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...OTC 3553 AN ACOUSTIC POSITION REFERENCE SYSTEM INTERGRATING LONG AND SHORT - BASELINE OPERATION by M.L. Neudoefer, Honeywell, Inc. '" Cop...wn that this technique reduces both operator training time - Short-baseline pinger operation and errors. - Short-baseline pinger and transponder Results of field experience in the calibration operati...ilities, handles the complete spectrum of offshore applications, from the initial Acoustic position reference systems are geophysical surveys through platform installation widely used in offshore operations t...
...Special display pages to provide Experience with in-house training on the complete information on operational system has...t of _-- data to enter. This decreases the occurrence of The RS/232 digital data interface permits errors. the system to be coupled to a navigation computer or to a digital data-recording device. I APPL...
...The system is illustrated in Figure 1 and ments and the reference element is measured, the consists of a beacon (pinger, transponder, or angles m and m can be, dete...one/projector, signal processor, (1). The angle' m, between the acoustic power amplifier, vertical reference unit, signal and the Z axis, is determined from and display console. A functional block diagram is ...sel's X, Y, and - Vessel Pitch and Roll. A vertical Z axes. As the acoustic wavefront reaches the reference sensor monitors vessel pitch hydrophone, the three elements measure the relative and roll at the i...
ABSTRACT This paper describes a new acoustic position indicator system that integrates ultra-short and long-baseline modes. Major design features are described, and results of field experience with long- and short-baseline modes are presented. The system has been designed to perform the full range of acoustic positioning tasks required in offshore operations. In its simplest form, positioning is done with free-running acoustic beacons. The complete system performs short baseline positioning with both pingers and transponders. It performs long-baseline positioning of both surface vessels and submersibles. A special feature of the complete system is the use of the short-baseline system to calibrate a long-baseline transponder grid. This flexibility makes it possible for one system to perform the full range of acoustic positioning tasks in offshore oil-field development. Applications of the system to geophysical surveys, exploratory drilling, platform construction, and pipeline installation are discussed. Special features that make the system adaptable to a wide variety of offshore applications are highlighted. A unique feature of the system is a conversational display console and keyboard. By changing labels on the variable-function keys and providing prompting messages, the system guides the operator through the steps necessary during system setup and operation. Field experience has shown that this technique reduces both operator training time and errors. Results of field experience in the calibration of long-baseline transponder arrays are presented for two water depths. The use of the short-baseline system to aid the long-baseline operation is also presented. INTRODUCTION Acoustic position reference systems are widely used in offshore operations to measure and display the position of surface and subsea vessels with respect to underwater acoustic beacons. Two basic types of positioning systems are used short-baseline and long-baseline. Long-baseline techniques determine the position of a vessel in relation to a fixed grid of transponders mounted on the sea floor. This approach provides high accuracy for operations carried out over broad areas or at great depths; however, careful calibration of the transponder grid is required to determine the transponder's precise positions with respect to one another. Short-baseline techniques, in contrast, require only a single beacon (either a free-running pinger or a transponder) and a single ultra short-baseline hydrophone or hydrophone/projector. This approach is convenient, since it does not involve grid calibration. In addition, it provides high accuracy for close-range work. Accuracy decreases, however, over broader areas and greater depths. Each of the two approaches is useful for specific types of offshore operations: longbaseline methods for far-reaching operations such as geodetic surveys or site inspections, and short-baseline methods for applications such as underwater construction, drilling, and pipe laying. Both have been used by the offshore industry for years-in separate systems. This paper presents a system that is field upgradable in three configurations:Short-baseline pinger operation Short-baseline pinger and transponder operation Long-baseline and short-baseline operation combined in one system The system, by combining long and short baseline capabilities, handles the complete spectrum of offshore applications, from the initial geophysical surveys through platform installation and pipe-line maintenance.
