Introduction

Summary

• Hole cleaning and cuttings bed prediction

• Suspension fluid hydraulics

• Solids transport in suspension

• Bed formation and transport

• Mass exchange between suspension and bed layers due to deposition and resuspension effects. Deposition and resuspension take into account:

  • Geometry and well trajectory

  • Operational parameters (ROP, flow rate)

  • Solids characteristics (cuttings average size, cuttings density)

  • Flow characteristics (fluid rheological model, flow conditions)

  • Constitutive equations can be calibrated to fit direct or indirect data

• Force exchanges between layers:

  • Layers accelerate and decelerate each other

  • The model will predict locations along the wellbore where the bed layer is moving or stationary

• Two layers cross-section geometry (cross-section areas, wet perimeters takes into account bed volume fraction, drill pipe eccentricity)

• Transient effects: Takes into account real-time inputs such as geometry and operational parameters variation, as well as previous two-layer model results (bed and suspended solids concentration status)

• Constitutive/closure equations allow calibration with field and laboratory data.

• Compute minimal flow for efficient cleaning.

• Lag time and Lag Depth: transient and steady-state