Influence of net confining stress on NMR T2 distribution and two-phase relative permeability

Adenutsi, Caspar Daniel; Li, Zhiping; Xu, Zhichao; Sun, Lili

doi:10.1016/j.petrol.2019.03.083

Cited by 22 publications

(9 citation statements)

References 25 publications

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“…Compaction affects relative permeability of the non-wetting phase more than relative permeability of the wetting phase. This is in agreement with previous experimental studies [26,27,30]. Moreover, relative permeabilities of the non-wetting phase were increased by compaction when Ω = 5.…”

Section: Relative Permeability Under Stresssupporting

confidence: 93%

“…Experiments conducted on water-oil systems also generated variable results. Some researchers reported that relative permeability of water slightly increased or did not change while that of oil decreased under increased stress [26][27][28][29][30]. However, experiments of Wilson [31] indicated that relative permeability of water decreased and that of oil increased when the overburden pressure was increased.…”

Section: Introductionmentioning

confidence: 99%

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DEM-LBM simulation of stress-dependent absolute and relative permeabilities in porous media

Huang

Xiao

Labra

et al. 2021

Chemical Engineering Science

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Section: Relative Permeability Under Stresssupporting

confidence: 93%

Section: Introductionmentioning

confidence: 99%

DEM-LBM simulation of stress-dependent absolute and relative permeabilities in porous media

Huang

Xiao

Labra

et al. 2021

Chemical Engineering Science

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“…In the experimental conditions, T 2 cut-off value calculated by using T 2 spectrum under saturated and centrifugal conditions is a key parameter for calculating irreducible water saturation and permeability. [13][14][15][16] This shows that T 2 spectrum in a centrifugal state is also of great significance. However, only T 2 spectral parameters (peak value, fractal dimension value) under a saturated state were adopted to predict T 2 cutoff value.…”

mentioning

confidence: 90%

Single and multi‐fractal dimension variation of tight sandstone by using centrifuge T₂ spectral curve

Feng,

Li,

Zhang

et al. 2023

Greenhouse Gases

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Pore‐fracture structure distribution heterogeneity (PFSH) affects dynamic variation of porosity‐permeability of tight sandstone reservoirs, then restricting gas production performance. A fractal model by low‐field nuclear magnetic resonance technology (LF‐NMR) has been used in the quantitative characterization of PFSH. Among some literature, PFSH was studied by using a saturated T2 spectrum. However, there are few studies on fractal characteristics of T2 spectral morphology in a centrifugal state and its influence on porosity‐permeability parameters. In this paper, 30 tight sandstone samples were collected from Taiyuan Formation in Qinshui Basin. Then LF‐NMR technology was used to analyze PFSH, and sample types were divided by using T2 spectra difference under saturated and centrifugal conditions. Meanwhile, single (model 1 and 2) and multi‐fractal model are adopted to calculate fractal parameters of saturated and centrifugal T2 spectra, and then a difference in fractal parameters under different water conditions was compared. Correlation between different fractal parameters, pore structure and T2 cut‐off value are studied, and a mathematical prediction model for T2 cut‐off value by using fractal and pore structure parameters are established. The results are as follows. (1) All the samples are divided into four types A/B/C/D. For example, the type A sample is characterized by a single peak of T2 spectrum and T2 value is less than 10 ms, which indicates that this type belongs a smaller‐pore developed. Type B sample is characterized by a single peak of T2 spectrum and T2 value is10–100 ms, which indicates that this type belongs to mesopore developed. (2) In saturated state (DS), PFSH of type A sample by using model 1 and 2 is stronger than that of type B, followed by type C and D. Then the multifractal model shows that PFSH of type B sample is stronger than that of other sample types. Correlation between fractal dimension calculated by using single fractal and pore structure parameters is stronger than that of multifractal dimension. (3) T2 spectrum in centrifugal state has fractal characteristics (Di), and there are certain correlation Di with Ds. Therefore, a mathematical prediction model for T2 cut‐off value by using fractal and pore structure parameters is established. © 2023 Society of Chemical Industry and John Wiley & Sons, Ltd.

