The Experts below are selected from a list of 663 Experts worldwide ranked by ideXlab platform
V. J. Kurian - One of the best experts on this subject based on the ideXlab platform.
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Mooring System Optimisation and Effect of Different Line Design Variables on Motions of Truss Spar Platforms in Intact and Damaged Conditions
China Ocean Engineering, 2019Co-Authors: O. A. Montasir, A. Yenduri, V. J. KurianAbstract:This paper presents the effect of mooring diameters, fairlead slopes and pretensions on the dynamic responses of a truss Spar platform in intact and damaged line conditions. The platform is modelled as a rigid body with three degrees-of-freedom and its motions are analysed in time-domain using the implicit Newmark Beta technique. The mooring restoring force-excursion relationship is evaluated using quasi-static approach. MATLAB codes DATSpar and QSAML, are developed to compute the dynamic responses of truss Spar platform and to determine the mooring system stiffness. To eliminate the conventional trial and error approach in the mooring system design, a numerical tool is also developed and described in this paper for optimising the mooring configuration. It has a graphical user interface and includes regrouping particle swarm optimisation technique combined with DATSpar and QSAML . A case study of truss Spar platform with ten mooring lines is analysed using this numerical tool. The results show that optimum mooring system design benefits the oil and gas industry to economise the project cost in terms of material, weight, structural load onto the platform as well as manpower requirements. This tool is useful especially for the preliminary design of truss Spar Platforms and its mooring system.
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evaluation of the dynamic responses of truss Spar Platforms for various mooring configurations with damaged lines
Ocean Engineering, 2016Co-Authors: Montasir Osman Ahmed, A. Yenduri, V. J. KurianAbstract:Safe mooring for any platform is of utmost importance and concern because of the number of accidents as well as lack of knowledge due to uncertainties in the mooring lines behavior. This has led researchers to investigate the possible effect on the responses of a floating platform due to mooring line damages. Hence, this paper addresses the responses of a truss Spar platform for various symmetric and asymmetric mooring configurations when one and two lines attached are damaged. To investigate this effect, the platform has been modeled as a three degree-of-freedom rigid structure and its motions are analyzed in time-domain. The force–excursion relationship of mooring lines is determined using quasi-static approach. It is observed that the effect of damaged mooring lines on symmetric and asymmetric configurations is nearly same. The migration distance of platform is considerably significant due to the damaged lines. It is more than thrice when two lines are damaged compared to one damaged line condition for symmetric and asymmetric configurations. However, the dynamic motions are not significantly affected.
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Effect of mooring line configurations on the dynamic responses of truss Spar Platforms
Ocean Engineering, 2015Co-Authors: O. A. Montasir, A. Yenduri, V. J. KurianAbstract:Considering the cost impact of mooring lines on the overall project, it is essential to find the best possible mooring configuration for a given platform and metocean data, which reduces the motion responses of the platform to an acceptable level. In this paper, the effect of symmetric and asymmetric mooring configurations in terms of line azimuth angles on the platform responses is studied. A truss Spar platform is modelled as a rigid body with three degrees-of-freedom and the dynamic response analysis of the platform is performed in time-domain by computing the wave kinematics and water wave force using linear Airy wave theory and modified Morison equation, respectively. The responses of the platform are found to be not significantly affected by changing mooring line configurations in terms of azimuth angles. However, the initial offset of the platform is significantly affected with mooring line configurations.
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A study on motion responses of classic Spar Platforms subjected to short crested waves
2013 IEEE Business Engineering and Industrial Applications Colloquium (BEIAC), 2013Co-Authors: V. J. Kurian, C. Y. NgAbstract:The wind generated sea state in the real sea condition is well represented by the short crested waves or the multidirectional waves. The short crested waves are identified as the linear summation of the randomly generated long crested waves that propagate to different directions. In this paper, experimental and numerical studies on the dynamic responses of the classic Spar Platforms subjected to short crested waves are presented. The experimental study was performed in the Offshore Laboratory of Universiti Teknologi PETRONAS. In the study, the classic Spar model was restrained by four mooring lines and subjected to short crested waves. A MATLAB code was developed to analyze the dynamic responses of the classic Spar. The classic Spar was modeled as a rigid body with three degrees of freedom in surge, heave and pitch motions. In each time step of the analysis, the mass, damping and stiffness matrices were computed. Newmark Beta method was employed to solve the dynamic equations of motion. Response amplitude operators (RAO) were estimated and compared with the measurements. The results compared well.
