In order to determine the shale oil resource potential of Da’anzhai Member, Jurassic Ziliujing Formation of Sichuan basin, the hydrocarbon generation potential, reservoir property, oil content, and shale oil mobility conditions were comprehensively evaluated by FE-SEM, CLSM, He-measured porosity and permeability, N2 adsorption, and rock pyrolysis experiments. The results show that the hydrocarbon generation potential is poor, reaching mature to high mature stage, and oil and gas coexist in the Da’anzhai Member. The intercalated limestone is dense. The inter-calite pore connectivity is poor. The foliation fracture, interlayer fracture, and calcite cleavage constitute the main occurrence space of shale oil. The oil content of foliated clay shale is good, and fracture development is the premise of shale oil mobility and high yield. Vertically, the fractures of the interbedded combination of shale and limestone are relatively developed, making it the preferred sweet spot for shale oil. Layered structures are conducive to the formation of bedding planes. Layered shale has exploration potential in areas with high levels of thermal evolution. Based on the organic matter abundance, oil property, and lithofacies combinations, it is proposed that the northern Yilong and southern Dazhou are favorable exploration areas for interlayer type shale oil. While the areas between Yilong and Dazhou are favorable exploration areas for pure shale type shale oil.

The tuff lava of the Yingcheng Formation in the Yingshan fault depression of the Songliao basin is characterized by ultra-low porosity and low permeability. In order to characterize the nanometer to micron multiscale reservoir space and evaluate qualitatively and quantitatively, the factors influencing tuff lava reservoir development in the Yingcheng Formation are discussed. Based on core observation and thin section identification, combined with FE-SEM, LTNA, HPMI, CPMI, and NMR, the micropore characteristics of the Yingcheng Formation tuff lava were characterized qualitatively and quantitatively at multiple scales. The results show that: The tuff lava of the Yingcheng Formation is mainly composed of vitric debris and rhyolitic debris. The reservoir space types are mainly devitrification pore, feldspar dissolved pore, and illite intercrystalline pore. A great number of secondary pores and fissures are formed during the devitrification process, and provide about 66.8% of pore volume, which is vital to improving the reservoir physical properties. 

The fracture conductivity is an important index to determine the fracturing effect of deep coalbed methane reservoirs. The three-dimensional digital core of a deep coal-rock reservoir in Daning block was constructed by using high-resolution CT scanning technology and the advanced mathematical algorithm of Avizo visualization software, and the microscopic pore structure characterization of different types of coal-rock reservoirs was carried out from multiple dimensions. On this basis, the linear flow fracture conductivity experimental device was used to evaluate coal rock fracture conductivity. The effects of proppant particle size, sanding concentration, different proppant particle size combinations, closure pressure, proppant embedding and pore throat structure on the fracture conductivity of coal rock were systematically studied. The results show that the pore structure characteristics of different types of coal rock samples in the study area are significantly different. The distribution form of pore throat is mainly continuous or isolated. The pore radius is distributed primarily in 5.23-34.85 μm, the throat radius is mostly 1.31-12.27 μm, and the pore throat coordination number is small. With the decrease in permeability, the connectivity of the pore throat worsens and the heterogeneity strengthens. The fracture conductivity under the support of large particle size proppant is stronger, but the fracture conductivity under the support of small particle size proppant is more stable. The fracture conductivity increases significantly with the increase of sanding strength but decreases with the increase of closure stress. When the propping agent is embedded in the coal and rock strata, the flow space of the fluid in the fracture will be compressed and blocked, and the fracture conductivity can be decreased by 12.2%. Under different proppant particle size combination ratios, the higher the proportion of large particle size proppant, the greater the conductivity. In general, the main controlling factors of fracture conductivity of coal-rock pressure in this area are sanding concentration, proppant particle size, and fracture closure stress.