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“…At present, image analysis and fluid injection methods are used to characterize the pore-fracture structure of the reservoir. − The former includes optical microscopy, field emission scanning electron microscopy, and then emerging imaging description technologies with high resolution, such as focused ion beam-scanning electron microscopy, focused ion beam-helium ion microscopy, broad ion beam-scanning electron microscopy, confocal laser scanning microscopy, etc. Meanwhile, the latter mainly includes a high-pressure mercury injection test, CO 2 and N 2 adsorption tests, etc.…”

Section: Introductionmentioning

confidence: 99%

Effects of Nanopore Structure Heterogeneity of Coal Samples on Adsorption Ability and Porosity–Permeability Variation

Yang

Zhang

et al. 2023

Energy Fuels

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The occurrence and migration process of coalbed methane are affected by the nanopore-fracture structure. Meanwhile, coal reservoir adsorption ability and porosity−permeability variation are two core factors to characterize the occurrence and migration characteristics. Research on the effect of nanopore structure heterogeneity on the surface free energy and variation of porosity and permeability is important. In this paper, the physical properties and pore size distribution of five groups of coal samples were analyzed using nuclear magnetic resonance (NMR) tests. Then, hightemperature and high-pressure isothermal adsorption (HTHP) and overburden porosity−permeability tests (OPPT) were used to characterize surface free energy and porosity and permeability variation rate parameters of coal reservoirs. Main conclusions are as follows. All the samples can be divided into adsorption pore-developed and larger pore-developed types. ( 1) Multifractal results show that total pore volume distribution heterogeneity (D −10 −D 10 ) is determined by a lower value area of pore volume (D −10 −D 0 ). D −10 −D 0 represents seepage pore distribution heterogeneity; as it increases, irreducible water saturation decreases. Also, D 0 −D 10 represents adsorption pore distribution heterogeneity and T 2,cut-off decreases with the increase in D 0 −D 10 . ( 2) With the increase in adsorption pressure, the reduction rate of surface free energy increases rapidly during lower pressure (adsorption pressure is smaller than 6 MPa), and then its change is smaller than that of higher pressure. At the same adsorption pressure, the reduction rate of surface free energy decreases with the increase in adsorption pore volume. The Langmuir volume and adsorption capacity gradually increase with the increase in D −10 −D 0 .(3) Compressibility by using permeability variation is between 0.06 and 0.08 MPa −1 . The porosity and permeability variation rate has a positive correlation with seepage pore volume and D −10 −D 0 , and then this value decreases with the increase in adsorption pore volume. (4) Mechanical parameters (Young's modulus and Poisson's ratio) have an obvious linear relationship with pore volume, and they are not affected by heterogeneity parameters (D 0 −D 10 and D −10 −D 0 ) of pore size distribution.

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Influence of net confining stress on NMR T2 distribution and two-phase relative permeability

Cited by 22 publications

References 25 publications

DEM-LBM simulation of stress-dependent absolute and relative permeabilities in porous media

DEM-LBM simulation of stress-dependent absolute and relative permeabilities in porous media

Single and multi‐fractal dimension variation of tight sandstone by using centrifuge T₂ spectral curve

Effects of Nanopore Structure Heterogeneity of Coal Samples on Adsorption Ability and Porosity–Permeability Variation

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Influence of net confining stress on NMR T2 distribution and two-phase relative permeability

Cited by 22 publications

References 25 publications

DEM-LBM simulation of stress-dependent absolute and relative permeabilities in porous media

DEM-LBM simulation of stress-dependent absolute and relative permeabilities in porous media

Single and multi‐fractal dimension variation of tight sandstone by using centrifuge T2 spectral curve

Effects of Nanopore Structure Heterogeneity of Coal Samples on Adsorption Ability and Porosity–Permeability Variation

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Single and multi‐fractal dimension variation of tight sandstone by using centrifuge T₂ spectral curve