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Industrial heritage, recognized as a significant aspect of historical and cultural heritage, has garnered considerable attention from scholars globally. To elucidate the spatial morphological characteristics and the underlying influencing factors of industrial heritage within karst regions, this study employs methods such as the interstice index, fractal dimension analysis, and spatial syntax. It conducts research on the spatial morphological characteristics of nine typical industrial heritages in Guizhou Province. The primary factors contributing to the variations in layout forms are the intricate karst topography and the functional requirements of production. The functional zoning of industrial heritage aligns with its layout, characterized by straightforward functional zones that have not developed into composite spaces. The overall connectivity of industrial heritage is relatively low, exhibiting weak integration, significant disparities in control values, low average depth values, and a deficiency in comprehensibility and diversity of options. This indicates that the internal connectivity of industrial heritage spaces is generally inadequate, with low accessibility, strong interrelations, average convenience, limited connectivity, and generally acceptable passage. The overall spatial, architectural, and roadway configurations of industrial heritage predominantly exhibit a uniform pattern. Importantly, industrial heritage reveals a highly variable overall spatial form, with an average fractal dimension of 1.57, complex architectural layouts (average fractal dimension of 1.50), and simplistic road network designs (average fractal dimension of 1.43), which collectively suggest high spatial complexity and irregular characteristics. This study can provide a reference for the analysis of spatial characteristics and influencing factors of other material cultural heritages, and it is of great significance for the systematic protection and revitalization of industrial heritage. [ABSTRACT FROM AUTHOR]

From core observations of shales of the Niutitang formation in the northern part of Guizhou Province, China, calcite was often found to act as a natural fracture filler and affect the extension of fractures in hydraulic fracturing. Therefore, it is crucial to understand the tensile mechanical behavior of shales by calcite veins. In this paper, by computed tomography scanning of shales containing calcite veins of different dip angles from the Niutitang formation, a three‐dimensional numerical model reflecting the internal fine structure of the shale was constructed. Direct tensile numerical simulations were carried out to investigate the effect of calcite veins at different angles on the fine‐scale damage process and mechanical properties of shale. The experimental results show that the tensile capacity of the shale increases with the increase in calcite veins. Depending on the dip angle of the calcite vein, the damage pattern of the shale is divided into three types of damage: pull‐off damage along the calcite vein, jagged damage, and horizontal damage perpendicular to the loading method. At high dip angles, the shale damage is more intense and the fracture network more complex. The temporal and spatial characteristics of the acoustic emissions provide a good indication of the microscopic behavior of the shale specimens during the damage process. The box dimension method was used to calculate the fractal dimension of the shale specimens at the final damage, and it was found that the damage was more intense and the fracture network was more complex at high dip angles, and there was an angular threshold. [ABSTRACT FROM AUTHOR]

Understanding the formation mechanism of bed separation in coal seam mining under a karst landform is needed for the prevention and control of roof-separated water damage in such areas. This research used a mine in the northern Guizhou coalfield, China, as a case study, and applied theoretical analysis, numerical simulation, and on-site measurement to develop a circular cave structure model in a key stratum. The dynamic evolution of a separation bed was analyzed from several aspects, including the formation mechanism, development location, the mechanical condition of local karst caves, fracture evolution, and fractal rules. Verification using in situ measurements is presented for the case study mine, and a quantitative evaluation method for water inrush from bed separation and improved fusion weighting is proposed based on a cloud model. The research results indicate the following: (1) Tensile cracks are prone to occur above and below a karst cave, which produce an impact of connectivity on the separated space. (2) When the working face advances to 270 m in coal mining, longitudinal tensile cracks below the karst cave gradually increase and the width of the bed separation crack shrinks to 68.2 m, with a maximum separation layer height of 3.01 m. (3) Based on the cloud model and the improved weighted fusion method, the risk of water inrush in bed separation is judged as "high". The En of the cloud digital features is 0.0622 and the He is 0.0307, achieving a quantitative evaluation of water inrush in the separation layer that is consistent with on-site practice, and is highly stable and reliable. This study improves the understanding of the development pattern of bed separation and water inrush risk assessment in coal seam mining under a karst cave landform. [ABSTRACT FROM AUTHOR]