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... In a third simulation study, the robustness against lidar wind platform pitch preview measurement errors is examined. For this investigation, a 4 turbulent wind field with turbulence class "A" according t...s of the 1 h simulation at 16 m/s. For the calculation of the Damage Equivalent Loads (DELs), 150 a reference number of cycles n ref 2 10 6 is used. Further, a Wöhler exponent of m 4 is assumed for th...
...ings of the The lidar data processing and the feedback and feedforward American Control Conference, pages 4434-4439, Portland, Oregon, controller are implemented in modular, compiled form such that USA. a ...eorologische the wave preview e.g. by wave radar systems can be used to Zeitschrift, volume 24(6), pages 565-579. additionally reduce the loads at the wave spectrum frequencies. Schlipf, D, Raach, S, Koch...predictive control of wind turbines using LIDAR," Wind Energy, greatly acknowledged. volume 16(7), pages 1107-1129. References Schlipf, D, Simley, E, Lemmer, F, Pao, L, and Cheng, PW (2015b). "Collective...
...nly canceling the impact of wind speed changes on controller based on a wind speed preview. A 10 MW reference the aerodynamic torque, but to the aerodynamic thrust as well. wind turbine is used on a semi subme...et al. (2020a)) with the floating offshore turbines (FOWTs) is even more promising, since DTU 10 MW reference wind turbine (Bak et al. (2013)), and their dynamics depend heavily on the aerodynamic thrust, see ...
ABSTRACT In this work a multi-variable feedforward controller for floating wind turbines is presented. The feedforward controller provides a pitch rate and a torque update to a conventional feedback controller based on a wind speed preview. A 10 MW reference wind turbine is used on a semi submersible floating platform to study the potential of the controller. An open-source simulation tool is extended with an realistic lidar simulator and the lidar data processing, feedforward controller, and feedback controller are implemented in modular setup. The lidar measurements are fully motion compensated and combined to provide a preview of the rotor-effective wind speed to the controller. The feedforward controller is designed to minimize structural loads and to decrease the platform pitch motion. In verification and simulation studies the concept is demonstrated and the multi-variable feedforward controller shows a promising improvement in speed regulation and load reduction on the floating wind turbine. INTRODUCTION Lidar-assisted control is a promising technology to reduce structural loads and increase energy production for wind turbines. The technology has proven its capability to improve control performance for onshore wind turbines in field tests. The impact on floating offshore turbines (FOWTs) is even more promising, since their dynamics depend heavily on the aerodynamic thrust, see Schlipf et al. (2015b). Nonlinear Model Predictive Controller (NMPC) with lidar wind preview was applied to a 5MW wind turbine by Schlipf et al. (2013) and Raach et al. (2014b). Also, a collective pitch feedforward controller was optimized for FOWTs by Schlipf et al. (2015b) to cancel out the impact of wind speed changes to the aerodynamic torque. Wave preview was subject of different works with the aim of canceling wave forcing through the knowledge of the incoming wave field. A state-space wave force model was developed in Lemmer et al. (2016a) in order to model the Froude-Krylov forces in real time based on the instantaneous free-surface elevation. The question of how to design a wave feedforward controller was addressed recently by Al (2019).
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...nventional: Honeywell RS/902 and RS/904 Acoustic - 1. Manual joystick control of heading Position-Reference Systems 2. Automatic heading hold 3. Manual joystick control of surge and sway Two taut-wire ...reference systems - 4. Automatic position hold - Two dual riser-angle ...reference systems Attitude Sensors Thruster Control Modes - Two gyrocompasses Each thruster on the SEDCO 71...
...as a color graphic CRT with a touch-activated keyboard. HARDWARE DESIGN Fifteen operator-selectable pages can be displayed on the CRT, giving an operator fast access to The PTCS equipment is based on Hone...ywell ASK controller and sensor set-up pages, and to summaries Series 3000 hardware. 'There are three major assemblies of sensor and thruster st...
...Sensor Interface Assembly (TSI) contains a 13-inch color CRT monitor that displaya up to 15 custom pages of data. The keyboard overlay The TSI interfaces the thrusters and sensors is custom designed for e...
