Carbonate fault-controlled fracture-cavity reservoirs are present in the Shunbei area of the Tarim Basin, NW China. Existing modeling algorithms struggle to accurately characterize the internal structure. Urgently needed is research on reservoir modeling algorithms that incorporate the internal structural characteristics of the fault-controlled body. This will establish a detailed three-dimensional geological model aligned with geological understanding and clarify the primary reservoir spaces for oil and gas.

In this paper, taking the Shunbei No.4 fault zone as an example, an object-based modeling method is proposed and applied for the first time. Combined with the idea of hierarchical simulation, the fracture plane and the development scale of caves type in the extrusion, pull-apart and translation stress sections are quantitatively characterized. By designing a grille-based reservoir trend line tracking algorithm, the center line that conforms to the development trend of the reservoir is found, and the idea of hierarchical simulation is integrated to describe the fracture plane and the grille-like filling structure model inside the cave type layer by layer.

Based on the established geological model. A property model is created using the phase-controlled method. This model is used for reserve calculation and numerical simulation. Preference is given to the fault-controlled body model with only fracture planes. The fit between the calculated fracture plane reserves and dynamic reserves is 96%. The model also fits bottom hole pressure and actual production data, with an error less than 10%.

The main reservoir types in the study area include fracture planes, caves type, and disordered bodies. A fault-controlled body contour model is established for different seismic attribute bodies. Logging interpretation identifies fracture plane and cave type internal developments within the bedrock and crush belt, forming an ordered grille structure. Crush belt further divided into breccia belt and fracture belt. An object-based modeling method creates a three-dimensional geological model of the reservoir’s grille structure. The model, optimized for fracture plane reservoirs, aligns with drilling and logging data and geological understanding. It provides a reference for guiding oil and gas reservoir development.

In order to study the dissolution damage and mechanical damage of carbonate rock by acidic filtration solution.

In this paper, through carrying out different flow conditions, different time length of phosphogypsum acidic leaching solution on the dissolution of limestone test research, analyze before and after the test of limestone specimens of the apparent characteristics, quality, porosity, uniaxial compressive strength, and acoustic emission counts and other indicators of the law of change, revealing the impact of the acidic leaching solution on the physical and mechanical properties of the carbonate rock.

The test results show that the dissolution rate and porosity increment of the rock samples are positively correlated with the dissolution time and the flow rate of filtration solution, and the mechanical strength is negatively correlated with the dissolution time and the flow rate of filtration solution. With the dissolution, the surface of the rock samples will be attached with thicker and thicker fluorite minerals, which makes the dissolution rate of the rock samples slower. The damage form of the uniaxial specimen gradually changed from shear damage to tensile damage. Under the acidic environment of phosphogypsum leachate dissolution, the internal mineral composition of limestone is dissolved, which causes changes in macro-mechanical parameters.

The research results can provide theoretical and experimental data for the stability analysis of karst media under the influence of acidic wastewater, acidic wastewater treatment, and tailing project safety design.

Seabed carbon dioxide (CO₂) geological sequestration technology has become a hot spot in carbon sequestration and carbon neutralization. There are favorable space and temperature and pressure conditions for the formation of CO₂ hydrate in the seabed sediments in the northern part of the South China Sea, and the formation of CO₂ hydrate in the cracks and pores can block the further upward migration of CO₂ and generate self-sealing capacity. However, the CO₂ leakage in the fracture and the effect of hydrate plugging and instability conditions are still unclear.

In this paper, the visualization experiment platform of hydrate growth and the instability process of water injection supercharging at high pressure and low temperature was used to observe the formation of CO₂ hydrate and experiment platform was used to simulate the conditions of seafloor sedimentary cover under the conditions of 2℃ and 3−4 MPa, and the hydrate instability condition and plugging effect were evaluated with the breakthrough pressure, breakthrough pressure difference, duration, permeability coefficient of initial instability stage and plugging rate as indicators.

The experimental results show that hydrate formation can be simplified into four processes: nucleation, expansion, forming and aggregation. Hydrate formed in cracks can efficiently block the migration of fluids such as water and CO₂, but the instability phenomenon begins when the fluid pressure gradually increases and reaches the critical breakthrough pressure. The instability process of hydrate can be simplified into two parts: particle size degradation and surface friction failure. The core of hydrate mass is unstable first, and the sealing state can be maintained before the surface of hydrate fails to friction fracture. The instability conditions of hydrate in the fracture are investigated experimentally. The breakthrough pressure is 6.414−6.966 MPa and the breakthrough pressure difference is 2.403−3.203 MPa. The instability rate of hydrate is mainly affected by the flow rate, followed by the saturation of hydrate, and the flow rate affects the instability rate through the interface effect. The key factors determining the breakthrough pressure of hydrate are temperature and pressure conditions, while the effect of flow rate is mainly reflected in regulating the specific time when hydrate enters the instability state. Under the condition of 3−4 MPa seafloor sedimentary cover, the sealing rate is 99.0%−99.6% and the permeability coefficient of initial instability stage is 0.555−1.260 md.

The experimental results provide a reference for the risk assessment of the overlying layer under similar conditions in the South China Sea for CO₂ seabed geological sequestration. The difference between the pressure under the capped CO₂ hydrate layer and the actual pressure on the seabed should be ensured to be less than 2 MPa to maintain the sealing effect of the hydrate.

This paper focuses on the shale of the upper fourth member of Shahejie Formation. Based on XRD, gas adsorption, high-pressure mercury injection, FE-SEM, and FIB-SEM, the lithofacies types of the shale were identified, the storage space types and structures of the shale were characterized, and the influencing factors of shale pore development were revealed.

The research results indicate that: ①There are mainly five lithofacies developed in the shale in the study area(organic-rich laminated calcareous shale, organic-rich laminated mixed shale, organic-rich layered mixed shale, organic-rich massive calcareous shale, and organic laminated calcareous shale); ②The main types of reservoir spaces include intergranular pores, dissolution pores, intergranular pores, and micro-fractures, with little development of organic pores. There are significant differences in the pore structure of different types of shale, organic-rich laminated shale have larger pore volumes; ③The abundance of organic matter and sedimentary structures (laminations) have a significant controlling effect on shale reservoirs. Organic acid dissolution forms a large number of dissolution pores, increasing shale reservoir performance. However, excessive abundance of organic matter enhances shale plasticity, which is not conducive to pore preservation. The laminated structure is beneficial for the reservoir properties of shale, and there are significant differences in reservoir properties among different types of laminated structures. The felsic lamination has better reservoir properties, followed by clay lamination, and the coarse calcite lamination has poorer reservoir properties.

Research results reveal the characteristics and controlling factors (organic matter abundance and laminations) of shale reservoirs in upper fourth member of Shahejie Formation, which has reference significance for the development of continental shale oil in the Bohai Bay Basin.

Rainfall-induced group-occurring shallow soil landslides have the characteristics of strong and sudden occurrence and high risk. It is of great significance to build a runout distance prediction model for landslide risk prevention and control.

