Magnetic Resonance Technology Research Articles

Long-term durability investigation of basalt fiber-reinforced geopolymer concrete in marine environment

The long-term durability of basalt fiber-reinforced geopolymer concrete (BFRGC) in marine environments is importance for the development of sustainable construction practices. This study examines the long-term durability of basalt fiber-reinforced geopolymer concrete exposed to dry-wet cycles and immersion treatment in marine conditions. A geopolymer concrete with 1% fiber content was prepared and subjected to dry-wet cycles and immersion treatments in a 5% sulfate solution (Tehmina et al., 2014; Nasir et al., 2016; John et al., 2016) [1-3]. Density measurements, ultrasonic pulse velocity tests, and uniaxial compression tests were conducted on the BFRGC after various treatment durations. The mechanical properties of BFRGC were compared with geopolymer concrete without fibers in marine environments. Additionally, the changes in compressive strength of geopolymer concrete with and without fibers in different immersion environments were further discussed. Using low-field nuclear magnetic resonance (LF-NMR) technology, the variations in pore structure were also analyzed. The results show that the mechanical property loss from dry-wet cycles was greater than from immersion treatment. In BFRGC, strength decreased by 10.1% after 192 days of dry-wet cycles, compared to a smaller decrease of 5.6% in immersion environments. The inclusion of basalt fibers effectively enhances stability. When in dry-wet cycle tests, BFRGC strength decreased from 49.6 MPa to 44.6 MPa, a reduction of 10.1%. Conversely, geopolymer concrete without fibers dropped from 49.7 MPa to 42.1 MPa, a reduction of 15.5%. LF-NMR test results show that the porosity of geopolymer concrete without fibers increased by 21.6% and 17.5% in dry-wet cycles and immersion environments, respectively. In contrast, the porosity of BFRGC increased by 16.1% and 12.7%.

Optimization of mechanical properties and pore structure of lightweight geopolymer concrete using GGBFS based on LF-NMR technology

Lightweight geopolymer can combine good physical and mechanical properties, good thermal and chemical stability, low CO2 emission and low energy. The development of high strength lightweight geopolymer concrete for load-bearing structures is important to expand the application range of geopolymer. This paper presents an improvement study on the mechanical properties and pore structure of lightweight geopolymer concrete (LGC) by adding ground granulated blast-furnace slag (GGBFS). The effect of GGBFS content on the mechanical properties of LGC was analyzed, including ultimate compressive stress and elastic modulus. The variation in the microscopic pore structure of LGC with different GGBFS content was further analyzed by low-field nuclear magnetic resonance (LF-NMR) technology. The lightweight geopolymer concrete with different strength grades was proposed including LC20, LC30 and LC40. The results show that as the GGBFS content increases, the ultimate compressive stress and specific strength of LGC increase while the strain corresponding to peak stress decreases, which means that the mechanical properties and deformation resistance of LGC are improved. The CO2 emissions of LGC are lower than that of cement-based lightweight concrete, which shows good sustainability. The results also show that the addition of GGBFS can produce more gel and reduce the volume proportion of capillary pores and air pores, resulting in the densification of the LGC. The recommended GGBFS contents corresponding to the strength grades of LC20, LC30 and LC40 are 0 ∼ 12.7 %, 12.7 % ∼ 24.6 % and 24.6 % ∼ 30%, respectively. The LGC has the characteristics of lightweight and high-strength, which has a potential application in civil engineering. Highlights [1] Mechanical properties and pore structure of LGC were improved by adding GGBFS. [2] The effect of GGBFS content on geopolymer concrete properties was discussed. [3] Effect of slag content on pore structure of geopolymer concrete were studied. [4] GGBGS content of geopolymer concrete with different strength grades was proposed.

Investigation of carbon-based nanofluid imbibition processes in low-permeability reservoirs using nuclear magnetic resonance

