Study Of Several Key Parameters On The Stroke Capacity Of TTR

The marine riser directly combined the wellhead and the seabed. The upper floater facilities move up and down under the combined load of wind, wave and current. The floater will deviate from its original equilibrium position which result the relative motion between the riser and the floater. We define it the riser stroke. The tensioner system is to play a controlling role of this relative motion between the riser and the floater, to compensation the stroke value. Based on national high technology program "Key Technologies of Deep water Top Tension Riser design and Installation", this paper present some researches on TTR stroke analysis and does the numerical simulation with professional software Orcaflex.After introducing the composition and working principle of tensioner system, the paper mainly discuss the affecting factor and analysis method of riser stroke. Calculated the riser stroke for one-year monsoon and hundred-years typhoon condition, then give the tensioner stroke range. Give a discussion on modeling tensioner in different ways, including impose constant tension, linear tension and non-linear tension, will make different results in riser stroke calculation and give a reasonable simulation way of modeling tensioner. Based on the result do a further research on the key parameters of riser stroke including the hydraulic tensioner system of the gas constant, the initial gas length of the tensioner, tensioner hydraulic cylinder angle, etc. Then it takes a series of calculations of riser interference to make out the role of tensioner system in order to provide some practical engineering operations reference.Through the above analysis and calculation, the following results and conclusions can be got:Different ways of modeling the tensioner system leads to the different result of riser stroke. Use non-liner spring to simulate the tensioner is the most reasonable way in recent research. Many key parameters will affect the riser tensioner efficiency. When there is a tensioner failed the others should increase tension in proportion to ensure the safety of the structure. Keep the adjacent riser tensioner payout equal and increase the tensioner stiffness can reduce the impact of the riser interference.