This study takes the "5.27" group-occurring landslide event in Wuping County, Fujian Province as the research object, and obtains 131 landslide characteristic data based on pre-disaster and post-disaster remote sensing images, digital elevation model, drone 3D model and field investigation. According to the location of the slip-out point and topographic characteristics, the landslides are divided into the foot slip-out type, the middle slope slip-out type and the cut slope slip-out type. The main factors affecting the runout distance of group-occurring shallow soil landslides were determined by correlation analysis, and the optimal prediction model for the runout distance of three types of landslides was established using stepwise nonlinear regression analysis.

Correlation analysis shows that the height of the sliding source area is the main influencing factor of the runout distance of rainfall-induced group-occurring shallow soil landslides. The established optimal predictive models exhibited a small residual sum of squares (RSS) and an adjusted R² value greater than 0.9, indicating high reliability and precision. Model validation showed that the relative errors between the predicted and actual values were small, with maximum relative errors of 15.6%, 13.5%, and 12.4% for foot slip-out, middle slope slip-out, and cut slope slip-out types, respectively.

This study established a predictive model for the runout distance of rainfall-induced group-occurring shallow soil landslides based on statistical analysis, providing a scientific basis for landslide disaster prevention in similar regions. Although the models demonstrated high predictive accuracy across different types of landslides, the data were primarily sourced from a specific area, and further validation is needed for their applicability in other regions. Future research could consider increasing the sample size and influencing factors to further refine the models.

In order to effectively predict and prevent dangerous rock failure and ensure the safety of highway transportation.

This paper carries out indoor modeling tests on the initiation of dangerous rock failure under four different working conditions by means of joint monitoring of acoustic emission and video, and combines the evolution characteristics of acoustic emission signals in the time, frequency, and time-frequency domains, as well as the temporal and spatial characteristics of video images, to study and analyze the initiation mechanism and precursor characteristics of the process of dangerous rock failure under a variety of different influencing factors.

The study and analysis of the initiation mechanism and precursor characteristics of the process of dangerous rock failure under a variety of different influencing factors were carried out, and the results showed that, in terms of the initiation mechanism, the main controlling factors of dangerous rock failure include the shift of the center of gravity of dangerous rock, the decrease of the adhesion between dangerous rock and slope surface, and the increase of the overall downward sliding force of the dangerous rock of the slope and the increase of the limit of the anti-sliding force. Among them, the decrease of bonding force between hazardous rock and slope surface (or mother rock) is the common initiating mechanism of slip type and tipping type collapse, the shift of center of gravity of hazardous rock is mainly the initiating mechanism of tipping type collapse, and the increase of overall downward sliding force of hazardous rock exceeding the limit of sliding resistance is mainly the initiating mechanism of slip type collapse. These three types of main control factors can be used as one of the judgment criteria for the initiation mechanism of actual slope failure. In terms of precursor characteristics, before the collapse of dangerous rocks, there are precursor phenomena such as localized falling blocks and small rock avalanches on the macro level, and the acoustic emission signals mostly appear in the middle and low frequency bands and the main frequency band is wide, and at the same time, the middle and high amplitude and energy signals account for a large number of the signals. Therefore, when multiple single precursor features appear simultaneously in the comprehensive precursor features, it can be used as one of the judgment criteria for the occurrence of actual slope failure.

The research in this paper can provide scientific basis and technical support for the monitoring and early warning of highway slope dangerous rock failure, which can help to improve the effectiveness and reliability of the prevention and control of dangerous rock failure disaster.

The geochemical characteristics and sedimentary environment of the Middle Section of Es₁ source rocks in the Binhai Slope were less well studied, which restricts the expansion of hydrocarbon exploration into the sea area.

Based on the newly drilled source rock samples from the Binhai Slope, the geochemical characteristics, depositional environments, and developmental models of the middle section of Es₁ source rocks were systematically investigated by means of petrographic pyrolysis, gas chromatography-mass spectrometry of saturates, and elemental logging techniques.

The results show that the middle section of Es₁ source rocks in the Binhai Slope are mainly Ⅱ₁-Ⅱ₂ kerogen, with TOC values ranging from 0.21% to 8.61%, an average TOC of 2.41% and an average S₁+S₂ of 9.73 mg/g, and are dominated by good–high quality source rocks. The middle section of Es₁ source rocks are in the low maturity–mature stage, with R_o values ranging from 0.58% to 1.32%. The organic matter of the middle section of Es₁ source rocks in the Binhai Slope originated from a mixture of terrestrial plants and aquatic organic matter, developed in a weakly oxidizing–weakly reducing freshwater environment. During the depositional period, the lake water in the basin was relatively deep, the climate is warm and humid, and the paleo-productivity of the lake water is at high level.

The Middle Section of Es₁ source rocks in the Binhai Slope are of good organic matter type, with high organic matter abundance and moderate maturity. The sedimentary environment was conductive to the enrichment and preservation of organic matter, and the Middle Section of Es₁ source rocks in the Binhai Slope have strong hydrocarbon generating capacity and exploration potential.

Currently, the understanding of the vertical and horizontal zonation of this volcanic weathering crust reservoir and the distribution patterns of favorable reservoirs remains unclear, hindering further exploration of volcanic oil and gas in the area. Therefore, an in-depth analysis of this unique volcanic weathering crust reservoir is necessary.

This study, based on data from well logging, drilling, lithology, and field geological profiles, analyzed the formation process of the volcanic weathering crust, its vertical and horizontal zonation, and favorable exploration directions.

The evolution of the Carboniferous volcanic weathering crust paleo-buried hill in the study area can be divided into four stages: the initial fissure-type volcanic eruption stage, the intermittent stage of volcanic eruptions, the stage of renewed volcanic activity, and the formation stage of the Carboniferous volcanic top weathering crust. The volcanic weathering crust reservoir mainly formed during the intermittent stages of volcanic eruptions, with the weathering materials consisting of volcanic rocks formed during the eruption periods and sedimentary rocks associated with volcanic activity. Multiple episodes of volcanic eruptions and weathering resulted in the formation of multi-layered weathering crusts within the volcanic rocks.

Each episode of the weathering crust can be divided, from bottom to top, into the bedrock layer, fracture layer, sandy layer, and sedimentary layer. Among these, the fracture layer and sandy layer have better reservoir properties and are the main oil and gas reservoirs. Horizontally, the weathering crust is divided into the dissolution platform area, dissolution slope area, and dissolution depression area. The dissolution slope area, where fractures and dissolution pores are most developed, is the most favorable exploration target. In contrast, the dissolution depression area suffers from severe cementation, resulting in the poorest reservoir properties.

The deep subsag zone of faulted lake basins are under-explored and are important exploration areas for finding strategic resource replacement, and research on hydrocarbon accumulation system in the deep subsag zone needs to be carried out.

This study takes the deep subsag zone of the Huanghua Depression as an example, and carries out in-depth research on the sedimentary, reservoir, source rock, and trap condition in the deep subsag zone, so as to clarify the distribution mechanism of sand, the mechanism of reservoir development, and the model of hydrocarbon accumulation in the deep subsag zone.