ABSTRACT Honeywell has integrated its dual redundant Automatic Station-Keeping (ASK?) System with a new thruster control system (TCS). The ASK System provides high-quality, high-reliability dynamic positioning performance, while the primary function of the TCS is to enable an operator to control each propulsion element individually. In this system, the TCS also provides automatic, coordinated steering and control of the propulsion system during transit (cruise) operation and during short-distance maneuvering, when three-axis control (TAC) is required. The new system is called a positioning/ thruster control system (PTCS). Final testing is in progress, and the first system will be installed on the SEDCO 710 semi submersible in the summer of 1982 Salient features of the new system are microprocessor- based electronics for growth and flexibility, color CRT displays, Kalman filtering of position and heading data, and a generalized thruster-allocation algorithm. The thruster allocation is composed of a fixed pointing-angle, minimum energy allocation for all thrusters, blended with an allocation that commands both thrust level and azimuth angle to all steer able thrusters. It includes power limiting and cutback algorithms to avoid vessel blackout. This paper gives an overview of the PTCS, including the design philosophy and the hardware and software architecture. The thruster allocation logic is discussed in some depth, paying particular attention to its operational flexibility and ability to perform efficiently in both light and heavy weather INTRODUCTION Deep-water drilling and related operations from Semi submersible vessels present many complex control problems. Traditional vessel control systems used for these applications employ both a dynamic-positioning (DP) system and a thruster control system (TCS). The thruster control system gives the operator manual control of each element of the propulsion system, e.g., rudder, steer able thruster, fixed-axis thruster, or main screw. The DP system automatically controls the propulsion elements to keep the ship on location and is the only source of coordinated automatic control of the vessel propulsion system. In January 1981, under contract from SEDCO, Honeywell Marine Systems Operations began developing an integrated DP and thruster control system, based on requirements dictated by SEDCO, the industry's most experienced DP operator. This new system, called a positioning/thruster control system (PTCS) retains the advantages of independent thruster control and DP systems, and also incorporates some of the conveniences of a computer-controlled automatic system into the TCS. The system uses modern microprocessor technology and advanced sensor processing techniques. The capability of former thruster control strategies was expanded and incorporated into both the TCS and DP system. The PTCS is now undergoing final system tests and will begin sea trials in the fall of 1982. This paper outlines briefly the PTCS system's functional design, hardware design, and software design. Special emphasis is placed on the new capabilities in the thruster allocation logic. FUNCTIONAL DESCRIPTION Design Requirements The new equipment was designed for the SEDCO 710, a large semi submersible with eight steer able thrusters for propulsion. Some important design objectives for the integrated PTCS were
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...ystem: - Three gyro compasses. - Three wind sensors. - Triple redundant DP unit. - Three vertical reference units. - Power management system. - Data logging system. The sensors are interfaced with the three... conputers. - Three position reference systems. Each conputer reads data from the sensors, sends the - Three of each; vertical ...reference unit, gyro data to the other two, and at the same time receives compass, and wind speed and direct...
... can be used as a standard SBL system. In T z -Significant wave period, sec. this case, a vertical reference unit (VRU) is used to minimize ...errors due to the pitch and roll motions ACKNOWLEDGEMENTS of the vessel. The authors thank the management... keeping performance has exceeded expectations. Both the LSBL and the satellite REFERENCES position reference systems keeps the vessel within an 8 ft [2.4 m] to 15 ft [4.6 m] diameter 1. American Petroleum In...
...r system. Engineering and equipment - Dynamic positioning system. procurement continues. - Position reference systems. - June 13, 1990: 0-534 arrives at the shipyard. - September 8, 1990: 0-534 departs the shi...
