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Fluid components in cores are crucial parameters in evaluating the quality of a shale reservoir in both laboratory analyses and log interpretation. In the Gulong area, shale reservoirs are characterized by a high clay content, with clay spaces hosting both oil and water phases, complicating the occurrence mechanism of fluid components, as a result, traditional research methods are no longer applicable. As an advanced technique, nuclear magnetic resonance (NMR) has been applied in oilfields to determine the specific petrophysical properties of rocks. To more accurately identify the types of fluid components, this study carried out a new, well-designed 2D NMR experiment, rock pyrolysis experiment, and quantitative oil and water detection experiment (QOWDE) to study the Gulong shale. This study measured the 2D NMR map of the original state, saturation state, centrifugal state, and pyrolysis at different temperatures, and conducted mutual verification between the QOWDE and 2D NMR pyrolysis experiments to obtain the distribution of different components of Gulong shale on the 2D NMR map. Based on the experimental results, this study developed a component identification template suitable for the Gulong area and calculated the 2D NMR porosity and saturation from it. This lays a foundation for the analysis and application of fluid components in the Gulong region and provides a new experimental basis and methodological support for porosity and saturation calculations. [ABSTRACT FROM AUTHOR]

The lithofacies analysis of logging data is an essential step in reservoir evaluation. Multiresolution graph-based clustering (MRGC) is a commonly used methodology that provides information on the best number of clusters and cluster fitting results for geological understanding. However, the cluster fusion approach of MRGC often leads to an overemphasis of the boundary constraints among clusters. MRGC neglects the global cluster distribution relationship, which limits its practical application effectiveness. This paper proposes a new methodology, named kernel multiresolution graph-based clustering (KMRGC), to improve the merging part of clustering in MRGC, and it can give more weight to the spatial relationship characteristics among clusters. The clustering performance of K-means, Gaussian Mixture Model(GMM), fuzzy c-means(FCM), Density-Based Spatial Clustering of Applications with Noise(DBSCN), spectral clustering, MRGC and KMRGC algorithm was evaluated on a publicly available training set and noisy dataset, and the best results in terms of the adjusted Rand coefficients and normalized mutual information(NMI) coefficients on most of the datasets were obtained using KMRGC algorithm. Finally, KMRGC was used for logging data lithofacies clustering in cased wells, and the clustering effect of KMRGC algorithm was much better than that of the K-means, GMM, FCM, DBSCN, spectral clustering and MRGC algorithms, and the accuracy and stability were better. [ABSTRACT FROM AUTHOR]

Addressing the poor performance of existing logging saturation models in low-permeability tight sandstone reservoirs and the challenges in determining model parameters, this study investigates the pore structure and fluid occurrence state of such reservoirs through petrophysical experiments and digital rock visualization simulations. The aim is to uncover new insights into fluid occurrence state and electrical conduction properties and subsequently develop a low-permeability tight sandstone reservoir saturation model with easily determinable parameters. This model is suitable for practical oilfield exploration and development applications with high evaluation accuracy. The research findings reveal that such reservoirs comprise three types of formation water: strongly bound water, weakly bound water, and free water. These types are found in non-connected micropores, poorly connected mesopores where fluid flow occurs when the pressure differential exceeds the critical value, and well-connected macropores. Furthermore, the three types of formation water demonstrate variations in their electrical conduction contributions. By inversely solving rock electrical experiment data, it was determined that for a single sample, the overall cementation index is the highest, followed by the cementation index of pore throats containing strongly bound water, and the lowest for the pore throats with free water. Building on the aforementioned insights, this study develops a parallel electrical pore cementation index term, ϕm′, to account for the differences among the three types of water and introduces a parallel electrical saturation model suitable for logging evaluation of low-permeability tight oil and gas reservoirs. This model demonstrated positive application effects in the logging evaluation of low-permeability tight gas reservoirs in a specific basin in the Chinese offshore area, thereby confirming the advantages of its application. [ABSTRACT FROM AUTHOR]