The results show that the deep subsag zone of the Cangdong Sag is a basin-margin sag situated close to the provenance area. Its source-fault-sag configuration controls the development of fan-delta deposits, characterized by a "sandstones-mudstones interlayer with lower source and upper reservoir" spatial configuration and an "early oil charging and early deep burial" temporal configuration between source rocks and reservoirs. In contrast, the deep subsag zone of the Qikou Sag is a basin-center sag farther from the provenance area. Its source-trench-slope configuration controls the development of far-shore submerged fan deposition, featuring a "mudstones covering sandstones with three-dimensional oil charging" spatial configuration and a "late oil charging and late deep burial" temporal configuration between source rocks and reservoirs. Both types of the deep subsag zones possess abundant mudstones and sandstones. The high-quality source rocks in these sags exhibit a high level of thermal maturity, conductive to large-scale hydrocarbon generation. Additionally, they possess favorable conditions for the development of large-scale sand bodies. The three controlling factors of "dominant minerals, organic acid dissolution, and anomalous overpressure" contribute to the development of effective reservoirs in the deep subsag zones. The deep subsag zones boast superior trapping conditions, primarily characterized by lithological hydrocarbon reservoirs. They exhibit features of source-reservoir coupling, proximal source charging, and zonal enrichment.

This study further confirms the excellent exploration potential of the deep subsag zones in faulted lake basins, providing insights and references for hydrocarbon exploration in such areas.

The provenance of detritus is a crucial factor in controlling the development and distribution of the Benxi Formation sandstone reservoir in the Yanchang exploration area.

Based on previous research, this study employed four methods for the provenance study of the Benxi Formation, including detrital zircon U-Pb ages, heavy mineral assemblages, trace elements, and sandstone gravel size statistical analysis, on sand and mudstone samples from 37 wells in the Yanchang exploration area.

The results show that zircon age populations with peaks at 1912 Ma and 2425 Ma correspond to the northern edge of the North China Craton, whereas the peak groups at 435-447 Ma and 952-976 Ma from five wells are related to the North Qinling Mountains. Based on these findings, the provenance of sedimentary rocks can be divided into two primary directions: north and south. Furthermore, heavy mineral assemblage analysis revealed higher zircon and tour Maline content in the southwest region, while the southeast region exhibited a higher rutile content, suggesting that the southern source can be further subdivided into southwest and southeast directions. Corresponding trace element analysis, particularly the Zr/Nb values, corroborated these findings, indicating two provenance directions of southwest Longdong and southeast Yuxi. Additionally, the spatial distribution of sandstone gravel diameters suggested a southeast source within the study area.

Comprehensive analysis concludes that the Benxi Formation in the Yanchang exploration area can be categorized into three prmary source areas: northeast, southwest, and southeast. These sources correspond to erosion areas along the northern margin of the basin, the southern margin of the Qilian Mountains, and the eastern section of the North Qinling Mountains, respectively. The southeast source area is closest to the Yanchang exploration area and contributes more sediments than other source terranes. This study illustrates the three provenance areas of the Benxi For Mation and their influence zones, which are significant for predicting the distribution of sand bodies and delineating sedimentary facies in the Yanchang exploration area.

In order to quickly and accurately assess the damage degree of reservoir dams hit by earthquakes,

This paper selects the earthquake damage details of each reservoir dam of the Wenchuan 8.0 magnitude earthquake, combines the structural characteristics of the dams and the intensity of earthquakes to construct the assessment index system and data set, uses the k-nearest-neighbor interpolation method to deal with the missing value of the samples and judges the sample feature correlation, and proposed a rapid assessment model of reservoir dam earthquake damage based on gradient boosting algorithm. Four hyper-parameter optimization methods, namely Grid Search (GS), Particle swarm optimization (PSO), Bayesian optimization (BO) and HyperBand Search (HS), are used to optimize the parameters of the Gradient Boosted Tree (GBDT) regression algorithm,compare the models based on their performance metrics (coefficient of determination R², root mean square error RMSE, mean absolute error MAE), and rank the feature importance of the optimal models.

The results show that the BO-GBDT model can assess the degree of earthquake damage of reservoir dams with the shortest time consumption as well as high accuracy, with a high coefficient of determination R² of 0.99, and a feature importance score indicating that the maximum crack width is the most influential factor. Comparing the results of using this model with those of the earth dam damage assessment model based on the improved empirical statistical model, the accuracy is further improved, which verifies the reliability of the model in the application of rapid investigation and assessment of post-earthquake damage of reservoir dams.

In order to find the relationship between borehole imaging and flow velocity and direction tests in calculating the permeability coefficient of a single fracture, and to propose a new and more convenient method for calculating the permeability coefficient.

Taking the borehole ZW2 in the Lichuan coal mining area as an example, this paper determines the equivalent permeability coefficient through the underground water flow velocity and direction test and the borehole imaging test and compares it with the result of the pumping test.

The results show that the equivalent permeability coefficients obtained from the borehole imaging test and the velocity and direction test are basically consistent with the permeability coefficient calculated by the pumping test, with errors of 40% and 9%, respectively. Comparing the results of the borehole imaging test with those of the velocity and direction test, there is a linear correlation between the two, with the regression equation being Y=−0.23+0.82X. By correcting the permeability coefficient obtained from the borehole imaging test through the linear relationship between the two, a new method for calculating the permeability coefficient has been obtained, which is more convenient and accurate.

This method is relatively reliable and can directly calculate the permeability coefficients of single fractures, regional fractures, and the entire borehole at different scales. It has the advantages of short test periods, less work, lower cost, and wide applicability.

As a front issue in the study of deposit geology and field geomechanics, the “end effect” of ore formation has attracted more and more attention from experts and scholars.

The research content of the “end effect” of ore formation mainly include the “end effect” of ore-forming structures and that of ore-forming fluids: for the former, the “end effect” of multi-scale ore-controlling structures in different tectonic settings and their role in controlling ore fields and ore deposits (bodies), especially the structural types, mechanical properties, and rock- and ore-controlling mechanisms of the “end” of deposit-level ore-controlling structures, the trapping effect of ore-forming fluids, and the location mechanism of ore deposits (bodies), are studied basis of the structural analysis of geomechanics of ore fields and in combination with structural(alteration) lithofacies mapping technique and geophysical probing technique; as for the latter, the characteristics of ore-forming fluids can be reflected through the study of fluid inclusions and isotopes/ Trace element geochemistry and the temporal and spatial evolution process of the “end” of ore-forming fluids can be finely depicted through the study of the zoning effect of the “end” of ore-forming fluids, thus revealing the limitation of the physicochemical conditions of structures on ore-forming process.

From the perspective of the coupling relationship between the “ends” of ore-forming structures and ore-forming fluids, an in-depth study of the rock and ore-controlling mechanisms under the “end effect” of structures and the genetic relation of structure-fluid coupled ore formation can be made by closely combining the study of deposit geology and fluid geochemistry, structural analysis of ore fields, and geophysical prospecting technique, thus providing a basis for the prediction for deep ore prospecting.

