The Bohai Bay Basin, situated within the Eurasian metallogenic belt, is one of the world's two largest belts for sandstone-type uranium deposits, exhibiting significant potential for uranium mineralization. Well logging data indicate the development of extensive high gamma-ray anomalies within the Minghuazhen Formation in the Dagang area.

To investigate uranium ore formation and guide exploration efforts, a multiscale sequence stratigraphic framework of the Minghuazhen Formation was established, including a detailed study of sedimentary microfacies and the delineation of redox zones.

The Minghuazhen Formation was subdivided into five sequences based on variations in log responses and lithological characteristics. Gamma-ray anomalies predominantly occur in the upper part of the lower member (SPN_m^xs) and the lower part of the upper member (SPN_m^sx) of the Minghuazhen Formation. Four sedimentary microfacies were identified: meandering river channel, levee, overbank, and floodplain. Uranium anomalies are primarily associated with the levee and channel sand bodies. The redox zones in these sections were classified into oxidation, transition, and reduction zones, with uranium anomalies mainly occurring in the transition zone.

The integration of sedimentary facies, redox zone distribution, uranium anomaly distribution, and oil and gas distribution suggests that the most favorable conditions for uranium mineralization are present in the levee and river channel microfacies within the transition zone near oil-gas enrichment areas. Consequently, the X7-14-2, X1603, G3-6-20, and G8-15-1 well areas are identified as the most prospective targets for sandstone-type uranium deposits in the Dagang area. This study provides valuable insights for the exploration of sandstone-type uranium deposits in the Bohai Bay Basin.

The dolomite of the Ordovician Majiagou Formation in the Ordos Basin, an important strategic replacement area, has been a research hotspot in recent years. There are few studies on the influence of faults on hydrocarbon accumulation in this set of dolomites. An unclear accumulation model has hindered further exploration and development of the middle and lower strata.

Using the middle and lower assemblages of the Majiagou Formation in the Daniudi Gas Field in the Ordos Basin as a case study, this paper comprehensively analyzes the reservoir distribution and trap types of presalt dolomite using data such as cores, thin sections, well logs, and fluid inclusions. The study analyzes the controlling effect of faults on gas-bearing properties. And the coupling relationship between multiphase fault activities and natural gas charging periods is clarified by establishing a fault-controlled mixed-source gas accumulation model with middle and lower combinations.

The findings indicate show that (1) the natural gas accumulation in the middle assemblage of the Majiagou Formation has the advantage of dual-source hydrocarbon supply in the Upper and Lower Palaeozoic, forming a "sandwich" accumulation with two sets of source rocks flanking the middle reservoir. The gas source of the combination is mainly hydrocarbon supply from the source rocks in the lower Palaeozoic, and the accumulation combination of self-generation and self-storage is developed. (2) Karst reservoirs distributed along faults in the study area are the most important reservoir types in the middle and lower assemblages; trap types, including low-amplitude structural traps and diagenetic circle diagenetic traps, are mainly controlled by reservoir development mechanisms and are the main trap types in the study area. (3) The Majiagou Formation experienced three main periods of fault activity: the Caledonian, Indosinian, and Yanshanian-Hishanian periods. The faults and fissures that formed during the early Yanshan Movement were the most effective and were favourable for natural gas charging. (4) Diagenetic traps, multistage active faults and reservoir types controlled the natural gas accumulation process of the dolomite in the middle and lower Majiagou Formation, thus establishing a fault-controlled mixed-source gas accumulation model.

This study provides a theoretical framework for exploring subsalt dolomite gas reservoirs in fault-prone areas with similar geological conditions.

The first deepwater and deep-stratum gas field was recently discovered in the Baodao 21-1 area of the Qiongdongnan Basin, which is of great significance for petroleum exploration in the deep-water area of the South China Sea.

Based on the newly acquired drilling-seismic data, the sedimentary characteristics of the Third Member of the Upper Oligocene Lingshui Formation and their significance in hydrocarbon exploration were analyzed in the Baodao 21-1 area.

Bidirectional sediment provenances controlled the deposition of the Third Member of the Lingshui Formation, resulting in the early deposition of fan delta in the adjacent uplands and the late deposition of braided river delta fed by sediment sources of the Hainan Uplift on the northwest and the Shenhu Uplift on the northeast. In addition, the routes of sediment transport between steep and gentle slopes show great variability. The evolution of the sedimentary system in the Third Member of the Lingshui Formation can be divided into three stages, including the fan delta deposition in the early stage, the fan delta and braided river delta depositions in the middle stage, and the braided river delta deposition in the late stage. Correspondingly, the sediment provenances changed from the adjacent highlands in the early stage, to both adjacent highlands and Shenhu Uplift in the middle stage, and finally to both Hainan Uplift and Shenhu Uplift in the late stage. The Baodao 21-1 area is close to the hydrocarbon kitchen of the Yacheng Formation and it contains the No.12-1 Fault-Fracture systems and the tectonic-lithologic traps, favoring the petroleum accumulation.

