Integrating Plug to Well-Scale Petrophysics with Detailed Sedimentology to Quantify Fracture, Vug, and Matrix Properties in Carbonate Reservoirs

Kansas Geological Survey
Open-file Report 99-47


For the USGS Geis #1 and USGS Ord #1 geometric mean permeabilities of core plugs are 0.1 md and of whole core are 15.5 md. Corresponding DST effective permeabilities are 50-300 md. The cores represent less than 5% of the DST test interval. Differences between the plug and whole core geometric mean permeabilities is due to two vuggy mudstone whole core samples. Arithmetic average permeability on these is not considered suitable because seven other samples in the core of a similar karst-induced vuggy mudstone lithology exhibit permeabilities less than 0.1 md. These permeabiities are consistent with vuggy mudtones shown in the general permeability-porosity (k-f) trend. Similarly, a single packstone sample exhibits 8.1% porosity and 11 md permeability. Using density and neutron log porosities and the k-f trend shown, arithmetic mean permeabilities for the DST intervals in both wells range from 20 md to 60 md. These permeabilities are largely influenced by approximately ten, thin (<4 ft), high porosity intervals distributed throughout the test interval. While there is uncertainty in interpretation of the DSTs, the pressure response indicates permeabilities are high. Comparison of arithmetic and DST permeabilities in the Ord #1, in conjunction with the generally low porosities evident in this interval, indicate fracture contribution to flow.

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Last updated November 2002