The vadose zone serves as a critical link between vegetation and groundwater, with its lithological structure being one of the main factors influencing groundwater ecological functions. However, the weak permeable interlayer in the structure of the venous zone has a delayed and delayed effect on the infiltration flow from the ground and local storage (water retention in the upper layer). Although the water volume of this part is very small, it has certain water supply significance for the maintenance of vegetation ecology in extreme arid areas. In order to explore how lithologic structure affects soil water content distribution,

Four soil columns were designed: homogeneous soil column (O), thin interbedded soil column (A), single thick interbedded soil column (B) and double interbedded soil column (C). The indoor drainage and infiltration experiments are conducted on these layered heterogeneous soil columns. The numerical simulation of variable saturation flow is carried out based on physical experiments.

During the experiment, the fine-grained soil interlayer structure causes water retention in the interlayer and at the upper and lower interfaces of the interlayer, forming a water accumulation area. Compared with column O, the water release duration of column A, column B and column C increased by 290 h, 500 h and 780 h, respectively, and the water holding capacity increased by 6.20 cm, 7.90 cm and 7.83 cm, respectively. The numerical simulation results show that the modified van Genuchten model can better simulate the layered soil moisture profile.

Fine-grained soil interlayer has a significant retarding effect on the underwater migration characteristics of infiltration, and water is mainly retained inside the interlayer and at the upper and lower interfaces of the interlayer. The increase in the thickness and number of interlayers will lead to more water retention inside the interlayer and at the interlayer interface. The corresponding relative permeability equation is divided into three stages, which can effectively improve the simulation accuracy of layered soil water content profile.

Excessive carbon dioxide (CO₂) emissions have caused global climate variability, leading to a series of environmental problems. As a key technology to reduce CO₂ emissions, carbon capture, utilization and storage (CCUS) plays an important role in relieving large-scale CO₂ emission reductions, and the application of CO₂ storage projects for the saline aquifer in offshore China has a broad application prospect and great technical and economic potential.

To address the problem of unclear understanding of the favorable areas and storage potential of CO₂ in the saline aquifers in the Ying-Qiong Basin, the suitability evaluation of geological storage of CO₂ is carried out by calculating the weights of the indicator components and the suitability score based on the geological characteristics of the Ying-Qiong Basin. In addition, the CO₂ storage potential of the saline aquifer in the Ying-Qiong Basin is preliminarily evaluated by combining the effective CO₂ storage coefficients calculated by numerical simulation method and different storage potential calculation methods.

Results show that the storage capacity obtained from EC method is less than that determined by the USDOE and CSLF methods. Since the CSLF method considers the storage mechanisms such as geological structure storage, residual gas storage and dissolution storage, the results seem more reasonable.

In summary, the CO₂ storage potentials of the saline aquifer in the Yinggehai Basin and Qiongdongnan Basin are 7.96×10⁶ and 4.40×10⁶ million tons, respectively, and the total CO₂ storage potential in the saline aquifer in the Ying-Qiong Basin is 1.24×10⁷ million tons, which further verifies the great potential of the industrial-scale pilot and demonstration projects of CO₂ storage in the saline aquifer of the Ying-Qiong Basin and provides a good opportunity for the next step of carrying out the CO₂ storage project in the saline aquifer of the Ying-Qiong Basin.

Hydrothermal barite deposits are the main exploration targets for barium. The Wuling-Miaoling area, located in the middle part of the Yangtze craton, contains abundant hydrothermal barite deposits. In recent years, some barite orebodies have been discovered within interlaminar fracture zone between the Upper Cambrian Loushanguan Formation and the in the Lower Ordovician Tongzi Formation in the region. The orebodies with stable extension are of great metallogenic potential. However, the genesis of the barite deposits in the Yuqing area are poorly understood, leading to ambiguity about the further ore exploration.

In this contribution, we investigate the barite deposits in the Yuqing area, presenting a metallogenic model based on detailed petrographic observations and major/trace elements and sulfur isotopic analyses.

Our results show that the interlayer fracture zone and tensile fracture generated by silica-calcium interface are the main ore-controlling structures of barite in this area. The geochemistry of barite shows that the ^δCe of wall rocks (dolomite) has no abnormalities. In contrast, the negative ^δCe anomaly (mean 0.66) of barite samples indicates that barite is formed under oxidation conditions. The Sr vs. (Cu Zn), Y/Ho ratios and sulfur isotopes suggest that ore-forming material (S and Ba) soured from marine evaporite in the Cambrian strata.

Based on previous studies, we propose that the Yanshanian tectonic event drove the migration of the basinal fluids that extracted the Ba-rich evaporite strata. The mixing with meteorite caused the precipitation of barite along the interlayer faults (silica-calcium interfaces).

In order to study effects of cadmium on mechanical and physical-chemical characteristics of loess,

a series of tests including compression test, direct shear test, compaction test, permeability test, acidity and alkalinity test, and particle size analysis were performed on remolded loess with different cadmium concentrations. Changes in microstructure of the cadmium contaminated loess were observed by Scanning Electron Microscope (SEM).

The results show that the pH value of loess decrease significantly while concentration of cadmium is higher than 300 mg·kg⁻¹, permeability increase first and then decrease with the increase of cadmium concentration, cadmium pollution has no obvious effect on particle size distribution of loess. With the increase of cadmium concentration, compressibility of loess enhances, cohesion decreases, angle of internal friction and shear strength increase first and then decrease, the optimal moisture decreases, and the maximum dry density increases. Porosity and proportion of medium pores increase under 30 mg·kg⁻¹ cadmium concentration, but decrease under 3000 mg·kg⁻¹, while proportion of small pores increase under 3000 mg·kg⁻¹ cadmium concentration.

The main reasons for changes on physical-chemical characteristics, mechanical characteristics and microstructure of cadmium contaminated loess are hydrolysis of cadmium nitrate in pore water, chemisorption reaction of cadmium on loess particles, and compressed double electric layer after adding cadmium. The results are intended to provide reference for evaluating engineering properties and mitigating engineering disasters of cadmium-contaminated soils in loess area.

Artificial intelligence technology has become a hot spot and frontier direction in the exploration and development of mineral and oil and gas fields, but in the field of geothermal field development, there are few relevant studies. This paper first analyzes the important value of large data and artificial intelligence application in oil and gas field development, and then introduces the application of artificial intelligence in geothermal field development at present.

Taking Xianyang geothermal field in Shaanxi province as an example, the single well geothermal water temperature time series model was constructed by using long and short term memory neural network (LSTM) under the predestined production mode. Random forest and XGBoost algorithm were used to predict the groundwater temperature of multiple geothermal wells.

The accuracy of the three models was above 95%, and the running speed is fast. The depth at the top of the water intake section is the primary influencing factor of geothermal water temperature in this area. The model verifies that the fault zone plays an important role in heat storage.

The application of the example verifies the superiority of machine learning in solving complex problems in geothermal field development, and the reasonable application of artificial intelligence technology can provide more effective decision-making basis for the efficient development of geothermal field and scientific cost reduction, quality improvement and efficiency improvement.

