Pore structure, fractal characteristics and permeability prediction of tight sandstones: A case study from Yanchang Formation, Ordos Basin, China

Dou, Wenchao; Liu, Luofu; Jia, Langbo; Xu, Zhengjian; Wang, Mengyao; Du, Chongjiao

doi:10.1016/j.marpetgeo.2020.104737

Cited by 47 publications

(24 citation statements)

References 36 publications

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“…This indicates that as the grain size increases, the difference in particle shape has a more obvious impact on the pore structure. It is widely acknowledged that the determination of the fractal dimension plays an important role in predicting the physical and mechanical properties of geomaterials [45,46]. Huang et al [45] quantified the fractal characteristics of the pore structure of shale and found a significant relationship between the fractal dimension and permeability.…”

Section: Effect Of Grain Size On the Microsrcture's Fractal Dimensionmentioning

confidence: 99%

“…Kong et al [47] established a fractal model of pore size distribution for porous geomaterials based on the fractal characteristics of pores, which could be used to study hydraulic properties. Based on the mercury intrusion test and image analysis, Dou et al [46] analyzed the effect of different fractal models of pores on the evaluation of sandstone's permeability and highlighted the role of the fractal dimension in determining the permeability. Therefore, accurate prediction of the fractal dimension is crucial for grasping and analyzing the engineering properties (e.g., permeability) of geomaterials.…”

Section: Effect Of Grain Size On the Microsrcture's Fractal Dimensionmentioning

confidence: 99%

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Effect of Grain Size on Microscopic Pore Structure and Fractal Characteristics of Carbonate-Based Sand and Silicate-Based Sand

Ding

et al. 2021

Fractal Fract

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In this study, a series of nuclear magnetic resonance (NMR) tests was conducted on calcareous sand, quartz sand, and glass bead with a wide range of grain sizes, to understand the effect of grain size on the micro-pore structure and fractal characteristics of the carbonate-based sand and silicate-based sand. The pore size distribution (PSD) of the tested materials were obtained from the NMR T2 spectra, and fractal theory was introduced to describe the fractal properties of PSD. Results demonstrate that grain size has a significant effect on the PSD of carbonate-based sand and silicate-based sand. As grain size increases, the PSD of sands evolves from a binary structure with two peaks to a ternary structure with three peaks. The increase in the grain size can cause a remarkable increase in the maximum pore size. It is also found that the more irregular the particle shape, the better the continuity between the large and medium pores. In addition, grain size has a considerable effect on the fractal dimension of the micro-pore structure. The increase of grain size can lead to a significant increase in the heterogeneity and fractal dimension in PSD for calcareous sand, quartz sand and glass bead.

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Section: Effect Of Grain Size On the Microsrcture's Fractal Dimensionmentioning

confidence: 99%

Section: Effect Of Grain Size On the Microsrcture's Fractal Dimensionmentioning

confidence: 99%

Effect of Grain Size on Microscopic Pore Structure and Fractal Characteristics of Carbonate-Based Sand and Silicate-Based Sand

Ding

et al. 2021

Fractal Fract

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“…Reservoir quality evaluation is the basis of tight sandstone oil development. Due to the influence of sedimentation and diagenesis, tight sandstone reservoirs have poor physical properties (Guo et al, 2021), complex pore throat structures (Yang et al, 2020), strong reservoir heterogeneity (Ding et al, 2014;Dou et al, 2021;Kong et al, 2020;Lian et al, 2010;Liu et al, 2018), and small pore throat radii (Nelson, 2009). Detailed characterization of tight sandstone reservoirs is the key to unconventional oil and gas resource exploration and development (Cao et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

A reservoir quality evaluation approach for tight sandstone reservoirs based on the gray correlation algorithm: A case study of the Chang 6 layer in the W area of the as oilfield, Ordos Basin

