Abstract

In this work, the effects of the viscous flow of fluids on torque and drag simulation results were investigated for down-hole strings. Torque and drag simulations were performed with and without the inclusion of viscous fluid effects, the influence viscous fluid effects inclusion had on torque and drag simulation results were determined and the consequence this margin of influence would pose to drilling operation. Well plan software was used for the simulation; two cases were considered. Case 1 considered the torque and drag simulation without the inclusion of viscous fluid effects. Case 2 considered the torque and drag simulation with the inclusion of viscous fluid effects. Simulations were run for open hole friction factors (OHFF) of 0.15, 0.2 and 0.25 and cased-hole friction factors (CHFF) of 0.2. From the results, it was realized that the maximum effective tension and maximum hookeload decreased by approximately 2.1 kilopounds (kips) for tripping in operation and by approximately 3.3 kips for tripping out operation, and sliding and drilling (rotating-on-bottom) operations remained unchanged due to the inclusion of viscous effects of fluid flow. Analyses of drag and torque revealed that the maximum drag decreased by 2.1 kips for tripping in (slack-off drag) and by 3.3 kips for tripping out (Pickup drag) operations and maximum torque during drilling operation increased by approximately 310.3 ft-lbs due to the inclusion of the viscous effect of fluid flow.

Key words: Well trajectory, downhole forces, tripping operation, well drilling, operational cost, friction factors.