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experimental investigation on dynamic responses of Spar Platforms subjected to multi directional waves
IEEE Business Engineering and Industrial Applications Colloquium, 2012Co-Authors: V. J. Kurian, M. S. LiewAbstract:In the real sea, only multidirectional waves or short crested waves are found. Nowadays, designers tend to use the directional wave statistics for the design of offshore structures. The main reason is to obtain the optimum design of the structures for cost and time effectiveness. In this paper, an experimental investigation on dynamic responses of Spar platform subjected to multi-directional waves is presented. The model tests were performed in the wave tank of Offshore Engineering Laboratory of Universiti Teknologi PETRONAS. In the tests, a standard cosine spreading law was added to the Pierson-Moskowitz (P-M) and JONSWAP spectra to generate the multi-directional waves. The response data were collected and processed to obtain the dynamic responses of the Spar model in terms of RAOs. The responses in 3 degree-of-freedom were presented and it was found that short crested waves, namely the multi-directional waves induce smaller responses compared to the long crested waves.
Mohammed Jameel - One of the best experts on this subject based on the ideXlab platform.
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Wind Induced Response of Spar-mooring-riser System
KSCE Journal of Civil Engineering, 2018Co-Authors: Abdulrahman Eyada Ibrahim, Mohammed JameelAbstract:In recent decades, the exploitation of hydrocarbon reservoirs under the seas and oceans has been regarded as a viable alternative. Several types of floating structures are utilized in deep and ultra-deep water oil and gas exploration and production. Spar Platforms are the most recent type of Platforms to be designed and utilized in deep water environments. This type of platform is an assemblage of a cylindrical hull, moorings and risers that responds to hydrodynamic and aerodynamic loads in a complex manner. Coupled behaviours of Spar–mooring–riser system influenced by the wind load in random wave environment have been studied using coupled analysis method. The Spar–mooring–riser system has been analysed to predict system responses induced by wind action under a long crested random wave using finite element approach. Wind load induces a significant shift in the Spar position away from its original place in the random sea state in addition to a notable heave motion reduction. The top tension magnitude of the moorings and riser significantly increased. The diminishing fluctuation highlights the firmness and controlled oscillations of the Spar platform relative to its new mean position.
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Non-linear dynamic analysis of coupled Spar platform
'Vilnius Gediminas Technical University', 2013Co-Authors: Mohammed Jameel, A Saiful B M Islam, Suhail Ahmad, Mohd Zamin ZummatAbstract:Spar Platforms are treated as cost-effective and resourceful type of offshore structure in deep water. With increasing depth there are significant changes in its structural behaviour due to coupling of Spar hull-mooring line along with radical influence of mooring line damping. So these phenomena should be precisely counted for accurate motion analysis of Spar mooring system. In present study, Spar platform are configured as a single fully coupled integrated model in ABAQUS/AQUA. Non-linear dynamic analysis in time domain is performed adopting Newmark-β automatic time incrementation technique. Non-linearities due to geometric, loading and boundary conditions are duly considered. Displacement and rotational responses of Spar and mooring tensions are obtained during long-duration storm. Spar responses get significantly modified and mean position of oscillations gets shifted after longer wave loading. The surge, heave and pitch responses are predominantly excited respectively. The energy contents of PSDs of these responses reduce considerably after long wave loading. Mooring tension responses are significantly different reflecting the damping effect of mooring lines. The pitch response is fairly sensitive to the wave loading duration. After long duration of storm the wave frequency response increases. However, low frequency and wave frequency responses may simultaneously occur due to synchronising sea states