The pore structure of coal has a great influence on the exploitation of coalbed methane. The primary coal and tectonic coal of the Faer Coal Mine and Wenjiaba Coal Mine in Guizhou, China, were selected for low-temperature liquid nitrogen and high-pressure mercury injection experiments. Based on the Frenkel–Halsey–Hill fractal model and multifractal model, combined with nano-CT system, the difference between primary structural coal and tectonic coal and their relationships with fractal dimension were analyzed. According to the results, coal can increase its pore volume and surface area by tectonic action. From the perspective of pore volume and surface area, micropores occupy the main part. According to the pore volume and pore surface area of micropores, that of primary structural coal was lower than that of tectonic coal. For the studied coal samples, their pores have fractal characteristics and complex structure. It can be seen from the fractional dimension that that of tectonic coal was higher than that of primary structure coal, indicating that the microscopic pore structure of coal tends to be complex after tectonic action. According to the results of multifractal and nano-CT analysis, the Hausdorff dimension of tectonic coal was slightly smaller than that of primary structure coal, but the multifractal parameter value was higher than that of primary structure coal. After tectonic action, the connected pores of coal increased by 142.86% compared with the connected pores of primary coal, and the adsorption capacity was further improved. It is further proved that the structure can affect the adsorption and desorption capacity by changing the distribution of pore structure. [ABSTRACT FROM AUTHOR]

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The eastern Guizhou Pb–Zn metallogenic belt (EGMB) is an important source of Pb–Zn resources and other critical minerals (including dispersed metals, such as Ge, Cd and Ga) in China. In order to ensure the continuous resource supply of Pb–Zn and associated dispersed metals, it is urgent to explore the direction of further prospecting for them. Fractal theory can realize the fractal structure characterization of fault structures and the spatial distribution of mineral deposits, which is helpful for mineral exploration. However, the fault fractal research and prospecting application are still seldom covered in the EGMB. We used fractal theory to determine fine-scale fractal structure characteristics of fault structures and ore deposits in the EGMB, and Fry analysis to delineate favorable metallogenic areas. The results show that within a scale range of 3.670–58.716 km, the integrated faults capacity dimension (CPD) is 1.5095, the information dimension (IND) is 1.5391, and the correlation dimension (CRD) is 1.5436, indicating fault structures with high maturity, which are conducive to the migration and accumulation of ore-forming fluids. The multi-fractal spectrum width and height are 0.3203 and 1.5355, respectively, implying a significant metallogenic potential. The spatial distribution fractal dimensions (SDD) of Pb–Zn specifically and metal deposits in general are 1.0193 and 1.0709, respectively; the quantity distribution fractal dimensions (QDD) are 1.4225 and 1.4716, respectively, and the density distribution fractal dimensions (DDD) are 1.422 and 1.472, respectively, indicating strong clustering. Hence, the favorable metallogenic regions can be divided into four grades, among which grade I region is continuously distributed in space and has the greatest prospecting potential. [ABSTRACT FROM AUTHOR]

Coal is a complex, porous medium with pore structures of various sizes. Therefore, it is difficult to accurately describe the characteristics of pore structure by using the traditional geometry method. The results from the present investigation suggest that the porous media system of the coal reservoir has obvious fractal characteristics at different scales. To study the complexity of the pores in the coal reservoir, 27 coal samples from Guizhou, SW China were studied. The fractal dimensions of coal pores were calculated, and the fractal dimension of a pore in a coal reservoir can be classified into two types: percolation and diffusion. The comprehensive fractal dimension can be obtained using the weighted summation method and the pore volume fraction of different fractal segments as the weight. The percolation fractal dimensions (Dp) of coal samples are between 2.88 and 3.12, the diffusion fractal dimensions (Dd) are between 3.57 and 3.84, and the comprehensive fractal dimensions (Dt) are between 3.05 and 3.63. The Dd values of all coal samples are all larger than the Dp values, which indicates that the random distribution and complexity of diffusion pores in coal are stronger than those of the percolation pores. The percolation fractal dimension decreases as the maturity degree increases, whereas the diffusion and comprehensive fractal dimensions increase. The diffusion pore volume fraction and total pore volume are all highly correlated with the comprehensive and diffusion fractal dimensions, respectively. The correlation between the comprehensive fractal dimension, diffusion pore volume fraction, and coal reservoir porosity is negative exponential, whereas the correlation between the total pore volume and coal reservoir porosity is positive linear. In comparison with the percolation and diffusion fractal dimensions, the comprehensive fractal dimension is better suited for characterizing the permeability of coal reservoirs. The fractal analysis of this paper is beneficial for understanding the relationship between the fractal characteristics of coal pores and properties. [ABSTRACT FROM AUTHOR]

