Improvement of Torque-and-Drag Modeling in Long-Reach Wells

Torque and drag modeling is regarded as an invaluable process to assist in well planning and to predict and prevent drilling problems. It discusses how to use torque and drag calculations and measurements to plan long-reach well profiles, to execute drilling operations that minimize torque and drag effects and to monitor hole cleaning. In this study a general overview on most of the available literature on the subject is presented. Different models that have been developed for torque and drag predictions along with pros and cons of the models will be discussed. The application of our new fully 3-dimensional analytical friction model will be presented. Moreover a new criterion has been implemented into the new model in order to capture the effect of weight in the horizontal section especially when BHA is dragged into/out of the wellbore. The model validity will be checked by applying the model for two field cases of ERD wells in North Sea. Field cases also demonstrate the importance of buoyancy effects, tripping speed, hydraulic piston force, pipe stiffness as well as well path effects.