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review of offshore energy in malaysia and floating Spar platform for sustainable exploration
Renewable & Sustainable Energy Reviews, 2012Co-Authors: A Saiful B M Islam, Mohammed Jameel, Mohd Zamin Jumaat, S M Shirazi, Firas A SalmanAbstract:Rapidly rising trends of fuel consumption indicate enormous energy crisis of global proportions in near future. Following the trend, Malaysia’s fuel consumption has been increasing by an annual rate of 7.2% since 1990 and has even reached 44.9 Mtoe in 2008. It is forecasted to reach 207.3 Mtoe by the year 2030. Due to serious depletion of reserves in various onshore locations, the exploration process is expanded to offshore deeper waters. Seven sedimentary basins belonging to Malaysia, in South China Sea, show great promise to be excellent sources of hydrocarbons. For deep-sea exploration fixed offshore structures are not feasible. An economical alternative is Spar Platforms, which are floating structures ideal for exploration of deep water deposits. In this research, Malaysian experience in offshore hydrocarbon exploration is investigated. Various kinds of operational Spar Platforms are censoriously explored and their recent technical developments are reviewed. The study reveals that Malaysia’s primary energy requirements were met (in year 2008) with natural gas by 43.4% of the total, crude oil by 38.2%, coal by 15.3% and hydropower by 3.1%; indicating evidently that natural gas and crude oil are still the predominant energy sources. Out of the total energy, around 70% oil and 85% natural gas come from offshore fields. These large figures highlight the necessity to consider economically viable alternatives. Spar platform is an innovative marine structure designed to conduct such deep sea explorations. First commissioned Spar at Kikeh field of Malaysia is testimony to immense potential and possibilities of incorporating Spar Platforms in the country’s deep reserves for sustainable energy generation. Classic Spar, Truss Spar, Cell Spar and Cell–truss Spar are identified to be well suited for these environments. Since the offshore fields are located at waters with more than 1000 m depth, Spar Platforms can be successfully installed at these Malaysian deep water fields.
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Oil and gas energy potential at malaysian seabed and Spar platform for deepwater installation
International Journal of Green Energy, 2012Co-Authors: A. B.m.saiful Islam, Mohammed Jameel, Mohd Zamin JumaatAbstract:Offshore sedimentary basins of Malaysian region indicate abundant sources of energy at its seabed. Furthermore, depletion of oil and gas reserves in its onshore land and shallow water depth has accelerated the exploration toward these deeper waters. Frequent increasing demand requires precise investigation to acquire these energies in optimum custom. A competent exploration structure is also desired for energy extraction from the deep water. In this study, oil and gas status in Malaysian scenario is reconnoitered. As the sea wave influences greatly on offshore structures, approaches for collecting wave data are sight-seen. The structural configuration and characteristics of compliant floating Spar platform for energy extraction are addressed. The study reveals that the continental shelf offshore of Malaysian waters is divided into seven sedimentary basins, among which three basins have major ongoing oil and gas extraction activity. Around 68% oil and 86% natural gas of the country's reserves are located in East Malaysia at offshore Sabah and Sarawak. Except the Kebabangan field, all the other offshore energy reserves are located at more than 1000 m depth. In lieu of a fixed platform, a floating platform will be a competent energy extraction structure in this deeper water. The deep water wave data can be appropriately obtained in satellite altimetry approach for its extent of accuracy. The first installed Spar at Kikeh field denotes bright possibilities of incorporating Spar platform in Malaysian sedimentary basins. If Spar Platforms are installed at these deeper vicinities, all the basins will certainly climb in optimum operation yielding a huge usable energy.
