The Dynamical Analysis And Numerical Simulation Of Deepwater Drilling Riser

More than 90% offshore hydrocarbon reserves exist in the deep-water sediments which is more than 1000m deep, and the main production of offshore hydrocarbon is in deep-water. The analysis of force and vibration of deepwater drilling riser is a key point because of the complex and tough stress state of drilling riser. The vibration destroy of drilling riser must be taken into account in deep-water drilling. The vibration resulted from coupling effects of instability of inner fluid and external load of ocean water is lack of research. So study on this point is of important realistic and academic value.This paper studied on the environmental loads of deep-water drilling riser based on fluid dynamics and stress wave theory. Equations of wave force and ocean current force are induced. Wave equation of fluid and vibration equation of drilling riser under the effects of inner fluids are introduced to support the inner loads of drilling riser.The large elastic deformation under small strain, the effects of axial stress and the effects of instability of inner fluids are taken into account. The mechanical model of drilling riser's loads and vibration differential equations are induced. The vibration characteristics of drilling riser are analyzed to support the vibration reduction.Case studies of numerical stimulation are conducted by ANSYS. The maximum radial deformation, the maximum radial rotation, the maximum stress and their positions when the riser is vibrating are determined. The veracity of the calculation is validated. The characteristics of drilling riser, top expanding pressure, effects of inner fluids and ocean environments loads are studied to optimize the parameters. The optimize scheme proposed in this paper could reduce the vibration of drilling riser dramatically. The conclusions will support the design and employment of drilling riser.