Hot dry rock is a widely distributed and abundant geothermal resource, and its development and utilization are of great significance in reducing fossil energy consumption, alleviating environmental pollution, and ensuring energy security. Enhanced geothermal systems are currently the main way of developing hot dry rock resource, generally implemented through several links such as engineering site selection, geothermal drilling, thermal reservoir stimulation, flow test, and power generation engineering. Among them, flow test is an important link in undertaking thermal reservoir stimulation and power generation engineering, used to form injection and production well groups, evaluate cycle circuits, expand heat exchange capacity, and lay the foundation for ultimately achieving power generation goals safely and stably. The implementation process of flow test has the characteristics of long-term and complexity, which can easily lead to problems such as insufficient connectivity, strong microseismic effects, liquid leakage, scaling of the circulating liquid, and insufficient equipment reliability. Therefore, the flow test of hot dry rock development sites internationally is often intertwined with drilling and reservoir stimulation, and accompanied by scheme adjustments, in order to gradually achieve the power generation goal.

This article briefly summarizes the flow test experience and exploration direction of typical hot dry rock development EGS systems at home and abroad, elaborates on the influence of various factors on flow test, and proposes development suggestions based on the actual situation of the Qinghai Gonghe site. It can be seen that in the past, improving the effectiveness of flow test was mainly achieved through methods such as adjusting the development layer and well group, long-term circulation, hydraulic fracturing, and chemical stimulation. However, current technicians mainly explore by accurately obtaining engineering parameters and improving the design of well groups and reservoir stimulation processes.

In summary, the formulation of the flow test plan needs to fully consider geological factors and adapt to local conditions. At the same time, key technologies in flow test, such as reservoir evaluation, reservoir stimulation, and engineering implementation, are worthy of in-depth research. The progress of these key technologies requires the establishment of the numerical models with more accuracy , the improvement of the accuracy and stability of various monitoring techniques, the application of more diverse hydraulic fracturing and chemical stimulation processes, and the establishment of a more comprehensive risk prevention and control system for induced earthquakes. In addition, the application of new technologies is also a possible breakthrough. Supercritical carbon dioxide and liquid nitrogen fracturing technology has advantages in thermal reservoir fracturing and energy enhancement in hot dry rock stimulation. Explosive fracturing technology has a certain effect on improving the complexity of near wellbore fractures and enhancing the injection capacity of well groups.Finally, with the goal of experimental power generation, focusing on key issues in multi well group flow test, improving the construction process of flow test is also an effective means to improve efficiency and save costs. With the increasingly mature development technology, hot dry rock geothermal resources will become an important part of China's energy structure, playing an important role in economic development and environmental protection.

To address this challenge, it is urgent to strengthen the research and geological exploration of new types of niobium deposits.

This study focuses on claystone in the lower part of Upper Permian Longtan Formation (P₃l) in Xingwen area of southern Sichuan. Based on the analysis of niobium content in collected samples, we combine various analytical techniques such as X-ray powder diffraction (XRD), scanning electron microscopy with energy dispersive spectrometer (SEM-EDS) and Electro-Probe Microanalyzer (EPMA), to conduct mineral identification and quantitative analysis on niobium-enriched samples.

The results reveal that the content of Nb₂O₅ in the claystone ranges from 41×10^-6 to 437×10^-6, with an average of 187.2×10^-6, which reaches the lowest industrial index of weathering crust type deposit, and the enrichment degree of Li, Ga and other elements is also high. The clay layer is rich in multiple critical metals and has significant ore-forming potential and prospecting prospect. Powder XRD analysis unveiled the abundant presence of anatase within the claystone in the study area. EPMA analysis revealed that the content of Nb₂O₅ within anatase varies from 0.09% to 3.40%, with an average of 1.17%.

According to the content of niobium in anatase, SEM-EDS scanning surface and the content of Nb₂O₅ in a whole rock sample, we believe that niobium within anatase primarily exists in the form of isomorphism, with a portion adsorbed by clay minerals. Niobium is mainly inherited from the weathering products of minerals such as sphene in the Emeishan basalt and the strength of weathering had an important influence on the enrichment and mineralization of niobium, which is a weathered-sedimentary deposit.

Studying the spatial distribution law of earthquake-induced landslides can not only provide an important basis for the investigation of hidden dangers of geological disasters in disaster areas, but also be of great significance for post-disaster reconstruction, post-disaster resettlement and site selection, and geological disaster prevention and control.

Taking the earthquake with M_s6.8 in Luding County, Ganzi, Sichuan Province on September 5, 2022 as an example, firstly, based on the optical image (DOM) with 0.2m resolution and the digital elevation model (DEM) with 0.5 m resolution obtained after the earthquake, the earthquake-induced landslides were interpreted by artificial visual three-dimensional remote sensing, and then combined with field investigation and correction, the final number of earthquake-induced landslides was determined. On this basis, the relationship between the geological background such as topography, geological structure and seismic factors and the distribution of earthquake-induced landslides was analyzed.

①The Luding earthquake event triggered 9248 landslides in the study area of about 680 km², mainly small and medium-sized landslides, and the highest area density of landslides was concentrated in the intersection of Xianshuihe fault, Daduhe fault and Jinping mountain fault. The total landslide area is about 45.57 km², and the average landslide area can reach 4941 m²; ②The distribution of landslides in this earthquake is mainly influenced by PGA and fault structures, and most of them are distributed within the range of PGA> 0.6g and 1km from both sides of the seismogenic fault; In addition, the development of landslide is negatively related to the distance from water system and road; Locally influenced by topographic factors, it mainly develops at the elevation of 1200-2400 m, the slope is 30-60, and the slope is eastward and southeast, and the stratum lithology is mostly hard rock; ③The relationship between the number and area of landslides and magnitude of Luding earthquake also follows exponential distribution; At the same time, due to the high accuracy of the basic data of this interpretation, the number of earthquake landslides obtained by interpretation is more than that of other documents, with a smaller minimum area and a larger total area.

The results obtained in this study have been applied to the post-disaster recovery and reconstruction in Luding earthquake-stricken area.

There are many factors affecting the bonding performance of the anchor-mortar interface, and the current research on the bonding performance of the interface focuses on the influence of a single factor, while the research on the bonding performance of the interface under the action of multiple factors still leaves a gap.

In this paper, we take the anchor-mortar as the research object, using electrochemical impedance spectroscopy to obtain the state of the anchor-mortar interface and electrochemical parameters under different influencing factors, obtain the bond strength of the anchor-mortar interface through the pullout test, and combines the electrochemical parameters to investigate the relationship between the electrochemical parameters and the pullout load when the specimen maintenance is completed and analyses the influence of the three factors on the bonding performance of the interface between the anchor-mortar.

The sensitivity analysis of orthogonal test shows that the pull-out load of the specimen is mainly controlled by the diameter of the anchor rod, the pore solution resistance (R_s) is mainly controlled by the water-cement ratio, and there is no obvious controlling factor for the charge transfer resistance (R_ct); at the early stage of specimen maintenance, under the influence of the three factors, there will be two kinds of states of the anchor-mortar interface, namely, complete passivation film and incomplete passivation film. The results of the study show that, within the range chosen for the test, the pullout load increases with the increase of fine sand particle size and the decrease of water-cement ratio, and the pullout load of the specimen is positively correlated with the pore solution resistance (R_s) and charge transfer resistance (R_ct).