Spontaneous imbibition has been demonstrated to be an important approach to enhance the oil recovery of unconventional reservoirs after hydraulic fracturing. Adding chemical agents to modulate the properties of the oil-water and oil-rock interfaces is a common method to enhance imbibition. Carbon-based nanofluid showed excellent ability to reduce interfacial tension and alter wettability due to their distinct surface properties and ultra-small particle size. However, there are few systemic studies on the imbibition process of carbon-based nanofluid and the unclear mechanism of the enhanced oil recovery (EOR) restricts their oilfield application. In this study, the carbon-based nanofluid was prepared by dispersing carbon nitride quantum dots (CNQDs) of 2.34 ± 0.34 nm synthesized by citric acid and urea in deionized water. The spontaneous imbibition process of nanofluids was monitored by nuclear magnetic resonance (NMR) technology. The T2 relaxation distribution results suggested that the oil recovery of CNQDS nanofluid by spontaneous imbibition was 24.6%, which was 5% higher than that of nano-SiO2 nanofluid. Moreover, the variations of oil saturation profiles analyzed based on NMR data indicated that the maximum imbibition distance of the carbon-based nanofluid was about 20.34 mm which is also larger than that of the nano-SiO2 nanofluid of 16.02 mm. The oil saturation variations of saturated oil cores imbibed in carbon-based nanofluid was also significantly improved compared with nano-SiO2 nanofluid. This finding was attributed to the fact that compared with nano-SiO2 nanofluid, the CNQDs nanofluid can not only promote the fluid to enter deeper matrix, but also effectively reduce the residual oil saturation in the area that the nanofluid accesses to. The interfacial tension and contact angle measurements were conducted to reveal the underlying EOR mechanisms of CNQDs nanofluid. This study provides vital insights into the prospective application of carbon-based nanofluid in low-permeability reservoirs.

Causal mediation analysis with a three-dimensional image mediator.

Causal mediation analysis is increasingly abundant in biology, psychology, and epidemiology studies and so forth. In particular, with the advent of the big data era, the issue of high-dimensional mediators is becoming more prevalent. In neuroscience, with the widespread application of magnetic resonance technology in the field of brain imaging, studies on image being a mediator emerged. In this study, a novel causal mediation analysis method with a three-dimensional image mediator is proposed. We define the average casual effects under the potential outcome framework, explore several sufficient conditions for the valid identification, and develop techniques for estimation and inference. To verify the effectiveness of the proposed method, a series of simulations under various scenarios is performed. Finally, the proposed method is applied to a study on the causal effect of mother's delivery mode on child's IQ development. It is found that cesarean section may have a negative effect on intellectual performance and that this effect is mediated by white matter development. Additional prospective and longitudinal studies may be necessary to validate these emerging findings.

Low-density lipoprotein particle profiles compared with standard lipids measurements in the association with asymptomatic intracranial artery stenosis

The Shiga Epidemiological Study of Subclinical Atherosclerosis was conducted in Kusatsu City, Shiga, Japan, from 2006 to 2008. Participants were measured for LDL-p through nuclear magnetic resonance technology. 740 men participated in follow-up and underwent 1.5 T brain magnetic resonance angiography from 2012 to 2015. Participants were categorized as no-ICAS, and ICAS consisted of mild-ICAS (1 to < 50%) and severe-ICAS (≥ 50%) in any of the arteries examined. After exclusion criteria, 711 men left for analysis, we used multiple logistic regression to examine the association between lipid profiles and ICAS prevalence. Among the study participants, 205 individuals (28.8%) had ICAS, while 144 individuals (20.3%) demonstrated discordance between LDL-c and LDL-p levels. The discordance “low LDL-c–high LDL-p” group had the highest ICAS risk with an adjusted OR (95% CI) of 2.78 (1.55–5.00) in the reference of the concordance “low LDL-c–low LDL-p” group. This was followed by the concordance “high LDL-c–high LDL-p” group of 2.56 (1.69–3.85) and the discordance “high LDL-c–low LDL-p” group of 2.40 (1.29–4.46). These findings suggest that evaluating LDL-p levels alongside LDL-c may aid in identifying adults at a higher risk for ICAS.

The Optimization of Microwave Field Characteristics for ODMR Measurement of Nitrogen-Vacancy Centers in Diamond

A typical solid-state quantum sensor can be developed based on negatively charged nitrogen-vacancy (NV−) centers in diamond. The electron spin state of NV− can be controlled and read at room temperature. Through optical detection magnetic resonance (ODMR) technology, temperature measurement can be achieved at the nanoscale. The key to ODMR technology is to apply microwave resonance to manipulate the electron spin state of the NV−. Therefore, the microwave field characteristics formed near the NV− have a crucial impact on the sensitivity of ODMR measurement. This article mainly focuses on the temperature situation in cellular applications and simulates the influence of structural parameters of double open loop resonant (DOLR) microwave antennas and broadband large-area (BLA) microwave antennas on the microwave field’s resonance frequency, quality factor Q, magnetic field strength, uniformity, etc. The parameters are optimized to have sufficient bandwidth, high signal-to-noise ratio, low power loss, and high magnetic field strength in the temperature range of 36 °C to 42.5 °C. Finally, the ODMR spectra are used for effect comparison, and the signal-to-noise ratio and Q values of the ODMR spectra are compared when using different antennas. We have provided an optimization method for the design of microwave antennas and it is concluded that the DOLR microwave antenna is more suitable for living cell temperature measurement in the future.

