NUMERICAL SIMULATION OF TRANSIENT CUTTINGS TRANSPORT WITH FOAM FLUID IN HORIZONTAL WELLBORE

With considering the interlayer mass transfer and fluid influx from the reservoir, a one-dimensional two-layer hydraulic model was established to describe the mechanism of transient cuttings transport with foam fluid in horizontal well section. The model was numerically calculated based on the modified SIMPLE algorithm, and the height of cuttings bed was predicted by the trial-and-error method. Sensitivity analysis was conducted on the affecting factors on the cuttings transport performance. Results show that cuttings deposition moves along the horizontal wellbore from the drilling bit, and finally achieves a steady state with dynamic balance. Dimensionless cuttings bed height decreases with the increase of foam quality or foam flow rate, but increases with the increase of drillpipe eccentricity, cuttings size or drilling rate. The influx of water and gas from the reservoir is helpful to improve the cuttings transport efficiency with foam. The proposed model offers theoretical guidelines for hydraulic parameter design and hole cleaning control in foamed horizontal drilling.