The research results are of great significance for the validation of the effectiveness of anchored structural mortar proportioning and application.

In order to clarify the development characteristics of such reservoirs and reduce the risks associated with deep-ultra-deep oil and gas exploration.

Based on the experimental analyses of well logging, thin section petrography, high pressure mercury injection and PVT phase diagrams, the characteristics of tight sandstone reservoirs and the causes of physical property differences were discussed.

The rock types of Bashijiqike Formation reservoir in Bozi area which the study highlights are medium-fine grained lithic feldspar sandstone and feldspar lithic sandstone. Notable differences exist in the spatial distribution of carbonate cement content. Original porosity in the medium-fine sandstone reservoirs that ranges from 32.4% to 38.1%, exhibiting comparable intergranular compaction strength primarily reliant on point-line contacts. Southern reservoirs maintain an average porosity of 8.6% and an average permeability of 3.4×10⁻² μm². Central reservoirs present an average porosity of 6.53% and an average permeability of 0.65×10⁻³ μm². The average porosity and permeability of the northern reservoir are 4.9% and 0.62×10⁻³ μm² respectively. Primary intergranular pores dominate the southern reservoir space, whereas residual intergranular pores and dissolution porosity prevail in the northern and central zones. Furthermore, superior pore-throat structures characterize the southern region compared to the northern and central sectors.

The physical properties of sandstone reservoirs in Bozi area are controlled by sedimentation, diagenesis and tectonic processes (fissures), among which carbonate cementation emerging as the principal factor of the late reservoir physical properties alterations. Overpressure, hydrocarbon fluid charging, and fracture development significantly affect carbonate cementation, subsequently causing variations in reservoir physical properties. Stronger overpressure, earlier oil and gas charging time and limited fracture filling result in better reservoir properties in southern Bozi than those in northern and central areas.

The development of karst reservoirs in the Maokou Formation of the Lower Permian in southern Sichuan is a key formation for conventional oil and gas exploration in southern Sichuan. The development level of supergene karst reservoirs is directly controlled by the rich and varied karst microgeomorphology, resulting in strong lateral heterogeneity of karst reservoirs.

This paper uses 3-D seismic data, combined with strata thickness, gradient structure tensor attributes, and geological body carving techniques, to characterize the microgeomorphic characteristics of Dongwu karst in the Yunjin area. Predicting favorable zones for surface karst reservoirs through model forward modeling and amplitude attributes.

Research suggests that:①The Yunjin area had significant differences in karst micro- geomorphology during the Dongwu period, with a series of karst caves developed, which exhibited a seismic feature of "pull-down" of the seismic event event axis at the top boundary of the Maokou Formation;②Effectively characterizing the distribution pattern of karst collapse bodies in Yunjin syncline area using gradient structure tensor attributes combined with geological body carving technology. There are three distribution patterns of karst collapse bodies on the plane: isolated, linear, or contiguous;③The seismic amplitude on both sides of the edge of the karst collapse body is weakened, and the karst process is strong, with the development of karst caves, which is a favorable zone for reservoir development.

This research result has guiding significance for the subsequent prediction of Maokou Formation reservoirs.

Concentrated recharge conditions often significantly impact the water quantity and quality of karst underground rivers. Therefore, it is of great importance to clarify the effects of different concentrated recharge conditions on these aspects.

Based on hydrogeochemical surveys, this study simultaneously monitored the hydrological and hydrochemical dynamics at the sinkhole entrance and underground river outlet of the Qinglongkou underground river system in western Hubei, to explore the impacts of different recharge conditions on the water quantity and quality of the underground river.

The results show that recharge intensity and soil moisture content directly control the generation and convergence processes of flow within the sinkhole, as well as the flow response of the karst underground river system. Rainfall events that do not reach a threshold will not trigger a flow response in the underground river.As concentrated runoff converges towards the sinkhole entrance, the concentrations of various hydrochemical ions increase significantly.The hydrochemical response observed at the outlet of the Qinglongkou underground river system is influenced by the intensity of recharge. Under heavy rainfall conditions, this response is further intensified due to the enrichment of hydrochemical ion concentrations at the sinkhole entrance.Following heavy rainfall, TIN (total inorganic nitrogen) and phosphates accumulate at the sinkhole entrance, leading to concentrations that are 2 to 3 times higher than the natural background levels. Pollutants introduced through concentrated recharge directly contaminate the underground river. In the hydrochemical response, N-${\mathrm{NH}}_4^+ $ enters the karst water cycle prior to N-${\mathrm{NO}}_3^- $, and the fluxes of nitrate and TIN increase at the outlet of the underground river system relative to the inlet. Meanwhile, the flux of ammonium N-${\mathrm{NH}}_4^+ $ gradually decreases over time as recharge occurs, suggesting nitrification reactions within the conduits.

The results of this study can provide a scientific basis for pollution prevention and control, as well as water environmental management of karst underground rivers.

Three-dimensional (3D) geological modeling is a technology which comprehensively uses computer technology, spatial information, scientific visualization, mathematical statistics and other cutting-edge technologies and methods to perform 3D digital representation, characterization and reconstruction of geological phenomena and processes. Its purpose is to provide a visualization platform that integrates scientific research, aided design and decision support for geoscientists, so as to understand and use the essential meanings and laws hidden behind geological phenomena and processes more deeply. [Progress] 3D geological models inferred from field data has become a necessary task for geological research and surveys involving basic geological survey, natural resource exploration and development, and geological disaster prediction and evaluation. This paper takes a comprehensive summarization for the recent progress of 3D geological modeling technology from research objects, data sources, spatial data models, and 3D geological modeling methods from three different perspectives. This paper also provides practical cases of 3D geological modeling technology in the fields of mineral exploration, geological disaster warning, urban underground space planning, oil and gas reservoir characterization, etc. [Prospect] In addition, the future trends of 3D geological modeling and related technologies are discussed.

Thermal structure analyses in the Songliao Basin are mostly confined to the sedimentary scale in the north-south zoning, and the lack of basin-wide thermal structure portrayal at the lithospheric scale constrains the genesis analysis in a geodynamic background.

Based on the published parameters of surface heat flow, geothermal gradient and thermophysical properties, this paper supplements the thermophysical properties of Yaojia Formation, Qingshankou Formation and Quantou Formation, and adds several geothermal field data to comprehensively characterize the geothermal field of the whole Songliao Basin, and analyze the characteristics of the present-day lithospheric thermal structure.

The results show that the geothermal gradient in Songliao Basin ranges from 21.10 to 63.45℃/km, with an average value of 41.41℃/km, which is higher than the global average value of 30℃/km; the distribution of surface heat flow values ranges from 30.38 to 106.58 mW/m², with an average value of 71.85 mW/m², which is higher than the global average value of 60 mW/m² and belongs to a typical "hot" basin. Under the influence of the Pacific plate subduction, the delamination and thermal erosion made the thinned thickness of the thermal lithosphere of 58.59 km. The heat flow contribution by radioactive elements in the thinned crust is only 16.40 mW/m², accounting for 22.83% of the surface heat flow; and under the influence of the dehydration of the stagnant plate, part of the molten mantle heat material is upwelled, the mantle heat flow contributes as high as 55.45 mW/m², accounting for 77.17% of the surface heat flow.