Abstract This paper discusses the upgrade of the Discoverer 534, from a turret moored 3500 ft [1100 m] rated drillship, to a fully dynamic positioned vessel rated at 6000 ft [1830 m] water depth. After the upgrade, the vessel commenced drilling in 3730 ft [1137 m] water depth which will be followed by a well in 5900 ft [1800 m] waters during the first quarter of 1991. This will be a world water depth record for a vessel with a 18-3/4 in. [476 mm] BOP stack and a 21 in. [533 mm] drilling riser. Introduction During the third quarter of 1989, BP Exploration set out to select a drilling vessel to explore its large deep water lease holdings in the Gulf of Mexico. It was necessary to acquire a drilling vessel that was capable of drilling in up to 6000 ft [1830 m] water depth to allow exploration of all the geological prospects in BP Exploration's inventory. An assessment of the global deep water drilling fleet was performed during the third and fourth quarter of 1989. This was done to identify the vessel best suited for BP's program and to assess required modifications to take it into the 6000 ft [1830 m] water depth. This paper discusses the primary systems installed or modified, procedures in effect, and challenges of the upgrade. It also lists the numerous other technical modifications that were carried out. RIG SELECTION Table 1 shows the global drilling fleet that was considered in the selection of a rig for the deep water program. In addition to considering availability and cost, an extensive technical evaluation was carried out to assess these rigs deep water capability including: station keeping, past performance, mooring capability, load carrying performance, mooring capability, load carrying capacity, vessel stability with drilling consumables and 6000 ft riser onboard, type of drilling riser, and riser hang-off and disconnect system. Additionally, the drilling contractor's safety program, safety record, engineering and operational support were evaluated. Based on the above assessments, the Discoverer 534 was selected for BP Exploration's deep water drilling program. ENGINEERING OF THE UPGRADE The major modifications, to qualify the Discover 534 for 6000 ft [1830 m] water depth, were decided upon prior to contracting the rig. Due to the extensive effort of upgrading and modifying the rig, and the short time available, many of the projects were performed right up until the vessel projects were performed right up until the vessel left the shipyard for sea trials. Sonat Offshore Drilling, in conjunction with BP Exploration and outside engineering resources, identified and designed the necessary modifications. Due to BP's tight exploration program, timely delivery of services and equipment was crucial. P. 699
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... 1: Maximum values of the simulation with an EOG at 25 m/s with perfect wind preview using the 5 MW reference floating rotor effective wind speed 35 wind turbine (see Figure 7). FB FF FB FB FF FB [%] 30 ...ated Lidar Measurements 0.2 In a second simulation study, the robustness against wind measurement errors is examined. For this investigation, a turbulent 0 wind field with turbulence class "A" according...ind preview the rotor-effective wind speed from the wind field and its filtered () using the 5 MW reference wind turbine. Feedback controller only () and with additional feedforward (). and time-shifted est...
...ind turbine," Technical Report NREL/TP-In this work a collective pitch feedforward controller for a reference 500-41958. floating wind turbine is designed and evaluated. The feedforward Jonkman, J and Buhl, ML...ness against model uncertainties: Assuming perfect wind wind turbines," Mechatronics, volume 21(4), pages 704 - preview, the combined feedforward-feedback controller is able to 719. almost perfectly cancel...nic Technology, to transform the large reduction in rotor speed and power variations volume 30(10), pages 2233-2240. into further reduction of structural loads and increase Schlipf, D, Rettenmeier, A, Haiz...
...tory is optimized for the 5 MW Below rated wind speed, the goal of the torque controller is onshore reference wind turbine using the method presented in to maximize the energy yield. Thus, the generator torque...llective pitch feedforward controller is derived is to complete the two main tasks for controllers (reference first for perfect and then for realistic wind preview. signal tracking and disturbance compensatio...
