US 12,460,118 B2
NMR logging method using superparamagnetic iron oxide nanoparticles
Shahid Ali Muhammad Arshad, Dhahran (SA); Safyan A. Khan, Dhahran (SA); and Mohamed A. Morsy, Dhahran (SA)
Assigned to KING FAHD UNIVERSITY OF PETROLEUM AND MINERALS, Dhahran (SA)
Filed by KING FAHD UNIVERSITY OF PETROLEUM AND MINERALS, Dhahran (SA)
Filed on Sep. 28, 2022, as Appl. No. 17/935,953.
Application 17/935,953 is a division of application No. 16/252,076, filed on Jan. 18, 2019, granted, now 11,479,702.
Prior Publication US 2023/0092055 A1, Mar. 23, 2023
This patent is subject to a terminal disclaimer.
Int. Cl. H01F 1/00 (2006.01); B82Y 30/00 (2011.01); C09K 8/03 (2006.01); E21B 47/13 (2012.01); E21B 49/00 (2006.01); B82Y 15/00 (2011.01)
CPC C09K 8/03 (2013.01) [B82Y 30/00 (2013.01); E21B 47/13 (2020.05); E21B 49/00 (2013.01); H01F 1/0018 (2013.01); H01F 1/0054 (2013.01); B82Y 15/00 (2013.01); C09K 2208/10 (2013.01)] 10 Claims
OG exemplary drawing
 
1. A method for NMR logging of a geological formation, comprising
injecting or otherwise incorporating hydrophilic hydrophilic-Fe3O4 superparamagnetic iron oxide nanoparticles (hydrophilic hydrophilic-Fe3O4 SPIONs) into the geological formation,
generating a magnetic field and detecting a magnetic signal,
wherein the hydrophilic hydrophilic-Fe3O4 SPIONs are made by a process comprising:
mixing an iron-containing precursor with a hydrophilic ligand or capping agent to form a homogeneous suspension;
heating the homogenous suspension to a temperature sufficient to bind the hydrophilic ligand to the iron-containing precursor,
cooling the resulting homogenous suspension,
adding a solvent to the cooled homogeneous suspension to precipitate the hydrophilic-Fe3O4 SPIONs into a slurry,
separating the precipitated hydrophilic-Fe3O4 SPIONs from the slurry, and
washing the hydrophilic-Fe3O4 SPIONs to remove unbound hydrophilic ligands or capping agent, thereby making the hydrophilic hydrophilic-Fe3O4 SPIONs,
wherein the iron-containing precursor is iron(III) acetylacetonate, the hydrophilic ligand or capping agent is polyethylene glycol 400 (PEG-400), the heating is at a pressure of about 15 to about 45 psi and at a temperature ranging from 175 to 185° C. for at least 12 to 36 hours, the solvent is a mixture of absolute ethanol and diethylether, and the hydrophilic-Fe3O4 SPIONs are washed in ethanol.