Therefore, controlled by lithospheric thinning and mantle upwelling, the Songliao Basin has "hot" basin properties and "hot mantle and cold crust" lithospheric thermal structure characteristics.

The seepage of fractured rock masses has non-uniformity and anisotropy, and its complexity is reflected in parameters such as density, orientation, and trace length of individual fractures, as well as the connectivity of fracture networks. The connectivity of fracture networks is a difficult problem in calculating the seepage parameters of three-dimensional fractured rock masses. At present, the calculation methods for seepage parameters of three-dimensional fractured rock masses have their own advantages and disadvantages due to different models. To analyze the hydraulic anisotropy and permeability coefficient of fractured rock masses, a new method for solving the permeability coefficient of three-dimensional fractured rock mass dense sections based on dimensionality reduction is proposed.

This method, founded on the simulation of three-dimensional fracture networks, approximates the fractured rock masses through dense sections in different directions, decomposing the three-dimensional fracture network into multiple continuous two-dimensional sectional fracture networks, using graph theory to analyze the hydraulic connectivity and permeability paths, and water head boundary conditions are set to calculate the permeability coefficient. Through the relationship between lines, surfaces, and volumes in space, the calculated permeability coefficient in two-dimensional space is expressed as the directionality in three-dimensional space, and the permeability tensor of the three-dimensional fractured rock mass network is constructed.

By treating the section permeability coefficient as a permeability ellipse, the new method calculates the equivalent permeability coefficient of the section and provides a solution formula for the equivalent permeability tensor of the rock mass. It also discusses the scale effect and the representation of anisotropy in the rock mass. By constructing three-dimensional and two-dimensional fracture networks, different sizes of unit cells were intercepted to calculate the permeability coefficient, and the side length of a typical unit cell was determined to be 20 m. The feasibility of the method was verified through field drilling water pressure experiments.

This method offers a reference for solving the permeability coefficients in different directions of heterogeneous fractured rock masses of various scales.

In recent years, significant progress has been made in the exploration of conventional sandstone reservoirs in Jingjingzigou Formation, Jinan Sag, Junggar Basin, with tertiary reserves exceeding 100 million tons and excellent exploration prospect. Although the main source rock as Lucaogou Formation of Middle Permian in Jinan Sag has been realized based on former research, the study on geochemical characteristics of source rocks and oil source correlation have been rarely reported.

Based on comprehensive utilization of test data such as total organic carbon, rock pyrolysis and characteristics of biomarkers,The geochemical characteristics of source rocks in different intervals of Lucaogou Formation and oils source correlation of Middle Permian have been studied in this paper.

The results show that:①Lucaogou Formation can be divided into three sections according to the characteristics of logging curves. P₂l₁ and P₂l₂ are excellent with high organic carbon content, hydrocarbon generation potential and soluble organic matter content, organic matter type asⅠ-Ⅱ₁ and maturity as early to peak, while P₂l₂ is better. The main of P₂l₃ is "non-general" source rock withⅠ-Ⅱ₁ organic matter type and high maturity affected by overlying.②General reduced environments with P₂l₁ as stratified saline water and P₂l₂ as fresh-brackish water, P₂l₃ is somewhere in between.beneficial to the preservation of organic matter are indicated by the molecular geochemical characteristics of source rocks. In terms of biological composition, it is proved that there are two characteristic hydrocarbon-generating parent materials in Lucaogou Formation, namely, green algae and cyanobacteria. The former evidence is a biomarker (C₂₈ sterane) related to age, while the latter is the detection of β -carotene and medium-chain monomethyl alkane, Hydrocarbon-generating organisms in different intervals are different with P₂l₁ and P₂l₃ mainly composed of aquatic organisms such as bacteria and algae, and cyanobacteria dominate, while P₂l₂ of high input of aquatic plants(green algae) and terrestrial plants. Differences in water salinity in lake basins are the key factors that affect the bloom of cyanobacteria and green algae in different layers of source rocks.③C₃₀αα- hopane was abundant in P₂l₁ and P₂l₂, but is lacking in the source rocks of P₂l₃, Based on the analysis of different isomerization parameters of sterane and hopane, C₃₀αα/αβ may be a possibe maturity parameter.④the Permian crude oil in Jinan Sag can be divided into three types. Type Ⅰ and Ⅱcrude oils were correspond to the source rocks of P₂l₁ and P₂l₂ respectively, and Type Ⅲ crude oil is different to P₂l source rocks, possibly correlated tomudstone of Jingjingzigou formation.

The research has reference significance for future oil and gas exploration and development in Jinan Sag.

In response to the problems of strong reservoir heterogeneity, low signal-to-noise ratio of seismic data, insufficient prediction accuracy of post stack reservoirs, and difficulty in identifying fractures in the ultra deep carbonate reservoirs in Shunbei, a new method for improving the prediction accuracy of fractured reservoirs is explored based on five dimensional seismic data.

Based on the study of the reservoir development characteristics of the Shunbei fault controlled fracture cave type oil and gas reservoir, this article conducts five dimensional seismic anisotropic forward simulation, establishes the relationship between seismic amplitude and fracture parameters, and optimizes the sensitive parameters for fracture prediction; Based on this, derive the Fourier series form of the directional elastic impedance equation, carry out fracture type reservoir prediction, and apply it in the Shunbei X well area.

Through research, the AVAZ seismic response characteristics of ultra deep carbonate rock fault controlled reservoirs have been clarified, and it is pointed out that fracture density is a sensitive parameter indicating fractured reservoirs; Meanwhile, by utilizing second-order Fourier coefficients to characterize the density of fracture development, a precise characterization of fracture type reservoirs was achieved in the Shunbei X well area, with a high prediction accuracy.

The five dimensional sesmic prediction technology based on amplitude attributes enriches the prediction of fracture development density and direction by mining amplitude and orientation information of wide azimuth seismic data. The established Fourier coefficient fracture density mapping relationship provides a quantitative prediction tool for fracture controlled fracture cave reservoirs, and offers new ideas for fracture prediction and target evaluation in fracture controlled fracture cave reservoirs.

To enhance the efficiency of slope stability system calculations for multiple profiles, this study introduces a method based on spatial slope stability coefficient calculations. Initially, the two-dimensional residual thrust method is expanded to incorporate spatial profiles, resulting in the residual thrust method for spatial profiles.

Subsequently, the calculation process is further optimized by realizing the automatic generation and management of the profile on the 3D slope engineering geological model. To achieve swift and efficient calculation of slope stability coefficients, a method based on multi-threaded parallel computation is introduced. Combining this with the residual thrust method for spatial profiles allows for more precise and efficient computation of stability coefficients for multiple spatial profiles.

Using a specific open-pit mine in Xilinhot, Inner Mongolia as a case study, we establish a three-dimensional slope engineering geological model for the internal dump site slope. Seven spatial profiles are automatically generated and stability coefficients are calculated using multi-threaded parallel computation. Finally, we present visual results through visualization techniques.