Introduction: This study investigates the key controlling factors of the occurrence state of deep coalbed methane (CBM). CBM is an abundant energy resource in China, particularly in deep coal seams. However, the exploration and development of deep CBM face numerous challenges, and the understanding of the controlling factors of its occurrence state is still limited. Methods: The study reveals that deep CBM primarily exists in the form of adsorbed gas and free gas within the pore-fracture system of coal. Factors such as formation temperature, formation pressure, pore structure, and water saturation collectively influence the occurrence state of deep CBM. By employing the Simplified Local Density (SLD) model and molecular simulation methods. Results and discussion: This study examines the impact of two external geological control factors (formation temperature, formation pressure) and three internal geological control factors (pore size, water saturation, Specific surface area) on deep CBM and establishes a theoretical model for gas content. Finally, the relationship between the adsorbed gas, free gas, total gas content, and burial depth is calculated using the model, uncovering the primary factors controlling the occurrence state of deep CBM. This research is of significant importance in providing key parameters for gas content in deep coal and optimizing deep CBM exploration. [ABSTRACT FROM AUTHOR]

Digital rock physics (DRP) is important for characterizing the pore characteristics and petrophysical parameters of rocks from a microscopic perspective. Among the digital rock reconstruction methods, the most widely used is the computer tomography (CT) scan method. However, the pore structure of rocks has multiscale features, and CT scan images with a single resolution cannot completely describe the pore structure characteristics of rocks. In this paper, we analysed reconstructed multisource and multiscale 3-D digital rocks based on the cycle-consistent generative adversarial network (CycleGAN) method. This method fully integrates the advantages of the large field of view of low-resolution images and the high-precision features of high-resolution images. To investigate the performance of the method, two sequences of CT scan images of a sandstone (sample A) and a carbonate rock (sample B) collected from oilfields were studied. Moreover, due to the high resolution of scanning electron microscope (SEM) images, we also constructed 3-D digital rocks with different resolutions of the Berea sandstone based on the combination of CT scan images and SEM images. Finally, the statistical properties and absolute permeabilities were calculated to evaluate the accuracies of reconstructed multisource and multiscale 3-D digital rocks. The results show that the reconstructed multiscale digital rocks based on the CycleGAN method have good accuracy in terms of statistical properties and petrophysical properties. Considering the computational cost and computational accuracy, for high- and low-resolution CT scan images and CT scan images with SEM images as training image data sources, we suggest that the resolution of the reconstructed multiscale digital cores is 4–8 times and 4–16 times higher than that of the low-resolution CT scan images, respectively. The findings of our research will be helpful in gaining insight into the petrophysical properties of heterogeneous rocks. [ABSTRACT FROM AUTHOR]

This paper presents an integrated study from fracture propagation modeling to gas flow modeling and a correlation analysis to explore the key controlling factors of intensive volume fracturing. The fracture propagation model takes into account the interaction between hydraulic fracture and natural fracture by means of the displacement discontinuity method (DDM) and the Picard iterative method. The shale gas flow considers multiple transport mechanisms, and the flow in the fracture network is handled by the embedded discrete fracture model (EDFM). A series of numerical simulations are conducted to analyze the effects of the cluster number, stage spacing, stress difference coefficient, and natural fracture distribution on the stimulated fracture area, fractal dimension, and cumulative gas production, and their correlation coefficients are obtained. The results show that the most influential factors to the stimulated fracture area are the stress difference ratio, stage spacing, and natural fracture density, while those to the cumulative gas production are the stress difference ratio, natural fracture density, and cluster number. This indicates that the stress condition dominates the gas production, and employing intensive volume fracturing (by properly increasing the cluster number) is beneficial for improving the final cumulative gas production. [ABSTRACT FROM AUTHOR]

Gas-bearing capacity is an important feature in the evaluation of the different properties of shale. The calculation of adsorbed gas and free gas content is the focus of the shale gas-bearing capacity evaluation, for which gas saturation is a key parameter. In the present study, the target area was the marine shales of the Wufeng–Longmaxi Formation in the Dingshan, Jiaoshiba, and Changning areas of the southern Sichuan Basin in China, while the purpose of the study was the more effective characterization of Langmuir's volume and Langmuir's pressure using well-logging data. The application of new well-logging technologies in the evaluation of shale gas-bearing capacity is seldom studied, and the conventional sand-mudstone saturation models calculate the shale gas-bearing capacity with low accuracy. Therefore, this study systematically analyzed the shale conductivity mechanism, which laid the foundation for a new calculation model for shale gas saturation. The analysis results of the influencing factors of shale conductivity in the study area showed that the resistivity of shale in the interlayer is mainly affected by the thin low-resistivity layers, and the resistivity of shale in laminates is affected by clay minerals, pyrite, overmature conductive organic matter, and pore fluids. Moreover, this study further clarified the main controlling factors of the conductivity mechanism by implementing a multiscale analysis. Herein, on the meter-scale, the influence of thin low-resistivity layers on the shale resistivity was characterized based on a horizontal resistivity model; on the centimeter-scale, the influence of pore fluids on shale resistivity was investigated based on the rock electrical experiments; and on the nanometer-scale, the influence of clay minerals, pyrite, and organic materials on shale resistivity was examined based on digital rock technology and numerical simulation of the electrical properties. The results showed that the factors affecting the conductivity of the shale, from the strongest to the weakest, are conductive organic matter, thin low-resistivity layer, clay mineral, pore water, and pyrite, respectively. [ABSTRACT FROM AUTHOR]

