scholarly journals A Comprehensive Review on Design, Monitoring, and Failure in Fixed Offshore Platforms

2021 ◽  
Vol 9 (12) ◽  
pp. 1349
Author(s):  
Nima Amiri ◽  
Mohammad Shaterabadi ◽  
Kazem Reza Kashyzadeh ◽  
Mahmoud Chizari

Offshore platforms have had diverse applications in the marine industry, for example, oil or gas platforms can provide facilities to store the oil and gas before transport those to refineries. Offshore wind turbines are another well-known use of the offshore platform for generating power. As platforms encounter various strong forces from water and wind currents, the materials used for these structures are mainly steel or concrete. These platforms are classified into different types, according to the depth of water and their applications. In addition, offshore platforms, as artificial reefs may be used for decades at different marine conditions. Consequently, their design and maintenance are very important, otherwise, they can cause irreparable damage to the environment. This paper presents the latest and most significant design and monitoring methods, such as the optimal probabilistic seismic demand model, multi-objective optimization, dynamic response assessment, robust fault-tolerant control, etc., under different environmental and geographical conditions. Moreover, the effective factors on the life and failure of these offshore structures are comprehensively introduced to enhance awareness of them, which can be very helpful to improve the design and construction of more reliable and durable structures.

Author(s):  
Mohammed E. Sayed ◽  
Markus P. Nemitz ◽  
Simona Aracri ◽  
Alistair C. McConnell ◽  
Ross M. McKenzie ◽  
...  

The oil and gas industry faces increasing pressure to remove people from dangerous offshore environments. Robots present a cost-effective and safe method for inspection, repair and maintenance of topside and marine offshore infrastructure. In this work, we introduce a new immobile multi-sensing robot, the Limpet, which is designed to be low-cost and highly manufacturable, and thus can be deployed in huge collectives for monitoring offshore platforms. The Limpet can be considered an instrument, where in abstract terms, an instrument is a device that transforms a physical variable of interest (measurand) into a form that is suitable for recording (measurement). The Limpet is designed to be part of the ORCA (Offshore Robotics for Certification of Assets) Hub System, which consists of the offshore assets and all the robots (UAVs, drones, mobile legged robots etc.) interacting with them. The Limpet comprises the sensing aspect of the ORCA Hub System. We integrated the Limpet with Robot Operating System (ROS), which allows it to interact with other robots in the ORCA Hub System. In this work, we demonstrate how the Limpet can be used to achieve real-time condition monitoring for offshore structures, by combining remote sensing with signal processing techniques. We show an example of this approach for monitoring offshore wind turbines. We demonstrate the use of four different communication systems (WiFi, serial, LoRa and optical communication) for the condition monitoring process. By processing the sensor data on-board, we reduce the information density of our transmissions, which allows us to substitute short-range high-bandwidth communication systems with low-bandwidth long-range communication systems. We train our classifier offline and transfer its parameters to the Limpet for online classification, where it makes an autonomous decision based on the condition of the monitored structure.


1994 ◽  
Vol 16 (2) ◽  
pp. 43-48
Author(s):  
Do Son

This paper describes the results of measurements and analysis of the parameters, characterizing technical state of offshore platforms in Vietnam Sea. Based on decreasing in time material characteristics because of corrosion and local destruction assessment on residual life time of platforms is given and variants for its repair are recommended. The results allowed to confirm advantage of proposed technical diagnostic method in comparison with others and have been used for oil and gas platform of Joint Venture "Vietsovpetro" in South Vietnam.


Author(s):  
S. M. S. M. K. Samarakoon ◽  
R. M. Chandima Ratnayake ◽  
S. A. S. C. Siriwardane

Structural integrity control (SIC) is an increasingly important element of offshore structures. Not only is it used in newly built and existing offshore structures (e.g. oil and gas (O&G) production & process facilities (P&PFs), wind turbine installations, etc.), but SIC is also essential for ageing offshore platforms which are subjected to an extension of their design service life. In these cases, SIC programs must be performed to assess the platforms. If any significant changes in structural integrity (SI) are discovered, then it is essential to implement an appropriate strengthening, modification and/or repair (SMR) plan. Currently, welded and grouted repairs are mostly used for SMR. Although a welded repair may typically restore a structure to its initial condition, if the damage is due to fatigue loading and welded repairs have been carried out, then historical evidence reveals that there is a high potential for the damage to reappear over time. On the other hand, mechanical connections are significantly heavier than grouted connections. Consequently, grouted repairs are widely used to provide additional strength, for instance, to handle situations such as preventing propagation of a dent or buckle, sleeved repairs, leg strengthening, clamped repair for load transfer, leak sealing and plugging, etc. This manuscript examines current developments in grouted connections and their comparative pros and cons in relation to welded or mechanical connections. It also provides recommendations for future research requirements to further develop SMR with grouted connections.