The pore structure of low-permeability sandstone is complex. The three-dimensional (3D) quantitative characterization of micro-nano scale fluid flow characteristics and the analysis of occurrence mechanisms are of great significance for fine reservoir description and enhanced oil recovery. Two water-wet sandstone samples with similar micro-pore structure characteristics from the upper Es₄ Member in G Oilfield were selected, and X-ray CT coreflooding experiments under relatively low and relatively high flooding rates were performed. The distribution of oil, water and particle phases in 3D pore space at different water flooding stages was obtained by image processing technology. The occurrence states and changes of oil phases in 3D pore space and individual pores during the water flooding process were discussed. In addition, combined with the finite volume method, the fluid flow characteristics under the control of multiple factors (e.g. microscopic pore structure heterogeneity, displacement mode and waterflooding rate) were also determined. The results indicate that the large and continuous oil drops were broken up and gradually separated into small oil droplets during the water flooding process, and the small oil droplets distributed in a discrete state in the 3D pore space. After water flooding, the connectivity of oil droplets becomes poorer and the geometry becomes smoother and more regular. The dominant fluid flow channels are generally well developed in the sandstones with strong microscopic heterogeneity and good pore connectivity, resulting in the development of the flow around and crossflow behaviors. Therefore, the water sweep efficiency in the sandstones with strong microscopic heterogeneity is low. The water flooding rate is also an important factor affecting the oil displacement efficiency and oil/water migration path. Increasing water displacement rate can significantly increase the number of water injection capillaries, thus enhancing oil recovery rate. This study also indicates that the oil displacement efficiency of low-permeability sandstones can be effectively improved by increasing the oil-water viscosity ratio and the injected capillary number under an appropriate interfacial tension. The research results provide an important theoretical basis for enhancing oil recovery (EOR) of low-permeability and water-wet sandstone reservoirs.

Shale oil in-situ mining technology has many advantages and can effectively improve mining efficiency. However, the operating conditions for shale oil in-situ mining are harsh, and the pipes used in these conditions will experience severe high-temperature corrosion over a long period. Hence, the material selection is key to a safe and effective in-situ shale oil exploitation. In this study, common oil well pipe materials J55, P110, and 3Cr were selected as research objects. Microstructural characterization, cross-sectional observation, and oxidation kinetics curve were used to study their high-temperature corrosion resistance performance at 600 ℃. The research results show that with the increase of corrosion time, the thickness of the oxide film on the surface of the three samples increases, the J55 has the thickest oxide film, and the 3Cr has the thinnest. Secondly, the oxidation weight gain of the three samples increases with the extension of corrosion time, the J55 has the highest oxidation weight gain, and the 3Cr has the lowest. Finally, the surface products of the three samples all contain Fe₂O₃, and the surface of 3Cr also has chromium oxide. The above results indicate that the 3Cr has the best high-temperature corrosion resistance performance among the three materials. In the high-temperature underground environment of shale oil in-situ mining, the chromium content is an important reference for material selection.

The Wulanhada-Chuludaban area in Inner Mongolia is located in the middle section of the Zhalantun volcanic rock-type uranium mineralization prospecting zone and is one of the hydrothermal uranium polymetallic mineralization clusters in Northern China. The area experienced intense and frequent Mesozoic volcanic eruptions, providing excellent geological conditions for mineralization and promising exploration prospects. Through the collation of previous data, comprehensive mapping, and uranium geological survey and evaluation, the geological characteristics and ore-controlling factors of volcanic rock-type uranium deposits in the Wulanhada-Chuludaban area have been preliminarily summarized. Through drilling verification, it is found that the volcanic rock-type uranium deposits in the research area can be classified into two types based on the main ore-controlling factors: subvolcanic rocks and altered fracture zones. It is believed that the peak period of uranium mineralization in the research area was from the Late Jurassic to the Early Cretaceous, mainly concentrated between 149 and 99 Ma, with the characteristics of a large time span and multiple stages. Uranium mineralization anomalies are mainly distributed along the NE-trending F_W2 trans-shell faults and are mostly found in the NE and NW-trending secondary faults and structural fracture zones. Uranium mineralization is mainly controlled by uranium source, strata and structure, subvolcanic rocks, and hydrothermal alteration. Hematitization, fluoritization, and silicification can be used as direct exploration indicators. The next exploration work should focus on searching for altered fracture zone-type uranium mineralization on both sides of the NE-trending F_W2 ore-controlling faults, and secondly, strengthen the exploration of uranium mineralization around volcanic structures and subvolcanic rocks.