The Muli area has dense lithology, high hardness, poor porosity and permeability, and well-developed micro-fractures, which is different from other gas hydrate regions with unconsolidated sediment characteristics. With the gradual deepening of gas hydrate scientific research in the Muli area, some unique low-resistivity gas hydrate phenomena have been discovered. The understanding of the genesis mechanism of low-resistivity gas hydrate is not clear, which makes it difficult to identify gas hydrate layers and adversely affects the evaluation of reservoir parameters and reserves prediction. In this investigation, the well logging response law of pore-filling and fracture-filling gas hydrate reservoirs is systematically combined and the associated reservoir characteristics relationships are evaluated as a function of lithology, physical properties, reservoir space, gas hydrate and fluid distribution characteristics. Then, the correlation between cementation index and pore structure complexity index was fitted. Finally, a new gas hydrate saturation calculation model is proposed. The results show that the new saturation calculation model is in good agreement with the well logging interpretation of gas hydrate, which can identify low-resistivity gas hydrate effectively. The results of this study thus assist in terms of reliable gas hydrate exploration in the Muli area. [ABSTRACT FROM AUTHOR]

Analyzing the petrophysical properties of gas hydrate reservoirs under different conditions by experimental methods is time-consuming, costly, and very difficult. Therefore, it is of great practical significance to accurately reconstruct gas hydrate digital rocks using numerical simulation methods. In this study, based on in situ observations of gas hydrate pore habits and variation laws in the laboratory, a hybrid method was adopted to simulate pore-scale spatial distribution characteristics of gas hydrate using a digital rock model. The hybrid method combined classical nucleation theory, the diffusion-limited aggregation model, and the cluster-cluster aggregation model. Then, the pore size distribution, local porosity distribution, and average seepage probability distribution of gas hydrate digital rock and gas hydrate–bearing sediments were calculated and compared. In addition, the finite-element method was used to simulate and compare the reconstructed digital rock's resistivity index and elastic modulus. The results showed that the hybrid method can effectively simulate the spatial distribution characteristics and variation laws of gas hydrate on the pore scale. In addition, the resistivity index and elastic modulus of the reconstructed gas hydrate digital rock were relatively close to those of gas hydrate–bearing sediments. However, compared with gas hydrate–bearing sediments, the average pore size of the reconstructed gas hydrate digital rock was smaller, and the pore connectivity showed a slight amount of difference. In summary, this investigation was of great significance in systematically studying the petrophysical properties of gas hydrate reservoirs. [ABSTRACT FROM AUTHOR]

Fault zone refers to the fracture zone in the stratum, which is of great significance to the migration and accumulation of hydrocarbons. Each fault zone has a unique, complex structure. Hence, the hydrocarbons migrate and accumulate differently from fault zone to fault zone. The accurate division of fault zone structure is critical to understanding fault-controlled hydrocarbon reservoirs. Currently, the fault zone structure is often roughly identified by logging, based on a summary of fuzzy response modes. The innovation of this paper lies in the following: according to the macro- and micro-characteristics of structural units with different lithology, different logging responses, and core data in Jiyang Depression, a fault zone structure identification method based on wavelet attributes of logging data is proposed. Through multi-scale processing, the proposed method reconstructs and highlights the high-frequency information of curve fluctuations on the appropriate scale, enabling the accurate identification of fracture development intervals. Taking Che-57 well which passes through fault zone in Jiyang Depression of Shengli Oilfield as an example, the structure of fault zone is identified by wavelet attribute. The results show that the three porosity wavelet attributes could accurately characterize the structure of the fault zone; the sliding fracture zone has a low frequency and a low amplitude; the induced fracture zone has a high frequency and a high amplitude; the density and acoustic wavelet attribute are more sensitive than the electrical curve. The research results shed new light on the identification of fault zone structure in carbonate stratum. [ABSTRACT FROM AUTHOR]

