Optimization Design And Software Development Of Casing Floating Technology In Extended Reach Wells

With the development of modern drilling technology,in order to meet the increasing demand of oil & gas development,gradually appeared extended reach well drilling technology.Because of the horizontal section of extended reach wells is too long,the string is always affected by the frictional resistance in the casing operation,making the string can not smoothly reach the target depth.In order to solve this problem,extended reach well completion operation use casing floating technology.Casing floating technology is a kind of technology which using seal device to seal light solution or gas in the lower casing section,reducing the positive pressure act on the string in the process of running casing,so as to lower the friction effect.In order to achieve the best operating results during the casing floating operation,asking for analyzing the force condition of casing,so as to obtain the optimal parameters combination which included the floating length,drilling fluid density,friction coefficient and other parameters.Therefore,forecasting the casing friction drag and hook load through the theoretical modeling,optimizing the floating length,drilling fluid density,frictional coefficient and other parameters,has a very important guiding significance to the floating casing technology on-site operation effect.In this article,first of all,using the cubic spline method to interpolate the trajectory data of the wellbore.Then analyzing the string force condition based on the interpolated wellbore trajectory data,so as to establish the “rigid rod modeling”,“two-dimensional soft rod modeling” and “three dimensional soft rod modeling” of casing.Last,considering the influence of the buckling and the fluctuation pressure,and according to the unique work condition of the casing floating technology,this paper establishes the friction mechanics modeling of the casing floating technology.Secondly,based on the established theoretical model,the software of casing floating technology optimal design is developed by using python language.The accuracy of the software calculation results is proved by the example calculation of the 24-3-A14 well in the South China Sea Xijiang oil field.Finally,the control variable method is used to analyze the factors that affect the operation effect of the casing floating technology,which provides the necessary theoretical support forthe field engineering practice.