Offshore Monitoring (Cyprus)

Abstract High speed crafts demand lighter structural weight to enhance transportation efficiency, which, in turn, increases the risk of premature structural failure. As such the use of aluminium structures requires closer attention to fatigue cracks. There is a clear technological trend towards equipping high-speed vessels with Structural Health Monitoring (SHM) systems that provide structural diagnosis and prognosis capabilities to support operation and maintenance decisions. The intelligent data processing capabilities of a digital twin make it an ideal platform for achieving real-time structural health awareness of the entire hull, even with a limited number of sensors. Unfortunately, current digital twin applications for ship structures are primarily implemented on large displacement cargo vessels or offshore structures and are not readily applicable to high-speed crafts due to the unique challenges associated with predicting their responses: (1) lack of information of the highly non-linear slamming load experienced at high-speed; (2) the absence of efficient models to predict non-linear hydrodynamic responses under dynamic operating conditions, including planning effects, porpoising, and wave-induced motions. To address these challenges, a customized SHM solution via digital twinning has been developed for an ultra-high speed patrol craft (Froude number Fn>2.0). This paper presents the research work conducted in Phase 1. The Dynamic Loading Approach (DLA) and Spectral-Based Fatigue Analysis (SFA) are utilized for structural evaluation when the craft navigates at loitering speeds (Fn<0.4), Whereas a coupled Computational Fluid Dynamics (CFD)+Finite Element (FE) analysis framework is developed to address the slamming load effects on global and local structure responses in semi-planning or planning state (Fn≥0.4). The insights gained from these numerical analyses have been instrumental in designing the sensor placement plan and developing the architecture of the SHM solution, which serve as the foundation for SHM system development in Phase II. At last, a quantitative cost-benefit analysis has been conducted, highlighting the economic feasibility and added value of SHM implementation for highspeed crafts.

Abstract A fully elastic containership model was experimentally tested in head sea and bow quartering sea conditions to investigate the effects of wave steepness and towing speed on global motions and loads. The study analyzed heave and pitch motions across different Froude numbers (Fn = 0.15 and Fn = 0.25), as well as vertical bending moment, vertical shear force, and torsional moment under varying wave conditions. The nonlinear behavior of global loads was examined, particularly in large wave amplitude cases. Finally, a linear numerical model, validated against the experimental data, was used to predict extreme responses of global motions and loads.

For over a decade, SBM Offshore, a global leader in offshore energy, has been developing a revolutionary wave energy converter (WEC) based on dielectric elastomer generators (DEGs). The development process has yielded numerous innovations across multiple domains, including hydrodynamic model test, material formulation and selection, large-scale manufacturing of dielectric elastomers, integration of DEGs into large watertight structures, and custom power electronics design. A prototype at scale has been tested in controlled water tank conditions. This paper presents the key achievements of the S3^® WEC development, providing comprehensive insights into the technological advancements. Moreover, we critically examine the principal technological challenges and limitations that need to be addressed for future research and development in the dielectric elastomer generator applications.

Ovaj rad istražuje utjecaj socioekonomskih varijabli, karakteristika zdravstvenog sustava, stanja okoliša i životnog stila na zdravstveni status populacije u zemljama Europske unije primjenom dinamičkih panel modela. Rezultati su potvrdili važnost, prethodno navedenih skupina varijabli. BDP po glavi stanovnika, privatna zdravstvena potrošnja, nezaposlenost, korištenje uslugama pitke vode, konzumacija alkohola i pušenje statistički su značajni i očekivanog predznaka. Udio visokoobrazovane radne snage u ukupnoj radnoj snazi, potrošnja za zdravstvo po stanovniku, javna zdravstvena potrošnja i emisija CO2 imaju statistički značajan utjecaj, ali im je predznak suprotan očekivanom. Negativan utjecaj javne zdravstvene potrošnje ukazuje na potrebu provođenja ekonomskih evaluacija pri donošenju odluka, uz provođenje mikroekonomskih reformi na strani ponude s ciljem povećanja učinkovitosti. S druge, pak, strane, značajan utjecaj konzumacije alkohola i pušenja zahtjeva multidisciplinarni pristup u promoviranju i poticanju zdravih životnih navika s naglaskom na jačanje primarne zdravstvene zaštite.

