US 11,852,576 B2
Method for determining the pore size distribution in a reservoir
Jun Gao, Dhahran (SA); Marwah Mufid AlSinan, Al Qatif (SA); and Hyung Tae Kwak, Dhahran (SA)
Assigned to SAUDI ARABIAN OIL COMPANY, Dhahran (SA)
Filed by SAUDI ARABIAN OIL COMPANY, Dhahran (SA)
Filed on Jan. 31, 2022, as Appl. No. 17/649,473.
Prior Publication US 2023/0243728 A1, Aug. 3, 2023
Int. Cl. G01N 15/08 (2006.01); G01N 33/24 (2006.01); E21B 49/02 (2006.01); G01N 24/08 (2006.01); G01V 3/32 (2006.01)
CPC G01N 15/088 (2013.01) [E21B 49/02 (2013.01); G01N 15/08 (2013.01); G01N 24/081 (2013.01); G01N 33/24 (2013.01); G01V 3/32 (2013.01)] 10 Claims
OG exemplary drawing
 
1. A method for determining the pore size distribution in a reservoir, comprising the steps:
drilling a core sample out of the reservoir,
determining a porosity distribution along the core sample,
obtaining T2-distributions at different saturation levels of the core sample with formation brine,
performing time domain subtraction on the T2-distributions to obtain T2-distributions at all saturation levels,
determining pore throat size distribution along the core sample,
determining first porosities from the T2-distributions at all saturation levels that correspond to second porosities of the pore throat size distribution for each saturation level,
determining T2-distributions at the first porosities from the T2-distributions,
determining pore throat sizes at the second porosities from the pore throat size distributions,
plotting the pore throat sizes as function of relaxation times T2 to obtain surface relaxation, and
determining the pore size distribution of the reservoir based on the obtained surface relaxation,
wherein saturation profiles and/or T2-distributions are obtained by nuclear magnetic resonance (NMR) measurements or by magnetic resonance imaging (MRI).