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While drones have been used on oil and gas facilities for video inspections and other tasks, they have been operated by an on-site pilot or one positioned on a bobbing workboat adjacent to an offshore platform. Now a proof-of-concept study conducted by TechnipFMC has tested the feasibility of a global drone system with drones operated remotely by pilots based anywhere in the world. The study is the subject of a paper (OTC 30241) presented at the Offshore Technology Conference Asia in Kuala Lumpur in November. Construction supervision and health, safety, and environmental (HSE) monitoring were the main drivers of the study. The construction supervision application is part of a larger digitalization ambition to monitor and manage construction activities with data generated from the drone ultimately feeding an internal software dedicated to this business process.
Today, drill bits and mud motor issues can account for more than half of the reasons for pulling out of hole before total depth (TD) on directional drilling wells. The complete paper presents a methodology designed for optimally matching drill bits, mud motors, and bottomhole-assembly (BHA) components for reduced failure risks and improved drilling performance. Work Flow The overall work flow includes detailed modeling of each sophisticated component and an algorithm to combine them efficiently at the system level without losing their specific nature. The drill-bit model is created in 4D—3D space modeling plus the transient behavior with time. The detailed cutting structure model may include specifying the number of cutters and how to place them in a 3D cutter space.
Achieving and sustaining performance drilling’s intended benefits—improved drilling efficiency with minimal downhole tool failures and the associated reductions in project cycle time and operational costs—requires new protocols in drilling-system analysis. Drilling-system components [bits, reamers, bottomhole assemblies (BHAs), drive systems, drilling parameters, and hydraulics] must be analyzed independently for their relevance on the basis of application types and project challenges. Additionally, the drilling system must undergo holistic evaluations to establish functional compatibility and drilling-parameter responses and effects, considering project objectives and key performance indicators. This comprehensive physics-based approach ensures durability and rate-of-penetration (ROP) improvements without compromising stability and downhole tool reliability. The success of this process is strongly dependent on vibration control.
At a recent discussion session at The Data Standard, we asked the question, “Are you ready for AI?” Josh Odmark and I hosted the session and introduced the topic. Here are the highlights of how to get ready for AI and improve your ODDS of the project giving you a great result. O. First, the organizational framework must be set up to create a supporting structure. This starts with support and buy-in from top-level management who are clear on the objectives. A lack of management support will usually mean that the project will either end when the going gets tough or not get deployed in the end.
Cerebras' CS-1 computer is a refrigerator-sized machine that contains the largest computer chip ever made. For certain classes of problems in high-performance computing, all supercomputers have an unavoidable, and fatal bottleneck: Memory bandwidth. That is the argument made this week by one startup company at SC20, a supercomputing conference that takes place in a different city each year, but this year is being held as a virtual event given the COVID-19 pandemic. The company making that argument is Cerebras Systems, the artificial intelligence computer maker that contends its machine can achieve speed in solving problems that no existing system can. "We can solve this problem in an amount of time that no number of GPUs or CPUs can achieve," Cerebras's chief executive officer, Andrew Feldman, told ZDNet in an interview by Zoom.
Yua, Songchen (College of Shipbuilding Engineering, Harbin Engineering University) | Li, Peng (College of Shipbuilding Engineering, Harbin Engineering University / Peng Cheng Laboratory) | Qina, Hongde (College of Shipbuilding Engineering, Harbin Engineering University) | Xua, Zhijing (College of Shipbuilding Engineering, Harbin Engineering University)
Marine fishery is gradually developing from the coastal area to the deep sea. The semi-submersible offshore fish farm is one of the most foreseeable aquaculture equipment. However, the vast and abundant deep sea also means that the fish farm will be in a harsh marine environment. A model test of a semi-submersible fish farm was carried out in this paper. In order to obtain the hydrodynamic response characteristics of the fish farm, the accelerations on five different positions and mooring forces of the model under different wave conditions and current were measured, the steady-state amplitudes of the first five harmonics experimental acceleration and mooring tension were obtained. The steady-state amplitudes of non-dimensional first-harmonic acceleration at different positions with different wave periods were compared, and the amplitude trends were analyzed. The influence of higher harmonics acceleration on the first ones was investigated. Besides, the amplitude trend of different harmonics acceleration was analyzed under different conditions. Furthermore, the trend and fluctuation range of mooring tension at front and aft positions under different conditions were compared, and the causes of occurrence of the peak value of the instantaneous amplitude were figured out.
