Downhole Weight on Bit Prediction with Analytical Model and Finite Element Method

Abstract

Horizontal drilling is an innovative technology applied for exploiting unconventional resources in North-America and around the world. To acquire better drilling performance, weight on bit (WOB) needs to be accurate and monitored. However, the weight on bit recorded on the surface panel is most often incorrect because wellbore friction along the drillstring is not considered. Drillstring force modeling computer simulation can be utilized to economically determine the actual WOB value. In this thesis, two drillstring force models are programmed and compared: an analytical model and a finite element method (FEM). In conclusion the analytical model computes faster, but FEM is more accurate. Simulations are performed to verify and compare both methods, where friction factors and WOB are calculated for a horizontal well in Western Canada, in a depth interval from 2500m to 3800m. The results from both methods are comparable to results obtained from measured downhole WOB (DOWB).