[agroup style=”plain” id=965][accordion title=”Torque and drug analysis for well planning through three-dimensional sub-surface basin” id=965] Directional drilling reduces the number of vertical wells needed, thus reducing operation time. It is a way to economically access and produce of unconventional resources such as shale oil, shale gas, tight oil, etc. However, torque and drag (T&D)is a limiting factor in directional drilling because drilling equipment can be damagedprior to reaching a target depth due to excessive T&D. Therefore, torque and drag analysis is considered essentially in the well planning phase to ensure the efficient, economical, and safe planning, especially in directional drilling because drilling equipment can be damaged or buckled prior to reaching a target depth due to excessive T&D. The T&D analysis was performed using a soft-string model to develop software via the graphic user interface (GUI) of MATLAB. The software runs multiple scenarios of operation modes, rotating off-bottom, rotating on-bottom, pulling of the hole, and running into the hole. The well planning can be updated with new data to rapidly improve the operation efficiency. Furthermore, it can be applied to almost all wellbore types, such as build, hold, drop, and horizontal. The well trajectory model can be illustrated in three-dimension. The normal contact force, axial force, buckling and torque can be presented in graphical form. Additionally, the effect of weight on bit (WOB), density of drilling fluid (DF), and heavy weight drill pipe (HWDP) on T&D values at the surface were investigated by the software. These effects will also help avoid the buckling problem. This program has the capability to evaluatean example field in Thailand with a reasonably accurate prediction of T&D values, including reduced drilling operation risks, such as bucking, stuck pipe, and wellbore instability.The program can detecttorque measurement with greater accuracy which is rarely available, and also help determine a more accurate confined compressive strength (CCS) that can be used to evaluate the rock formation from the drilling parameters.This program is also user friendly. A user can predict T&D values through wellbore data and drilling parameter input. Consequently, it will help engineers identify feasible well designs and define drilling limitation for particular field developments as well as provide data for the new wellsin the same field with improved efficiency and safety, while protecting health and environment. [/accordion][/agroup]