Abstract In this work a collective pitch feedforward controller for floating wind turbines is presented. The feedforward controller provides a pitch rate update to a conventional feedback controller based on a wind speed preview. The controller is designed similar to the one for onshore turbines, which has proven its capability to improve wind turbine control performance in field tests. In a first design step, perfect wind preview and a calm sea is assumed. Under these assumptions the feedforward controller is able to compensate almost perfectly the effect of changing wind speed to the rotor speed of a full nonlinear model over the entire full load region. In a second step, a nacelle-based lidar is simulated scanning the same wind field which is used also for the aero-hydro-servo-elastic simulation. With model-based wind field reconstruction methods, the rotor effective wind speed is estimated from the raw lidar data and is used in the feedforward controller after filtering out the uncorrelated frequencies. Simulation results show that even with a more realistic wind preview, the feedforward controller is able to significantly reduce rotor speed and power variations. Furthermore, structural loads on the tower, rotor shaft, and blades are decreased. A comparison to a theoretical investigation shows that the reduction in rotor speed regulation is close to the optimum.
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...sel, one (or several) drilling operations to abandon the well head acoustic transponder(s) near the reference for a long period of time and come back to it point(s), and a three (or more) hydrophone base after...terrogation rate) - the precise knowledge and monitoring of the Whenever necessary in the following pages, instants of interrogation makes it possible the two basic versions-computer controlled to adjust a...e as to channel and leads to equal systematic detection be measured (fig. 2a), are those of a given errors on the hydrophones, independant of the point M in a rectangular trihedral, with the transponder. x...
...X'y'z'system tied to the vessel, knowing from In these equations Rand P have to be known a vertical reference unit (VRU) the roll and with an accuracy that does not affect a 1 % precision pitch_ angles Ran...t). As a matter of system tied to the measuring base and chosen in fact it is more the fast varying errors of the such away as to obtain simplified formulas that VRU (noise) that have to be avoided than the...n the 0 x y Z 1 placed in the immediate vicinity of nr 1 system are related by hydrophone. The reference trihedral Sh! 1j l. is x::: X. - o. cos (lX. -'!') then determined by (fig. 3a): 1 fl 1 n ...
... for are required of the relative position between a this purpose by CIT-ALCATEL has been specially reference point underwater and the sea surface designed to ensure a highly reliable functioning vessel. This ...t hydrophones on the vessel, and transponders are encountered: drilling noises are strong, near the reference pcint(s). Accurate acoustic irregular, with high peak transients; propellers travel times are thus ...
ABSTRACT Many offshore operations, such as the dynamic positioning of a drilling vessel, require accurate data of the vessel location with respect to a referential point (drill hole). The Acoustic Measuring System (AMS) developed for this purpose by CIT-ALCATEL has been specially designed to ensure a highly reliable functioning in severe environmental conditions : drilling noise, propellers noise and disturbances, signal reflections, etc .. This article describes the system and gives theorical accuracies and practical results obtained during drilling operations. The equipment consists-of a redundant assembly of interrogation transducers and receiving hydrophones on the vessel, and transponders near the reference point(s). Accurate acoustic travel times are thus possible on two-way propagation paths, which makes it possible to completely solve the geometry in all cases and, above all, enables the use of a sophisticated monitoring procedure by a digital computer. Erroneous signals resulting from reflections are eliminated, as well as most After high level noise transients. In addition, the system uses coded signals and adapted signal processing that increases its noise rejection capabilities. The equipment has been successfully employed in the dynamic anchoring of the ship "LE PELICAN" during drilling operations in the North and Labrador Seas. INTRODUCTION There are many instances in modern operations at sea where accurate and reliable data are required of the relative position between a reference point underwater and the sea surface vessel. This is the case in particular for the localization of a remote controlled fish (in pipe-line surveillance, submarine rescue, etc...) and for dynamic positioning purposes. The use of acoustic devices for obtaining the desired coordinates is one of the most frequent. There are, however, a number of difficulties, especially in the case of dynamic positioning, because severe conditions of environment are encountered : drilling noises are strong, irregular, with high peak transients; propellers or thrusters generate somewhat more steady but still very loud noises. up to high frequencies, and moreover they are sources of water agitation with air bubbles that interfere with the propagation of acoustic signals; the surrounding waters are congested with all sorts of acoustic obstacles (well head structure, riser, diving bell) and can be disturbed by mud projections, etc...)
