciras Bay site. These criteria and how the Algeciras Bay site satisfied them are summarized in Table 1. The Algeciras Bay deep casting basin site is owned by the Algeciras Port Authority (APBA). APBA manages the 11th largest container port in Europe. Although the site is leased from APBA for construction and integration of the terminal, the Andalusian regional government and the San Roque local government also have jurisdiction over the site for regulatory purposes. The site is located in an industrial area with a refinery and chemical plant in the vicinity. The perimeter of the casting basin consists of mass concrete quay walls. The natural material behind these walls is very impermeable overconsolidated clay, which minimizes the amount of seepage into the basin. The basin was previously used for the construction of a concrete breakwater structure for Monaco and is included in APBA's plans for use as a container port. Figs. 3a and 3b show the Algeciras Bay site in November of 2003, before the ALNG Terminal Project and March 2007 after the arrival of the LNG tanks from South Korea.
Abstract This paper presents a coupled geomechanics and compositional model and applies it to the oil and gas recovery process. An equation of state compositional simulator called the General Purpose Adaptive Simulator (GPAS), developed at the University of Texas at Austin, which uses a finite difference method for the solution of its governing partial differential equations (PDEs), is iteratively coupled with a geomechanics model that is developed using a finite element method in this research. An elastic constitutive model is applied to represent deformation behaviors of rocks in the geomechanics model. Porosity is selected as the coupling parameter between two coupled models. The unknowns located on nodes and block-centers in the two models are evaluated using an area weighting technique The proposed model has been implemented on the Linux PC clusters for solving 2D compositional reservoir problems considering geomechanics effects. These results indicate that the geomechanics-coupled compositional reservoir simulator developed in this study can be used to complete simulations for stress-dependent or stress-sensitive reservoirs. Introduction It has been more than twenty years since researchers realized the importance of geomechanics for hydrocarbon production in stress-sensitive or stress-dependent reservoirs, e.g. reservoir subsidence, well-bore stability, sand production, pipe crash, etc. Geomechanics plays an important role in stress-sensitive fields. Examples of such fields are Venice (Italy), Latrobe Valley (Victoria, Australia), the Wairakei Geothermal field (New Zealand), the Valhall field (North Sea, Norway), the Ekofisk field (North Sea, Norway), Bolivar Coast (Venezuela), Wilmington field (Long Beach, California, USA), and the South Belridge field (Kern Country, California, USA). Coupled geomechanics simulators are very useful tools for evaluating and analyzing oil and gas production from stress-sensitive fields. Two elements, fluid (water, oil, and gas) and solid (porous rock), reside in the same reservoir. The porous medium serving as a skeleton may contain oil, gas, and water in its pores. There are many interactions between its associated seepage field (i.e. rock compressibility, permeability, and porosity etc.) and the in situ stress field (i.e., rock stress, strain, and displacement). Reservoir subsidence is caused by depletion of underground fluid during production from stress-sensitive or stress-dependent reservoirs, such as highly compactable reservoirs, low-permeability reservoirs, chalk reservoirs, unconsolidated (soft or oil) sands, a cyclic steam recovery of heavy oil, etc. The subsidence problem has motivated reservoir engineers to investigate the interactions between the fluid and the deformable solid in recent decades. The subsidence is considered as not only a positive for the production, which is a hydrocarbon driver with compaction of the porous volume, but also as a negative, which can lead to sand production, pipe crashes, wellbore casing damage, and even well failure. For such reservoirs, interactions between the seepage field and the in situ stress field are complex, and affect hydrocarbon recovery. A coupled geomechanics and fluid-flow model can capture these relations between fluid and solid and thereby present more precise history matchings and predictions for better well planning and reservoir management decisions. A traditional reservoir simulator cannot adequately or fully represent the ongoing coupled fluid-solid interactions during production. Many researchers have studied multiphase models coupled with geomechanics models over the past fifteen years.