The discovery of the Baodao 21-1 gas field is a breakthrough in deepwater petroleum exploration in China, pointing out that the fracture transition zone of marine basins is a key area for future deepwater exploration.

The middle Miocene submarine fan in the Qiongdongnan Basin is an important target for natural gas exploration in the northern South China Sea. However, there has been no consensus on the source of submarine fan sediments for a long time. Provenance analysis will be important for the optimization of natural gas exploration in this area.

In this paper, the detrital zircon U-Pb age spectrum characteristics of drilling cores from the middle Miocene submarine fan in the Qiongdongnan Basin were analysed and compared with the U-Pb ages of zircons from potential provenance areas to determine the source of submarine fans in the study area.

The results show that ① the U-Pb ages of detrital zircons from the N-1, N-2, N-3 and N-4 wells in the northern part of the basin are characterized by Yanshanian (160, 157, 133, 107, 102, 99 Ma), Indosinian (249, 241, 239 Ma) and Caledonian (466, 455 Ma) age peaks and have high similarity with the U-Pb age characteristics of detrital zircons from Hainan Island sediments but low similarity with the U-Pb age characteristics of detrital zircons from Red River and central Vietnam sediments. ② The detrital zircon U-Pb ages of three wells (S-1, S-2, and S-3) in the southern part of the basin show peak ages of Caledonian (435, 431, 425 Ma), Hercynian (396, 392 Ma), Indosinian (242, 238, 237 Ma), and Yanshanian (143 Ma). The S-2 well has a younger unimodal Himalayan (21 Ma) age peak.

The provenance of the middle Miocene in the northern part of the basin is Hainan Island. The influence of the provenance on the Red River and Central Vietnam is very limited. The provenance of the middle Miocene in the southern Qiongdongnan Basin was a double-source supply from the Red River and Hainan Island and was dominated by the former, with an obvious difference from west to east.

To understand the formation conditions and mineralization regularity of cobalt deposits in this area,

this paper summarizes the geological characteristics, controlling factors, and spatiotemporal distribution patterns of typical associated cobalt deposits in Weiningbeishan based on detailed field investigations and previous exploration results and proposes future exploration directions.

Research has shown that the Datonggou copper cobalt deposit, Chaliangzi iron cobalt deposit, and Tuyao iron cobalt deposit are currently three representative associated cobalt deposits discovered in Weiningbeishan area. Among them, three copper cobalt ore bodies were discovered in Datonggou, with the highest Co grade of 0.06%. Cobalt-bearing minerals mainly include pyroxenite, cobalt-bearing pyrite and cobalt-bearing limonite. There are 4 ore belts and 8 iron cobalt ore bodies are distributed in Chaliangzi, with the highest Co grade of 0.03%. The cobalt-bearing minerals are mainly cobalt-bearing limonite. Only one iron cobalt ore body was found in Tuyao, with the highest Co grade of 0.20%. The cobalt-bearing minerals are similar to those of Chaliangzi. Cobalt mineralization is evidently controlled by faults, with the western cobalt deposit mainly controlled by east-west faults and their combined control with northeast faults, while the eastern cobalt deposits are mainly controlled by north-south faults. Cobalt ore are mainly found in the Upper Carboniferous Tupo Formation, which was the main source strata. Lithological control is mainly observed at the "silica-calcium interface" and the lithological combination interface with different competence, which controlled the mineral precipitation. The cobalt metallogenic era was the Indosinian. Cobalt was closely related to Cu, Au, Fe and Mn. Cobalt related to Cu and Au were mainly distributed in the west, while cobalt related to Fe and Mn were mainly distributed in the east. The diversity of mineral species in this region may be attributed to the multistage superimposition of structures and hydrothermal activity.

The most favourable locations for identifying cobalt deposits are the east-west faults and their intersections with the northeast faults in the western part, the north-south Carboniferous and Devonian interface faults in the eastern part, the " silica-calcium interface " within the Tupo Formation, and the lithological combination interfaces with different competence. Malachite alteration and ferritization are the most important prospecting indicators for copper cobalt deposits and iron cobalt deposits.

It is of great significance for shale oil exploration to clarify the controlling factors of the organic-rich shale lithofacies with low content of gypsum and salt.

Well C1 penetrated stratigraphic unit of the Xingouzui Formationin the Chentuokou Depression, Jianghan Basin was studied. Based on the core and thin section observations and the analyses of whole rock mineral compositions, organic carbon contents (TOC), and geochemical elements, a systematic study on lithofacies, sedimentary environment, and main controlling factors of organic matter accumulation were conducted.