The ore-bearing rock mass of Xiaogushan gold deposit in western Liaoning is a suit of pyroclastic rock assemblage, which was originally divided into Yixian Formation of Lower Cretaceous of Mesozoic. In order to accurately determine the age of this rock body, and to explore the petrogenesis and tectonic significance of the rocks in the western part of the Liaoxi region, petrography, LA-ICP-MS zircon U-Pb dating and petrogeochemical analysis were carried out on the ore-bearing tuff of the Xiaogushan gold deposit. The results show that the weighted average age of the tuff is 2 510.7-2 508.9 Ma, which is the product of Late Neoarchean magmatism. The geochemical characteristics of the major elements show that the tuff is rich in silicon (w (SiO₂) is 68.99%-71.82% ), rich in alkali and potassium (w (Na₂O+K₂O) is 7.13%-8.82%, w (K₂O) is 6.94%-8.59%), poor in magnesium (w(MgO) is 0.51%-0.66%), and poor in calcium (w (CaO) is 0.43%-0.90%). The aluminum saturation index (A/CNK) ranges from 1.16 to 1.42, which belongs to the peraluminous calc-alkaline shoshonite series rocks. The rocks are enriched in LREEs and LILEs such as Rb, Th, U, K and Pb, and depleted in HREEs and HFSEs such as Nb, Ta and P. The rare earth distribution pattern shows a right-leaning gentle low “V” curve, with obvious fractionation of light and heavy rare earth elements. (La/Yb)_N is between 15.19 and 38.23, with weak Eu anomaly (δEu is 0.60-0.72). Petrogenesis and magma source discrimination show that the rocks have the characteristics of S-type granite, and the magma originated from the partial melting of metamorphic mudstone in the lower crust. Combined with the regional tectonic evolution, tectonic discrimination and geochronological characteristics, it is believed that the ore-endowed tuffs of the Xiaogushan gold deposit were formed in the tectonic environment of syn-collision after the subduction of the Longgang block and the Langlin block in the eastern part of the North China craton, which reflects the formation and evolution of the consolidated basement of the North China craton in the Archean period, and provides evidence for the tectonic mechanism of the North China craton in the Archean.

Cu polymetallic deposits are developed in the Bolishuangxing area, Heilongjiang Province. The ore-forming rock masses (granodiorite and granodiorite porphyry) are closely related to Cu deposits. In order to determine its mineralization era and geodynamic background, based on field survey work, this paper investigate the petrographic, chronological, and geochemical characteristics of intrusive rocks in Cu deposits of Bolishuangxing area, and explores the formation age, petrogenesis, and tectonic background of the intrusive rocks in the study area.The results show that the LA-ICP-MS zircon U-Pb products of Late Mesozoic Early Cretaceous magmatic activity (granodiorite at (120.94 ± 0.70)Ma, granodiorite porphyry at (120.88 ± 0.61)Ma ), which indicates that the formation time in Cu deposits of Bolishuangxing area was approximately 120.9 Ma, consistent with the peak period of mineralization in the region. Research on rock geochemistry shows that granodiorite and granodiorite porphyry contain(w(SiO₂)(61.04%-67.08%), w(Al₂O₃)(14.07%-15.86%), w(Na₂O+K₂O)(6.40%-7.15%),w(TFeO)(4.52%-6.69%), w(CaO)(2.30%-4.43%), δEu(0.74-1.27)), the europium anomaly is not obvious. They are enriched in light rare earth elements and large ion lithophile elements(Rb, Ba, Sr, etc.), and relatively deficient in heavy rare earth elements and high field strength elements (Nb,Ta,Zr, etc.). The magma source area is partial melting of newly enriched lower crustal material, showing I-type granite characteristics. Based on relevant research results, it is considered that the geodynamic setting of the formation of granodiorite and granodiorite porphyry in the study area is an extensional environment formed by the subduction and retreat of the ancient Pacific plate towards the Eurasian continent.

