Determination of Critical Gas Saturation

A method of determining critical gas saturation for a core sample, the method comprising:

• (a) mounting a core sample within a core holder in a system, wherein the system comprises:
• a magnetic resonance apparatus comprising a gradient set configured to image the core sample and a probe configured to control a temperature within the core holder, wherein the probe is positioned within the gradient set, and wherein the core holder is positioned within the probe;
• the core holder configured to receive the core sample and a saturation fluid, the core holder being compatible with the magnetic resonance apparatus and configured to be positioned within the probe;
• an upstream injecting system fluidly coupled to an inlet of the core holder and configured to inject the saturation fluid into the core holder to saturate the core sample;
• and
• a downstream receiving system fluidly coupled to an outlet of the core holder and configured to control a pressure within the core holder and receive at least a portion of the saturation fluid exiting the core holder;
• (b) inserting the core holder containing the core sample within the probe of the magnetic resonance apparatus;
• (c) injecting at least one saturation fluid within the core holder to saturate the core sample within the core holder;
• (d) performing a controlled pressure change of the core sample using the downstream receiving system;
• (e) collecting magnetic resonance data for the core sample during the controlled pressure change;
• and
• (f) determining the critical gas saturation from the magnetic resonance data for the core sample.