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Improved Control of Floating Offshore Wind Turbine Motion by Using Phase-Resolved Wave Reconstruction and Forecast
Albertson, Shawn T. (University of Rhode Island Narragansett) | Gharankhanlou, Mojgan (University of Rhode Island Narragansett) | Steele, Stephanie C. (University of Rhode Island Narragansett) | Grilli, Stephan T. (University of Rhode Island Narragansett) | Dahl, Jason M. (University of Rhode Island Narragansett) | Grilli, Annette R. (University of Rhode Island Narragansett) | Hashemi, M. Reza (University of Rhode Island Narragansett) | Alkarem, Yuksel R. (University of Maine Orono / Advanced Structures & Composites Center) | Huguenard, Kimberly (University of Maine)
...tion misfit over a relevant temporal domain. As indicated before, however, even more important than errors on surface elevations, we are concerned in this problem with potentially large ...errors in wave phases that could cause faulty control commands to be issued in the float control system. T...ss-correlation function, which convolves surface elevations computed in the WRP to those serving as reference (i.e., observed or computed with a NWT), with a varying time lag τ. The time lag τ max that max...
...) ICWM. The nonlinear phase shift for the LWT-CDR and ICWM models, better aligns waves with the NWT reference data. See also Fig. 9. Vertical dash lines mark the boundaries of the prediction zone [t min = ... with E F 2% for all nonlinearity, while LWT-CDR performs almost as well, with less than 2.6%. Errors with the LWT and CWM models are larger in all cases, by at least 50%. For the phase misfit, Fig. 9 ...
...emic in model physics, to issue a safe control command to the FOWT control system. In this respect, errors on the phasing of wave loads are the main concern since a phase mismatch could cause larger motion ...eir WRP predictions using noisier wave tank data and found this in general increased the prediction errors, although these still stayed quite reasonable. This aspect will be crucial for the future field dep...atio-emporal Data Acquired by a Flash LiDAR Camera. Proc. 21st Intl. Offsh. and Polar Engng. Conf., pages 275-282. Grilli, S. T., Grilli, A., Bastien, S. P., Sepe, R. B., and L, S. M. (2011b). Small buoys ...
ABSTRACT Floating Offshore Wind Turbines (FOWT) can be actively controlled to minimize their wave induced motions, improving wind energy harvesting efficiency and increasing structural life by reducing fatigue loads. Here, we report on the development and validation of Wave Reconstruction and Prediction (WRP) algorithms that improve the active control of floating structure motions, achieved, e.g., by moving mass or ballast. Specifically, given a sensing method, here assumed to be LiDAR-like, that acquires dense spatiotemporal surface elevation data at some distance from the FOWT in the incident wave direction, we present and validate deterministic WRP algorithms, based on fast nonlinear and dispersive Lagrangian wave models, and integrate their predictions with in-the-loop hardware and a real time control system that is informed by computations with a digital twin (DT) model of the floating structure. We implement multiple WRP wave models including a model based on linear wave theory (LWT) with a correct dispersion accounting for nonlinearity (LWT-CDR) and a 2nd-order "Choppy" wave model with improved nonlinear dispersive properties (ICWM), initialized with a linear prediction. Although we run laboratory experiments of the complete system, which are reported elsewhere, here the WRP implementation is validated against fully nonlinear potential flow simulations in a Numerical Wave Tank (NWT), which shows both LWT-CDR and ICWM models appear to provide reasonable short-term predictions at the float. Implications for the real time control system are discussed; in a companion paper, the use of short-term wave predictions with the WRP is shown to improve the real time control of float motions in waves. INTRODUCTION Many offshore wind farms are in development along the US East Coast, with about 3GW of total installed power, that will be equipped with turbines installed on static foundation support structures. The current goal of the US administration, however, is to install ten times as much offshore wind power in US waters by 2030, and to meet this goal, it will be necessary to develop farms also in deeper waters, beyond the continental shelf, made of floating offshore wind turbines (FOWT). In some areas of the US, such as the Gulf of Maine or the West Coast, which feature a narrow shelf, FOWTs are the only viable option.