The widespread Mesozoic granitoids in the Great Xing’an Range play a pivotal role in deciphering the tectonic-magmatic evolution of Northeast China. To constrain the emplacement age, petrogenesis, and tectonic setting of granites in the northern segment of the Great Xing’an Range, this study conducts integrated petrographic, LA-ICP-MS zircon U-Pb geochronological, zircon Hf isotopic, and whole-rock geochemical investigations on the Kuzhong granitic pluton. Zircon U-Pb geochronology yields a crystallization age of (136.5±1.7) Ma, placing the magmatic event in the Early Cretaceous. Whole-rock geochemical data reveal that the pluton represents a highly fractionated calc-alkaline I-type granite, characterized by high silica (w(SiO₂)=70.40%-73.54%), elevated alkalis (w(Na₂O+K₂O)=8.77%-9.30%), enrichment in large-ion lithophile elements (e.g., Rb, Ba), and depletion in high-field-strength elements (e.g., Nb, Ti, P). Chondrite-normalized rare earth element patterns exhibit right-dipping trends with pronounced negative Eu anomalies. The homogeneous zircon Hf isotopic compositions (εHf(t)=5.1-8.8, mean 6.7) suggest magma derivation predominantly from partial melting of juvenile lower crust. Synthesizing regional tectonic evidence, we propose that the Kuzhong granite formed in a post-orogenic extensional setting following the closure of the Mongol-Okhotsk Ocean, overprinted by lithospheric thinning and asthenospheric upwelling driven by Paleo-Pacific plate rollback. This thermotectonic process facilitated melting of juvenile lower crustal materials, ultimately generating highly fractionated calc-alkaline I-type granites.

In the vicinity of Wujianfang Village, Lianggang Town within the Trans-North China orogen (TNCO) of the North China craton (NCC), we have discovered a set of garnet amphibolitesduring the 1/50 000 regional geologic survey. The garnet amphibolites were exposed as lenses in the paragneisses of Yuanfang Formation of the Fuping Group, showing typical “white-eye socket” structure, indicating that they were probablyretrograded eclogites or high-pressure mafic granulites. In order to gain a deeper understanding of the metamorphic genesis and geological significance of this suite of garnet amphibolites, detailed studies were conducted on their petrology, mineral chemistry, geochemistry, metamorphic evolution, and zircon U-Pb geochronology. The results suggest that they underwent three stages of metamorphic evolution: An early prograde metamorphic stage (M₁), a peak high-pressure granulite facies stage (M₂), and a retrograde stage (M₃). The early prograde stage features mineral assemblages of Am+Pl+Q inclusions within garnet, with metamorphic p-T conditions of approximately 756.0 ℃/ 6.0×10⁸ Pa; The peak high-pressure granulite facies stage shows a mineral assemblage of Grt+Cpx+Pl+Q+Melt, with p-T conditions of 884.1-987.5 ℃ / (12.2-14.2) ×10⁸ Pa; The retrograde stage is characterized by a “white-eye” structure around garnet and partial replacement of clinopyroxene by late amphibolewith residual ilmenite, forming a mineral assemblage of Am+Pl+Q+Ilm ± Grt and showing p-T conditions of 706.6-776.7 ℃/(3.7-4.2)×10⁸ Pa; The metamorphic evolution of these garnetamphibolites generally exhibits aclockwise p-T includinga near-isothermal decompression (ITD) process. LA-ICP-MS zircon U-Pb dating indicates a retrograde metamorphic age range of 1.86-1.84 Ga. The geochemical characteristics reveal that their protoliths were tholeiitic basalt formed under an island arc environment of convergent plate margin. Combined with previous studies, the garnetamphibolites exposed in the Lianggang region are retrograde products of high-pressure granulites,which are similar to the formation process of the Hengshan-Huai’an-Xuanhua-Chengde high-pressure granulite belt of the TNCO. This suggests they may also be a result of the collision between the eastern and western block that occurred at about 1.85 Ga. This understanding extends the high-pressure granulite and retrograde eclogite belt in the north-central part of the TNCO southeastward to the Yixian-Laiyuan area in Hebei Province.

At present, most constitutive models are difficult to simultaneously reflect the creep behavior of soft and hard rocks, and their applicability is limited. To construct a more widely applicable rock creep model, based on the generalized Kelvin-Voigt model, the theory of fractional calculus operators and damage mechanics theory were introduced to construct a new rock fractional creep model considering time-dependent damage, which is extended to three-dimensional stress space. Model validation analysis is found that: 1) Simulating uniaxial compression creep tests on marble and triaxial compression creep tests on sandstone using newly constructed one-dimensional and three-dimensional models, the average R² (goodness of fit) was of 0.994 4 and 0.994 2 respectively, proving the feasibility of the newly constructed models; 2) At the same time, the newly established model and the fractional-order creep model in related literature were used to simulate the triaxial creep data of sandstone, and the average R² was 0.994 2 and 0.992 7, respectively, and the average R2 of the newly established model was 0.001 5 higher than that of the previous model; 3) The simulation of triaxial compression creep test data for four types of rock hardness, namely granite, slate, mudstone, and fully weathered granite, showed an average R² of 0.989 9, demonstrating the applicability of the new model.

