Multi-scale pore structure characterization of lacustrine shale and its coupling relationship with material composition: An integrated study of multiple experiments

Zhao, Rixin; Xue, Haitao; Lu, Shuangfang; Li, Junqian; Tian, Shansi; Wang, Min; Dong, Zihan

doi:10.1016/j.marpetgeo.2022.105648

Cited by 41 publications

(39 citation statements)

References 83 publications

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“…It was not until the large-scale exploitation of shale gas in North America began that shale gradually an attention as a reservoir. Although the shale is very tight, the development and application of a series of high-resolution analysis and testing techniques ,,− have made the nanoscale pores of organic and inorganic matter in shales more intuitively investigated. Using these techniques comprehensively, it can be found that there are abundant pores in shales, ranging from micropores of less than 2 nm to larger macropores, but the tiny nanoscale pore–throats are more developed.…”

Section: Challenges and Perspectivesmentioning

confidence: 99%

Research Progress of Microscopic Pore–Throat Classification and Grading Evaluation of Shale Reservoirs: A Minireview

Xiao

et al. 2022

Energy Fuels

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The grading evaluation of shales helps in understanding the shale reservoir formation and sweet-spot screening of physical properties. Reservoir formation of shale is closely related to the size, distribution, and connectivity of shale pore−throats. Therefore, characterization and classification of microscopic pore−throats are the basis for shale reservoir grading. However, previous microscopic pore−throat classification schemes for materials science are unsuitable for shales with strong heterogeneity. In recent years, the author's team has proposed a new classification method for microscopic pore−throats of shale reservoirs based on the comprehensive characterization of numerous shales with varied maturities in different basins. Results show that the microscopic pore−throats for all shales can be divided into micropores, small pores, mesopores, and macropores. The component, size, and distribution of microscopic pore−throats in shales in different basins differ due to the differences in mineral composition and diagenetic evolution of shales caused by varying depositional environments and burial histories. Correspondingly, the demarcation points of different types of pore−throats are different. After clustering statistical analysis of different types of microscopic pore−throats, shales can be divided into grade I, II, III, and IV reservoirs, regarded as good, medium, poor, and nonshale reservoirs, respectively. Grading evaluation criteria for shale reservoirs were then established. Further, a new technique for evaluating the reservoir flow zone index (FZI) and dividing flow units based on logging data was constructed using the relationship of permeability with porosity in the same hydraulic flow unit. The grading evaluation criteria can be applied to single wells, multiwells, and planes using logging data. The application in numerous shale oil and gas exploration areas in China shows that the established classification scheme can be applied to the grading evaluation and sweet-spot screening of shale reservoirs.

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Section: Challenges and Perspectivesmentioning

confidence: 99%

Research Progress of Microscopic Pore–Throat Classification and Grading Evaluation of Shale Reservoirs: A Minireview

Xiao

et al. 2022

Energy Fuels

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“…The TOC values are not controlled by any specific lithofacies. The single method with its limitations cannot characterize the full-scale structure due to the wide ranges of shale pore distribution (Zhao et al, 2022;Daigle et al,2015). The whole pore aperture was quantitatively achieved with the combination of LPNA and MIP results (Figure 8).…”

Section: Pore Structures Of Different Shale Lithofaciesmentioning

confidence: 99%

Shale Lithofacies and Its Effect on Reservoir Formation in Lower Permian Alkaline Lacustrine Fengcheng Formation, Junggar Basin, NW China

Tang

Zheng

et al. 2022

Front. Earth Sci.

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Lower Permian Fengcheng Formation is considered to be a high-quality alkaline lacustrine shale oil resource in the Junggar Basin, NW China. Based on core and thin section observation, X-ray diffraction, scanning electron microscope, low-pressure N2 adsorption, and high-pressure mercury intrusion porosimetry, different shale lithofacies, and pore structures were examined. According to the mineral composition, shales in well My 1 are divided into five types: dolomitic mudstone, calcareous mudstone, siliceous mudstone, tuffaceous mudstone, and argillaceous mudstone, each of which shows its pore structure distribution. Intragranular pores, inter-crystalline pores associated with clays and pyrites, dissolution pores, and microfractures were commonly observed. There are three segments of pore structures including <50 nm, 50 nm-4 μm, and >4 μm. Clay minerals mainly contribute to mesopores, especially in argillaceous mudstones. The dissolution of carbonate minerals and feldspars is significant for macropores predominantly in dolomitic mudstones and tuffaceous mudstones, respectively. Micron-scale microfractures associated with laminae dominate in dolomitic mudstones. Therefore, the dolomitic mudstones, especially with lamination, and tuffaceous mudstones are proposed to be favored shale lithofacies with great exploration potential in the Mahu Sag.

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“…The NMR method has been used in reservoir characterization since 1956 (Brown and Fatt, 1956). With the development of NMR instruments, NMR has been widely used to determine petrophysical properties and fluid characteristics in coal and shale (Liu et al, 2020;Zheng et al, 2020;Zhao et al, 2022). From Ea.…”

Section: Effectiveness Evaluation Of Shale Pore Detection By Multiple...mentioning

confidence: 99%

Qualitative–quantitative multiscale pore characteristics of black shale from the Upper Ordovician and Lower Silurian black shale in the Southern Sichuan Basin, China

et al. 2022

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Accurate investigation of shale pores is critical to the assessment of shale-gas reservoir properties. Qualitative and quantitative methods have been commonly conducted in shale pore studies. In this study, we take the black shale from the Upper Ordovician and Lower Silurian black shale in the Southern Sichuan Basin as an example. Both qualitative and quantitative methods were used to study the pores at multiple scales, and we discuss the effectiveness of shale pore detection by multiple methods. The following results were obtained: 1) The black shale is composed of quartz, feldsaper, calcite, dolomite and clay minerals in the study area, and its average TOC and porosity are 2.19 and 2.12%, respectively. 2) The CT results show that the pore size of macropores (pore size >0.5 μm) mainly ranges from 2 to 16 μm. Nitrogen adsorption analysis shows that organic-rich shale has abundant organic matter pores with narrow necks and wide bodies. The pores of organic-poor shale are mainly composed of mineral-associated pores with narrow slit shapes. The NMR results show that with increasing TOC, the left peak T2 relaxation times move leftwards, meaning that organic matter pores have a larger pore size than matrix pores at the mesopore scale. 3) CT data identify lamellation fractures and bed-cutting fractures, and their development is controlled by mineral type and content, TOC and laminae density. 4) The determination of segmentation thresholds in CT and transverse surface relaxivity in NMR seriously affects the accuracy of the results.

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Multi-scale pore structure characterization of lacustrine shale and its coupling relationship with material composition: An integrated study of multiple experiments

Cited by 41 publications

References 83 publications

Research Progress of Microscopic Pore–Throat Classification and Grading Evaluation of Shale Reservoirs: A Minireview

Research Progress of Microscopic Pore–Throat Classification and Grading Evaluation of Shale Reservoirs: A Minireview

Shale Lithofacies and Its Effect on Reservoir Formation in Lower Permian Alkaline Lacustrine Fengcheng Formation, Junggar Basin, NW China

Qualitative–quantitative multiscale pore characteristics of black shale from the Upper Ordovician and Lower Silurian black shale in the Southern Sichuan Basin, China

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