SYSTEM AND METHOD FOR CALIBRATION OF HYDRAULIC MODELS BY SURFACE STRING WEIGHT

摘要

There is disclosed a method for tuning a hydraulic model to be used for estimating down hole dynamic pressure as a function of flow rate, characterized in that the method comprises the steps of : a) selecting a non-tuned hydraulic model estimating the relative magnitude of the pressure losses in various annulus sections of the well bore; b) applying the non-tuned hydraulic model to give a first order estimate of the pressure gradients and the shear stresses at the drill string; c) applying the same non-tuned model to estimate the flow lift area for two different flow rates, where the first flow rate is zero or much lower than the second flow rate being sub- stantially equal to a typical flow rate obtained during drilling; and d) performing a model tuning test where the string is rotated off bottom while said two dif- ferent flow rates are used to obtain corresponding string weights. There is also disclosed a system for carrying out the method as well as computer- readable medium being provided with instructions for carrying out the method.