To enhance the economic efficiency of engineering geological investigations for construction projects and accurately reveal the correlations between the physical and mechanical parameters of cohesive soils, in this study taking the cohesive soils in central urban area of Changchun as the research object, based on the data from 1 092 physical tests, compression tests and direct shear tests, two multiple regression models were constructed to emphatically analyze the rationality of the model’s premise assumptions and the interaction effects among explanatory variables. The results show that: 1) The residual probability density plot and residual normal Q-Q （quantile-quantile） plot confirm that the model error terms follow a normal distribution, with homogeneous and mutually independent variances, satisfying the basic assumptions of the multiple regression model. 2) The two-factor interaction effect plots and Johnson-Neyman plots indicate significant interaction effects among water content, density, void ratio and liquidity index. A regression model considering interaction effects can more accurately predict the compression coefficient. It is feasible to use multiple linear regression to analyze the correlations between physical and mechanical parameters of cohesive soils.

Ground subsidence, a slowly occurring and irreversible geological disaster, is an environmental geological problem which commonly occurs in the process of urbanization. In order to solve the problems of incomplete subsidence information obtained by the existing ground subsidence monitoring network and the lack of precision in monitoring urban ground subsidence, it needs to be optimized. In this paper, taking the ground subsidence monitoring network of Nanjing Yangtze River floodplain as an example, using the regionalized variable theory of geostatistics and the variational function theory, Kriging interpolation method is used to establish the variational function model for the ground subsidence monitoring network of the study area, and the standard deviation distribution characteristics of each monitoring network of the Yangtze River floodplain in Nanjing area are investigated for the optimization of the deployment. The results show that the ground subsidence monitoring networks in the study area has the problem of unreasonable distribution. After the optimization, 34 redundant and marginal monitoring wells are eliminated and 16 new monitoring wells are added; 49 redundant and marginal level points are exempted and 21 new level points are added; 18 groups of stratified settlement monitoring network are eliminated and 13 groups of stratified settlement monitoring points are added. The improved monitoring well network can maximize the acquisition of monitoring data while meeting the accuracy requirements, and efficiently optimizes the arrangement of the settlement monitoring network, with reasonable results.

Halk Mountains are situated in the northern Tianshan range. Their complex geological structure and intense topographic dissection have resulted in well-developed fractures and well-developed fissures within river valleys. This area significantly impacts the overall water resources and ecological environment of the northern Tianshan piedmont. To evaluate groundwater infiltration capacity in this region and explore the permeability characteristics of bedrock fractures in Halk Mountains area, this study proposes a coupled simulation method of discrete fracture-equivalent continuous medium based on the theoretical foundations of discrete fracture network (DFN) model and equivalent continuous medium (ECM) model. Firstly it analyzes the spatial characteristics of regional fissures by integrating the hydrogeological background and natural fissure network characteristics, then performs discrete fissure network simulation according to the natural fissure network characteristics to establish a discrete fissure network model consistent with the regional actual geological conditions, and finally achieves fissure-geological unit coupling based on the equivalent medium model theory to calculate the equivalent permeability of the fissure network. The results indicate that: Fractures in the study area are influenced by Halk Mountain fault structure, with an overall strike predominantly NWW and NEE; The fissure widths follow a log-normal distribution, and the spatial distribution of fissures adheres to a Fisher distribution; The equivalent radius of the fissures ranges from 312.9-780.6 m, the fissure width spans 1.43-25.19 mm, the permeability varies from 2.3-66.7 mD, and the fissure density ranges from 0.10-5.25 m^-1; The equivalent permeability values are 0.050-1.877 mD in the xx direction, 0.050-1.947 mD in the yy direction, and 0.100-2.825 mD in the zz direction, with the permeability of the entire region being less than 3 mD. The bedrock fissure network in Halk Mountains area exhibits relatively low permeability, with fault zones and river valley fissure development zones serving as the primary pathways for groundwater flow in the mountainous region. Comparing the simulation results with previously conducted hydrogeological test results shows good agreement, validating the reliability of the coupled discrete fracture-equivalent continuum simulation method.