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...require to approach "cautiously" critical values where the simulator might stop working and produce errors (e.g. a very small inner diameter of a pipe). In conclusion, we suffered from the fact that most ty...and interactive visualizations, even 3D, with rich interfaces. Most of us use browsers to visualise pages similar to documents, perhaps with animations and some clickable or touchable regions. Actually the...
...oud computing" philosophy. The business targets were: 1) Higher efficiency in studies, with special reference to rework to support fast-track projects 2) Enhanced decision-oriented attitude versus the simulati...on-oriented attitude 3) Improved quality control, with respect to human errors and also to simulator "glitches" 4) Stronger cohesion in methods and tools of the internal Flow Ass...
...p the Operating Philosophies. The concept was very effective, and we could also spot many modelling errors and misalignments between models, which would have gone otherwise unnoticed. This technical machine...
Abstract Most of the Flow Assurance studies performed in-house are devoted to the early design of new fields, in which the main issues are identified and the recommended field architecture and operating philosophies are defined. Such early design stages are characterized by the occurrence of significant changes along the course of the studies, as long as new information becomes available. For example, production profiles or well positioning and line routing can change; or early-production phases, with limited flowrates, may be introduced, etc. Such changes are particularly frequent in fast-track engineering, where several studies are parallelized, and this fact gives to the Flow Assurance specialists the additional task to understand as quickly as possible the implications of each change and help finding the best development options. The above situation typically requires continuous rework and the review of previous decisions with modified constraints. In this context, to increase the internal productivity and the robustness of Flow Assurance studies, we have internally developed a tool to support the Flow Assurance workflow. Such tool is based on the following components:a High Performance Computing facility to run the simulations, endowed with a scheduler to optimize the usage of software licenses and hardware resources; an innovative post-processing system, conceived to facilitate the extraction of the relevant information from the simulations (which we call Key Engineering Variables) and document the adopted decisions; a fully browser-based interface, to explore the simulations, examine the effect of the design constraints and launch new simulations, even from tablets without any specialized software and a new Field Model description, from which simulation input files can be automatically generated, built with the purpose to easily apply changes, to follow the evolution of the field architecture from the early phase to the as-built stage and to store the information for several years, being tabular and independent from ever-changing simulator input formats. The Field Model structure will be described elsewhere, while this paper relates to the other points. The system has been developed along the past two years and has been in use, as a prototype, for several months during which improvements in the architecture and the interface were carried out. The main conclusions of the test phase, which led to the first stable version, are the following:Flow Assurance decision making was faster than before and could sometimes be discussed during interactive team-work, by leveraging on the innovative browser-based tools re-work became less labour-intensive and faster, leading to improved change-management and facilitating critical thinking the quality of the simulations could be assessed more pervasively, allowing faster debugging and achieving better technical results engineering analyses became more standardized and explicit, facilitating team alignment and tracking of previous reasoning the Field Model description, being able to accommodate both as-built geographic information and design assumptions, allowed to speed-up expansion studies of existing fields, where several new wells had to be integrated into existing gathering networks. The paper will describe the system, which has been called e-fast™ (eni Flow Assurance Simulation Toolbox), in the light of the above experiences.
...lso, the dynamic part of the axial compressive force should be multiplied by 1.2, as pointed out in Reference [11, whenever tendons are attached to the columns. one f the unique features of the model and ...thods of analysis suggested in Reference [1] is the classification of load effect components. The effects of dead and live loads, including ...4]) use approximations in dealing with the ccmplex structural problem of inelastic instability. The errors induced in approximate formulations such as these must be established through calibration with expe...
