Field Validated Hydraulic Model Predictions Give Guidelines for Optimal Annular Flow in Slimhole Drilling

Abstract

Abstract Accurate prediction of annular flow is of primaiy importance in slimhole drilling. A model was developed that better represents actual annular configurations. It accounts for axial variations of drillpipe eccentricity and for effects arising from drillpipe rotation. The model is validated with data obtained from 3 industrial slimhole wells (4"3/4 and 3"3/8 phases). Based on model predictions, guidelines are given to define flow parameters and to adapt fluid rheology in order to obtain optimal hole cleaning under safe drilling conditions.