The Hexi area is the main emergency groundwater source for Xiangtan City, Hunan Province, ensuring the urban water supply safety demand. Identifying the spatio-temporal evolution process of water supply hydrochemical components under the long-term influence of climate change and human activities has important practical guiding significance for the local development and utilization of groundwater resources and pollution control. In order to quantitatively reveal the evolution processes of karst hydrochemistry under long-term controls of precipitation and human activities, as well as the spatio-temporal distribution and evolution patterns of hydrogeochemical characteristics in the karst areas of Southern China, this study applies multivariate statistical analysis, geostatistical analysis, hydrochemical methods，and Piper diagrams, Gibbs models, and major ion ratios to analyze the spatio-temporal variation patterns and influencing factors of karst hydrochemistry in the study area, based on national groundwater quality monitoring data (2002—2021). The results show that: The karst hydrochemistry in the study area exhibits horizontal zonation in space, which can be divided into Hydrochemical Zone Ⅰ and Hydrochemical Zone Ⅱ. Along the overall flow direction of karst water from Zone Ⅰ to Zone Ⅱ, the hydrochemical components show a “positive increase”. The concentration of karst water chemical components has shown a phased change on the annual time scale over the past 20 years, with the overall evolution process being “stationary-rising-declining-stationary”. The key time nodes are 2007, 2011, and 2017. The spatial differences in karst hydrochemistry are mainly influenced by human activities. On the one hand, agricultural non-point source pollution and urban domestic sewage enter the aquifer through surface infiltration, increasing the concentration of some components in Zone Ⅱ; On the other hand, artificial groundwater exploitation alters the local karst water flow field, causing hydrochemical components within the study area to exhibit “reverse change” characteristics along the overall flow direction of karst water. The evolution process of karst hydrochemistry on the annual time scale is influenced by changes in annual precipitation, and the influence time can be traced back to 2-3 years ago. This study comprehensively applied mathematical and chemical methods to quantitatively reveal the evolution process of karst hydrochemistry under the long-term control of precipitation conditions and human activities, which can provide reference for analyzing the spatio-temporal distribution and evolution law of hydrogeochemistry in karst areas of Southern China.

It is scientifically significant to establish soil remediation standards for the synergistic management of soil and groundwater. Previous studies often assumed that contaminant sources directly affect the saturated zone, with little consideration for the lag, attenuation, and variations in pollutant sources during migration in the vadose zone. Addressing this issue, in this paper coupling the one-dimensional vertical transport analytical solution of pollutants in soil with the three-dimensional transport analytical solution of pollutants in groundwater, the influence of factors affecting pollutant migration and transformation on the synergistic remediation threshold of soil and groundwater is investigated. The results indicate that without considering the synergistic remediation of soil and groundwater, based on the screening values of soil for the first category of land use in current standards, benzene and chlorobenzene should be remediated to 1 mg/kg and 68 mg/kg respectively. Considering the synergistic remediation of soil and groundwater and aiming for compliance with downstream groundwater quality standards, the calculated synergistic remediation thresholds for soil and groundwater are 0.150 mg/kg and 150.000 mg/kg respectively. Failure to consider the synergistic remediation of soil and groundwater may result in inadequate or excessive soil remediation at the site.

Iron containing minerals are earth-abundant, low cost, and able to tragger H₂O₂ and persulfate (PS). Biotite contains Fe²⁺ and has reducing properties, and there are limited studies on its activation of PS to remove pollutants. In this study powdered biotite (PB) was used to activate PS for degradation of a reactive azo dye, reactive green 19 (RG19). Results showed that PB was able to efficiently activate PS to produce OH· and SO₄^-·, which were responsible for the degradation of RG19. Approximately 95% of 5.0×10^-5 mol/L RG19 was decolorized in 15 min and azo bonds were completely broken down under the conditions of 5.0×10^-3 mol/L PS,1.0 g/L PB, initial pH 6.0, and 55 ℃. Decolorization process followed a pseudo-second-order (PSO) kinetics. The American dye manufacturers institute (ADMI) color scale and total organic carbon removal were both taken in consideration and the oxidative degradation efficiency at 98.2% and 71.2%, respectively. The high activation energy of 34.96 kJ/mol indicated that the reaction was significantly affected by temperature. PB can be used as an efficient activator for PS to degrade dye wastewater.

