Method and apparatus for measuring stress dependency of shale permeability with steady-state flow

A method for determining stress-dependent permeability, comprising:

• providing a core sample in a pressurized core container of a testing apparatus;
• generating a steady-state flow of gas from an upstream reservoir in the testing apparatus along an axial direction through the core sample into a downstream reservoir in the testing apparatus;
• during the steady-state flow, measuring an inlet pressure at an inlet to the core container, an outlet pressure at an outlet of the core container, and a midpoint pressure at a midpoint of the core sample;
• and
• calculating the stress-dependent permeability from a flow rate of the gas through the core sample and the measurements of the inlet pressure, the outlet pressure, and the midpoint pressure.

A method for determining stress-dependent permeability, comprising:

• loading a core sample into a core container;
• generating a steady-state flow of gas through the core sample under a confining pressure;
• taking a plurality of measurements during the steady-state flow of gas through the core container, comprising:
• measuring a flow rate through the core sample;
• measuring an inlet pressure at an inlet to the core sample;
• measuring an outlet pressure at an outlet of the core sample;
• and
• measuring a midpoint pressure at a midpoint of the core sample;
• and
• calculating the stress-dependent permeability from the measurements of the inlet flow rate, the inlet pressure, the outlet pressure, and the midpoint pressure.