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nonlinear analysis of fully coupled integrated Spar mooring line system
The Twenty-first International Offshore and Polar Engineering Conference, 2011Co-Authors: Mohammed Jameel, Suhail Ahmad, Abul Bashar Mohammad Saiful Islam, Mohd Zamin JumaatAbstract:Oil and gas exploration have moved from shallow water to much deeper water far off the continental shelf. Spar Platforms under deep water conditions are found to be the most economical and efficient type of offshore platform. The number of operational Spar Platforms such as SB-1, Shells ESSCO, Brent Spar, Oryx Neptune Spar, Chevron Genesis Spar and Exxons Diana Spar in the Gulf of Mexico and North Sea prove the effectiveness and success of such Platforms in deepwater conditions. For Platforms in deeper waters, mooring lines generally contribute significant inertia and damping due to their longer lengths, larger sizes, and heavier weights. Accurate motion analysis of Platforms in deep waters requires that these damping values be included. The most common approach for solving the dynamics of Spar platform is to employ a decoupled quasi-static method, which ignores all or part of the interaction effects between the platform and mooring lines. Coupled analysis, which includes the mooring lines and platform in a single model, is the only way to capture the damping from mooring lines in a consistent manner. The present coupling is capable in matching the forces, displacement, velocities and acceleration at the fairlead position along with all possible significant non-linearities. The output from such analyses will be platform motions as well as a detailed mooring line response. The computational efforts required for coupled system analysis considering a complete model including all mooring lines are substantial and should therefore mainly be considered as a tool for final verification purposes. In actual field problems hydrodynamic loads due to wave and currents act simultaneously on Spar platform and mooring lines. In finite element model, the entire structure acts as a continuum. This model can handle all non-linearities, loading and boundary conditions. The commercial finite element code ABAQUS/ AQUA is found to be suitable for the present study. The selected configuration of the offshore Spar platform is analysed under the regular wave loading and its structural response behavior in steady state is studied. The response of Spar-mooring system is obtained after 1 and 3 hours of storm. The result shows the effect of mooring line damping due to fully coupled analysis of Spar-mooring system.
Firas A Salman - One of the best experts on this subject based on the ideXlab platform.
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review of offshore energy in malaysia and floating Spar platform for sustainable exploration
Renewable & Sustainable Energy Reviews, 2012Co-Authors: A Saiful B M Islam, Mohammed Jameel, Mohd Zamin Jumaat, S M Shirazi, Firas A SalmanAbstract:Rapidly rising trends of fuel consumption indicate enormous energy crisis of global proportions in near future. Following the trend, Malaysia’s fuel consumption has been increasing by an annual rate of 7.2% since 1990 and has even reached 44.9 Mtoe in 2008. It is forecasted to reach 207.3 Mtoe by the year 2030. Due to serious depletion of reserves in various onshore locations, the exploration process is expanded to offshore deeper waters. Seven sedimentary basins belonging to Malaysia, in South China Sea, show great promise to be excellent sources of hydrocarbons. For deep-sea exploration fixed offshore structures are not feasible. An economical alternative is Spar Platforms, which are floating structures ideal for exploration of deep water deposits. In this research, Malaysian experience in offshore hydrocarbon exploration is investigated. Various kinds of operational Spar Platforms are censoriously explored and their recent technical developments are reviewed. The study reveals that Malaysia’s primary energy requirements were met (in year 2008) with natural gas by 43.4% of the total, crude oil by 38.2%, coal by 15.3% and hydropower by 3.1%; indicating evidently that natural gas and crude oil are still the predominant energy sources. Out of the total energy, around 70% oil and 85% natural gas come from offshore fields. These large figures highlight the necessity to consider economically viable alternatives. Spar platform is an innovative marine structure designed to conduct such deep sea explorations. First commissioned Spar at Kikeh field of Malaysia is testimony to immense potential and possibilities of incorporating Spar Platforms in the country’s deep reserves for sustainable energy generation. Classic Spar, Truss Spar, Cell Spar and Cell–truss Spar are identified to be well suited for these environments. Since the offshore fields are located at waters with more than 1000 m depth, Spar Platforms can be successfully installed at these Malaysian deep water fields.
Mohd Zamin Jumaat - One of the best experts on this subject based on the ideXlab platform.
