Porosity and Permeability - Council Grove Group
Panoma Field, Southwest Kansas

Permeability and Porosity

Permeability is a function of several variables including pore throat size, porosity, grain size, and shale bedding architecture. Both low-permeability sandstones and carbonates exhibit near log-linear relationships between permeability and porosity.

The Council Grove low-k carbonates and Frontier and Mesaverde low-k sandstones can be divided into unique k- regions on the basis of lithofacies and for carbonates Dunham classification. Similarities between low-k carbonates and sandstones petrophysical properties
include:

For any given porosity, Council Grove carbonates exhibit higher permeability than Frontier and Mesaverde sandstones. Lower permeabilities in the Western sandstones can be attributed primarily to the influence of shale laminae, more complex micro-architecture in the sandstones, and pore lining and bridging clays.

Greater permeability variance in the carbonates at any given porosity may be attributed to greater pore size heterogeneity resulting from complex grain packing and cementation.

Frontier and Mesaverde lithofacies tend to exhibit a more narrow range of porosity for each lithofacies compared to the range exhibited by lithofacies in the Council Grove. Permeability in the phylloid algal bafflestones is controlled by fracturing and vuggy porosity development.
In the mudstones to grainstones, permeability is more strongly controlled by matrix properties. Dolomitization improves permeability by a factor of 2, though partial dolomitization does not have significant influence.

Click on each type of rock to see greater detail