The accurate prediction of wellhead pressure in process of hydraulic fracturing is a keypoint to guide the design and construction of the fracturing, and does help in choosing appropriate wellhead equipment and pipeline. This paper calculates the formation breakdown pressure by using a self-made formation stress calculation software, analyzes perforation friction and near-wellbore friction on the basis of Michael theory, eatablishes a model of wellbore friction through Darcy-Weisbach equation and the momentum interaction theory of two-phase flow, and according to the composition of wellhead pressure, makes calculation software which can also analyze the influencing factor of wellbore friction, such as delivery rate, pipe diameter, fracturing fluid density and proppant size. Finally, case analysis verifies the accuracy of the computing method.
