Dimensioning of Twistlocks in Modular Offshore Platform Designs for Arctic Regions

2013 ◽  
Author(s):  
Josefine Michel ◽  
Patrick Kaeding
Keyword(s):  
Regression Analysis ◽  
Friction Coefficient ◽  
Offshore Platform ◽  
Roll Angle ◽  
Offshore Platforms ◽  
Arctic Regions

To mount service modules in a flexible manner on offshore platforms twistlock systems are used. If the application is not in accordance with standard conditions the existing regulations are not sufficient. Therefore new regulations with appropriate dimensioning equations must be generated. The results of the OMAE 2013 paper “Assessment of Container Mountings in Modular Offshore Platform Designs for Arctic Regions” are applied in this paper to reach such equations. The stress on twistlocks which mount standard containers to the offshore platform deck in arctic regions depends on roll angle of the offshore platform and friction coefficient — depending on temperature — and is analyzed by regression analysis in this paper. The results show that a local twistlock system can be used to simplify the calculation. Also the application of a crane module is simulated. The regression analysis is divided into two parts — the cone and the base of the twistlock: these parts take most of the load again depending on roll angle and friction coefficient. The result of this paper consists of dimensioning equations for these two different applications of twistlock systems in arctic regions.

Assessment of Container Mountings in Modular Offshore Platform Designs for Arctic Regions

2012 ◽  
Author(s):  
Josefine Michel ◽  
Patrick Kaeding
Keyword(s):  
Friction Coefficient ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Offshore Platform ◽  
Harsh Environment ◽  
Offshore Platforms ◽  
Friction Coefficients ◽  
Cold Temperatures ◽  
Elastic Range ◽  
Arctic Regions

Regularly the twistlock system is used to mount containers on container vessels or on offshore platforms as service containers in normal climate regions. In this paper the twistlock system is analyzed with respect to mounting auxiliary systems as well as accommodation and service modules to the deck of offshore platforms in arctic regions. When the twistlock systems are used in harsh environment it is also important that the twistlocks withstand the acting forces without great displacements and without exceeding the elastic range. But in arctic regions the mountings must resist additional forces due to ice interaction, cold temperatures and small friction coefficients. Because the existing rules do not include regulations how to analyze the strength of these mountings in arctic regions the influence of the friction coefficients and the Young’s modulus were of interest in this study. This paper summarizes some numerical works on these new discoveries. The results of the computations show that the Young’s modulus has no influence on the stress and the displacement of the bodies. However, the friction coefficient has influence on the stress specified in the simulations for large roll angles.

Installation of Long Span Boat Landing on Float Over Platforms - A Case Study

2021 ◽  
Author(s):  
Charles John George ◽  
Cibu Varghese ◽  
Faris Ragheb Kamal
Keyword(s):  
Production Process ◽  
Energy Absorption ◽  
Arabian Gulf ◽  
Offshore Platform ◽  
Offshore Platforms ◽  
Long Span ◽  
Heavy Lift

Abstract Fixed offshore platforms are normally provided with landing platforms that enable berthing of supply vessels, crew boats etc. These landing platforms or ‘Boat landings’ are energy absorption structures provided on substructures (jackets) of offshore platforms. Their purpose is to facilitate personnel access from vessel to platforms for performing various tasks including manning the platform, its maintenance etc. Vessel also approach the platforms for providing supplies in case of a manned platform and for providing bunkers, spares etc. As such, boat landing is an integral part of offshore platform and its design and installation becomes equally important. They are preferably located at leeward direction as far as practical, to avoid accidental vessel drift into the platform. For smaller standalone offshore platforms installed with Heavy Lift Crane Vessels, boat landing is installed after the jacket is piled to seabed. Since sequence of installation of boat landing is prior to that of Topside, such installations are straightforward and without obstructions from the Topside. For the bigger accommodation, production, process platforms located in super-complex (or standalone) with topsides installed by float over method, boat landings sometimes are in the wide float over barge slots. In such cases, installation of boat landing becomes very critical due to the post installation after the Topside and associated obstructions from the Topside. This is similar or more critical than a boat landing removal / refurbishment activity carried for a brownfield project. This paper explores the challenges and associated steps adopted to execute the safe installation of these critical structures underneath a newly installed Topside. This case study details the installation of ∼300mt boat landings onto recently installed Greenfield platforms in Arabian Gulf using efficient rigging, suiting the EPC Contractors’ crane assets.

