CHEMICALLY SELECTIVE IMAGE FORMING DEVICE FOR FORMATION OF FLUID IMAGES IN A SUBTERRANEAN FORMATION AND METHOD OF ITS USE Russian patent published in 2020 - IPC E21B49/08 G01R33/44 G01N24/08 

FIELD: physics.

SUBSTANCE: present invention discloses relates to methods of reservoir evaluation, such as obtaining images of underground formations and fluids in them. Device comprises a body having a sidewall forming a passageway for receiving a core sample of the subterranean formation through it, wherein the housing is configured to be located in the downhole tool such that the imaging device can operate when the downhole tool is arranged in the wellbore, and the housing has an inlet for receiving fluid from the subterranean formation into the passageway; permanent magnet located in side wall of housing, oriented to direct magnetic field through passage channel; a radio-frequency coil located in the side wall of the housing between the permanent magnet and the pass channel, wherein the radio-frequency coil is oriented to direct the radio-frequency field through the pass channel; magnetic field gradient located in side wall of housing between permanent magnet and radio frequency coil for selective direction of gradient field through passage channel; and a chemically selective imaging unit configured to generate independent hydrocarbon and water-based images in the core sample and functionally connected to radio-frequency coil for selective supply of frequency pulses, using pulse sequence of fast reception with improvement of relaxation (RARE) combined with compressed probing, whereby separate fluid measurements of the core sample are generated and, based on differences in the chemical shift in the nuclear magnetic resonance (NMR) spectrum, contrast images of said hydrocarbons and water-based fluids are generated.

EFFECT: technical result is higher accuracy of estimating underground formations.

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