Existing saturation models cannot effectively describe the specific fractured-vuggy carbonate reservoir in area A of the Sichuan Basin, southwestern China. This reservoir has got a wide pore size distribution, strong heterogeneity, high gas saturation and complex electrical conductivity mechanism. Hence, the present study attempted to establish a new saturation calculation equation for this carbonate reservoir based on the microscopic conductivity mechanism of the rock. Here, we first used the multiscale computed tomography (CT) scanning method to build multiscale digital rocks. Subsequently, we applied the maximum sphere algorithm to extract the pore space structure and constructed the multiscale pore network models. By using the cross-scale fusion method, four different pore configurations were determined. Then, the percolation theory was implemented to simulate the conductivity mechanism of the constructed pore network models. As a result, the fluid distribution characteristics and the resistivity variation trends of the different pore structures were obtained. The simulation results showed that the fracture system of the studied reservoir had a much greater effect than the vug system on the carbonate rock's electrical conductivity, and the conductivity was closely related to the fluid distribution. In addition, based on the simulation results, a new conductivity model was proposed that incorporates the coupling phenomenon of pores, vugs and fractures; and also a new saturation calculation equation for triple-porosity media was established. The observations indicated that the field application of the proposed equation had an acceptable performance with an error value of less than 2.56%. The results from the present study provide new insights into the evolution of electrical properties in triple-porosity carbonate systems. [ABSTRACT FROM AUTHOR]

Pressure dependency of seismic properties of porous rocks is important for a range of geophysical applications. Recently, a theoretical model has been developed to interpret the pressure and frequency dependent squirt-flow attenuation in fluid saturated porous rocks based on the dual porosity concept. We implemented laboratory measurements of dry rock porosity and ultrasonic (compressional and shear wave) velocity and saturated rock velocity and attenuation on two sandstone samples with varying confining pressures from 5 to 60 MPa to test the pressure dependent attenuation of the squirt-flow model. Based on the experimental data, the pressure dependent compliant and stiff porosity were obtained by fitting the dual porosity model to the measured variation of total porosity with pressure, and the compliant pore aspect ratio was estimated as a free parameter to make the model predicted velocity of the saturated rocks best fit their laboratory data. Comparison of the modelled attenuation with the measured variation of attenuation with pressure showed that the squirt-flow attenuation is consistent with the measurement at low-pressure regime but underestimates the experimental data when the confining pressure becomes higher. The results confirm the validation of the squirt-flow model to explain the attenuation at low pressures and suggest the requirement of the combination with other theoretical models to fully interpret the attenuation at high confining pressures. [ABSTRACT FROM AUTHOR]

Core samples of the tight sandstone reservoir in the Bonan Oilfield were analyzed by using multiple petrophysical experimental techniques, then a multi-scale three-dimensional digital rock model was constructed. The pore structure parameters of tight sandstone and homogeneous Berea sandstone were compared. The electrical simulation method based on the digital rock model was utilized to quantitatively reveal the influence of five micro-pore structure parameters (pore size, throat size, pore-throat size, coordination number, and shape factor) on the rock's electrical properties. In addition, the saturation of tight sandstone reservoirs was evaluated in combination with the three-component automatic mixed-connection conductivity model. The results show that the "non-Archie" phenomenon in sandstone is obvious, which is mainly caused by the small radius of the maximum connected pore throat and the complex structure of the pore throat. We noted that: with an increase in pore radius, throat radius, and coordination number, the formation factor decreases and tends to be stable; the pore-throat size increases and the formation factor decreases in the form of power function; the shape factor increases, and the formation factor increases; the larger the pore–throat ratio and shape factor, the greater the resistivity index; with an increase in coordination number, the resistivity index decreases; and the pore-throat size has no effect on the resistivity index. The calculation accuracy of oil saturation is improved by 6.54% by constructing the three-component automatic mixed-conductivity saturation model of tight sandstone. [ABSTRACT FROM AUTHOR]