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review of offshore energy in malaysia and floating Spar platform for sustainable exploration
Renewable & Sustainable Energy Reviews, 2012Co-Authors: A Saiful B M Islam, Mohammed Jameel, Mohd Zamin Jumaat, S M Shirazi, Firas A SalmanAbstract:Rapidly rising trends of fuel consumption indicate enormous energy crisis of global proportions in near future. Following the trend, Malaysia’s fuel consumption has been increasing by an annual rate of 7.2% since 1990 and has even reached 44.9 Mtoe in 2008. It is forecasted to reach 207.3 Mtoe by the year 2030. Due to serious depletion of reserves in various onshore locations, the exploration process is expanded to offshore deeper waters. Seven sedimentary basins belonging to Malaysia, in South China Sea, show great promise to be excellent sources of hydrocarbons. For deep-sea exploration fixed offshore structures are not feasible. An economical alternative is Spar Platforms, which are floating structures ideal for exploration of deep water deposits. In this research, Malaysian experience in offshore hydrocarbon exploration is investigated. Various kinds of operational Spar Platforms are censoriously explored and their recent technical developments are reviewed. The study reveals that Malaysia’s primary energy requirements were met (in year 2008) with natural gas by 43.4% of the total, crude oil by 38.2%, coal by 15.3% and hydropower by 3.1%; indicating evidently that natural gas and crude oil are still the predominant energy sources. Out of the total energy, around 70% oil and 85% natural gas come from offshore fields. These large figures highlight the necessity to consider economically viable alternatives. Spar platform is an innovative marine structure designed to conduct such deep sea explorations. First commissioned Spar at Kikeh field of Malaysia is testimony to immense potential and possibilities of incorporating Spar Platforms in the country’s deep reserves for sustainable energy generation. Classic Spar, Truss Spar, Cell Spar and Cell–truss Spar are identified to be well suited for these environments. Since the offshore fields are located at waters with more than 1000 m depth, Spar Platforms can be successfully installed at these Malaysian deep water fields.
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Oil and gas energy potential at malaysian seabed and Spar platform for deepwater installation
International Journal of Green Energy, 2012Co-Authors: A. B.m.saiful Islam, Mohammed Jameel, Mohd Zamin JumaatAbstract:Offshore sedimentary basins of Malaysian region indicate abundant sources of energy at its seabed. Furthermore, depletion of oil and gas reserves in its onshore land and shallow water depth has accelerated the exploration toward these deeper waters. Frequent increasing demand requires precise investigation to acquire these energies in optimum custom. A competent exploration structure is also desired for energy extraction from the deep water. In this study, oil and gas status in Malaysian scenario is reconnoitered. As the sea wave influences greatly on offshore structures, approaches for collecting wave data are sight-seen. The structural configuration and characteristics of compliant floating Spar platform for energy extraction are addressed. The study reveals that the continental shelf offshore of Malaysian waters is divided into seven sedimentary basins, among which three basins have major ongoing oil and gas extraction activity. Around 68% oil and 86% natural gas of the country's reserves are located in East Malaysia at offshore Sabah and Sarawak. Except the Kebabangan field, all the other offshore energy reserves are located at more than 1000 m depth. In lieu of a fixed platform, a floating platform will be a competent energy extraction structure in this deeper water. The deep water wave data can be appropriately obtained in satellite altimetry approach for its extent of accuracy. The first installed Spar at Kikeh field denotes bright possibilities of incorporating Spar platform in Malaysian sedimentary basins. If Spar Platforms are installed at these deeper vicinities, all the basins will certainly climb in optimum operation yielding a huge usable energy.
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nonlinear analysis of fully coupled integrated Spar mooring line system
The Twenty-first International Offshore and Polar Engineering Conference, 2011Co-Authors: Mohammed Jameel, Suhail Ahmad, Abul Bashar Mohammad Saiful Islam, Mohd Zamin JumaatAbstract:Oil and gas exploration have moved from shallow water to much deeper water far off the continental shelf. Spar Platforms under deep water conditions are found to be the most economical and efficient type of offshore platform. The number of operational Spar Platforms such as SB-1, Shells ESSCO, Brent Spar, Oryx Neptune Spar, Chevron Genesis Spar and Exxons Diana Spar in the Gulf of Mexico and North Sea prove the effectiveness and success of such Platforms in deepwater conditions. For Platforms in deeper waters, mooring lines generally contribute significant inertia and damping due to their longer lengths, larger sizes, and heavier weights. Accurate motion analysis of Platforms in deep waters requires that these damping values be included. The most common approach for solving the dynamics of Spar platform is to employ a decoupled quasi-static method, which ignores all or part of the interaction effects between the platform and mooring lines. Coupled analysis, which includes the mooring lines and platform in a single model, is the only way to capture the damping from mooring lines in a consistent manner. The present coupling is capable in matching the forces, displacement, velocities and acceleration at the fairlead position along with all possible significant non-linearities. The output from such analyses will be platform motions as well as a detailed mooring line response. The computational efforts required for coupled system analysis considering a complete model including all mooring lines are substantial and should therefore mainly be considered as a tool for final verification purposes. In actual field problems hydrodynamic loads due to wave and currents act simultaneously on Spar platform and mooring lines. In finite element model, the entire structure acts as a continuum. This model can handle all non-linearities, loading and boundary conditions. The commercial finite element code ABAQUS/ AQUA is found to be suitable for the present study. The selected configuration of the offshore Spar platform is analysed under the regular wave loading and its structural response behavior in steady state is studied. The response of Spar-mooring system is obtained after 1 and 3 hours of storm. The result shows the effect of mooring line damping due to fully coupled analysis of Spar-mooring system.