scholarly journals Investigating Vapour Cloud Explosion Dynamic Fatality Risk on Offshore Platforms by Using a Grid-Based Framework

Processes ◽  
2020 ◽  
Vol 8 (6) ◽  
pp. 685
Author(s):  
Usama Muhammad Niazi ◽  
Mohammad Shakir Nasif ◽  
Masdi Muhammad ◽  
Faisal Khan
Keyword(s):  
Risk Analysis ◽  
Well Being ◽  
Offshore Platform ◽  
Offshore Platforms ◽  
Plant Design ◽  
Maximum Increase ◽  
Fatality Risk ◽  
Dynamic Risk ◽  
Vapour Cloud ◽  
Grid Based

The reliability of petroleum offshore platform systems affects human safety and well-being; hence, it should be considered in plant design and operation in order to determine its effect on human fatality risk. Methane Vapour Cloud Explosions (VCE) in offshore platforms are known to be one of the fatal potential accidents that can be attributed to failure in plant safety systems. Traditional Quantitative Risk Analysis (QRA) lacks in providing microlevel risk assessment studies and are unable to update risk with the passage of time. This study proposes a grid-based dynamic risk analysis framework for analysing the effect of VCEs on the risk of human fatality in an offshore platform. Flame Acceleration Simulator (FLACS), which is a Computational Fluid Dynamics (CFD) software, is used to model VCEs, taking into account different wind and leakage conditions. To estimate the dynamic risk, Bayesian Inference (BI) is utilised using Accident Sequence Precursor (ASP) data. The proposed framework offers the advantage of facilitating microlevel risk analysis by utilising a grid-based approach and providing grid-by-grid risk mapping. Increasing the wind speed (from 3 to 7 m/s) resulted in maximum increase of 21% in risk values. Furthermore, the integration of BI with FLACS in the grid-based framework effectively estimates risk as a function of time and space; the dynamic risk analysis revealed up to 68% increase in human fatality risk recorded from year one to year five.

Research and Development of Offshore Platforms for SMS Mining: Part 2—Conceptual Design of the Platform

2010 ◽  
Author(s):  
Sotaro Masanobu ◽  
Shunji Kato ◽  
Shigesuke Ishida ◽  
Shotaro Uto
Keyword(s):  
Conceptual Design ◽  
Integrated Design ◽  
Design Tool ◽  
Offshore Platform ◽  
Offshore Platforms ◽  
Design Support ◽  
Support Tool ◽  
Dynamic Positioning System ◽  
Operation Conditions ◽  
Design Support Tool

National Maritime Research Institute of Japan (NMRI) has been developing the integrated design support tool, called “Harmonic Design Tool”, for evaluating economical / safe / environmental aspects of the offshore platform. We are also conducting the conceptual design of the offshore platforms for assessing the availability and accuracy of this design support tool. Seafloor massive sulphides (SMS) are high-grade hydrothermal deposits rich in copper, zinc and lead with a high gold and silver content. The Japanese Economic Exclusive Zone (EEZ) is well known to have high potential of SMS. Thus we decided the SMS mining as one of the most promising applications for the offshore platform technologies. Based on the published potential map of resources and the metocean database established in this project, we decided Izu-Bonin Arc as the target sea area and derived the design and operation conditions for the offshore mining platform. Then we proceeded to the basic concept such as the production rate and storage capacity, dynamic positioning system for station keeping and operation availability. This paper presents the review of the conceptual design of the offshore platform for SMS mining.

scholarly journals High Response Performance of a Tuned-Mass Damper for Vibration Suppression of Offshore Platform under Earthquake Loads

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Qiong Wu ◽  
Xilu Zhao ◽  
Rencheng Zheng ◽  
Keisuke Minagawa
Keyword(s):  
Vibration Suppression ◽  
Initial Period ◽  
Offshore Platform ◽  
High Response ◽  
Experimental Investigations ◽  
Offshore Platforms ◽  
Earthquake Loads ◽  
Response Characteristics ◽  
Response Performance ◽  
The Stability