Experimental study on the influence of external fluids on the pore structure of carbonaceous shale

Shale reservoirs have complex mineral compositions and are rich in micro-scale pores. It is of great scientific and engineering significance to explore the mechanism of external fluids on the pore throat structure of shale. In this paper, pure carbonaceous shale is taken as the research object, and the mechanism of the influence of slip water and reflux fluid on the pore throat structure is analyzed by using nuclear magnetic resonance (NMR) technology. Then, the sensitivity of different types of shale to external fluids is comparatively analyzed and summarized. The results show that (1) the oil slick has a certain effect on the total porosity of different types of shale. The rate of change is shown as carbonaceous shale (− 7.1%) > pure shale (− 1.6%). (b) For slickwater, the average reduction of macro- and micro/nanopores in carbonaceous shale is 90.0% and 5.0%, respectively, while the average reduction of macro- and mesopores in pure shale is 17.7% and 6.8%, respectively. (c) Total porosity of different shale types is insensitive to refluxing fluids. The average increase in macro-, meso-, and small pores of carbonaceous shale is 31.8%, 23.6%, and 20.2%, respectively; the average increase in macro- and small pores of pure shale is 17.1%.

Pore fractal characteristics and ANN model of polyacrylonitrile fiber reinforced concrete under the synergistic effects of freeze-thaw and erosion

The degradation of the concrete pore structure is a major concern among scholars due to its negative impact on durability. This study conducted a salt freezing test on polyacrylonitrile fiber concrete (PANFRC) using a composite freeze-thaw medium consisting of Na2SO4, MgSO4, and NaCl (5 % + 5% + 3.5 %). The pore volume fractal dimension was determined by analyzing the T2 spectrum obtained through nuclear magnetic resonance technology. The study explored the influence of different types of pores on frost resistance and developed an artificial neural network-based machine learning model to predict macroscopic frost resistance using the pore volume fractal dimension. The experimental findings indicate that plain concrete exhibits a density loss of 4.67 % upon failure, whereas the density loss in PANFRC is reduced to less than 3 %. The frost resistance durability index is observed to improve as the fiber mass fraction increases within specific ranges. Notably, when the fiber content surpasses 1.2 kg/m³, the durability factor (DF) can be effectively doubled. Drawing from the concept of freeze-thaw cycles, a novel frost-thaw erosion damage model was developed, which incorporates the influence of fiber content under the combined action of freeze-thaw cycles and erosion. The analysis of pore dimensions reveals that the fractal characteristics become more pronounced with the increase in pore size, although this does not extend to the micro-pore range (i.e., those smaller than 0.1 μm). In comparison to other machine learning algorithms, the ANN demonstrates its superiority by establishing a meso-macro transfer prediction model with enhanced generalization capabilities.

T2 magnetic resonance (T2MR®) technology for managment of patients with sepsis

T2 magnetic resonance (T2MR®) technology for managment of patients with sepsis

SEI/dead Li-turning capacity loss for high-performance anode-free solid-state lithium batteries

Anode-free solid-state lithium metal batteries (AF-SSLBs) have the potential to deliver higher energy density and improved safety beyond lithium-metal batteries. However, the unclear mechanism for the fast capacity decay in AF-SSLBs, either determined by dead Li or solid electrolyte interface (SEI), limits the proposal of effective strategies to prolong cycling life. To clarify the underlying mechanism, herein, the evolution of SEI and dead Li is quantitatively analyzed by a solid-state nuclear magnetic resonance (ss-NMR) technology in a typical LiPF6-based polymer electrolyte. The results show that the initial capacity loss is attributed to the formation of SEI, while the dead Li dominates the following capacity loss and the growth rate is 0.141 mA h cm−2 cycle−1. To reduce the active Li loss, the combination of inorganic-rich SEI and self-healing electrostatic shield effect is proposed to improve the reversibility of Li deposition/dissolution behavior, which reduces the capacity loss rate for the initial SEI and following dead Li generation by 2.3 and 20.1 folds, respectively. As a result, the initial Coulombic efficiency (ICE) and stable CE increase by 15.1% and 15.3% in Li-Cu cells, which guides the rational design of high-performance AF-SSLBs.

