About Hole Cleaning

Mud Conditioning

  • Well circulation after the casing has landed and prior to cementing is critical
  • Reduction in plastic viscosity and yield point of the mud improves the rheological hierarchy
  • Mud should be conditioned for minimal increase in static gel strength over time
  • Low mud filtrate loss improves the quality of the cement job

Separation Fluids (Spacer and Flushes)

  • Provides a fluid boundary between drilling fluid and cement systems
  • Used to clean and carry drilling fluid from cement placement locations
  • Must provide wellbore wettability and be compatible with drilling fluid and cement system

Pipe Movement

  • Use of pipe movement (rotation and/or reciprocation) helps to ensure positive fluid displacement and aids in removing difficult to mobilize drilling fluid

Fluid Pump Rate

  • Increasing fluid pump rate results in increased energy downhole to remove the drilling fluid. It is recommended that the pump rate be increased as much as possible while still maintaining mixability and well circulation

Centralization

  • Centralizers are used to “center” the casing effectively in the wellbore allowing for better fluid coverage around the pipe and more effective drilling fluid removal