A Saiful B M Islam - One of the best experts on this subject based on the ideXlab platform.
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Non-linear dynamic analysis of coupled Spar platform
'Vilnius Gediminas Technical University', 2013Co-Authors: Mohammed Jameel, A Saiful B M Islam, Suhail Ahmad, Mohd Zamin ZummatAbstract:Spar Platforms are treated as cost-effective and resourceful type of offshore structure in deep water. With increasing depth there are significant changes in its structural behaviour due to coupling of Spar hull-mooring line along with radical influence of mooring line damping. So these phenomena should be precisely counted for accurate motion analysis of Spar mooring system. In present study, Spar platform are configured as a single fully coupled integrated model in ABAQUS/AQUA. Non-linear dynamic analysis in time domain is performed adopting Newmark-β automatic time incrementation technique. Non-linearities due to geometric, loading and boundary conditions are duly considered. Displacement and rotational responses of Spar and mooring tensions are obtained during long-duration storm. Spar responses get significantly modified and mean position of oscillations gets shifted after longer wave loading. The surge, heave and pitch responses are predominantly excited respectively. The energy contents of PSDs of these responses reduce considerably after long wave loading. Mooring tension responses are significantly different reflecting the damping effect of mooring lines. The pitch response is fairly sensitive to the wave loading duration. After long duration of storm the wave frequency response increases. However, low frequency and wave frequency responses may simultaneously occur due to synchronising sea states
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review of offshore energy in malaysia and floating Spar platform for sustainable exploration
Renewable & Sustainable Energy Reviews, 2012Co-Authors: A Saiful B M Islam, Mohammed Jameel, Mohd Zamin Jumaat, S M Shirazi, Firas A SalmanAbstract:Rapidly rising trends of fuel consumption indicate enormous energy crisis of global proportions in near future. Following the trend, Malaysia’s fuel consumption has been increasing by an annual rate of 7.2% since 1990 and has even reached 44.9 Mtoe in 2008. It is forecasted to reach 207.3 Mtoe by the year 2030. Due to serious depletion of reserves in various onshore locations, the exploration process is expanded to offshore deeper waters. Seven sedimentary basins belonging to Malaysia, in South China Sea, show great promise to be excellent sources of hydrocarbons. For deep-sea exploration fixed offshore structures are not feasible. An economical alternative is Spar Platforms, which are floating structures ideal for exploration of deep water deposits. In this research, Malaysian experience in offshore hydrocarbon exploration is investigated. Various kinds of operational Spar Platforms are censoriously explored and their recent technical developments are reviewed. The study reveals that Malaysia’s primary energy requirements were met (in year 2008) with natural gas by 43.4% of the total, crude oil by 38.2%, coal by 15.3% and hydropower by 3.1%; indicating evidently that natural gas and crude oil are still the predominant energy sources. Out of the total energy, around 70% oil and 85% natural gas come from offshore fields. These large figures highlight the necessity to consider economically viable alternatives. Spar platform is an innovative marine structure designed to conduct such deep sea explorations. First commissioned Spar at Kikeh field of Malaysia is testimony to immense potential and possibilities of incorporating Spar Platforms in the country’s deep reserves for sustainable energy generation. Classic Spar, Truss Spar, Cell Spar and Cell–truss Spar are identified to be well suited for these environments. Since the offshore fields are located at waters with more than 1000 m depth, Spar Platforms can be successfully installed at these Malaysian deep water fields.