Surface Relaxivity Calculations using
Nuclear Magnetic Resonance Measurements
Milad Saidian and Manika Prasad
Summary: A method to determine the surface relaxivity on unconventional rock
Description: Pore size distribution is a critical parameter in evaluating oil and gas
reservoir producibility. The only direct downhole representation of pore size
distribution is Nuclear Magnetic Resonance (NMR) logging T2 distribution data,
and a reliable estimate of surface relaxivity is required to convert time domain T2
data to a pore size distribution. The available techniques to estimate the surface
relaxity are in the form of correlations and do not apply in rocks with very fine
grains such as shales. This work provides a method and workflow diagram that
can be used to precisely calculate the surface relaxivity by coming NMR
laboratory measurements, 3D rock models, and NMR simulation. This method can
be used on both conventional and unconventional rock formations.
Main Advantages of this Invention:
 Can be applied to unconventional rock formations such as shale.
Potential Areas of Application:
 Oil and gas development
ID number: 15002
Intel ectual Property Status: US provisional patent 62/079,481 filed
Opportunity: We are seeking an exclusive or non-exclusive licensee for
implementation of this technology.
For more information contact:
William Vaughan, Director of Technology Transfer
Colorado School of Mines, 1500 Illinois Street, Guggenheim Hall Suite 314, Golden, CO 80401
Phone: 303-384-2555; e-mail: