Systems and methods for differentiating non-radioactive tracers downhole

A method for evaluating a gravel pack or cement in a wellbore, comprising:

• obtaining a first set of data in a wellbore using a downhole tool, wherein the downhole tool comprises a pulse neutron logging tool;
• pumping a first tracer comprising gadolinium or samarium into the wellbore after the first set of data is obtained;
• pumping a second tracer comprising boron into the wellbore, wherein the first tracer and the second tracer flow into a gravel pack or cement in the wellbore;
• obtaining a second set of data in the wellbore using the downhole tool after the first and second tracers are pumped into the wellbore;
• and
• comparing the first and second sets of data, wherein comparing the first and second sets of data comprises comparing a detector capture gamma ray count rate in the first and second sets of data in a time window after neutron bursts, wherein the detector capture gamma ray count rate varies by less than 1% for the first tracer and decreases by more than 10% for the second tracer;
• and
• determining a location of the first tracer or the second tracer in a fracture of the wellbore based on the comparison of the first and second sets of data.