Rock fissures constitute the main habitat type in the karst rocky desertification (KRD) area, but the effects of their network morphology on soil properties remain unknown. To address this, we investigated 46 rock vertical profile plots in Guizhou Province of China and classified their habitats using the morphological characteristics of their fissure networks. The response characteristics of soil nutrients and enzyme activities to the rock fissure morphologies in different rock habitats were discussed, and the main factors affecting soil nutrients and enzyme activities were comprehensively analyzed. Rock fissure networks were divided into three types: Type 1, a random type, with a low dip angle, long trace length, multiple turns, multiple connections, and high density; Type 2, a uniform type, with a moderate dip angle, moderate trace length, fewer turns, fewer connections, and moderate density; and Type 3, an aggregation type, with a high dip angle, short trace length, fewer turns, moderate connections, and low density. Soil nutrient levels and enzyme activities were the highest in Type 1, followed by Types 2 and 3. There were no significant differences between the total phosphorus and available phosphorus content in Types 1–3. The dip angle, fractal dimension, and average trace length were identified as the main factors affecting soil nutrients and enzyme activities, and Type 1 was the most conducive for soil nutrient and enzyme accumulation. The restoration of Type 2 and 3 areas should be emphasized in future research, as these results will help guide vegetation restoration in KRD areas. [ABSTRACT FROM AUTHOR]

The karst landscape is widespread in the southern region of China. As a result of underground mining activities, the original stress equilibrium is disrupted, causing the redistribution of stress in the overlying rock layer, inducing the longitudinal fracture of mining to expand and penetrate upwards, resulting in the rupture and destabilization of the karst cave roof, thus triggering a series of engineering problems such as karst cave collapse, landslide, the discontinuous deformation of the ground surface, and soil erosion. In order to study the evolutionary characteristics of buried rock fissures in shallow coal seam mining under the karst landform, taking the shallow coal seam with the typical karst cave development landform in Guizhou as the engineering background, based on the similarity simulation experiment and fractal theory, the evolution law of buried rock fissures and network fractal characteristics under the disturbance of the karst landform mining are analyzed. The research shows that the mining-induced fracture reaches the maximum development height of 61 m on the left side of the cave, and the two sides of the cave produce uncoordinated deformation. The separation fracture below the cave is relatively developed, and the overall distribution pattern of the cave rock fracture network presents a "ladder" shape. The correlation coefficient of the fractal dimension of the rock fractures under different advancing distances is more than 0.90, and the rock fracture network under the karst landform has high self-similarity. The variation of fractal dimension with the advancing degree of the working face can be divided into four stages. The first and second stages show an exponential growth trend, and the third and fourth stages show linear changes with slopes of 0.0007 and 0.0014, respectively. The fluctuation of the fractal dimension is small. The periodic weighting of the upper roof in the cave-affected zone is frequent, the fragmentation of the fractured rock mass becomes larger, and the fractures of the upper rock mass are relatively developed. The research results can provide a reference for the study on the evolution law of mining-induced rock fissures under similar karst landforms. [ABSTRACT FROM AUTHOR]

