Systems and methods for tri-axial NMR testing

A method of testing properties of a test sample with a tri-axial nuclear magnetic resonance apparatus, the method including:

• providing the tri-axial nuclear magnetic resonance apparatus having:
• a tri-axial load frame encasing:
• a tri-axial load cell having a tri-axial sample holder and defining a radial space surrounding the tri-axial sample holder;
• a piston assembly;
• at least one end cap operable to contact the tri-axial load cell;
• a nuclear magnetic resonance instrument located external of the tri-axial load cell;
• and
• an axial pressure line in fluid communication with the piston assembly, a confining pressure line in fluid communication with the radial space, and a pore pressure line in fluid communication with the test sample, where the axial pressure line, the confining pressure line, and the pore pressure line are independent and separate fluid flow paths so that all pressure surfaces of the piston assembly are free of fluid communication with the tri-axial load cell;
• obtaining the test sample;
• loading the test sample into the tri-axial sample holder;
• loading the tri-axial sample holder in the tri-axial load cell to create a loaded tri-axial load cell;
• applying an axial pressure by providing an axial pressure fluid through the axial pressure line;
• applying a confining pressure by providing the confining pressure fluid through the confining pressure line, the confining pressure being less than and independent of the axial pressure;
• circulating temperature control fluid around the tri-axial sample holder by providing the temperature control fluid through a temperature control flow line to the radial space;
• and
• measuring data from the nuclear magnetic resonance instrument;
• where
• the at least one end cap includes two end caps, with one of the two end caps contacting a first end of the tri-axial load cell, and an other of the two end caps contacting a second end of the tri-axial load cell that is opposite the first end;
• applying an axial pressure includes providing an axial pressure fluid through the axial pressure line;
• and
• applying a confining pressure includes providing the confining pressure fluid through the confining pressure line that extends through both of the two end caps.