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Abstract This paper is a review of the experiences and issues with the use of polyester fiber ropes as mooring lines in deepwater applications. Early studies showed that polyester rope taut-leg mooring systems could provide better offset-restoring properties in deep water than the traditional wire rope catenary mooring systems. But there was reluctance to use such moorings without further knowledge of fiber rope properties. Polyester and other fiber ropes were studied for deepwater moorings in several Joint Industry Projects (JIP) in the early 1990s. These studies provided vital information and answered many critical questions. They showed that polyester rope has desirable stretch characteristics and very good durability for use as mooring lines. The use of polyester mooring systems was pioneered by Petrobras in the late 1990s. Mobile Offshore Drilling Units (MODU) began using polyester mooring lines in the Gulf of Mexico (GOM) in the early 2000s. The first permanent applications of deepwater polyester mooring systems in the Gulf of Mexico were the Mad Dog and Red Hawk platforms, installed in early 2004. The use of polyester and other fiber rope mooring systems into even deeper water depths will present new challenges. Stiffer ropes may be necessary to achieve desirable mooring system characteristics. Longer, larger volumes of polyester rope will be difficult to handle. More knowledge of the properties of the alternative, high-modulus, high-strength fiber ropes may be needed. INTRODUCTION Fifteen years ago there was much reluctance to use polyester and other fiber ropes in deepwater mooring systems for oil exploration and production platforms. The tendency was to continue to use and adapt wire rope mooring systems into deeper water. That skepticism has now been overcome. Polyester mooring lines are now used on platforms in Brazil, the GOM and elsewhere. The experiences have been favorable. Several polyester platform moorings survived the recent hurricanes without incident. Now there is interest in installing polyester and other fiber rope mooring systems in even deeper water. But as water depth increases, other - stiffer and stronger - fiber ropes might be preferred. This paper discusses the history, present status, and possible future of polyester and other fiber rope moorings in deep water. ADVANTAGES OF FIBER ROPES Fiber ropes have a number of advantages over steel wire rope in deepwater mooring systems. Lighter Weight. Lower Loads on Platform The principal advantage is weight. Fiber ropes are nearly or essentially neutrally buoyant in sea water. They can be used in taut-leg mooring arrangements. The advantages of the taut-leg mooring might not be obvious. Figure 1 illustrates three possible ways of mooring a floating platform in deep water. Wire rope in the form of a catenary is the traditional way of mooring platforms. However, as water depth increases, the weight of suspended wire rope increases and the downward angle of the catenary at the platform becomes steeper. This results in a large downward pull on the platform which decreases payload or increases required buoyancy. (As discussed later, the steep catenary also initially produces very little horizontal restoring force)
- North America > United States > Gulf of Mexico > Central GOM (0.93)
- South America > Brazil > Rio de Janeiro > South Atlantic Ocean (0.68)
- Energy > Oil & Gas > Upstream (1.00)
- Materials > Chemicals > Commodity Chemicals > Petrochemicals (0.46)
- South America > Brazil > Rio de Janeiro > South Atlantic Ocean > Campos Basin > Marlim Field > Macae Formation (0.99)
- South America > Brazil > Rio de Janeiro > South Atlantic Ocean > Campos Basin > Marlim Field > Lago Feia Formation (0.99)
- South America > Brazil > Rio de Janeiro > South Atlantic Ocean > Campos Basin > Espedarte Concession > Block BM‐C‐36 > Espadarte Field (0.99)
- (18 more...)
Abstract The objective of this study is to predict and analyze the viscous flow and the ship-ship interaction between two different tankers KVLCC2 and Aframax advancing in shallow water with same speed and with a fixed separation distance by solving the unsteady RANS equations in combination with the k-ω SST turbulence model. The computational results of the resistance, lateral force, yawing moment, as well as wave height measured by the wave gauge are validated against EFD conducted in Flanders Hydraulics Research (FHR) towing tank. Though the error for case A is not so satisfactory by up to 73%EFD, the tendency is agreed well with EFD data. Moreover, the error case B is much batter by less than 6.25% for both ships. For better understanding of the ship-ship interactions, the wave pattern of the free surface, surface pressure distribution of the ship hull, the asymmetric ship wake and vortex system are also given. Introduction With the birth of the very large crude carriers (VLCC) and ultra large crude carriers (ULCC), which have been proven to be one of the best solution to satisfy the demands of oil transportation, a new problem arose. Many ports, which may not be deep enough or have narrow entrances or small births, are not suited to receive ships of such big seizes. On the other hand, a commercial ship which is not under navigating is just a very expensive warehouse. Therefore, the time spent in the harbor, which is mainly determined by the time needed to unload and re-load the oil, must be as short as possible. Both the two problems can be solved by the lightering operation. However, manoeuvring such large vessels without the assistance of tugs at a precision of meters is highly difficult. On top of these difficulties, hydrodynamic interaction forces take place, which influence greatly the relative motion of the vessels. This can result in accidents with important consequences as oil spills or severe damage to the vessels.