The current paper studies the influencing factors of permeability in shales of the Longmaxi Formation, located in the southern Sichuan Basin, China. The methodologies used in the present study include overburden pore permeability experiments, whole rock analysis and geochemical tests, NMR measurements of fluid saturation, pore size distribution and specific surface area distribution, SEM and extraction of pore structure parameters, and core analysis. The results show the following: (1) high TOC and high maturity generate a large number of organic pores, which may improve the permeability of shale. (2) Mineral composition and rock relative permeability also have influence on permeability to a certain degree, since different minerals have different effects on shale permeability. Clay in the study area has an adverse effect on permeability. The results show that the organic-rich siliceous clay mixed shale facies in this area has the best permeability. (3) A large specific surface area and total pore volume are associated with good shale permeability, while average pore size does not correlate with permeability. A small fractal dimension of pore morphology and simple pore structure result in good permeability, and bedding is the key controlling factor for the anisotropy of shale permeability. (4) Water in shales can influence the permeability of microfractures by binding to clay minerals. Low permeability in shales with high bound water saturation suggests that water and clay mineral absorption may block flow channels, resulting in poor permeability. The purpose of this study is to clarify the influencing factors on shale permeability of the Longmaxi Formation in the study area and to provide a reference for the exploration and development of shale gas in this area of the Sichuan Basin. [ABSTRACT FROM AUTHOR]

The occurrence and migration of coalbed methane (CBM) is inseparably associated with the pore structure within the coal seams. Three Permian Longtan Formation tectonic coal samples (QL, XL, XT) from Guizhou Province were studied to determine pore size distribution and characteristics, as well as factors that influence adsorption. Adsorption test results show that all samples generally have "ink bottle"-type pores, with large pore capacity but poor connectivity. Furthermore, the fractal dimension Df, the tortuosity "τ", and tortuous fractal dimension DT of samples were calculated. Among the studied tectonic coals, moisture, ash, tortuosity, and volatile fraction have a positive effect on the maximum adsorption capacity (VL), whereas intact coals' tortuosity volatile has a negative correlation with the maximum adsorption capacity (VL). [ABSTRACT FROM AUTHOR]

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To reveal the effect of confining pressure on the mechanical properties and rupture modes of quartz-bearing shale, the shale core of the no. 3 block of Fenggang, Guizhou Province, China, was analyzed by nuclear magnetic resonance, polarized light microscope thin section observation and identification, and core X-ray whole-rock minerals diffraction analysis to determine the distribution of shale minerals in the Niutitang Formation. On the microscale, based on digital image processing technology, this paper characterizes the nonuniformity of minerals in shale, a numerical model that can reflect the true microstructure of shale. Then, the failure process of shale under different confining pressures was simulated. The results show that when the shale is loaded with vertical displacement under different confining pressures, the compressive strength and elastic modulus of the sample change significantly. The failure mode can be roughly divided into three types: the inverted V-shaped (0 MPa, 2 MPa, and 4 MPa), V-shaped (6 MPa and 8 MPa), and inverted Z-shaped (10 MPa). Since the development of fractal theory provides a new space for studying the damage and fracture of rocks, the damage evolution and failure process of shale can also be regarded as the fractal process of cracks, in which the fractal dimension is the core parameter. The calculation is different under different stress levels. The fractal dimension under the condition of confining pressure shows that the value of the fractal dimension is greatly affected by the effect of confining pressure. When the fractal dimension is higher, the fracture mode is more complicated, and the internal damage degree is more serious. The research results provide important theoretical guidance for shale gas fracturing production. [ABSTRACT FROM AUTHOR]

