Innovative Tool for Optimizing Hole Cleaning Efficiency in Deviated and Extended Reach Wells

Abstract

Poor cuttings transport in deviated wells is considered a main factor limiting drill rate; inducing excessive torque and drag; or in severe cases, resulting in stuck pipes. This study presents a computational fluid dynamics (CFD) model for investigating cuttings transport phenomena in deviated wells under different conditions. Moreover, data-driven models based on dimensionless parameters were developed to shift results from lab-scale to field-scale applications. A CFD model was developed and validated with our experiments conducted in the TAMUQ horizontal flow loop and open literature to study the impact of Herschel Bulkley fluids on cuttings transport at various drilling conditions. The Eulerian-Eulerian approach is used to simulate solid-liquid laminar flow in annular geometry utilizing hexahedral and polyhedral mesh under transient conditions. Finally, the developed data-driven models utilized regression techniques to estimate cuttings concentration and stationary bed height in deviated wells. Results show that the developed CFD model is a robust tool for evaluating hole cleaning efficiency during the drilling planning phase, while the developed data-driven models are reliable tools for real-time hole cleaning optimization. The best approach to cleanout horizontal wells flowing under a turbulent flow regime is to keep η⁄Κ value high and for the laminar flow to increase YP/PV ratio. The most critical range for efficient hole cleaning is from 0-200 RPM and increasing RPM above 200 will have a marginal impact on improving hole cleaning. Cuttings size of 0.004 m was determined to be the critical particle size for solid particle removal. It is advisable to use drilling motors with less bend angle and a shorter bit to bend distance for efficient cuttings transport in lateral sections. Finally, the developed data-driven models show good accuracy in estimating cuttings concentration and bed height with a ±20% error margin in most cases. These correlations will provide the industry with a real-time tool for optimizing hole cleaning efficiency in deviated and horizontal wells.