- Transportation > Marine (1.00)
- Energy > Oil & Gas (1.00)
- Transportation > Freight & Logistics Services > Shipping > Tanker (0.53)
ABSTRACT The use of composites has gained interest in defense as well as commercial applications in recent years. High costs associated with processing, materials and availability of quantitative standardized data have been limiting factors in the widespread usage of composite materials. The expectancy from engineered structures has extended beyond conventional designs to provide integrated features with multifunctional benefits. With emergence of newer techniques for processing, there is lack of historical databases for process-structureproperty relationships. The present study focuses on application of composites for armored vehicles (for e.g. tanks and trucks). Thicksection laminated and multi-layered integrated composites have been processed/manufactured with the aim of providing multi-functionality including easy reparability, quick deployment, enhanced ballistic damage and fire protection. In the present study, cost-effective liquid molding processes such as resin transfer molding (RTM) and vacuum assisted resin transfer/infusion molding (VARTM) have been utilized to produce thick-section and integrated designs. The processing of thick-section composite panels and integral armor has been discussed. In-situ flow and cure monitoring of the resin in the fiber perform has been conducted using embedded direct current (DC) as well as dielectric (AC) sensors. The concept of through the thickness perform stitching to enhance damage tolerance in VARTM processed composites is presented, with supporting results from dynamic high strain rate (HSR) impact testing. INTRODUCTION Lighter weight ground combat vehicles; marine bodies and aircraft structures are candidate applications for fabric/textile composites and/or layered material architecture. Composites offer improved deploy ability, survivability, and agility for such applications [1–3]. Recent developments include use of composite materials in components such as armored tank hull, crew capsule, rear engine bulkhead, ramp and sidewalls etc. Several types of fabric architectures and resin compositions (for example, S-2 glass, vinyl ester, epoxy and phenolic resins) are applicable either as monocoque or sandwich constructions [1–5].
- North America > United States (0.46)
- Europe (0.46)
- Government > Military (0.87)
- Materials > Chemicals > Commodity Chemicals > Petrochemicals (0.66)
- Energy > Oil & Gas > Upstream (0.46)
The PDF file of this paper is in Russian. Pollution of waters that appears as a result of oil spills in the ice seas of the Arctic region inevitably leads to considerable violations in vulnerable ecosystems of the Arctic and also leads to negative social, economic and geopolitical consequences. The problem of effective elimination of emergency spills in the Arctic shelf acquires the increasing relevance for Russian oil and gas enterprises that realize the Strategy of the Arctic Zone Development and Ensuring National Security until 2020. The most perspective method of oil spills emergency elimination in Arctic conditions since the end of the last century has considered is an application of dispersants – the surfactants accelerating process of natural dispersion of oil in the thickness of seawater due to weakening of an interphase tension on border of phases «oil-water». Under the influence of the energy of mixing arising from the waves movement, dispersants influence on an oil membrane, dividing it into globule from 1 to 5 micron which are absorbed by bacteria or are besieged on a bottom. At the same time, the unique feature of dispersants is their «dot» applicability. The efficiency of a dispersant of the same structure substantially differs while using it in different weather conditions or because of the change of salinity of seawater. It also can be different for various oils and even for viscosity of oil of one brand at her cooling or aeration. This feature demands from producers of dispersants and from interested in it gas and oil enterprises considerable volume of pilot studies for determination of efficiency of dispersants at their use in specific conditions. This work includes the analysis of methods of determination of dispersants efficiency from the point of applicability of such surfactants for elimination of emergency oil spills in the ice seas of the Arctic region. Requirements to methods of determination of dispersants efficiency in the ice seas are formulated and the concept of development of methods and means of determination of dispersants efficiency for elimination of oil spills emergency in the Arctic water areas which can become base for development and introduction of such domestic developments in the import substitution tendencies is offered.
Seismic fault detection with iterative deep learning
Zhou, Ruoshui (University of Electronic Science and Technology of China) | Cai, Yufei (University of Electronic Science and Technology of China) | Yu, Fucai (University of Electronic Science and Technology of China) | Hu, Guangmin (University of Electronic Science and Technology of China)
ABSTRACT Due to the strong nonlinear fitting ability and feature extraction ability of deep learning, a large number of researches choose deep neural networks for seismic fault detection and have got good results. However, the fault detection results lack the constraint of continuity. Inspired by the process of human learning knowledge: When learning new knowledge, humans often use the experience accumulated in the past to deepen the understanding of knowledge, but the experience may contain error information, therefore we need to constantly revise our understanding with examples until we master knowledge. We proposes iterative deep learning: in order to improve continuity, we use automatic image processing with geological expert experience to correct the fault detection results of deep learning. The complexity of the actual geological situation makes some differences between the image processing results and the actual situation. Therefore, we iteratively corrected the model through seismic data examples and image processing results. The experimental results demonstrate the effectiveness of our method. Presentation Date: Tuesday, September 17, 2019 Session Start Time: 1:50 PM Presentation Time: 3:55 PM Location: Poster Station 2 Presentation Type: Poster