2005 ◽  
Vol 29 (5) ◽  
pp. 463-469 ◽  
Author(s):  
Anders Moller

In the oil and gas industry, the foundations of offshore platforms have, for decades, used the grouted technique. This technology has now been transferred into the offshore wind turbine industry. This paper gives details of the use of the technology in some of the first offshore windfarms in Europe and considers future design possibilities.


Author(s):  
John Murray ◽  
Apurva Gupta ◽  
Foo Kok Seng ◽  
Asbjorn Mortensen ◽  
Wong Toh Tung

Designs for offshore structures that will be deployed in arctic regions have to consider ice forces, which can be the governing design load. In shallow-water areas (< ∼100 m), fixed bottom caisson designs and artificial islands usually offer the best solutions. In deeper water, however, moored floating systems such as the ship-shaped Floating Production Unit (FPU), the Spar and the Single Column Floater (SCF™) are practical solutions. Even in shallower water where earthquakes are a threat, a moored floater can be a better option because of its ability to avoid seismic effects of the quake due to its suspension in the water above the sea floor. It is estimated that about 30% of the remaining oil and gas reserves lie in the arctic regions of the world. Special care has to be taken to design offshore platforms to survive these extreme arctic environments. Along with severe environmental conditions, there is a possibility of icebergs and multi-year ice sheets as well. A practical solution is to remove the floating structure in case of the expected loads on the structure exceed the maximum design loads. The platform can be brought back to location after the extreme environmental condition has passed. This paper describes a design for a disconnectable mooring system that comprises of external fairleads, submerged chain locker boxes and diverter units along with quick release mechanism and a single handling winch for each group of lines. The system works in tandem with the rig’s ROV and an anchor handling tugboat when connecting the system, while disconnection is automatic without any external assistance other than an emergency release signal. The paper provides the rationale for selecting this configuration based on its strength, redundancy requirements, quick disconnectable ability, without interfering with normal operation and presents a range of applications for this design.


CivilEng ◽  
2020 ◽  
Vol 1 (3) ◽  
pp. 310-325
Author(s):  
Foteini Konstandakopoulou ◽  
George Papagiannopoulos ◽  
Nikos Pnevmatikos ◽  
Konstantinos Evangelinos ◽  
Ioannis Nikolaou ◽  
...  

Oil and gas offshore structures are essential infrastructures which are subjected to several categories of environmental loads such as wave and wind actions. These loads commonly designate the structural design of offshore platforms. Additionally, several offshore platforms are founded in earthquake-prone areas and the design of them is intensely affected by seismic ground motions. To be sure, various investigations have studied the earthquake response of offshore structures under the action of far-field seismic events. However, the inelastic behavior of platforms under the action of simple pulses has not been examined yet, where the latter loads can successfully simulate near-fault earthquakes. This work investigates, for the first time to our knowledge, the dynamic inelastic response of offshore platforms subjected to triangular, exponential, sinusoidal, and rectangular pulses. Thus, three-dimensional offshore structures are examined also considering the dynamic soil-pile-platform interaction effects, satisfying all the pertinent provisions of European Codes and taking into account geometric and material nonlinearities as well as the effects of the different angles of incidence of seismic waves on the overall/global response of offshore platforms.


Author(s):  
Mohamad khaled Abed El Rahim ◽  
Moath Al Husban

Offshore structures are used around the world for many functions, and these structures vary according to the depth of the water, the depth of water and environmental conditions are the main factors that determine the type of platform and method of drilling, appropriate planning, manufacturing, transportation, installation, and start-up. At the beginning of the twentieth century, oil and natural gas were discovered in the Middle East, specifically in the Lebanese basin. This discovery opened the door for Lebanon and entered the club of oil states. This paper is a study and analysis of blocks No. 4 and No. 9 that may contain the largest amount of oil and natural gas in addition to studying and analysing the types of marine installations (fixed and movable) and provide the best suggestions for the type suitable platform for the process of extracting oil and natural gas from the Sea of Lebanon according to the depth of water and factors Natural. The option of a drillship for drilling is the most appropriate option, given the lack of sufficient information about the nature of the soil in the Lebanese Sea. The drillship is considered an optimal solution given for ease of movement and in the absence of oil, the cost is much lower than the installation of fixed platforms. Semisubmersible rig for drilling and Tension Leg Platform or Semisubmersible Platform as well as Subsea System for oil/gas extraction are good alternatives to be employed in the Lebanese oil/gas fields.