...sis of Structural Safety", Jaurnal of Structural Engineering, ASCE , Volume 109, No 3, Itirch 1983, pages 721 - 740. 13. Home, M R and Price, P H: "Commentary on the Level-II Procedure", Supplement to CIR...IA-63, (See Reference 6 above), July 1977. 14. Wirsching, shore P H: "Probability Based Fatigue Design Criteria for Off ...
...ral bgsic vQrigblQs such Qs the structural dimensions, material properties, load effects, madelling errors, etc. These basic parameters are also random variables, and hence the probability of failure should...
Abstract This paper is intended to discuss the basic issues involved in structural reliability in conjunction with a limit state approach for design and analysis of offshore structures. Emphasis will be placed an a systematic semiprobabilistic approach suitable for strength evaluation of major structural elements. Problems arising from quantification of uncertainties of the pertinent random variables, load combination, and in the development of limit state functions involving both ultimate failure and fatigue, will also be discussed. Introduction The goal of any structural design is to produce a sound structure that will be able to maintain its integrity for the duration of its intended service life and in a manner capable of performing its intended functions. To the extent that it is able to meet this goal, the structure is considered safe. Traditionally, the safety of structures and their components have been determined through a series of checks based on design criteria which, in essence, require that the structural resistance (strength) must be greater than the anticipated loading. One such approach for evaluating structural safety, well known and widely adopted, is the working stress format. In a traditional working stress approach, the design loading may, for instance, be selected to simulate the most probable severe condition expected during the projected service life of a structure. The sizes and dimensions of the various structural components con then be determined by a set of stress limits based on the material properties and types of loading under consideration. properties and types of loading under consideration. Uncertainties associated with load predictions and strength assessments are presumably compensated for by introducing nominal safety factors derived primarily from post experience. Until the recent increased interest in tension leg platforms and other types of compliant structures, offshore structural design has also been primarily based on technology employing such traditional approaches. It is to be recognized that such a traditional design procedure or offshore structures has some important shortcomings with regard to both loading and strength determination. On the loading side, the inherent assumptions usually result in a great deal of conservatism, since factors such as directionality and joint probabilities of occurrence are often not taken into consideration. probabilities of occurrence are often not taken into consideration. p. 9–1 p. 9–1
- Facilities Design, Construction and Operation > Offshore Facilities and Subsea Systems (0.67)
- Management (0.48)
- Well Drilling (0.46)
...This first goal brought us many advantages as: more accurate and reliable information; reduction of errors caused by interpretation and mistyping and the elimination of typing activities. Only by digitalizi...
... a Semi-Submersible Unit Figure 4--LTE coverage at 700 MHz and 1800 MHz for a FPSO Unit Just as a reference, during the commissioning, we fixed the setup of the test in 5 MHz of frequency channel width; SISO...
...ed reality technologies on the customer experience, Journal of Business Research, Volume 100, 2019, Pages 547-560, ISSN 0148-2963, https://doi.org/10.1016/j.jbusres.2018.10.050...
Abstract Innovation and new technologies come hand by hand in the Oil and Gas industry adding value and improving processes and safety at the same time reducing costs. This paper presents how the improvement of wireless connectivity in offshore platforms has been supporting critical mission activities, deployment of IIoT devices and field workers mobility. Wireless networks were expanded in industrial environments enabling a wide variety of new services. Meanwhile, the most impacted operational processes were selected where disruptive technologies could generate more value, such as maintenance and inspection processes. After this, we evolved each insight through the Technology Readiness Level steps; beginning with the Proofs of Concept for decision making until we could scale it up and measure its benefits. Explosion-proof devices were used to provide mobile connectivity to robots and IIoT devices. Augmented reality glasses running remote and guided assistance software, increased collaboration, adding more expertise and knowledge to operational activities at Campos basis.
- Facilities Design, Construction and Operation > Offshore Facilities and Subsea Systems (0.91)
- Data Science & Engineering Analytics > Information Management and Systems > Artificial intelligence (0.69)