Research On Prediction Method Of Casing Running Capacity In Shallow Extended Reach Well

The shallow extended-reach wells for several decades have been widely applied in Bohai oilfield.However,one difficulty of running casing to the target depth in light of reality due to the shallow true vertical depth and buckling of casing strings inside borehole.Therefore,this thesis gives a complete description of the maximum depth of running casing strings in ERWs,which is of considerable referential importance in practical engineering.In order to reduce the influence of torque and drag,the thesis begin with describing the shape of well trajectory by applying the tension spline interpolation method.The torque and drag models of two-dimensional and three-dimensional for casing strings are established respectively,as well as the inversion of friction factors.With the effects of axial force and boundary conditions,the capacity of casing running as an objective function is optimized to predict the maximum depth of casing running.According to hook load,the floating length and mud density are optimally selected to provide technical assurance for completion operations.A comparison of the predicted value which is calculated by the prediction software,developed in Python language.Results obtained from this thesis indicates that rotation speed will increase with the hook load increasing.When selective flotation is applied,the float length decreases with the mud density increasing.It is therefore recommended to increase the mud density under the condition of well stability.The measured value have verified the reasonableness of the torque and drag models established in this thesis,which provides a theoretical basis and technical guidance for well completion operations.