Torque and drag (T&D) modeling is regarded as extremely helpful in well planning because it helps to predict and prevent drilling problems that might occur during the drilling process. Although T&D software has existed since the 1990s, some confusion still exists over the validity of the models that are used to characterize drilling operations, especially as we extend the length of modern horizontal wells. Moreover, it seems that only minimal improvements have been made to the underlying mathematical models over the last two decades. For normal planning on extended-reach and other challenging wells, T&D modeling provides a guideline for performance. Better modeling is especially important in complex three-dimensional wellbores. To optimize well design, T&D modeling needs to be incorporated into the planning of each well. The following factors should be evaluated: - Optimizing the well planning design - Adapting casing or tubular designs - Changing annulus fluids; for example, oil-based mud lubricates are better than water-based mud - Adjusting operating drilling processes such as reducing sliding distances or rotating to the bottom This project develops software that will give more accurate 3D T&D calculations. Moreover, this research is also widely beneficial in handling wellbore tortuosity which is explained in detail in the text. The new software will optimize the wellbore path and assist significantly in torque and drag calculation in well design.

Torque and drag (T&D) modeling is regarded as extremely helpful in well planning because it helps to predict and prevent drilling problems that might occur during the drilling process. Although T&D software has existed since the 1990s, some confusion still exists over the validity of the models that are used to characterize drilling operations, especially as we extend the length of modern horizontal wells. Moreover, it seems that only minimal improvements have been made to the underlying mathematical models over the last two decades. For normal planning on extended-reach and other challenging wells, T&D modeling provides a guideline for performance. Better modeling is especially important in complex three-dimensional wellbores. To optimize well design, T&D modeling needs to be incorporated into the planning of each well. The following factors should be evaluated: - Optimizing the well planning design - Adapting casing or tubular designs - Changing annulus fluids; for example, oil-based mud lubricates are better than water-based mud - Adjusting operating drilling processes such as reducing sliding distances or rotating to the bottom This project develops software that will give more accurate 3D T&D calculations. Moreover, this research is also widely beneficial in handling wellbore tortuosity which is explained in detail in the text. The new software will optimize the wellbore path and assist significantly in torque and drag calculation in well design.