Study On The Tripability Of Completion String In Horizontal Well

With the fast development of horizontal well technology, study on the tripability and the strength of completion string becomes more and more hot nowadays. Simulation analysis of wellbore trajectory data was conducted by least squares method and cubic spline interpolation method in this paper. Meanwhile, through force analysis and research on the tripping process, three mathematical models were set up to predict the friction drag, including two-dimensional"soft string"model, two-dimensional"stiff string"model and three-dimensional"soft string"model.On the basis of theoretical research, resolution method of prediction mathematical models was induced in detail. Then, software to analyze the tripability of completion string in horizontal well was developed by Visual Basic. This software can fulfill the functions to draw the curve of wellbore trajectory, to calculate the friction drag of completion string during the tripping process and to evaluate the strength of completion string.Furthermore, mathematic simulation of the tripping process of completion string in an available horizontal well was carried out with the finite element analysis software ANSYS. During the simulation calculation, the stress condition and accepted axial force of the string in tripping process were figured out and the actual contact status between completion string and borehole wall was revealed. Finally, the application of actual project proves that the self-developed analysis software and the analysis method with ANSYS can precisely determine the tripability of compltion string in horizontal well. The research of this paper was showed to have great instructive significance to the completion operation of horizontal well in field.