New types of aquaculture equipment are gradually put into the ocean to relieve the environmental pressure in coastal area. As a typical new type of aquaculture equipment, semi-submersible fish farm is in a harsher marine environment than the traditional offshore cage. In order to ensure the normal operation of semi-submersible fish farm and the normal survival of aquaculture products, the hydrodynamic performance of which will be the focus of attention. The hydrodynamic analysis of semisubmersible fish farm is similar to that of traditional cage, but there are also differences.
For traditional net cage, Lader et al. (2005, 2007) carried out a series of experiments on different solid ratio of net, and the hydrodynamic forces induced by different current velocity were compared. Fredriksson et al. (2007) compared the experimental data and numerical results of static deformation of a floating collar. By numerical simulation, Huang et al. (2008) studied the hydrodynamic performance of gravity cages induced by wave and current. Taking rigid and flexible floating collars as the object of study, Li and Faltinsen (2016, 2018) carried out model tests of single floating collar under different wave steepness. By comparing the results with that of numerical simulation by WAMIT, the importance of 3D flow, hydroelasticity and strong hydrodynamic frequency dependency was demonstrated; the changes of additional mass and damping coefficients were emphatically analyzed. Xu et al. (2020) studied the drag and wake of an individual long-line mussel dropper using computational fluid dynamics approaches. They found that surface roughness and sharp crowns on the rough cylinder resulted in larger drag coefficients and Strouhal numbers. By numerical simulation, Qin et al. (2020) addressed the probability distribution of the heave motion under irregular waves and extended the conditions of the most probable maximum normalized bending stress distribution of the floating collar. Qin et al. (2020) devised an experimental study of an offshore aquaculture cage induced by wave-structure interactions. The relationship between the first-, second-harmonics acceleration and wave amplitude were analyzed, and the effects of mooring loads were assessed. Concerning the safety and economic efficiency, Liu et al. (2019) conducted a series experiments to obtain the optimum submergence depth of a fish cage. By model test and numerical simulation, Yang et al. (2020) studied the hydrodynamic responses and optimize mooring design factors of a floating rope enclosure. Li et al. (2012) studied the deformation of the floating collar, and they found the flexible effects on the dynamic responses. Kristiansen and Faltinsen (2015) conducted an experiment of a net cage. Results with only waves as well as combined waves and current were obtained.
Shi, Yu-min (Key Laboratory for Mechanics in Fluid Solid Coupling Systems, Institute of Mechanics, Chinese Academy of Sciences / School of Engineering Science, University of Chinese Academy of Sciences) | Gao, Fu-ping (Key Laboratory for Mechanics in Fluid Solid Coupling Systems, Institute of Mechanics, Chinese Academy of Sciences / School of Engineering Science, University of Chinese Academy of Sciences) | Liu, Jian-tao (Geophysical Services Division, China Oilfield Services Limited) | Zhu, You-sheng (Geophysical Services Division, China Oilfield Services Limited)
For the High-Pressure High-Temperature (HPHT) pipelines susceptible to global buckling, a reasonable risk assessment is particularly significant for their safe operation and structural integrity. The complex physical and mechanical characteristics of deep-sea sediments could bring great uncertainty to the pipe-soil interaction and the corresponding lateral buckling predictions. In this study, the physical and mechanical characteristics of undisturbed sediment samples recovered from certain deep-water locations of South China Sea are analyzed statistically, which exhibit inherent natural variability. Such statistical variability can be well quantified with the Coefficient of Variation (COV). Results indicate that the COV of mechanical properties is generally more pronounced than that of physical properties. The probability distributions of most soil parameters generally follow normal distributions by statistical hypothesis testing. Reliability analysis for the pipeline lateral buckling is then performed on the basis of analytical models by Hobbs (1984) etc. The pipe-soil friction coefficient is described by a random variable with an appropriate type of probability distribution to reflect the randomness of pipe-soil interaction. Monte Carlo simulations indicate that the probability for pipeline lateral buckling could be up to 50% compared to the deterministic method. Moreover, the COV values of the critical safe temperature, the corresponding buckle length and buckle amplitude are closely related to, but smaller than that of the basic random variable. In comparison with deterministic analyses, the present analyses may provide a beneficial insight into the lateral buckling of HPHT pipelines by considering the statistical characteristics of deep-sea sediments.
As offshore developments extend into deeper waters, the relatively high internal pressure and temperature becomes a dominant factor for the safety of deep-water exposed pipelines. Due to the seabed resistance against the pipeline thermal expansion, axial compressive force generates and accumulates along pipeline length (see Shi et al., 2019). Once the axial force reaches or exceeds the critical buckling force, the pipeline would experience lateral global buckling. Although lateral buckling is not a structural failure mode, the resulting excessive compressive force and bending moment may lead to structural failure. Hence, in the lateral buckling design procedure for exposed pipelines, first decision task is to check the susceptibility to experience buckling (DNV GL-RP-F110, 2018). If a pipeline is not susceptible to global buckling, only the axial walking check needs to be considered. Otherwise, the limit state check for the uncontrolled post-buckling would be further performed (DNV GL-ST-F101, 2017).