The classification of fine-grained sediments and the saline lacustrine sedimentary model in Jianghan Lake Basin were established. Lithofacies of oil group Ⅱ, the lower Member of Xingouzui Formation Xingouzui Formation in Well C1 can subdivided into seven types: organic-rich laminated dolomite facies, organic-rich layered dolomite facies, organic-contain massive dolomite facies, organic-rich laminated mixed shale facies, organic-rich layered mixed shale facies, organic-contain layered siltstone, and organic-poor massive gypsum-salt rock facies. The co-evolution of paleoclimate, paleosalinity, and paleoredox resulted in the diversity of lithofacies development, and the main controlling factor of organic matter accumulation was the anoxic palaeo-water body. The favorable lithofacies for shale oil exploration are organic-rich/organic-contain laminated/layered dolomite/mixed shale, which deposited in semi-deep lake with brackish water, anoxic condition.

This study reveals the controlling factors for the development of organic-rich lithofacies and its depositional environment of oil group Ⅱ, the lower Member of Xingouzui Formation in the Chentuokou Depression, which can provide valuable insights for shale oil exploration of Xingouzui Formation in related Depression in Jianghan Saline Basin.

In the gentle slope zone of the Dongying Depression, the first member of the Kongdian Formation and the lower part of the fourth member of the Shahejie Formation can be split by a distinctive assemblage of reddish sediments, which originated from both fluvial and lacustrine processes. Extensive research has substantiated the significant exploration potential of the Palaeogene red bed in the Dongying Depression. Nevertheless, the sedimentary facies type of the red bed remains a subject of debate among researchers.

To address this issue, we present a comprehensive analysis of wells W1, W2, and W3, which are located in the Wangjiagang area within the southern gentle slope zone of the Dongying Depression. This analysis mainly focused on evaluating the grain size distribution, grain size parameters, and grain size probability accumulation curves of the red bed.

This study revealed the distinctive characteristics of the red sandstone reservoirs in the study area. These include thin single sand body thicknesses ranging from 1 to 7.7 m and fine particle sizes, changing from 2.24ϕ to 4.73ϕ. The grain size distribution is mainly characterized by unimodal positive skewness curves, suggesting the dominance of the relatively coarse fraction. The grain-size parameter discriminant function and bivariate grain-size parameter plots suggest a fluvial environment. The grain size accumulation probability curves of most samples exhibit a significant transition component (over 50%), and the graphs in the C-M bivariate plot are parallel to the C=M baseline, reflecting the characteristics of density flow. Moreover, the logging curves mainly exhibit box and bell shapes with medium to high amplitudes, indicating that the sedimentary processes primarily involved vertical accretion and lateral accretion. The core analysis revealed the presence of blocky bedding indicative of rapid sediment accumulation, parallel bedding characteristic of unidirectional flow, and small cross-bedding suggestive of weak flow.

In conclusion, it is believed that the red sandstone resulted from distributive fluvial systems deposited with both palaeo-geomorphic features and hot-arid palaeo-climate factors in the study area. From upstream to downstream, the hydrodynamic conditions gradually weakened, the bifurcation of river channels strengthened, the flood erosion ability decreased, the single sand body thickness and sediment grain size decreased progressively, and the fluid properties transitioned from density flow to traction flow. The novel insights of this study offer a fresh perspective for the exploration of petroleum in the red sandstone of the study area. In forecasting such reservoirs, particular emphasis should be placed on analyzing palaeo-provenance and paleo-current while enhancing the identification and characterization of individual-stage flood channels.

Shale generally contains water, and it is highly important to clarify the occurrence characteristics of adsorbed water in shale to improve the drainage effect of shale gas.

This study analysed shale cores from the JY11-4 and JY41-5 wells in the Jiaoshiba area of Fuling. The influence of high-pressure conditions on the occurrence characteristics of adsorbed water in shale was investigated using custom-designed frozen nitrogen adsorption experiments and nuclear magnetic resonance experiments.