Due to the presence of obstacles in the observation site or the unique characteristics of the target object, it is not always possible to lay out survey lines for electrical resistivity tomography in a straight manner. In some cases, even the electrode array cannot be placed directly above the target body. As a result, there are limitations on the application of resistivity tomography method under certain site conditions. This paper focuses on studying 3D electrical resistivity tomography technology for restricted observation sites. The study begins by designing three electrode array observation systems specifically tailored for restricted observation sites: “□” shaped observation system, “U” shaped observation system, and “L” shaped observation system. Subsequently, we investigate the 3D inversion imaging method for determining resistivity using any type of observation system. Finally, we analyze the detection effectiveness of different observation systems through model testing and apply “□” shaped observation system to detect the base structure of an ancient tower in Zhejiang Province. Based on both geoelectric model detection results and the actual site conditions, all three special observation systems for 3D electrical resistivity tomography can effectively capture 3D electrical characteristics below the restricted observation site, thereby providing valuable references for analyzing anomalies within the target area. Among them, the “□” shaped observation system demonstrates the best imaging performance, followed by the “U” shaped observation system, while the “L” shaped observation system shows relatively weak performance. In practical applications, it is essential to consider site conditions and exploration objectives when selecting the electrode array geometry and the number of electrodes, in order to optimize the imaging results.

The direct current resistivity method, as one of the important methods in geophysical exploration, has played a significant role in various geological exploration fields. This paper conducts a study on the electrical response characteristics of intrusive rock models using a three-dimensional direct current numerical algorithm based on space-wavenumber hybrid domain. The total electric field normalization coefficient T₃ is introduced, and the electric field response characteristics of pole-dipole array and dipole-dipole array configuration of non-mineralized and mineralized intrusive rock models are comparatively analyzed. Special consideration is given to the effects of isotropic and anisotropic mineralization zones, as well as the induced polarization effect, in order to reveal the response differences under different electrical conditions. The analysis results show that the total electric field normalization coefficient has a more pronounced response to the underground medium than electric field components. The T₃ response anomaly detected by dipole-dipole array is superior to that of pole-dipole array, and different electrical mineralized zones exhibit significant differences in T₃ response features. Compared to polarizability anisotropy, resistivity anisotropy has a more profound impact on the observation results. The response characteristics of the mineralized model are far more complex than those of the non-mineralized model, especially when the mineralized zone is electrically anisotropic, the observed T₃ morphology of different electrical parameters is quite different.

The method of seismic data reconstruction is an important way to improve sampling density and obtain complete wavefield information in seismic signal processing. The data collected from field exploration is often incomplete or irregularly sampled due to limitations in surface conditions and cost control. Therefore, studying methods for reconstructing irregular seismic signals is of great significance. Based on the assumption that irregular seismic data can be regarded as random sparsity of regular complete data, the mathematical statistical distribution of the two data is highly consistent in the data interval and the performance in the sparse domain is extremely similar, this paper proposes a method of data reconstruction by using residual convolutional encoder-decoder to reduce the dimensionality of the data to the sparse domain and then increase it. Furthermore, this paper proposes amplitude consistency correction processing on the input data of the network to balance energy, in order to address the serious impact of inconsistency in amplitude depth and shallow layers caused by seismic attenuation, as well as significant differences in mathematical statistical distribution between different data, on the training and generalization of neural networks. The synthetic data example proves that the proposed method has higher accuracy than traditional two-dimensional prediction error filter and residual network interpolation methods, and is more efficient than traditional three-dimensional prediction error filter interpolation method. Different field land and ocean data examples have achieved good reconstruction results, proving that this method greatly increases the generalization ability of the network and reduces the training difficulty of the network.