Copyright of Natural Gas Geoscience is the property of Natural Gas Geoscience and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The pore structure of marine-continental transitional shales from the Longtan Formation in Guizhou, China, was investigated using fractal dimensions calculated by the FHH (Frenkel-Halsey-Hill) model based on low-temperature N2 adsorption data. Results show that the overall D 1 (fractal dimension under low relative pressure, P / P 0 ≤ 0.5) and D 2 (fractal dimension under high relative pressure, P / P 0 > 0.5) values of Longtan shales were relatively large, with average values of 2.7426 and 2.7838, respectively, indicating a strong adsorption and storage capacity and complex pore structure. The correlation analysis of fractal dimensions with specific surface area, average pore size, and maximum gas absorption volume indicates that D 1 can comprehensively characterize the adsorption and storage capacity of shales, while D 2 can effectively characterize the pore structure complexity. Further correlation among pore fractal dimension, shale organic geochemical parameters, and mineral composition parameters shows that there is a significant positive correlation between fractal dimensions and organic matter abundance as well as a complex correlation between fractal dimension and organic matter maturity. Fractal dimensions increase with an increase in clay mineral content and pyrite content but decrease with an increase in quartz content. Considering the actual geological evaluation and shale gas exploitation characteristics, a lower limit for D 1 and upper limit for D 2 should be set as evaluation criteria for favorable reservoirs. Combined with the shale gas-bearing property test results of Longtan shales in Guizhou, the favorable reservoir evaluation criteria are set as D 1 ≥ 2.60 and D 2 ≤ 2.85. When D 1 is less than 2.60, the storage capacity of the shales is insufficient. When D 2 is greater than 2.85, the shale pore structure is too complicated, resulting in poor permeability and difficult exploitation. [ABSTRACT FROM AUTHOR]

In this paper, the heterogeneity of adsorption pores in middle and high rank coal samples were analyzed by using low temperature N2 and CO2 adsorption technology and fractal theory. The following results were achieved. 1) According to the results of volume and surface fractal dimension, meso‐pores can be classified into Mep‐1, Mep‐2, and Mep‐3, respectively. Micro‐pore can be classified into Mip‐1, Mip‐2, and Mip‐3, respectively. 2) Pore types play an important role in affecting the heterogeneity of meso‐pores. The volume heterogeneity (VHY) of Mep‐1 is simpler than that of Mep‐2 and Mep‐3 in type A samples. However, the VHY of Mep‐1 becomes gradually larger than that of Mep‐2 and Mep‐3 from type A to type B and C. The VHY of open pore in the same diameter is higher than that of semi‐open or closed pore. Meanwhile, the surface heterogeneity (SHY) of types A and B samples is significantly larger than that of type C, the SHY of semi‐open or closed pores is more complicated than that of open pores. 3) Coal rank mainly affects the heterogeneity of micro‐pores. The heterogeneity of type A is always smaller than that of type B and C. The VHY of Mip‐1 is more complicated than that of Mip‐2 and Mip‐3 in the same samples, and the sensitivity of the VHY of Mip‐1 and Mip‐2 to the degree of coal rank is smaller than that of Mip‐3. Meanwhile, the SHY of Mip‐1 and Mip‐2 is simpler than that of Mip‐3 in the same sample, the SHY of micro‐pores remains stable as the pore size decreases, and the affect of coalification level on SHY decreases with the decrease in pore diameter. Full‐scale fractal characterization has enabled quantitative characterization of adsorption pore properties and provided useful information with regards to the similarity of pore features in different coal reservoirs. [ABSTRACT FROM AUTHOR]

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Organic-rich shale samples from marine-continental transitional facies of the Late Permian Longtan Formation in southwestern Guizhou were investigated using organic petrography analysis, X-ray diffraction analysis, mercury intrusion capillary pressure experiments, gas adsorption experiments, nuclear magnetic resonance, scanning electron microscopy image analysis, and multi-fractal theory to quantitatively and qualitatively investigate the full-size pore structure and fractal characteristics of the shale. The correlations among the total organic carbon (TOC) content, mineral composition, and pore structure were discussed. The fractal dimension was used to evaluate the production potential of a shale reservoir. Results show that samples have a high TOC content (4.38 wt % on average), low permeability (less than 0.001 mD), and complex pore structure. The pore volume (PV) varies from 0.001997 cm3/g to 0.03653 cm3/g, with an average of 0.02864 cm3/g, and the specific surface area (SSA) varies from 14.144 m2/g to 29.740 m2/g, with an average of 21.533 m2/g. Mesopores (diameter between 2 and 50 nm according to IUPAC) are the predominant contributors to the pore volume, while mesopores and micropores (diameter less than 2 nm) are the main contributors to the specific surface area. The shale samples with higher TOC and clay mineral content have larger PVs and SSAs and higher fractal dimensions than those that do not. A high fractal dimension indicates a rough pore surface and complicated pore structure. Shale with higher D 1 and D A (representing the pore surface roughness and the adsorption space, respectively) has high adsorption capacity and favors gas accumulation, while shale with higher D 2 and D S (representing the pore structure complexity and the seepage space, respectively) has greater flow capability and favors gas diffusion. • Quantitative methods were combined with qualitative methods in this study to investigate the full-size pore structure characteristics of marine-continental transitional shale. • The fractal characteristics of transitional Longtan shale were investigated using multi-fractal concept and different experiments. • The fractal dimension was used to evaluate the production potential of shale reservoir. [ABSTRACT FROM AUTHOR]