Currently, tuned-mass dampers (TMDs) are widely applied to maintain the stability of offshore platforms in hostile environments; however, the stability system of offshore platforms faces considerable challenges under critical earthquake loads of the initial period. Therefore, this study concentrated on the high response performance of a simple passive TMD system, and numerical and experimental investigations were performed using a 1 : 200-scale prototype. The obtained results indicated that the displacement, acceleration, and their power spectral density all decreased significantly for the offshore platform with the TMD system. By further analyses of its high response characteristics, it was validated that the TMD reactions can commence within the first 3 s of earthquake excitation, while the fundamental natural frequency was consistently tuned for the TMD system dependent on the dynamic magnification factor. The evaluation indices also confirmed that this method is effective in reducing the overall vibration level and the maximum peak values of the offshore platform exposed to earthquake excitations, mainly because of its high response characteristics.

scholarly journals Application of GNSS Methods for Monitoring Offshore Platform Deformation

2018 ◽  
Vol 34 ◽  
pp. 01019
Author(s):  
Khin Cho Myint ◽  
Abd Nasir Matori ◽  
Adel Gohari
Keyword(s):  
Phase Measurement ◽  
Satellite System ◽  
Deformation Monitoring ◽  
Offshore Platform ◽  
Offshore Platforms ◽  
Navigation Systems ◽  
Correlated Errors ◽  
Carrier Phase Measurement ◽  
Satellite Navigation Systems ◽  
Global Navigation Satellite

Global Navigation Satellite System (GNSS) has become a powerful tool for high-precision deformation monitoring application. Monitoring of deformation and subsidence of offshore platform due to factors such as shallow gas phenomena. GNSS is the technical interoperability and compatibility between various satellite navigation systems such as modernized GPS, Galileo, reconstructed GLONASS to be used by civilian users. It has been known that excessive deformation affects platform structurally, causing loss of production and affects the efficiency of the machinery on board the platform. GNSS have been proven to be one of the most precise positioning methods where by users can get accuracy to the nearest centimeter of a given position from carrier phase measurement processing of GPS signals. This research is aimed at using GNSS technique, which is one of the most standard methods to monitor the deformation of offshore platforms. Therefore, station modeling, which accounts for the spatial correlated errors, and hence speeds up the ambiguity resolution process is employed. It was found that GNSS combines the high accuracy of the results monitoring the offshore platforms deformation with the possibility of survey.

scholarly journals Development of a collaborative material management system for offshore platform projects using agent technology

2017 ◽  
Vol 9 (2) ◽  
pp. 168781401769143 ◽  
Author(s):  
Duanfeng Han ◽  
Qinghua Zhou ◽  
Jinghua Li ◽  
Jiaxuan Wang ◽  
Boxin Yang ◽  
...  
Keyword(s):  
Management System ◽  
Offshore Platform ◽  
Agent Technology ◽  
Prototype System ◽  
Offshore Platforms ◽  
Material Management ◽  
Information Unit ◽  
Multi Agent ◽  
Material Information ◽  
Material Management System

Accuracy management of production materials plays an important role in offshore platform projects. To improve both the efficiency and accuracy of material management in offshore platform projects, a novel material management system characterized by the notion of a material information unit was proposed in light of a review of the industrial Internet of Things and multi-agent technology. The material information unit is used to carry data on production materials and serve as a basic information unit in the system. Furthermore, agents of different functions are employed to tackle assorted tasks. Using this system, material information can be precisely recorded, tracked, and traced during the manufacture of offshore platforms. In addition to this system, an algorithm targeting at multi-agent negotiation is designed. Finally, a prototype system is developed to verify the feasibility and efficiency of this material management process.