Feature - As the majority of oil and gas operators are acutely aware, the worldwide expansion of the industry's services market in recent years has resulted in a growing need for skilled workers.

ABSTRACT A study of the vertical dynamics of marine riser-load systems has been performed to determine the amplitude of dynamic forces and displacements caused by heave action. The analysis predicts circumstances under which slackening or compression, and subsequent failure of a riser can occur. Results show that a suitably designed heave compensator can reduce the dynamic stress amplitude to acceptable values under all operating modes including hang off, by increasing compliance at the riser vessel interface. Finally, recommendations for the design of heave compensation equipment intended to limit the dynamic force amplitude on riser-load systems hanging in deeper waters and harsher environments are presented. INTRODUCTION As work is performed in increasingly deeper and harsher seas, the vertical dynamics of the equipment and risers employed gain fundamental importance; a particular concern being to maintain an adequate and reasonably constant tension on the riser structure under any depth or environmental conditions. We understand a marine riser is the structure that links a submerged load with a floating vessel. A variety of configurations is possible under this description, but they can be subdivided into two main classes of different characteristics: Pipe risers and cable risers. The following analysis applies to both types, except where noted. A riser is initially designed from static load premises. This can lead to dynamic failure as a consequence of reduced tension that results from the dynamic force amplitude. A vertical dynamic analysis of the initial design is required to ensure the dynamic tension amplitude is smaller than the static tension. Large dynamic forces capable of inducing failure can develop from:Dynamic force amplification due to excitation at or near the system's natural frequency.Downward acceleration of the vessel at the riser suspension point approaching or being greater than the free fall acceleration of the riser system. The first cause of failure is of concern in deep water and when lower elastic modulus materials are used for riser construction, because the riser's natural frequency can approach the heave frequency. The second situation can arise when:Using very massive loads or risers, with low overall wet weight/wet mass ratio; orhandling loads with large horizontal surfaces that produce large drag forces. Situation "A" can occur with buoyant pipe risers, such as those used for drilling or mining purposes. Situation "B" is more likely with cable risers, such as those used for deep sea load handling (i.e. Template landing or Remote Vehicle operation). When a riser is subjected to dynamic excitation, a dynamic stress component develops. When this exceeds the value of the static stress due to the wet weight, a cable riser goes slack, and on the following part of the cycle violently retightens, creating a so-called "snapload": a sudden shock load on the system that can part the cable or cause other damage depending on overall system dynamics.

