Cuttings Transport Simulation Combined with Large-Scale Flow Loop Experiment and LWD Data Enables Appropriate ECD Management and Hole Cleaning Evaluation in Extended-Reach Drilling

Abstract

Abstract We have performed experimental and theoretical studies on cuttings transport in directional wells for more than 15 years. During that time, we developed a one-dimensional (1D) two-layer model transient cuttings transport simulator that predicts the transient behaviors of cuttings bed height, suspended cuttings concentration, cuttings slip velocity, annular pressure, and equivalent circulating density (ECD) along the entire trajectory of the complex extended-reach well. Model parameters, such as annulus friction factor, cuttings deposition rate, and re-entrainment rate, were determined on the basis of numerous experiments we previously performed using a large-scale cuttings transport flow-loop apparatus developed to simulate complex flows in borehole annuli with various inclination angles from vertical to horizontal. In this study, we performed model validation and cuttings transport analysis using field data in a directional well where the annulus ECD was measured by logging while drilling (LWD), and the returned cuttings rate was measured at the surface. On the basis of the simulation study, we discussed the potential of the transient cuttings transport simulator developed in the predrilling and postdrilling phase analyses and real-time analysis during drilling. Moreover, we demonstrated the interpretation of LWD data and the appropriate management of the ECD and evaluated the hole cleaning condition from the LWD data.