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How to Determine the Klinkenberg Effect Graphically

The Klinkenberg effect illustrates that the flow of gas through a porous sample and the average pressure in the sample are not constant, but vary depending on the type of gas used in the measurement. In addition, there can be an overestimation of the permeability at different pressures, and this leads to the Klinkenberg effect. The Klinkenberg effect is also referred to as gas slippage. This can be determined graphically through plotting the gas permeability versus the reciprocal mean pressure at the time of the gas permeability measurement from data measurements.

Things You'll Need

Oil and gas reservoir cores
Surface outcrop sandstone cores
Digital gas permeameter

Instructions

Determine Klinkenberg Effect from a Graph
- 1
  Conduct atmospheric flow measurements to determine the Klinkenberg effect using oil and gas reservoir cores or surface outcrop sandstone cores and a digital gas permeameter. Gas slippage or the Klinkenberg effect is corrected for by making permeability measurements with gas at different pressures and forming a graph of the measured permeability versus the reciprocal of the mean pressure in the core of the sample.
- 2
  Plot gas permeability in millidarcies on the y-axis of the graph. Plot the inverse mean pressure (1/pm) for the porous media from your data set on the x-axis of the graph. Extrapolate 1/pm to equal zero, where pm equals infinity. The Klinkenberg effect demonstrates that plotting gas permeability against the inverse mean pressure forms a straight line and is approximately equal to the liquid permeability.
- 3
  Look at the straight line on the graph. Look to where the line intersects with the y-axis at the 1/pm=0. That is the Klinkenberg permeability. This tells you that this is the permeability at which that specific gas is compressed by infinite pressure and is in the liquid phase. This value is also referred to with the symbol kL.

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