Abstract During the past year, a new mechanical pile connector has been introduced to the offshore construction industry. This connector has been the culmination of an extensive development and fullscale testing program by Vetco Offshore, Inc. A family of driveable pile connectors has since been produced, ranging in size from 30" O.D. to 72" produced, ranging in size from 30" O.D. to 72" (762 mm to 1829 mm). Included in this family are standard releasable connectors and remote-releasable connectors for skirt pile applications, and a slightly modified design recommended for permanent pile applications. pile applications. Specifically designed for skirt pile and permanent pile applications, the pile connector permanent pile applications, the pile connector incorporates field-proven features that have been used on Vetco wellhead and riser connectors. The design phase included a finite element optimization and a fatigue analysis of the connector. Special anticorrosion considerations have been taken to ensure long life in the marine environment. The connector was tested extensively at both in-plant and field facilities. These tests included tensile, pressure, bending, functional, and pile driving tests. Following the development tests, the connector was supplied to several users for actual field trials. Since the connector has been introduced to the offshore industry, it has been used in a variety of skirt piles and permanent pile applications. To date, the pile connector pile applications. To date, the pile connector has been supplied in 30", 40", 42", 48", 54" and 72" (762 mm, 1016 mm, 1067 mm, 1219 mm, 1372 mm and 1829 mm). Introduction It has been found that the handling, stabbing, and connecting of individual pile sections often represents a critical phase during offshore construction. These operations are particularly acute during heavy weather conditions. Considerations for men and machinery safety often dictate a work slowdown, or even a stoppage, until a suitable weather window is available. In addition, a significant amount of time is consumed during pile welding operations. Weld time must include pile positioning, preheat, welding, cool-down, and inspection. For welding larger diameter, heavy-wall pipe sections, these welding operations become increasingly time consuming and expensive. Recognizing these increased costs of offshore welding and rig time, Vetco has developed a mechanical connector for large diameter pile sections (Figure 1). The Vetco Pile Connector is a heavy-duty, driveable connector designed specifically for connecting sections of drive string, platform piling and other large diameter applications. it piling and other large diameter applications. it is a threadless connector and does not require rotation for makeup. When made up, the connector provides a strong, pressure-tight and rigid provides a strong, pressure-tight and rigid connection which efficiently transfers the driving energy throughout the length of the piling string. This results in a faster, more economic driving operation. Since the pile connector is preloaded during makeup, this condition greatly enhances the fatigue strength of the joint, ensuring that it has longer fatigue life than the basic pile section. The design and materials of the connector have been carefully considered to ensure that it has maximum corrosion resistance and is suitable for application in a permanent offshore installation. During the pile connector design phase, experience gained from producing several other field-proven mechanical and hydraulic connectors was utilized. In particular, Vetco's long experience in marine drilling riser connectors and subsea hydraulic connectors was used to adapt several successful features to the pile connector. This paper presents a technical description of the Vetco Pile Connector. In doing so, it describes the development of the connector from design through prototype testing and field application stages.

During the past year, a new mechanical pile connector has been introduced to the offshore construction industry. This connector has been the culmination of an extensive development and fullscale testing program by Vetco Offshore, Inc. A family of driveable pile connectors has since been produced, ranging in size from 30

American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc. This paper was prepared for the 45th Annual California Regional Meeting of the Society of Petroleum Engineers of AIME, to be held in Ventura, Calif., April 2–4, 1975. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor of the appropriate journal provided agreement to give proper credit is made. Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines. Abstract In order to meet the needs of drilling offshore oil and gas wells in water depths exceeding 3,000 ft., a deep water guidelineless drilling system has been conceived and is being developed. The operation of this system will be discussed, and the new and improved products in the specific areas of the wellhead products in the specific areas of the wellhead system, the re-entry equipment, the blowout preventer stack, and the riser system will preventer stack, and the riser system will be described. Introduction At the present time, most offshore floating drilling vessels can drill in water depths of approximately 1,000 ft.. There are only several drilling vessels which can drill in water depths as much as 3,000 ft. To date, the deepest water depth in which one of these vessels has drilled a well has been just over 2,000 ft. As the need for oil increases and the demand for finding this oil offshore also increases, a need is developing for exploring for oil in water depths beyond 3,000 ft. and ranging up to 6,000 ft. The drilling vessels, which now have a capability of drilling in about 1,000 ft. of water, are moored in position using anchors. Guidelines are used to guide subsea drilling equipment from the drilling vessel to the ocean floor. It is believed by some researchers that guideline technology is applicable only to water depths of approximately 1,500 ft. or less. Other researchers believe guidelines may be used to 3,000 ft. or more. Nonetheless, even deep water drilling using guideline technology requires special techniques and additional equipment to perform drilling operations with the same degree perform drilling operations with the same degree of reliability found when using conventional drilling methods in shallow water. There are some distinct disadvantages in using guidelines in deep water, such as the size of the line necessary to insure adequate strength, the size of the machinery required to handle this line, the requirement for motion compensation equipment, and the maintainability of these guidelines during a drilling operation. In an attempt to overcome some of these disadvantages and to easily extend drilling operations into water as deep as 6,000 ft., guidelineless drilling technology has been called upon as a means of achieving this objective. The majority of drilling vessels which are capable of drilling in the deeper water depths will be dynamically positioned and will be guidelineless.