Research On The Mechanical Characteristics Of Deepwater Drilling Mechanical Systems Under Environmental Loads

Subsea deepwater drilling is one of the most innovative part in the frontier domains of petroleum engineering.Because of the features of ocean environment such as the randomness,uncertainty and high pressure,low temperature of deepwater,compare with the land drilling engineering,ocean drilling engineering’s cost and difficulty is much higher than the former.In the area of deepwater drilling,the water-air interface spreads the drilling system into offshore platform part and underwater part.In this article,the research of the underwater part is given with the consideration of the influence from the ocean environment systematically.The mechanical response is the nuclear clue in use of analyzing the target theme of the thesis,which the research contents is given as:(1)The influence analysis of the deepwater drilling riser from wave and fluidBased on the ocean wave and fluid mechanics theory,the combined influences are researched with the considering of inner drilling tools working.The elasticity theory is used to construct the mathematical model of riser system and its equation of state is solved by finite difference method and the results is showed by data visualization method.The compared study is also given in different situation of platform’s drift,wave and water depth.(2)The analysis of the influence of wellhead from water fluidThe classical method(use cylinder or square column in SSBOP analyzing model)is replaced in this article,a relative more integrated mechanical response is given by a precise model construction and the limitations of classical method is also given based on FSI.A new way to calculate the drag coefficient is showed and used in a simulation of 1000m class deepwater wellhead.(3)The systematical research of the influence from condition to subsea drilling system based on pile theoryThe pile theory is used in analyzing the subsystem which consists of condition and cement loop under the mad line.The p-y curves method is used in analyzing the lateral and vertical load bearing capacity in soil layer and working condition,the working levelness changing is also discussed.