A New Approach for Dynamic Reliability Analysis of Offshore Platforms

2003 ◽  
Author(s):  
Wei-Liang Jin
Keyword(s):  
Reliability Analysis ◽  
Failure Criterion ◽  
Offshore Platform ◽  
Seismic Action ◽  
Offshore Platforms ◽  
Structural Dynamic ◽  
Jacket Platform ◽  
Dynamic Reliability ◽  
Strength Failure ◽  
Offshore Jacket Platform

The theoretical framework of a new dynamic reliability analysis approach for offshore jacket platforms is constructed in this paper. In this approach, the structural dynamic reliability analysis integrates the structural dynamic response theory with the random sampling technique on stochastic variables of the platform. Offshore jacket platform is assumed as a shear type one and is controlled by its horizontal resistance bearing capacity. The failure criterion of offshore platform dynamic reliability includes two aspects: strength failure criterion and deformation failure criterion. The strength failure criterion is based on the double-damage criterion of ultimate dynamic analysis, while the deformation failure criterion depends on the requirement of the offshore oil production. The dynamic reliability formula of offshore platforms is gained on the basis of the first crossing theory. In this paper, uncertainties of offshore jacket platform dynamic reliability subjected to wave hydrodynamic and seismic action are studied respectively. The probabilistic distributions and its statistical characteristics of wave hydrodynamic and seismic action are given on the base of limit bearing state of the platform. The dynamic reliability analysis of an offshore platform W11-4C, located at the gulf of Weizhou, South China Sea, is carried out. Some valuable conclusions are summarized.

scholarly journals Study on vibration characteristics of periodic truss structure of offshore platform

2020 ◽  
Vol 12 (11) ◽  
pp. 168781402097288
Author(s):  
Xia Zhaowang ◽  
Xu Xiangxi ◽  
Ju Fuyu ◽  
Wang Zongyao ◽  
Lu Zhiwei ◽  
...  
Keyword(s):  
Vibration Control ◽  
Band Gap ◽  
Periodic Structure ◽  
Structural Parameters ◽  
Vibration Characteristics ◽  
Offshore Platform ◽  
Truss Structure ◽  
Truss Structures ◽  
Offshore Platforms ◽  
Vibration Band

Using the band gap properties of the periodic structure, the truss structure of an offshore platform is designed as a one-dimensional periodic conduit structure, and the band gap characteristics are used to realize the vibration control of the truss structure of the offshore platform. The finite element method is used to simulate the vibration characteristics of the periodic conduit, and the influence of the structural parameters (length and wall thickness) of the periodic conduit on the vibration band gap of the periodic conduit is analysed. The frequency response characteristics of the periodic truss structure of an ocean platform are calculated and compared with those of a traditional truss structure. The results show that the periodic truss exhibits better suppression of vibration transmission than the traditional truss, especially for the vibration in the band gap, which is greatly attenuated. This study shows that the periodic structure has broad application prospects in vibration isolation design of truss structures for offshore platforms. The research provides a new technical approach for vibration control of truss structures on offshore platforms.

scholarly journals Multirobot searching method of natural gas leakage sources on offshore platform using ant colony optimization

2020 ◽  
Vol 17 (5) ◽  
pp. 172988142095901
Author(s):  
Tao Ma ◽  
Shuhai Liu ◽  
Huaping Xiao
Keyword(s):  
Natural Gas ◽  
Ant Colony Optimization ◽  
Ant Colony Algorithm ◽  
Search Algorithm ◽  
Offshore Platform ◽  
Ant Colony ◽  
Detection Methods ◽  
Offshore Platforms ◽  
Gas Leakage ◽  
Source Positioning

Natural gas leakage on offshore platforms has a great impact on safety production, and effective and reasonable leakage detection methods can prevent the harm caused by natural gas leakage. This article proposes a method based on ant colony optimization (ACO) for multirobots to collaboratively search for leaking natural gas sources on offshore platforms. First, analyze the structure and environment of the offshore platform, use Fluent software to simulate the diffusion process of natural gas leaked from the platform, and establish a diffusion model of natural gas leaked from various aspects, such as the layout of different platforms, the number of leaked gas sources, and the concentration of leaked gas sources. In terms of multirobot cooperative control, we analyzed and improved the ant colony algorithm and proposed a multirobot cooperative search strategy for gas search, gas tracking, and gas source positioning. The multirobot search process was simulated using MATLAB software, and the robot on the detection effect of multirobots was analyzed in many aspects, such as quantity, location of leak source, and a number of leak sources, which verified the feasibility and effectiveness of the multirobot control strategy based on optimized ACO. Finally, we analyze and compare the two control algorithms based on ACO and cuckoo search algorithm (CSA). The results show that the ACO-based multirobot air source positioning effect is significantly better than CSA.

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