This study presents a dual-functional system, which is a submerged fluid-filled semi-circular piezoelectric membrane for breakwater and wave energy converter. The mixed Eulerian-Lagrangian method is used to simulate the fully nonlinear waves, deformation of the membrane and variation of voltage on the load . The simulation found that the variation frequency of the strain in the piezoelectric membrane is 2 times of the wave. There exists an optimum resistance of the load that can give the maximum electrical output power. The maximum electrical output power of the piezoelectric membrane occurs as the transmission coefficient of the wave approaches its minimum value.
The utilization of wave energy has been studied by many scholars for several decades. Most of studies focused on the wave energy converter (WEC) with higher wave energy extraction efficiency. This study presents a submerged fluid-filled piezoelectric membrane WEC , which is called SFPMWEC in the following section. Compared with traditional WECs, the wave energy extraction efficiency of SFPMWEC is lower. However, the construction cost of SFPMWEC is much lower than traditional WECs. Other advantages of SFPMWEC are easier maintenance and deployment, non-intrusion and cost sharing with breakwaters. As breakwaters, a submerged fluid-filled flexible membrane has been studied by some scholars. Ohyama et al (1989) had done experiments to study transmission and reflection waves over a submerged bottom-mounted fluid-filled membrane . Phadke and Cheung (1999,2001) studied the response of fluid-filled membrane in linear gravity waves by boundary element method (BEM) coupled with finite element method (FEM). The geometric nonlinearity due to the larger deformation of the membrane is considered in the work of Phadke and Cheung (2003). Das (2009) assumed small amplitude of surface waves and membrane deflection and used the threedimensional, coupled boundary element and finite element model to study the response of a bottom mounted fluid-filled membrane in a wave flume. Liu and Huang (2019) used the mixed EulerianLagrangian method to simulate the fully nonlinear interaction of waves and the submerged fluid-filled flexible membrane. These studies show that the submerged fluid-filled flexible membrane breakwater can reduce the transmission waves greatly at resonance of the membrane system. The resonance of the membrane system means that the maximum response of the membrane occurs as the natural frequency of the membrane system equal to the frequency of the incident wave. Therefore, it is possible to use a submerged fluid-filled piezoelectric membrane as both breakwater and WEC.
The Spar-type FOWT, which is a kind of the stable offshore wind generator, has been widely adopted and investigated in recent years. As a permanent mooring structure, it faces the issue on mooring line fracture. In the present work, the simulations are conducted in time domain to investigate its transient response in scenarios with fractured mooring lines. Towards this end, our in-house code SFND, which is a coupled aero-hydro-elastic numerical model is adopted to perform the simulations. The methodology includes a blade-element-momentum model for aerodynamics, a nonlinear model for hydrodynamics, a nonlinear restoring model of SPAR buoy, and a fully nonlinear dynamic algorithm for intact and fractured mooring lines. The simulations are conducted under both stochastic and freak wave scenarios. The motions of platform, the tensions in the mooring lines and the power generation performance are documented in different cases. According to the results, the large drift motion is observed and the transient response is discussed.
During the recent decades, the wind energy has attracted more and more attention because of its advantages and features, such as no pollution, no carbon emission, and so on. However, with the issues on the land limitation and the noise, the installation of the onshore wind turbines nearly reaches the bottleneck. Therefore, the wind turbines are designed to be supported by the offshore foundations, in order to catch the offshore wind energy, which is less turbulence and more strength than the onshore one. Generally, the fixed foundations, including pile, gravity, jacket, etc., are widely adopted. Nevertheless, according to previous research, the costs and difficulties of the installation and maintenance increase exponentially when the water depth exceeds 50m (Leimeister et.al, 2020). To overcome this situation, the floating offshore wind turbines (FOWTs) are proposed.
The conceptual designs of the floating foundation are basically based on the experiences from the oil and gas industry (Hsu, 2017). Hereby, the different types of the floating foundations can be majorly divided into three types, which contains the Spar type, the Semi-submersible type and the Tension Leg Platform (TLP) type. Among these innovative designs, the Spar buoy shows both well hydrodynamic performance and robustness according to numerical simulations and wave basin tests (Yang et.al, 2020, Salehyar et.al, 2017, Li et.al, 2018a, Duan et.al, 2016). Even more, the first floating wind farm, Hywind Scotland, also adopted five Spar-type FOWT and successfully generate power more than two years.