Dipolar NMR relaxation of adsorbates on surfaces of controlled wettability  

作　　者：Siegfried Stapf Igor Shikhov Christoph Arns Bulat Gizatullin Carlos Mattea 

机构地区：[1]Department of Technical Physics II,University of Technology Ilmenau,PO Box 100565,98684,Ilmenau,Germany [2]School of Minerals and Energy Resources Engineering,University of New South Wales,Sydney,NSW,2052,Australia

出　　处：《Magnetic Resonance Letters》2023年第3期220-231,I0003,共13页磁共振快报（英文）

基　　金：the Deutsche Forschungsgemeinschaft(STA 511/15-1 and STA 511/15-2)is gratefully acknowledged.

摘　　要：In reservoir rocks,the term“ageing”refers to extended exposition to crude oil;a typically water-wet sandstone will then gradually become oil-wet as a consequence of the deposition of insoluble fractions of oil onto the surface grains.Rocks have been aged artificially by subjecting them to a bitumen solution at elevated temperature in order to achieve comparable surface properties for three different types of rock:Bentheimer,Berea Buff and Liege Chalk.Using saturated and aromatic model compounds as proxies for crude oil,the nuclear magnetic resonance(NMR)relaxation dispersion in native and aged rocks was compared and correlated to the properties of paramagnetic impurities in these rock types.Perfluorated liquids were found to follow the same trend as deuterated and naturally occurring oil components,suggesting they can be used as suitable tracers for wettability studies since the ^(19)F nucleus is absent in natural sources.By combining electron paramagnetic resonance(EPR)and dynamic nuclear polarization(DNP)it becomes possible to identify and quantify the origin of the dominating relaxation processes between native and aged rocks,providing an alternative approach to assess wettability in natural rocks.

关 键 词：ROCKS WETTABILITY RELAXOMETRY NMR DNP Oil 

分 类 号：O4[理学—物理]