[Display omitted] • A fractal dimension calculation program based on the Matlab platform was developed to perform a fractal analysis of the gold concentration values (g/t). • Fractal dimension can be used to better constrain possible ore-bearing fluid flow paths. • Realized the quantitative description of the spatial variation characteristics of ore-forming elements. • The fractal dimension gradient plays a significant role as a spatial proxy to locate the potential economic gold deposits. • The mechanisms of dispersion and aggregation as well as the spatial and temporal distribution patterns of mineralised elements during the formation and evolution of the mineralised system are revealed. The spatial distribution of ore-forming element grades typically exhibits strong nonlinear characteristics as a result of continuous geological processes. The trend of change in ore grade sequences is a crucial indicator of the degree of enrichment of an ore deposit. Therefore, quantitative evaluation of the spatial distribution of ore-forming elements holds great significance for understanding ore-forming processes as well as for ore exploration. In this work, based on the principles of fractal theory, a MATLAB-based program to calculate fractal dimensions was developed, and fractal analysis was conducted on the gold concentration values (g/t) of 25 drill holes in the Lannigou Gold Mining Area, Guizhou, China. Rescaled range analysis and the fractal correlation integral were utilized to obtain the spatial distribution of gold concentrations in the drill holes. Rescaled range analysis revealed that the Hurst exponent (H R/S) values vary in the range of 0.58–0.97, which reflected the persistent behavior of vertical variation in gold tonnage at the studied wells. Furthermore, the relationship between gold grade distribution and associated fluctuations in the fractal dimension derived from the correlation dimension (D C) was discussed. The D C value was found to vary between 1.01 and 1.59, indicating that high-grade gold deposits were distributed along steep fractal gradients and that fractal dimension values could be used as a reliable proxy to efficiently understand the migration pathways of auriferous fluid. Studies have shown that the Hurst exponent of the Au grade sequence exhibited a strong dependence on the grade of mineralization, with gold mineralized veins persisting throughout the studied drill holes. Thus, fractal dimension gradients can serve as an important proxy for identifying the locations of potential economic gold deposits in unexplored areas. Moreover, this approach can be employed to map the distribution patterns of other types of ore deposits. [ABSTRACT FROM AUTHOR]