ABSTRACT This study is mainly aimed at developing a two-dimensional numerical wave flume based on a VOF method to compute nonlinear interaction between wave and a moving structure. The numerical algorithm developed here is verified by comparing the numerical results with the theoretical ones on the movement distance of bottom-seated and bottom-detached structures in water. The numerical results, furthermore, reveal that the interaction of wave and a moving flap-type structure causes the difference of water levels between the offshore and onshore sides of the structure and has a strong effect on water surface elevation and water particle velocity field around the structure. INTRODUCTION Storm surges have so far caused serious damages to human lives and properties in coastal areas. It is, therefore, of importance to prevent storm surge disasters from both hardware and software sides. As for hardware measures, the design of a flap-type storm surge barrier, which is one of the coastal structures considering not only wave control but also landscape and environmental conservation in coastal zones, has been examined. The main aspect of the barrier is as follows; the barrier can rapidly stand up from the sea bottom in order to protect coastal areas from storm surges and high waves only during extreme storm waves. The barrier is stored in the sea bottom in calm weather so as not to affect water exchange, ship navigation and the environment in coastal sea areas. This type of the barrier is being adopted in Venice, Italy to protect Venice city and the lagoon, and this project is called MOSE project. Tomita et al. (2003) conducted hydraulic experiments on wave force acting on a flap-type storm surge barrier fixed at various inclination angles and transmitted wave characteristics.
ABSTRACT Protective coating corrosion failure is a complicated process that involves various phenomena which are hard to test for separately. An adequately protected pipe can be in service for a relatively long time without exhibiting any signs of corrosion failure, and then all of a sudden it corrodes over a short period of time. Failure will definitely happen if the interface between the pipe surface and its protective coating system is somehow compromised or exposed to the environment. While corrosion reactions have quite a bit of variability in terms of time, the situation is further complicated when corrosion is coupled with the protective coating mechanical failure. Similar to materials fracture, corrosion failures are governed by the laws of probability, where multiple variables control the ultimate outcome. The coating system needs to be adequately tested before placing it in service, so there is a strong need for a meaningful corrosion test. A typical test would incorporate exposing scratched coating surface to certain corrosive environments for a fixed amount of time, trying to simulate the real conditions as close as possible. Sometimes, a so-called freeze step is introduced to stress the coating prior to exposing it to the test environment, ultimately causing its failure. Due to the differences in thickness, elastic, thermal and adhesion properties, various coatings would exhibit different results when exposed to a fixed freeze temperature. One needs to understand the mechanics of the freeze in order to properly utilize it. This paper considers the coating delamination and fracture mechanics, including the freeze step mechanics in terms of the strain energy release rate, and coating sub-critical debonding. This research is sponsored by the NACE University Research Seed Grant. INTRODUCTION There is a large variety of corrosion protective coating systems. They all serve the main ultimate goal of long-term corrosion protection. One has to realize though that due to the nature of the corrosion process, which brings the material to a lower energy, thermodynamically favorable state, most coatings will eventually fail, and the material they are protecting will corrode. Figure 1 shows examples of vintage mirror silver backing failures. Although the coatings do not serve the purpose of corrosion protection in this case, they probably set some of the oldest examples of mass-produced coatings failures. Even nowadays mirror coatings are prone to failures, presenting a technological challenge . FIGURE 1 Pictures FIGURE 1. a) Mirror backing corrosion failure. The Art Institute of Chicago, circa 1820; b) Buckling mirror silver backing delamination failure, Correr Museum, Venice, Italy, 18th century. Unfortunately, premature failures can be costly, especially when the offshore applications are considered. It is extremely important to test corrosion protective coatings before they are deployed. Various tests have been designed for evaluating coatings performance. See reference  for a comprehensive review, which also inspired this publication. Anti-corrosive performance testing serves the purpose of comparison and ranking the coatings, as well as eliminating the ones likely to exhibit premature failure. Unfortunately there is no single test available, capable of fully predicting protective coatings performance and their lifespan. Although, based on a combination of tests, one can make an assessment and compare various coatings? performance. It is important to understand how the coating properties influence test outcomes, so that they will be properly interpreted. Here, we address the mechanical aspects of anti-corrosive coatings performance tests.