Cement Plug Calculator

Calculate balanced plug volumes, spacer requirements, and displacement

Plug Design Parameters

Enter wellbore geometry and plug requirements

Depth of stinger/pipe end

Typical Class G: 1.15, Class H: 1.06

Typical 10-30% for open hole

Balanced Plug Principle

  • Cement level inside and outside pipe equal
  • Prevents U-tubing and contamination
  • Spacer protects from mud contamination

Plug Design Results

Enter parameters and click Calculate

Formula Reference

Balanced Plug Volume

V_cement = V_annular + V_pipe_balanced V_annular = Capacity_ann x Plug_Length x Excess_Factor V_pipe = Capacity_pipe x Height_in_pipe For balanced plug: Height_in_pipe = Plug_Length x (Cap_ann / (Cap_ann + Cap_pipe))

Displacement Volume

V_displacement = Pipe_Capacity x (Pipe_Depth - Plug_Top - Height_in_pipe) Where: Pipe_Capacity = (ID^2 / 1029.4) bbl/ft Ann_Capacity = ((Hole_ID^2 - Pipe_OD^2) / 1029.4) bbl/ft

Recommended Spacer Volumes

Spacer Ahead: 10-20 bbl or 500 ft of annular height Spacer Behind: 5-10 bbl or 300 ft in pipe