Spontaneous increasing of sensitivity and resolution in parahydrogen-induced hyperpolarization by RASER

Enhancing the sensitivity of nuclear magnetic resonance (NMR) technology has been the focus of NMR research for decades, which offers the potential to significantly expand its applications in chemistry, biology, and medical imaging. Parahydrogen-induced polarization (PHIP) emerges as a cost-effective approach to substantially enhance the sensitivity of NMR. Nevertheless, the amplification of the 1H signal in PHIP is susceptible to interference from the thermal polarization state 1H NMR signal. Employing RASER (radiofrequency amplification by stimulated emission of radiation) proves effective in mitigating such interference, which can reduce the linewidth and increase the sensitivity at the same time. In this work, we utilized PHIP and RASER to enhance the signal-to-noise ratio (SNR) of a series of biocompatible alkynyl organic acid molecules. The alkynyl acid with the highest enhancement factor was first identified through PASADENA (parahydrogen and synthesis allow dramatically enhanced nuclear alignment) experiments. Subsequently, RASER experiments were carried out through hyperpolarization of 5-hexynoic acid, exploring its signal characteristics under varying flow rates and pressures. The SNR of proton signals of 5-hexynoic acid surpassed 150,000, an 18.62-fold improvement compared with traditional hyperpolarized signals in PASADENA, and a markedly narrowed linewidth of 0.06 Hz.

Analysis of damage models and mechanisms of mechanical sand concrete under composite salt freeze–thaw cycles

Mechanical sand concrete (MSC) deterioration in bridge engineering within cold-salt environments in the West was investigated. This study evaluated the salt-freezing resistance and damage models of granite mechanical sand concrete (GMSC) and tuff mechanical sand concrete (TMSC) under composite salt freezing-thaw cycles, using multiple indicators such as mass loss, relative dynamic elastic modulus, flexural strength, and compressive strength. A mechanistic study on the evolution of microscopic pores was conducted using nuclear magnetic resonance technology. The results showed that with an increase in composite salt freeze–thaw cycles, both TMSC and GMSC exhibited a decreasing trend in all indicators except for mass loss, which initially decreased and then increased. The relative dynamic modulus of elasticity decreased by 13.8 % and 17.4 % after 125 freeze–thaw cycles for TMSC and GMSC; compressive strength decreased to 36.16 MPa and 35.01 MPa; and flexural strength decreased to 4.977 MPa and 4.973 MPa, respectively. Combined with the T2 spectrum analysis of NMR, it can be seen that with the increase of the number of freeze-thaw cycles of the composite salt, the internal porosity of the TMSC structure increases from 1.91 % to 2.55 %, and the GMSC from 2.1 % to 2.86 %, and the harmful pore percentage increases by 1.73 times and 1.75 times, in turn, compared with that before the freeze-thaw.Thus, TMSC demonstrated superior salt-freezing resistance compared to GMSC. This study offers a reference and guidance for adopting MSC in cold and salty western regions.

Flow Characterization in Fractured Shale Oil Matrices Using Advanced Nuclear Magnetic Resonance Techniques

The evaluation of flow dynamics in fractured shale oil reservoirs presents significant challenges due to the complex pore configurations and high organic material concentration. Conventional methods for petrophysical and fluid dynamic evaluations are insufficient in addressing these complexities. However, nuclear magnetic resonance (NMR) technology is an effective technique for quantitatively delineating fluid micro-transport properties across the reservoir core. This study presents an experimental methodology rooted in NMR technology to quantify the flow capabilities within the shale oil matrix. This approach incorporates high-pressure saturation flow experiments across seven distinct core samples to gauge the micro-transport phenomena of fluids across various pore dimensions. The results revealed that under high-pressure saturation, shale cores devoid of fractures demonstrated an average crude oil saturation rate of merely 19.44%. Cores with evident stratification exhibited a 16.18% increase in flow capacity compared to their non-stratified counterparts. The flow dynamics within these shale reservoirs exhibited a range of behaviors, from non-linear to linear. In lower-permeability zones, non-linear patterns became increasingly apparent. An NMR T2 spectrum analysis was used to identify the minimum effective pore size conducive to shale oil flow within the matrix, which was between 8 and 10 nanometers. These insights provide a foundation for a deeper understanding of the mechanisms behind oil and gas migration in fractured shale oil matrices, offering valuable insight into their extractive potential.

