Determination of Required Reserved Strength Ratio in Ultimate Strength Limit for Assessment of Existing Offshore Platforms in the Persian Gulf

2008 ◽  
Author(s):  
M. M. Amiri ◽  
B. Asgarian
Keyword(s):  
Persian Gulf ◽  
Statistical Data ◽  
Oil And Gas Industry ◽  
Offshore Structures ◽  
Wind Loading ◽  
Offshore Platforms ◽  
Strength Ratio ◽  
Effective Parameters ◽  
Original Design ◽  
The Persian Gulf

The offshore infrastructures are used by the oil and gas industry to meet over twenty percent of the world’s demand for the hydrocarbon productions. Offshore platforms are subjected to various environmental, operational and accidental loads. Environmental loads include wave, current, wind earthquake and ice loads. Considering the reuse of old platforms, design criteria for offshore structures have changed significantly over the post decades. Most of existing structures have been designed based on the previous codes. Many of these structures are now called upon for extended service beyond their original design life. This makes the need to assess the platforms under different environmental conditions such as wave, current and wind loading. Since the proposed amounts of Reserve Strength Ratio (RSR) in the guidelines are for the special geographical zones (i.e. Gulf of Mexico and other parts of US), and also since the methodologies used for estimation of RSR have not been determined explicitly, this study aims to explain more the effective parameters for the assessment of existing offshore platforms. Because the calculation of these parameters is based on statistical data for specific regions, to achieve the RSR ratio related to the Persian Gulf, we utilize the environmental statistical data for this region. And consequently a relevant RSR is proposed. Ultimately, the reserved strength of three sample platforms located in this zone will be assessed according to proposed criterion.

Sovereign Wealth Funds in the Persian Gulf States

2017 ◽  
Author(s):  
Gawdat Bahgat
Keyword(s):  
United Arab Emirates ◽  
Persian Gulf ◽  
Oil And Gas ◽  
Oil Prices ◽  
Oil And Gas Industry ◽  
Detailed Examination ◽  
Data Availability ◽  
Sharp Drop ◽  
Sovereign Wealth Funds ◽  
The Persian Gulf

The period from early 2000s to 2014 witnessed unprecedented and sustained high oil prices transforming the main oil and gas exporters in the Persian Gulf into major players in global finance. The Islamic Republic of Iran and the six GCC member states (Bahrain, Kuwait, Oman, Qatar, Saudi Arabia, and the United Arab Emirates) have been using these massive oil revenues to assert their economic and political leverage on the regional and international scene. A key component of this effort has been the creation of sovereign wealth funds (SWFs). This chapter examines the SWFs in Iran and the GCC states. It includes discussion of the emergence and evolution of the oil and gas industry in the region, analysis of the sharp drop in oil prices since 2014 and how this cycle is different from previous ones, and detailed examination (based on limited data availability) of Iran’s and the GCC’s major SWFs.

Elastic-Plastic Analysis of the Interaction between Ice and Offshore Structures

2009 ◽  
Vol 417-418 ◽  
pp. 897-900
Author(s):  
Tao Yu ◽  
Wei Yang ◽  
Li Qiang Tang
Keyword(s):  
Mechanical Properties ◽  
Constitutive Equation ◽  
Stress Field ◽  
Offshore Structures ◽  
Offshore Platforms ◽  
Pressure Sensitivity ◽  
Strength Ratio ◽  
Structure Interaction ◽  
Plastic Analysis ◽  
Distribution Of Stress

In this paper, the mechanical properties of ice, which are affected by the existence of cavities and the different tensile-compression strength ratio, are analyzed in micromechanics view. Then the constitutive equation is established, and the distribution of stress field caused by the ice-structure interaction is constructed with the constitutive equation. Finally, the ultimate bearing capacity of ice is also discussed with different values of pressure sensitivity parameter and the tension-compression ratio. Thus, this paper provides the theoretical reference for offshore platforms design.