Author(s):  
R. Abdel-Ghany ◽  
S. Saad-Eldeen ◽  
H. Leheta

In steel offshore platforms used for drilling and production of oil and gas, failures of structural steel members can occur due to pitting corrosion and corrosion fatigue at welded nodes where the brace members are joined. These nodes are areas of high stress concentration due to the complex geometry of these locations. The purpose of this paper is the application of FEM structural analysis to a model of K-T joints of a jack-up rig leg to explore the effect of random pitting corrosion on its strength capacity. The results are presented along with those previously published for the same model for the case of uniform corrosion.


Author(s):  
Daniel Povel

For the approval process of offshore platforms and offshore wind farms, risk analyses that consider collisions between ships and stationary offshore structures are helpful and sometimes necessary. Ship traffic, meteorological and hydrological data are important input information for the investigated sea area. Possible collision scenarios with powered ships sailing into the structures and disabled ships drifting into the structures have to be investigated to determine the collision probabilities and the consequences. Furthermore, risk control measures have to be examined and assessed in such risk analyses. In recent years, Germanischer Lloyd has developed and applied suitable methods and procedures to evaluate the collision risk, including the influence of risk control measures. For these analyses, Germanischer Lloyd developed an analysis software that uses Monte Carlo simulations. For the evaluation of different risk control measures, Bayesian nets are used to determine the reduction of the collision probabilities for powered and drifting vessels and the corresponding risk. In this paper, the methods and processes that were developed are presented together with results of a sample collision risk analysis. Moreover, experience in the practical application of collision risk analyses is discussed, as part of the approval process for offshore wind farms.


2021 ◽  
Author(s):  
Sari Amelia ◽  
Jing Shuo Leow ◽  
Bisri Hasyim ◽  
Dega Damara Aditramulyadi ◽  
Hooi Siang Kang ◽  
...  

Abstract More than a thousand fixed oil and gas offshore structures were installed in the Southeast Asia region. Indonesia currently has more than 600 offshore oil and gas platforms, nearly half of which need to be decommissioned within the next few years. While the regulators and operators are developing procedures and regulations for the decommissioning process of the offshore platforms, there is also a need to ensure that onshore facilities are available to receive the decommissioned structures and equipment and subsequently process them safely. At the moment, there is no yard in Indonesia that is well-placed to undertake onshore decommissioning activities. The aim of this study is to develop recommendations for yard owners to assure their yards are ready for the upcoming decommissioning projects. Research data was collected directly from field survey in an offshore fabrication yard, owned by PT. Meitech Eka Bintan, Indonesia. In the current study, research data was analyzed by comparing with decommissioning yard facilities in ABLE Seaton Port, United Kingdom which was used as offshore structure decommissioning yard since 1985. Recommendations include the work required to assure the yard comply with respective guidelines and industry best practices. The research begun with identifying the yard's potential to receive onshore decommissioning work based on current primary facilities which are quay and fabrication area properties. After that, a yard modernization assessment was carried out as to identify the best location for the upgrade on the missing required facilities. The results indicate that the primary facilities of the yard are comparable to ABLE Seaton Port with both having similar depth at quayside, capable of mooring barges and Heavy Lift Vessel (HLV), both having liquid containment system at the fabrication area and the large fabrication area at PT. Meitech Eka Bintan yard is sufficient similar to the area utilized by ABLE Seaton Port for Brent Delta topside decommissioning works. However, since the yard's main business is currently on offshore structure fabrication, hence there is a lack of waste handling facilities such as waste handling workshop and covered waste storage area to fulfill the respective guidelines and regulations. A case study was carried out to identify the onshore decommissioning working area and the location of the waste handling facilities on the yard. This study is expected to assist towards improving the readiness of yards to carry out onshore decommissioning not only in Indonesia but also in Southeast Asia region.


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