High resolution is one of the goals of seismic data processing. Inverse Q filtering is a common method to achieve high resolution of seismic data. When the signal-to-noise ratio (SNR) of seismic data is low, the conventional stable inverse Q filtering method has the challenge of enhancing the noise energy. In this paper, an inverse Q filtering method with adjustable amplitude compensation operator under SNR constraints is proposed based on self-adaptive gain-limited inverse Q filtering method. This method presents a new amplitude compensation operator. By calculating the SNR of seismic data, the cutoff frequency of the effective frequency band is obtained, enabling the amplitude compensation operator to be dynamically adjusted according to the characteristics of the seismic data itself. The high-frequency noise energy is further suppressed by introducing a dynamically adjustable amplitude compensation curve. The test results of theoretical synthetic data and field data show that: the method proposed in this paper can compensate the amplitude well and improve the seismic data resolution. Compared with the traditional stable inverse Q filtering method and the self-adaptive gain-limited inverse Q filtering method, the method proposed in this paper has a better ability to suppress noise energy enhancement, and the SNR of the processing result is higher.

The Yishu fault zone is located in the middle section of the Tanlu fault zone, consisting of multiple nearly north-northeast trending faults. Significant variations in crustal structure are present on both sides of the fault zone. The seismic velocity and velocity variations are important parameters for understanding the deep structural characteristics of the earth and the potential damage of the medium. Based on the continuous seismic waveforms from permanent stations in the Yishu fault zone and surrounding regions from January 2011 to December 2014, we perform ambient noise tomography to monitor the phase velocity variations of Rayleigh wave. The results show that the velocity variations correlate well with the small earthquake activities. The earthquakes (M>2) are mainly concentrated near the velocity reduction and velocity transition zones. The velocity variations near the Yishu fault zone are not significant, indicating that the fault activity is relatively weak recently. The velocity variations in the Jiaobei uplift are notable between 2013 and 2014, which is related to surface deformation. It is speculated that the compression effect of regional stress is the main factor for the velocity increase in the Jiaobei uplift.

In the domains of oil and gas exploration and geoengineering, precise lithology identification holds paramount importance for the assessment and utilization of resources. The inherent complexity of geologic data and the imbalanced distribution of lithology samples pose significant challenges to traditional methods in terms of lithology identification. In this paper, we propose a methodology for lithology identification that combines SMOTE (synthetic minority over-sampling technique) with extra trees. Firstly, the SMOTE method is employed to enhance the representation of minority class samples, thereby improving the balance of the training data. Secondly, the lithology classification model is constructed using the high efficiency and strong generalization ability of extra trees. The experimental findings demonstrate that the recognition accuracy of extra trees is 85.54%, which is 5.58%, 2.55%, 2.35%, and 2.08% higher than that of other machine learning methods—gradient boosting decision tree (GBDT), extreme gXGBoost), light gradient boosting machine (LightGBM), and random forest method, respectively. The prediction bias of the model caused by sample imbalance is mitigated by SMOTE sampling, resulting in enhanced recognition accuracy for specific lithology categories within each model. Consequently, this leads to an overall enhancement in the performance of the model. The extra trees model exhibits the best performance, achieving an identification accuracy of 86.62%, which represents improvements of 4.71%, 2.56%, 1.55%, and 2.02% over GBDT, XGBoost, LightGBM, and random forest, respectively. These results confirm the effectiveness of combining SMOTE with extra trees for lithology identification.

The intelligent identification of shale scanning electron microscope (SEM) images can rapidly analyze shale reservoir minerals, which is one of the important means of predicting the “sweet spot” of shale oil reservoirs, and is also a future technological development trend. Traditional methods have problems such as low automation, low sample suitability, and limited feature extraction when identifying mineral components. To this end, this paper proposes a BlendMask-based SEM image characterization method for shale. Firstly, image preprocessing techniques such as bilateral filtering, Laplacian, and image normalization are used to denoise, sharpen, and unify the pixel of original images to improve the quality of training samples; Then, image augmentation methods such as rotation, scaling, and luminosity change are used to construct augmentation strategies to expand the number of datasets; And finally, the BlendMask network is improved by using the attention mechanism and the depth separable convolution which is used to realize the component segmentation and recognition of images. The experimental results of shale SEM images applied to Haita basin show that the segmentation accuracy and recall of the improved method are improved by 0.02-0.20 and 0-0.59, respectively, and the segmentation time is reduced by 1.29-2.70 s compared to the BlendMask model.