New Proposed Model for Torque and Drag Modeling
Excessive drill string torque and drag is one of the major limitations of extended-reach and horizontal drilling. The torque and drag models are used in the planning phase and during the drilling of a well, as a tool used for monitoring developing hole problems. The models used throughout the industry today are mostly based on equations presented more than two decades ago, little work have been done to improve upon these.
The new 3D model presented by Aadnoy (2010) has some inaccuracy for the lower part of the string with low tension, since the side force due to the weight of the string is not accounted for. The Model Presented in this paper has improved the above-mentioned deficiency and results are more accurate with this model.
It has been also shown the importance of correcting for friction in the draw works sheaves to get realistic friction factors. A recently published model is used and work has been done to improve this model further.