Research On The Mechanical Properties And Application Of Deepwater Drilling Risers

With the development of economy,people's demand for oil and gas resources is increasing.In order to alleviate the problem of oil and gas supply and demand in China,it is imperative to exploit deep-water offshore oil and gas resources.As the water depth increases,marine drilling becomes more and more difficult.As an important pipe string connecting the offshore drilling platform and the subsea wellhead,the marine riser is critical to deepwater drilling.Therefore,in order to ensure the reliability of the riser and reduce the loss of offshore drilling,the mechanical properties and field application of the riser in the deep water Marine environment need to be studied.This paper studies the mechanism and calculation model of wave load,current load and eddy load.And based on the software programming,the deep water characteristics of three major ocean loads are analyzed.Based on the dalmabel principle,the paper setted up a cross-water transverse mechanical response equation of the riser.The equation was solved by finite difference method.At the same time,based on the study of the mechanical model,the influence of various sensitivity factors on the statical properties of the riser was analyzed.This paper studied the theory of natural frequency and modal vibration mode,and through the software programming and ANSYS modeling analyzed the inherent characteristics of the riser.The inherent characteristic parameters of the riser were substituted into the theoretical calculation of the fatigue damage of the riser.The fatigue damage of the riser under different conditions of different wall thickness,different top tension ratio and different sea condition is analyzed.While based on the vortex induced vibration effect of the helical strak structure,a new type of quick coupling of riser of helical strake was designed,and the patent certification was obtained.Fatigue damage characteristics of quick coupling of riser of helical strake were analyzed through ANSYS modeling.Based on finite element software,the vortex-induced vibration effect of the modified model of the helical strake riser joint was analyzed qualitatively and quantitatively.Based on the results of mechanical analysis,the optimal configuration scheme of the deep water riser system is analyzed,and the configuration of the riser system based on the optimal configuration of buoyancy block and the optimized configuration of the helical strake riser joint was put forward.Based on the theory study of the riser,the paper has written the analysis software of the mechanical properties of the deep water riser.The software has the function of analyzing the mechanical characteristics of the riser and the inherent characteristics of the riser.The study of this paper improve the statics,dynamics analysis of deepwater drilling riser,and design a quick coupling of riser of helical strake,and optimized the riser system configuration,which provided the idea for the design and configuration of the actual deep water drilling riser system.