A steady state liquid permeability system was developed to measure permeability at reservoir conditions on fully saturated unconventional shale plugs. Liquid permeability experiments are more representative of true matrix permeability to flow of liquids (oil and brine) than other currently used laboratory measurements. Plug condition is verified via micro-CT to eliminate plugs with underlying artifacts which would contribute to enhanced flow. Saturation levels of plugs are measured by NMR to precisely match those of the reservoir.

For some tests, a special setup is utilized where the entire testing process can be run in a 12 MHz high-field NMR to monitor the changes in water and oil fluid saturations in the core sample over the duration of the test. This allows for additional knowledge of shale wettability on flow of liquids and provides derivation of relative permeability in nano-Darcy rock systems. Successful testing of effective permeability to brine, dead crude and live crude has been performed on a wide variety of different organic shale and tight rock samples. Single digit nano-Darcy level permeability values have accurately been measured.

The technique allows for assessing the degradation of effective oil permeability from the forced imbibition of water and hydraulic fracturing fluids. This in turn helps in evaluating completion fluids combinations that are detrimental to oil productivity and those that can help enhance productivity. Methods such as gas soaking, surfactant injection, and completion fluid chemistry are currently being tested to help mitigate degradation.

The utilization of measured liquid permeability to water and oil in reservoir simulation models has resulted in better history matching of production of oil, gas and water; and in assessing initial and effective SRV changes over time.

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