Myocarditis in children 2024, new themes and continued questions.

While pediatric myocarditis incidence has increased since the coronavirus disease 2019 (COVID-19) pandemic, there remain questions regarding diagnosis, risk stratification, and optimal therapy. This review highlights recent publications and continued unanswered questions related to myocarditis in children. Emergence from the COVID-19 era has allowed more accurate description of the incidence and prognosis of myocarditis adjacent to COVID-19 infection and vaccine administration as well that of multi-system inflammatory disease in children (MIS-C). As cardiac magnetic resonance technology has shown increased availability and evidence in pediatric myocarditis, it is important to understand conclusions from adult imaging studies and define the use of this imaging biomarker in children. Precision medicine has begun to allow real-time molecular evaluations to help diagnose and risk-stratify cardiovascular diseases, with emerging evidence of these modalities in myocarditis. Recent information regarding COVID-19 associated myocarditis, cardiac magnetic resonance, and molecular biomarkers may help clinicians caring for children with myocarditis and identify needs for future investigations.

Two-dimensional spectrum characteristics and oil movability study of the shale oil reservoir

Shale oil is mainly stored in the nano–micro-pores of shale in the form of adsorption or in a free state. Among them, only free-state oil is the main contributor to shale oil production under natural elastic energy. Therefore, it is crucial to evaluate the movability of crude oil effectively. In this paper, focusing on the Jurassic shale oil reservoir core in the middle-eastern Sichuan region of China, low-field nuclear magnetic resonance (NMR) technology is used to analyze the basic characteristics of shale oil core samples. Experiments on the low-field NMR one-dimensional and two-dimensional spectrum characteristics of the original core, heat-treated core, and thermogravimetric-treated shale core are carried out. The effects of the TG-MS method, T2 method, and the volatilization of light oil components on the movability of shale oil reservoirs are analyzed, and the movability characteristics of shale oil reservoirs in the middle-eastern Sichuan region are preliminarily clarified. The results show that under thermal treatment, the distribution range of the two-dimensional spectrum of the core oil occurrence area is significantly reduced, and the T1 and T2 distribution ranges are reduced by 10.9% and 60.7%, respectively. According to the TG-MS method, the mobile oil, bound oil, and adsorbed oil account for 74.7%, 8.1%, and 17.2%, respectively. The quantitative calculation of movable oil saturation by NMR combined with heat treatment is 65.6%, which is lower than that calculated using the thermogravimetric method. In order to calculate the movability more accurately, the scale effect between different samples should be considered. This study could provide a theoretical basis for the subsequent shale oil development program.

Fractal evolution model of proton spatial distribution in low water/binder cement-based composites (LW/B-CC) during early-age hydration process

This study establishes the fractal evolution model of proton spatial distribution in low water/binder cement-based composites (LW/B-CC) based on fractal theory and low field nuclear magnetic resonance (LF NMR) technology. The results show that the fractal evolution process of gel water, capillary water and surface water distributions in LW/B-CC presents three stages: the first 4–6 h after the beginning of hydration, 4–6 h to 12 h, and 12 h to long-term stage. In the first and second stages, the fractal dimensions of gel and capillary water increase linearly with hydration time, while the fractal dimension of surface water decreases linearly. The boundary is a sudden change of fractal dimensions after about 4–6 h of hydration. The third stage starts after about 12 h of hydration, at which time the fractal dimensions begin to converge to fixed values. Besides, this study reveals the mathematical relationship between fractal dimension (Df) and particle size distribution modulus (q), which is conducive to achieve the full-cycle regulation of LW/B-CC.