The binding energy of a hydrogenic donor impurity in a zinc-blende GaN/AlGaN cylindrical quantum well wire (QWW) is calculated in the framework of effective-mass envelope-function theory using the plane wave basis. It is shown that the donor binding energy is highly dependent on the impurity position, the radius of the wire and the external electric field. In addition, Stark shift dependence on the radius of the QWW and the external electric field is also calculated. The donor binding energy has a maximum when the impurity is located at the center of the QWW. The donor binding energy decreases with the increase of the external electric field, but stark shift increases with the increase of the external electric field or the radius of the QWW. [ABSTRACT FROM AUTHOR]

A 3-D digital core describes the pore space microstructure of rocks. An X-ray micro CT scan is the most accurate and direct but costly method to obtain a 3-D digital core. In this study, we propose a hybrid method which combines sedimentation simulation and simulated annealing (SA) method to generate 3-D digital cores based on 2-D images of rocks. The method starts with the sedimentation simulation to build a 3-D digital core, which is the initial configuration for the SA method. We update the initial digital core using the SA method to match the auto-correlation function of the 2-D rock image and eventually build the final 3-D digital core. Compared with the typical SA method, the hybrid method has significantly reduced the computation time. Local porosity theory is applied to quantitatively compare the reconstructed 3-D digital cores with the X-ray micro CT 3-D images. The results indicate that the 3-D digital cores reconstructed by the hybrid method have homogeneity and geometric connectivity similar to those of the X-ray micro CT image. The formation factors and permeabilities of the reconstructed 3-D digital cores are estimated using the finite element method (FEM) and lattice Boltzmann method (LBM), respectively. The simulated results are in good agreement with the experimental measurements. Comparison of the simulation results suggests that the digital cores reconstructed by the hybrid method more closely reflect the true transport properties than the typical SA method alone. [ABSTRACT FROM AUTHOR]

In this paper, we obtained three dimensional digital cores using X-ray CT to describe the rock microstructure and applied the open morphology algorithm to simulate oil and formation water distribution in the pore space at different water saturations during the oil-displacing water flood process. The resistivity, formation factor, and resistivity index of rocks were calculated using the finite element method (FEM) and we studied the effect of rock wettability on electrical properties. The numerical simulation results indicate that the simulated formation factor and resistivity index of the water wet rock agrees well with experiments over the whole range of water saturation and extends the traditional resistivity experiment. The rock wettablilty has a large influence on the rock resistivity index. The resistivity and saturation exponent of oil wet rock are obviously larger than three of water wet rock. [ABSTRACT FROM AUTHOR]

Based on the percolation network model characterizing reservoir rock’s pore structure and fluid characteristics, this paper qualitatively studies the effects of pore size, pore shape, pore connectivity, and the amount of micropores on the I-S w curve using numerical modeling. The effects of formation water salinity on the electrical resistivity of the rock are discussed. Then the relative magnitudes of the different influencing factors are discussed. The effects of the different factors on the I-S w curve are analyzed by fitting simulation results. The results show that the connectivity of the void spaces and the amount of micropores have a large effect on the I-S w curve, while the other factors have little effect. The formation water salinity has a large effect on the absolute resistivity values. The non-Archie phenomenon is prevalent, which is remarkable in rocks with low permeability. [ABSTRACT FROM AUTHOR]

The oil-based mud filtrate will invade the formation under the overbalanced pressure during drilling operations. As a result, alterations will occur to the nuclear magnetic resonance (NMR) response characteristics of the original formation, causing the relaxation time of the NMR T2 spectrum of the free fluid part to move towards a slower relaxation time. Consequently, the subsequent interpretation and petrophysical evaluation will be heavily impacted. Therefore, the actual measured T2 spectrum needs to be corrected for invasion. For this reason, considering the low-porosity and low-permeability of sandstone gas formations in the East China Sea as the research object, a new method to correct the incorrect shape of the NMR logging T2 spectrum was proposed in three main steps. First, the differences in the morphology of the NMR logging T2 spectrum between oil-based mud wells and water-based mud wells in adjacent wells were analyzed based on the NMR relaxation mechanism. Second, rocks were divided into four categories according to the pore structure, and the NMR logging T2 spectrum was extracted using the multidimensional matrix method to establish the T2 spectrum of water-based mud wells and oil-based mud wells. Finally, the correctness of the method was verified by two T2 spectrum correction examples of oil-based mud wells in the study area. The results show that the corrected NMR T2 spectrum eliminates the influence of oil-based mud filtrate and improves the accuracy of NMR logging for calculating permeability. [ABSTRACT FROM AUTHOR]

