Rationalization of Structural Stiffness of Offshore Platform with Rocking-Wall

2013 ◽  
Vol 351-352 ◽  
pp. 923-926
Author(s):  
Gu Yue Han ◽  
Zhi Wei Jiang ◽  
Li Wu Nie ◽  
Ji Gang Zhang
Keyword(s):  
Material Properties ◽  
Offshore Platform ◽  
Wall Structure ◽  
Offshore Platforms ◽  
Structural Stiffness ◽  
Seismic Capacity ◽  
Rocking Wall

This paper presents a new offshore platform with rocking wall structure, and studies how to use the material more adequately by varying offshore platforms story rigidity. The results show that the greater the story stiffness, the more it can give full play to the material properties, as well as to improve the seismic capacity.

Research on Vibration Control of Offshore Platform Based on Self-Recentering Rocking Wall

2014 ◽  
Vol 610 ◽  
pp. 173-177
Author(s):  
Ji Gang Zhang ◽  
Qun Niu
Keyword(s):  
Simulation Analysis ◽  
Offshore Platform ◽  
Offshore Platforms ◽  
Nodal Displacement ◽  
Finite Element Software ◽  
Ice Load ◽  
Wall Stiffness ◽  
Earthquake Load ◽  
Rocking Wall ◽  
Main Factor

Self-recentering rocking wall is used in JZ20-2 north high wellhead platform, making simulation analysis to the whole structure subjected to ice load and earthquake load by the finite element software ANSYS, then analyses the nodal displacement and acceleration responses under the condition of different platform rocking wall stiffness, different floating box’s location, different buoyancy case. The results show that stiffness is the main factor affecting the seismic performance of offshore platforms, floating box can effectively reduce the dynamic response of offshore platform.

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.

Shaking table test for externally-hung self-centering rocking wall structure

2020 ◽  
Author(s):  
Xiangmin Li ◽  
Fuwen Zhang ◽  
Kun Tian ◽  
Zhuolin Wang ◽  
Lu Jiang ◽  
...  
Keyword(s):  
Shaking Table Test ◽  
Shaking Table ◽  
Wall Structure ◽  
Rocking Wall

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.

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.

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.

Study on Seismic Performance of Offshore Platform with Rocking Wall - TMD System

2014 ◽  
Vol 610 ◽  
pp. 78-83
Author(s):  
Ji Gang Zhang ◽  
Zhi Wei Jiang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Seismic Performance ◽  
Tuned Mass Damper ◽  
Offshore Platform ◽  
Element Analysis ◽  
Mass Damper ◽  
Jacket Offshore Platform ◽  
Rocking Wall ◽  
Wall System

Offshore platform rocking wall system and tuned mass damper are briefly introduced, and the paper integrates the advantages of these two kinds of seismic method, and the TMD is attached to the jacket offshore platform - rocking wall system, using the ANSYS for finite element analysis, and the analysis results are optimized. The results show that compared with the offshore platform - rocking wall system, additional TMD can give full play to the performances of the two kinds of seismic methods, which is remarkable.

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.

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