Time-Variant Ultimate Reliability Analysis of Jacket Platforms Considering a New Probabilistic Corrosion Model for the Persian Gulf

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
Hossein Gholami ◽  
Behrouz Asgarian ◽  
Saeed Asil Gharebaghi
Keyword(s):  
Reliability Analysis ◽  
Probabilistic Model ◽  
Persian Gulf ◽  
Structural Integrity ◽  
Actual Condition ◽  
Offshore Platforms ◽  
Gulf Region ◽  
Corrosion Loss ◽  
Reliability Method ◽  
The Persian Gulf

Corrosion is identified as one of the most important deterioration factors for structural integrity of offshore platforms. For reliability analysis of these platforms, a probabilistic model for prediction of long-term corrosion loss as a function of time is essential. The purpose of this study is to propose a novel model for steel corrosion of jacket platforms in the Persian Gulf region. Field measurements for members in seawater are collected and statistically analyzed to identify the probability function for corrosion loss at different times. A new probabilistic model with time-dependent parameters is suggested, based on the statistical analysis results. Application of above-mentioned model in the reliability analysis of jacket platforms is investigated by introducing a new reliability analysis framework. This framework is a general solution for probabilistic analysis of jacket platforms with several stochastic variables which can be used for the platforms with different configuration and loads. In this framework, direct analysis is performed in each stage of first-order reliability method (FORM) instead of using the response surface method which is a common approach to obtaining the required response. This framework is applied to three jackets and the annual probability of failure (Pf) over the platforms service life is computed. Comparison of results revealed that among the years beyond the platform design life, the amount of annual Pf is increased in parabolic function. Also, studying the results is illustrated that in the case of ignoring the corrosion loss as a stochastic variable, Pf is estimated 7% lower than values obtained in actual condition.

Effect of Structural Member Uncertainties in the Jacket Type Offshore Platform Assessments

2006 ◽  
Author(s):  
B. Asgarian ◽  
M. M. Amiri
Keyword(s):  
Offshore Platform ◽  
Offshore Platforms ◽  
Actual Behavior ◽  
Strength Ratio ◽  
Structural Elements ◽  
Structural Element ◽  
Bias Factor ◽  
Predicted Values ◽  
The Persian Gulf ◽  
Reserve Strength

In the assessment of an old jacket type offshore platform, the Reserve Strength Ratio (RSR) should be computed and it is used for accepting or rejecting the platform for the future. There are many parameters affecting the Reserve Strength Ratio of such a structure. One of the important parameter is the bias factor (Br) of the structural element ultimate capacity. The bias factor is defined as the ratio of best estimate or true values to the nominal or predicted values. This parameter must be obtained for all structural elements including bracing members (in buckling or tension), joint strength, and piles lateral capacity by considering actual behavior of element material. Most of the recommended bias factors for the structural elements are evaluated from experimental results. In this paper, a review on the parameters affecting Reserve Strength Ratio of the Jacket Type Offshore Platforms subjected to Metocean loading is performed and a method is presented for the obtaining of bias factor related to structural element capacity. The method is applied to evaluate assessment of three sample platforms in the Persian Gulf. The results in terms of RSR are compared with the analysis results using previous recommended bias factors.

scholarly journals The Limpet: A ROS-Enabled Multi-Sensing Platform for the ORCA Hub

2018 ◽  
Author(s):  
Mohammed E. Sayed ◽  
Markus P. Nemitz ◽  
Simona Aracri ◽  
Alistair C. McConnell ◽  
Ross M. McKenzie ◽  
...  
Keyword(s):  
Condition Monitoring ◽  
Communication Systems ◽  
Oil And Gas ◽  
Low Cost ◽  
Cost Effective ◽  
Oil And Gas Industry ◽  
Offshore Structures ◽  
Offshore Wind ◽  
Sensor Data ◽  
Offshore Platforms

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.

The Pearl Fishing in the Persian Gulf

1917 ◽  
Vol 83 (2146supp) ◽  
pp. 100-101
Author(s):  
Edwin E. Calverley
Keyword(s):  
Persian Gulf ◽  
Pearl Fishing ◽  
The Persian Gulf

A method of technical diagnostics for offshore structures

1994 ◽  
Vol 16 (2) ◽  
pp. 43-48
Author(s):  
Do Son
Keyword(s):  
Diagnostic Method ◽  
Joint Venture ◽  
Oil And Gas ◽  
Residual Life ◽  
Life Time ◽  
Offshore Structures ◽  
Technical Diagnostics ◽  
Offshore Platforms ◽  
South Vietnam ◽  
Local Destruction

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.

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