Liu

Zhang

Shi

et al. 2021

Energy Exploration & Exploitation

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As an important type of unconventional hydrocarbon, tight sandstone oil has great present and future resource potential. Reservoir quality evaluation is the basis of tight sandstone oil development. A comprehensive evaluation approach based on the gray correlation algorithm is established to effectively assess tight sandstone reservoir quality. Seven tight sandstone samples from the Chang 6 reservoir in the W area of the AS oilfield in the Ordos Basin are employed. First, the petrological and physical characteristics of the study area reservoir are briefly discussed through thin section observations, electron microscopy analysis, core physical property tests, and whole-rock and clay mineral content experiments. Second, the pore type, throat type and pore and throat combination characteristics are described from casting thin sections and scanning electron microscopy. Third, high-pressure mercury injection and nitrogen adsorption experiments are optimized to evaluate the characteristic parameters of pore throat distribution, micro- and nanopore throat frequency, permeability contribution and volume continuous distribution characteristics to quantitatively characterize the reservoir micro- and nanopores and throats. Then, the effective pore throat frequency specific gravity parameter of movable oil and the irreducible oil pore throat volume specific gravity parameter are introduced and combined with the reservoir physical properties, multipoint Brunauer-Emmett-Teller (BET) specific surface area, displacement pressure, maximum mercury saturation and mercury withdrawal efficiency parameters as the basic parameters for evaluation of tight sandstone reservoir quality. Finally, the weight coefficient of each parameter is calculated by the gray correlation method, and a reservoir comprehensive evaluation indicator (RCEI) is designed. The results show that the study area is dominated by types II and III tight sandstone reservoirs. In addition, the research method in this paper can be further extended to the evaluation of shale gas and other unconventional reservoirs after appropriate modification.

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“…However, they note the difference in bulk permeability of the samples with varying binder levels. Dou et al [ 28 ] studied different fractal models that combined the pore structure and the permeability of tight sandstones. They used mercury intrusion porosimetry to study the correlation between the pore characteristics and the permeability of sandstones.…”

Section: Introductionmentioning

confidence: 99%

On the Relation between the Gas-Permeability and the Pore Characteristics of Furan Sand

Sundaram

Svidró

et al. 2021

Materials

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Furan sand is one of the most commonly used chemically bonded molding materials in foundries across the world. It consists of a furfuryl alcohol-based resin and an acid-based liquid catalyst. When the molding material comes in contact with the molten metal, it undergoes a thermal shock accompanied by a certain release of volatile gases. In order to evacuate these gases, molds and cores should have optimal gas permeability values and proper venting by design. If the volatile compounds are not appropriately evacuated, they are prone to enter the melt before the first layer of solidified metal is formed which can lead to the formation of gas-related casting defects. Standard gas permeability measurements are commercially available tools used in the industry to compare and to quality control different sands, however, they only provide reference numbers without actual units. Permeability in a standard unit, m2, provides uniformity and helps the comparison of results from difference sources. In this paper, a new method using Darcy’s law (prevalent in earth sciences), was adapted to measure the gas-permeability of furan samples made of silica sand with various grain size distributions. The effect of grain size distribution on the gas-permeability of furan sand samples was studied. Gas-permeability values in m2 were then correlated with mercury-porosity measurement results to bring new light on the relation between pore size, pore volume and the permeability of molding materials.

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Pore structure, fractal characteristics and permeability prediction of tight sandstones: A case study from Yanchang Formation, Ordos Basin, China

Cited by 47 publications

References 36 publications

Effect of Grain Size on Microscopic Pore Structure and Fractal Characteristics of Carbonate-Based Sand and Silicate-Based Sand

Effect of Grain Size on Microscopic Pore Structure and Fractal Characteristics of Carbonate-Based Sand and Silicate-Based Sand

A reservoir quality evaluation approach for tight sandstone reservoirs based on the gray correlation algorithm: A case study of the Chang 6 layer in the W area of the as oilfield, Ordos Basin

On the Relation between the Gas-Permeability and the Pore Characteristics of Furan Sand

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