The Study Of Different Kinds Of Anchor Foundation Of Spar Platform

Withthedevelopmentofoceanengineeringindeepwaterarea,floatingplatformsand compliant platforms are often used in practice. At the same time, with the waterdepth increment, costs of fixed platforms grow rapidly. In practice, Gravity platformsand jacket platforms have been unable to meet deepwater oil field development.Therefore, it is necessary to develop the technology of floating platforms andcompliantplatforms.Sparplatformisakindofoilplatformsthatisusedindeepwater,and suction anchor or pile foundation are the main anchor foundation of the Sparplatform. The new types of platform make it possible to exploit oil and gas fieldslocated in deepwater. Nowadays, the water depth, most Spar platforms locating, is1000m~2000m.One of the critical problems in the design of Spar foundation is to determine theultimate bearing capacity. In this thesis, we summarize the theories about how tocalculatethecapacityofsuctionanchorandpilefoundations.Then,thesoilprofilesofthe South China Sea, Gulf of Mexico and the North Sea are compared to find thecharacteristicsofSouthChinaSea.Afterwards, abriefintroductionismadeaboutthefinite element analysis software--Plaxis 3D Foundation that is used to analyze theultimate capacity of the foundations, detailed description the calculation of principleand constitutive model. Finally, five soil profiles based on the South China Sea, Gulfof Mexico and the North Sea condition are chosen to do analysis. Three-dimensionFEA with Mohr-Coulomb elasto-plastic constitutive model calculation are done forsuctionanchorwith2,4,6&8aspectratioandthepilewith30m,60m&80mlength.Thepurposeofourstudyis tofindtheultimatebearingcapacityofthesuctionanchorand pile foundation, and the influence of shear strength, load angle and the aspectratioonthem.At thesametime, thedifferent advantages ofdifferent kinds ofanchorsare discussed, and the different application conditions of them are evaluatedrespectively.At present, the platforms are being constructed in deepwater or even inultra-deepwater. It is important to know more about foundation of Spar platform forhelpingustoexploitChinaSouthSeaefficiently.