Some inter-salt shale reservoirs have high oil saturations but the soluble salts in their complex lithology pose considerable challenges to their production. Low-field nuclear magnetic resonance (NMR) has been widely used in evaluating physical properties, fluid characteristics, and fluid saturation of conventional oil and gas reservoirs as well as common shale reservoirs. However, the fluid distribution analysis and fluid saturation calculations in inter-salt shale based on NMR results have not been investigated because of existing technical difficulties. Herein, to explore the fluid distribution patterns and movable oil saturation of the inter-salt shale, a specific experimental scheme was designed which is based on the joint adaptation of multi-state saturation, multi-temperature heating, and NMR measurements. This novel approach was applied to the inter-salt shale core samples from the Qianjiang Sag of the Jianghan Basin in China. The experiments were conducted using two sets of inter-salt shale samples, namely cylindrical and powder samples. Additionally, by comparing the one-dimensional (1D) and two-dimensional (2D) NMR results of these samples in oil-saturated and octamethylcyclotetrasiloxane-saturated states, the distributions of free movable oil and water were obtained. Meanwhile, the distributions of the free residual oil, adsorbed oil, and kerogen in the samples were obtained by comparing the 2D NMR T1-T2 maps of the original samples with the sample heated to five different temperatures of 80, 200, 350, 450, and 600 °C. This research puts forward a 2D NMR identification graph for fluid components in the inter-salt shale reservoirs. Our experimental scheme effectively solves the problems of fluid composition distribution and movable oil saturation calculation in the study area, which is of notable importance for subsequent exploration and production practices. [ABSTRACT FROM AUTHOR]

It has been found that the relatively low abundance of gas hydrate in the Muli area of the Qilian Mountain causes gas hydrate reservoirs to have low-resistivity characteristics similar to those of low-resistivity oil and gas reservoirs. Therefore, it has great significance to research the main controlling factors affecting the electrical properties, and then come up a new logging identification and evaluation model for low-resistivity gas hydrate reservoirs. In this investigation, the rock samples of sandstone from gas hydrate reservoirs were scanned by CT and combined with gas hydrate distribution characteristics. The three-dimensional digital rocks with different hydrate saturation were constructed using the diffusion limited aggregation (DLA) model, and the resistivity was simulated via the finite element method. After sorting out the influencing factors of electrical characteristics, the sensitivity of the factors affecting electrical properties was evaluated using orthogonal analysis, using variance analysis and trend analysis to quantitatively evaluate the influencing factors of rock electrical sensitivity, so as to distinguish the main and secondary factors affecting rock electrical sensitivity. The results show that the sensitivity of rock electrical properties to the six influencing factors from strong to weak are: formation water salinity, water film thickness, shale content, conductive mineral content, micropores, and average coordination number. [ABSTRACT FROM AUTHOR]

X-ray CT scanning is one of the main methods to study the pore structure of the rocks. However, low resolution is currently one of the major challenges of this method, which does not allow for the identification of microscopic pores. Even though adopting images of higher resolutions could reflect the microscopic pores of the rocks, due to the small size of the scanned rock sample in the x-ray CT scanning method, the rock parameters cannot be effectively obtained, especially for the rocks with strong heterogeneity. This would cause the loss of important pore information, such as fractures’ information. Focusing on this problem, the current research tries to propose a method for constructing high-precision digital rocks of complexly porous rocks. This method is based on the simultaneous application of x-ray CT scanning images, nuclear magnetic resonance measurements, as well as mercury injection experimental data and fractal discrete fracture network. These methods effectively compensate for the shortcomings of the scanning method where it cannot capture pores smaller than the scanning resolution and for the lack of fracture information due to rock sampling. The research results showed that compared with the digital rock models constructed by single-resolution scanning, the high-precision complex pore digital rock constructed by this method can effectively improve the accuracy of the results of porosity and permeability calculations. These results were closer to the results of rock physics experiments. This approach provides a solid foundation for the numerical simulation of rock parameters in unconventional reservoirs with complex pore structures, such as carbonate, tight sandstone and shale reservoirs. [ABSTRACT FROM AUTHOR]