The research findings suggest that adopting multi-threaded parallel computation for computing slope stability coefficients of multiple profiles can fully utilize computing resources and significantly improve computational efficiency. Furthermore, practical implementation of this method in engineering projects affirms its applicability and feasibility.

However, the study on the genesis of threshold-value elements and the related hydrochemical evolution processes are rare. In addition, some sampling points have exceeded the threshold value, which directly affects the development and utilization of mineral water and is an urgent problem that needs to be solved.

In this study, the Huangshui River Catchment was considered as a target area. Hydrogeochemical and modeling methods were employed to uncover the hydrochemical features and genesis of mineral water by collecting spring samples from the catchment, which can play an important role in understanding the hydrogeochemical processes within the groundwater system in the Huangshui River Catchment.

Most of the groundwater samples in this study area reach the standards of the National Drinking Natural Mineral Water, and all the strontium concentration is higher than 0.2 mg/L with a few samples being rich in lithium and metasilicic acid. The Hydrogeological result shows that the groundwater moving from recharge area to discharge area has a transition of hydrochemical type from HCO₃-Ca·Mg to SO₄-Na, which is the result of gypsum dissolving in groundwater. The relationships between Sr and the major anions such as HCO₃⁻、SO₄²⁻ and Cl⁻ show that carbonates have a limited contribution on Sr concentration in groundwater. Instead, the gypsum layers may contain a certain number of Sr-bearing minerals because of the atom exchange between Ca and Sr. Those Sr-bearing minerals are responsible for the high concentration of Sr in groundwater. In terms of the genesis of Li and Si in groundwater, the ancient salt lake sedimental environment may explain the former one and the dissolving of aluminumsilicate minerals may explain the latter. The inverse modeling shows that the groundwater mainly dissolves gypsum, rock salt and illite, while the dissolution of azurite and lithium pyroxene contributes strontium and lithium in the northern catchment. The dissolution of gypsum and halite leads to the high TDS of groundwater in the southern catchment, combined with the dedolomitization process.

The whole research findings can serve as scientific basis for exploration and preservation of mineral waters.

The distribution of structural planes plays a significant role in determining the engineering and mechanical properties of rock masses. Accurately obtaining information about structural planes is crucial for analyzing the characteristics and stability of rock masses.

Three-dimensional point cloud data of a steep rock slope was acquired using 3D laser scanning technology. After the filtering preprocessing of the point cloud data, the open-source program Discontinuity Set Extractor (DSE) was then used to semi-automatically recognize and classify the point cloud data, obtaining key parameters and clustering information of the slope rock mass structural planes, such as attitude, trace length, and spacing. By fitting the point cloud clustering information, a probability distribution model was created, and a Discrete Fracture Network (DFN) model was established. Furthermore, a three-dimensional block discrete element model of the steep slope was developed using the "Rhino-Griddle-3DEC" integrated modeling method based on the point cloud data. The model investigated the stability of slope and potential failure area.

The results show that under the gravity condition, the safety factor of the whole slope is about 1.5 and the potential unstable area is the dangerous rock mass located on the top of the slope.

Therefore, the structural plane parameters identified by this method can better reflect the engineering properties of the rock mass, providing important guidance for the analysis and evaluation of the stability of steep rock slopes.

Carrying out land surveys and evaluations and developing special industries is a very important task for China to realize rural revitalization and consolidate the results of poverty alleviation. In order to more accurately and effectively guide regional agricultural production layout and specialty industry development, a selenium-rich land survey and evaluation was conducted in Tunliu District, Changzhi City, Shanxi Province, China.

Therefore, the indicators of selenium-rich industry quality, ecological environment and arable land strength were selected to construct a comprehensive quality evaluation system for selenium-rich land, and then fuzzy mathematical method, entropy weighting method, and composite index method were applied to evaluate and grade the land in the study area, and ArcGIS was used to implement the results.

The results show that: ① the land with soil selenium content grades of high selenium and moderate selenium in Tunliu District accounted for 54.47% of the statistical area, and these soils were concentrated in the eastern part of the district; the distribution of cultivated land strength grades in Tunliu District was uneven, and the overall characteristics showed that it was low in the western part and high in the eastern part; the results of the evaluation of ecological environment grades were clean in the whole district. ② There are 299.33 square kilometers of selenium-enriched land in Tunliu District with comprehensive quality grade of first class, accounting for 26.61% of the statistical area, and concentrating in the plain area in the east. ③ Wheat, sharp peppers and green peppers in Tunliu have reached the standard of selenium enrichment of crops. Among them, the selenium enrichment rate of sharp peppers is 100%. In addition, the results of heavy metal element testing show that the crops in the district are in good clean condition.

Based on the evaluation results of land and crops, and in conjunction with the spatial planning of land in Tunliu District, the land is divided into three types: A, B and C. Among them, type A land is characterized by high soil selenium content, rich nutrients and clean environment, so it is recommended to build selenium-enriched wheat and green vegetable planting bases in the area where this type of land is concentrated and develop tourism agriculture at the same time. Class C land is characterized by low soil selenium and nutrient content, which is unsuitable for planting crops, so it is recommended to build deep-processing factories for agricultural products in the areas where this type of land is concentrated, and to develop agricultural trade and tourism at the same time. It provides theoretical support and scientific suggestions for the planning of selenium-rich agriculture industry in Tunliu District and the synergistic development of the region.

In tunnel engineering, the prerequisite for tunnel design and construction safety is to accurately assess the amount of deformation of tunnel surrounding rock.

In this paper, the Firefly Algorithm (FA), Whale Optimization Algorithm (WOA) and Gray Wolf Optimization Algorithm (GWO) are combined with optimized Support Vector Regression (SVR), and based on which three hybrid swarm intelligent optimization prediction models are constructed to predict deformation of extruding surrounding rock tunnels. A database containing 62 samples was constructed, and seven initial parameters of tunnels and surrounding rocks were selected as the input parameters of the prediction models, and the radial deformation of tunnels as the output quantities. The coefficient of determination (R²), root-mean-square error (RMSE), and mean absolute error (MAE) were selected as the evaluation indexes of the model prediction effect. Finally, the effects of different input parameters on the prediction results of tunnel rock deformation were evaluated using normalized mutual information values.

The FA-SVR model demonstrated superior predictive performance during both the training and testing phases compared to the GWO-SVR and WOA-SVR models. For the training set, the corresponding R² values were 0.9634 and 0.9648, respectively, while the RMSE values were 18.786 and 14.699, and the MAE values were 9.460 and 11.170. The ranking of predictive capability was as follows: FA-SVR > WOA-SVR > GWO-SVR.

The results show that the firefly algorithm, the whale optimization algorithm and the gray wolf optimization algorithm can improve the prediction performance of the support vector regression model, the FA-SVR model has the best prediction effect, and the optimized hybrid prediction model performs significantly better than the classical models. The sensitivity analysis shows that joint frequency is the most important parameter that affects the predicted value of deformation of tunnel surrounding rock.