NMR-based analysis of fractal characteristics of the pore structure of fully aeolian sand concrete under carbonation-dry-wet cycles

The evolution law of the pore structure of concrete is important for the study of concrete durability. To study the quantitative relationship between pore structure and macroscopic mechanics of aeolian sand concrete(ASC) under carbonation-dry-wet cycle(DWCs), the fractal characteristics of ASC under carbonation DWCs were analyzed by means of nuclear magnetic resonance(NMR) technology. The results showed that the carbonization product CaCO3 filled the pores and the compressive strength of ASC increased as the carbonization time increasing. When the DWCs was 0 times, the compressive strength of C1 and C2 groups increased by 9% and 13.6%, respectively, compared with C0. The compressive strength of C0 and C1 groups reached the maximum value when the DWCs was 40 times, while the C2 group reached the maximum value when the DWCs was 20 times. Compared with C0, the compressive strength of C1 and C2 increased by only 4% and 6%, respectively, after 100 DWCs. The fractal dimension Dmax reflected the proportion of harmless and multiple harmful pores in the damaged ASC. The fractal dimension Dmax was proportional to the proportion of harmless pores, and the correlation coefficient was 0.9303. The fractal dimension Dmax was inversely proportional to the proportion of harmful pores, and the correlation coefficient was 0.9565. The macroscopic mechanical properties were mainly affected by harmless pores and harmful pores, while the influence of less harmful pores and harmful pores was weak. This study will provide a theoretical justification for the use of ASC in practical engineering.

Giving Bodies Back to Data: Image Makers, Bricolage, and Reinvention in Magnetic Resonance Technology by Silvia Casini (review)

Giving Bodies Back to Data: Image Makers, Bricolage, and Reinvention in Magnetic Resonance Technology by Silvia Casini (review)

Fluid Spontaneous Imbibition Under the Influence of Osmotic Pressure in Deep Coalbed Methane Reservoir in the Ordos Basin, China

Summary The flowback rate of a hydraulic fracturing fluid is related to coalbed methane (CBM) production in gas wells. The deep (&amp;gt;2000 m) CBM reservoir in the Ordos Basin has an extremely high salinity (&amp;gt;200 000 mg/L), which results in a very low flowback rate of fracturing fluid. The mechanism underlying the extremely low flowback rate of the fracturing fluid remains unclear. This study experimentally simulated two patterns of osmotic pressure variation that exist at a hydraulic fracturing site: the processes of injection of a low-salinity fracturing fluid into a high-salinity reservoir and a high-salinity fracturing fluid into a low-salinity reservoir. Low-field nuclear magnetic resonance (NMR) technology was used to monitor dynamic fluid migration and fluid distribution in the coals. Results showed that osmotic pressure is a driving force for spontaneous imbibition when the salinity of the fracturing fluid is lower than that of the reservoir water, and more fluid enters the coal as the osmotic pressure increases. This causes the displacement of the high-salinity fluid already present in the micropores by the low-salinity fracturing fluid. In high-salinity deep coal seams, both osmotic pressure and capillary forces cause the spontaneous imbibition of the fracturing fluid from fractures into pores, promoting CH4 desorption, alleviating the water-blocking effect, and enhancing the filtration loss of the fracturing fluid. In contrast, the injection of a high-salinity fluid into the reservoir with a low-salinity brine (LSB) creates an osmotic pressure difference that prevents fluid imbibition. In shallow, low-salinity coal seams, the injection of high-salinity fracturing fluids can result in high flowback rates. Therefore, these two injection schemes are significant for an understanding of the role of osmotic pressure in deep CBM extraction and serve as valuable guides for optimizing the selection of the fracturing fluid and improving its effective flowback.

Influence of Reservoir Microstructure on the State of Residual Oil According to Nuclear Magnetic Resonance (NMR) Spectroscopy

The influence of core properties on the state of residual oil in the process of oil displacement by water at the micro level is investigated. The pore size distribution, core permeability, dynamics and morphology of residual oil were studied. The analysis of the available experimental approaches to the study of the properties of the core and residual oil in the core samples showed that the existing methods do not provide complete information about the studied parameters. To solve these problems, it is proposed to use a combination of innovative relaxation-diffusion spectroscopy technology of nuclear magnetic resonance with traditional technology. A combination of mercury injection and nuclear magnetic resonance is used to measure the pore size distribution. The core permeability was determined using the nuclear magnetic resonance method. Two-dimensional nuclear magnetic resonance spectroscopy makes it possible to study the microscopic state of residual oil in an undisturbed core during the displacement process. With the help of the proposed methodology, a core study of the Shengli deposit in China was carried out. Pore size distributions were obtained, permeability and residual oil saturation at different stages of displacement were studied. Four types of residual oil are distinguished: strip-shaped (island), film, mesh, continuous. The influence of permeability on the fraction content of different types of residual oil in the process of displacement is shown. The research results demonstrate the influence of the pore space structure and wettability on the state of residual oil.