Determining parameters of a rock sample

A system for determining one or more properties of a rock sample, comprising:

• a permeability test assembly configured to perform a plurality of series of permeability measurements of a rock sample to derive a plurality of permeability values, where:
• each series of the plurality of series comprises a plurality of permeability measurements of the rock sample at a respective, constant differential pressure between a particular confining pressure and a particular pore pressure,
• the particular confining pressure and the particular pore pressure increase with each permeability measurement within each series of the plurality of permeability measurements, and
• the respective, constant differential pressure increases with each subsequent series of permeability measurements in the plurality of series of permeability measurements;
• and
• a control system configured to perform operations comprising:
• identifying the plurality of permeability values, the respective, constant differential pressure for each series, the particular confining pressures, and the particular pore pressures from the permeability test assembly;
• for each series of the plurality of series, performing a curve fit operation to determine a slope and an intercept of a curve associated with a selected Biot coefficient that is between 0 and 1, the permeability values of the series, and the particular pore pressures of the series to generate a plurality of slope values and a plurality of intercept values;
• determining an effective stress coefficient of the rock sample based on the respective, constant differential pressure and the generated plurality of slope values and plurality of intercept values;
• and
• determining an actual Biot coefficient of the rock sample based on the determined effective stress coefficient and the plurality of slope values.

A computer-implemented method for determining one or more properties of a rock sample, comprising:

• identifying, with one or more hardware processors, information from a plurality of series of permeability measurements of a rock sample taken by a permeability test assembly, the information comprising a plurality of permeability values, with each series of the plurality of series comprising a set of permeability measurements of the rock sample at a respective, constant differential pressure between a particular confining pressure and a particular pore pressure, with the particular confining pressure and the particular pore pressure increasing with each permeability measurement within each series of the plurality of permeability measurements, and the respective, constant differential pressure increases with each subsequent series of permeability measurements in the plurality of series of permeability measurements;
• for each series of the plurality of series, performing, with the one or more hardware processors, a curve fit operation to determine a slope and an intercept of a curve associated with a selected Biot coefficient that is between 0 and 1, the permeability values of the series, and the particular pore pressures of the series to generate a plurality of slope values and a plurality of intercept values;
• determining, with the one or more hardware processors, an effective stress coefficient of the rock sample based on the respective, constant differential pressure and the generated plurality of slope values and plurality of intercept values;
• and
• determining, with the one an actual Biot coefficient of the rock sample based on the determined effective stress coefficient and the plurality of slope values.