Shale pore heterogeneity (as described by the fractal dimension) may influence the shale gas-bearing property (GBP). Previous studies on the fractal dimension and its influence on shale GBP were mainly focused on the dry shale samples. Our study investigates the pore structure characteristics under both the dry and moist conditions utilizing low-pressure N 2 /CO 2 adsorption experiments, water-bearing property, and GBP on the eleven as-received (moist) marine Longmaxi shale sampled from the XK3 well in northern Guizhou. Moreover, the fractal dimensions D1 (P/P 0 : 0–0.5) and D2 (P/P 0 : 0.5–1.0) for the dry and moist shales were determined respectively, using low-pressure N 2 adsorption data based on the Frenkel-Halsey-Hill (FHH) method. The results show that the ranges of D1 and D2 for the dry shales are 2.5759–2.7387 and 2.7681–2.8756, respectively, with averages of 2.6970 and 2.8470, while those for the moist shales are 2.0879–2.2215 and 2.6190–2.7252 respectively (averages 2.1591 and 2.6903). Shale water occurs mainly on nonmicropores (>2 nm) surfaces, and part of water fills the micropores (<2 nm), which reduces the nonmicropores BET specific surface area (S BET), micropore volume (V mic), and pore size distribution (PSD) and increases the average pore size (APS), thus reducing the D1 and D2 (19.94 and 5.50% on average, respectively). The shales have high gas contents with an average of 2.59 m3/t, which is dominated by adsorbed gas (75.21% on average). Compared with D2, D1 is more suitable for indicating the pore heterogeneity (especially nonmicropores surface heterogeneity) and shows stronger positive linear relationships with the shale GBP, implying that a larger pore surface heterogeneity is favorable for gas adsorption. Water mainly occurs in the clay minerals and reduces the D1 of the clay pores, thus the TOC content controls the D1 and shale GBP. • Calculation of fractal dimensions (D1 and D2) for both the dry and moist shales. • Water reduces the heterogeneity of the shale effective pore. • D1 relates more closely to shale heterogeneity and gas-bearing property than D2. • TOC content controls the D1 and shale gas-bearing property. [ABSTRACT FROM AUTHOR]

Suitable soil structure and nutrient security are important for plant growth and development. The fractal dimension of soil, along with the distribution of physical and chemical properties and their interactions, plays an important role in studying the stability of soil structures and water and fertilizer cycles. As a sustainable management model, intercropping has positive benefits for erosion control, the spatial optimization of resources, and improving system productivity. The effects of four intercropping methods on the fractal dimension and physicochemical properties of soil were investigated by intercropping Salvia miltiorrhiza with forage and S. miltiorrhiza with forest under typical karst rock desertification habitats in Guizhou. The results showed that the soil nutrient content when intercropping was significantly higher than that of monoculture. The organic carbon content of soil grown under forest is higher than other treatments, and there was a non-significant change in soil water content when intercropping compared with monoculture. The soil fine-grained matter when intercropping was significantly higher than that of monoculture, while the soil fractal dimension showed a tendency to become larger with an increase in fine-grained matter. Intercropping planting, due to its component types and spatial and temporal configurations, leads to differences in soil water and fertilizer interactions, which can be combined with other ecological restoration measures to optimize the composite model and jointly promote the restoration and development of ecologically fragile areas. [ABSTRACT FROM AUTHOR]

To explore the influence of brittle mineral composition and morphological characteristics within the shale matrix on the generation of complex fractures and reservoir reconstruction, the microstructure and fractal characteristics of minerals within the shale matrix of the Lower Cambrian Niutitang formation in northern Guizhou were investigated using X-ray diffraction (XRD), scanning electron microscopy with energy dispersive spectrometer (SEM-EDS), and micro-computed tomography (Micro-CT). Based on image processing technology and digital core modelling, a three-dimensional shale digital core model was established. The distribution and morphological characteristics of brittle minerals within the shale matrix were studied from the fractal perspective. The model for evaluating the mineral particles and pores within the shale matrix was established. The results show that the siliceous mineral composition is high, and it is mainly derived from the interaction of continental detrital quartz particles and biogenetic effects; the density of the brittle minerals is greater than other mineral components mainly distributed in the range of equivalent diameters of 200–800 μm; the distribution complexity of the brittle minerals was quantitatively analysed from the fractal perspective; the fractal dimension partly reflects the generating ability of complex fractures; the distribution angle and complexity of brittle mineral particles within the shale matrix partly determine the fracture morphology characteristics. The physical properties of shale reservoirs were studied from three aspects: complex fracture generation ability, pore connectivity and heterogeneity, and the evaluation model of mineral particles and pores was established using the value of fractal dimension, ratio of organic matter pores, tortuosity of pores, relative deviation of pore size distribution, and relative deviation of specific surface area. The model provides a basis for further study on the relationship between reservoir reconstruction potential and physical properties of shale reservoirs. • Distribution features of brittle mineral in shale was studied by fractal perspective. • The fracture generation ability with distribution of brittle mineral was studied. • The evaluation model of mineral particles and pores was established. [ABSTRACT FROM AUTHOR]