What is Formation Damage?


Definition of Formation Damage

Unintended impedance  to the flow of fluids into, or out of, a wellbore.

It relates to either a reduction in either rock conductivity or fluid mobility through the pore space

Damage mechanisms:

  • Reduction in absolute permeability

  • Reduction in relative permeability

  • Increase in fluid viscosity


  • Solids plugging

  • Clay swelling

  • Saturation changes

  • Wettability reversal

  • Emulsion blockage

  • Aqueous filtrate blockage

  • Precipitation of soluble salts

  • Fines migration

  • Deposition of paraffins or asphaltenes

  • Condensate banking

  • Others

Quantifying Formation Damage

Darcy’s Experiments

Henry Phillibert Gaspard Darcy (1803 ~ 1858)

  • Hydraulic engineer

  • 1828, Designed 12.7 km long waterway in Dijon, France

  • 1856, Suggested Darcy’s Law in his book

  • One of the Legendary scholars in Hydraulic/Petroleum Eng. area 

Measured flow rate from vertical pipe full of sand.

Flow rate of fluid is proportional to;

  • Area

  • Difference in hydraulic head (pressure)

  • Length of pipe

It explains the flow of fluid in porous media.

Pressure Drop Calculation

  • Radial flow condition

  • Constant Flow Rate

  • Darcy’s Law

Ideal Drawdown vs. Actual Drawdown

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