The results show that (1) under atmospheric pressure, the average volume of adsorbed water per unit mass calculated by the "weighing method" is 0.017 3 mL/g. The volume proportion of water in the micropores and mesopores (average of 90.94%) significantly exceeds that in the macropores (average of 9.06%). This may be because water molecules cannot occupy the adsorption sites in all the shale pores when the relative pressure is relatively low. Most water molecules condense in micropores and mesoporous pores, and only a few water molecules enter the macropores. In addition, the small and medium pores in clay-rich shale become "filled and blocked" by water molecules in the process of water adsorption. (2) Under a saturated water pressure of 30 MPa, the average adsorbed water volume per unit mass of the sample calculated by the "weighing method" is 0.021 6 mL/g. The volume proportions of water in the micropores and mesopores (average of 40.26%) is lower than that in macropores (average of 59.74%), which may be related to the fact that water molecules can occupy more adsorption sites on the inner surface of micropores and mesoporous pores under the action of capillary forces when the relative pressure is significantly increased. (3) Compared with normal pressure, high-pressure conditions increase the volume of water adsorbed per unit mass of shale (approximately 25% increase in the experiment), and the proportion of water volume in large pores is greater than that in micropores and mesoporous pores. (4) During hydraulic fracturing, the relative pressure of the reservoir increases significantly. Under the action of capillary forces, fracturing fluid may enter large pores that cannot enter under the pressure of the original reservoir to "relieve" the "unsaturated state" of the original shale reservoir. After fracturing is completed, the pressure around the reservoir is gradually released, and the fracturing fluid that originally enters the adsorption pores of the shale may have difficulty overcoming the capillary resistance at the pore, making it difficult to return.

Traditional exploration and geochemical studies have primarily focused on the extraction, interpretation and evaluation of metallogenic element anomalies. This approach, however, overlooks valuable ore prospecting information, which may be provided by other major and trace elements. Consequently, altered minerals cannot be effectively extracted, and geochemical data is under utilized for ore prospecting. Therefore, the author extracts alteration minerals from a mineralogical perspective and make metallogenic prediction.

This paper introduces a new method for extracting alteration minerals based on geochemical data and the stoichiometric ratios of different elements in the mineral chemical formula, referred to as the general element ratio analysis.

Based on geochemical data obtained from 1∶ 25 000 debris geochemical survey in the Gaoshishan area of the Beishan orogenic belt, results show that sericite, K-feldspar and other alteration minerals are closely related to porphyry deposits, which can be effectively identified from SiO₂, Al₂O₃, Na₂O, K₂O and other data. The mapping results reveal that sericite is mostly distributed along the intrusion's margins, while K-feldspar is mainly concentrated in the center of theintrusion. Then, based on the ore-controlling factors and ore-prospecting information, such as alteration minerals, magmatic rocks, structures, and traditional geochemical anomalies. This study further conducts metallogenic prediction for the Gaoshishan area using the weight-of-evidence method, delineating five target areas.

The alteration information extracted in this study has been validated through field investigations confirming that the proposed method is feasible and can provide critical prospecting insights beyond those offered by traditional metallogenic prediction methods.

Chemical oxidation and infiltration technology has become a mature method for shale gas exploitation. This study aims to investigate the influence of geochemical factors on the exploitation process.

In this study, the Doushantuo Formation shale in Yichang, Hubei Province, which exhibits significant potential for shale gas exploitation and contains a high organic matter content along with pyrite, was selected as the research object. Two commonly used oxidants, 15% H₂O₂ and 0.5 mol/L Na₂S₂O₈, were selected for oxidation corrosion experiments conducted at normal temperature and pressure. Post-reaction measurements included cation concentration, pH, Eh, mass loss and XRD analysis.

The results show that Na₂S₂O₈ outperforms H₂O₂, and the advanced oxidation process driven by pyrite and the erosion effect of carbonate under acid production make the acidic environment more suitable for the dissolution of carbonate-rich shale. An increase in temperature enhances the thermal decomposition of Na₂S₂O₈ and H₂O₂. The thermal decomposition of H₂O₂ produces O₂, and Na₂S₂O₈ produces H₂SO₄, O₂ and SO₄^- with strong oxidation. Thus, the temperature's enhancement effect on Na₂S₂O₈ is greater than that on H₂O₂. Sodium ions (chloride) can promote the release of Ca²⁺ and Mg²⁺ during Na₂S₂O₈ and H₂O₂ oxidation, indicating that a high concentration of NaCl in groundwater plays a positive role in the oxidation and dissolution of shale. Both calcium ions and sulfate ions can cause gypsum precipitation by influencing the interactions between the reactions, thus affecting the oxidative dissolution of shale. Low concentrations of exogenous calcium ions reduce the buffering effect of carbonate and promote its dissolution, while high concentrations of exogenous calcium ions cause secondary mineral precipitation, block shale pores and hinder the oxidation and dissolution of shale. However, the effect of sulfate ions on the oxidative corrosion of shale differs from that of calcium ions. A low concentration of exogenous sulfate ions inhibits the oxidative corrosion of shale by generating secondary ore and impeding the oxidation of pyrite.

Therefore, in the future process of shale gas oxidative fracturing for extraction, it is necessary to preassess the water chemical parameters of the exploitation formation in advance and select the oxidation liquid and mining modes based on the temperature, pH and cationions.

To clarify the oil and gas accumulation patterns and main controlling factors of the thin weathered crust volcanic rock reservoir at the top of Member 2 of the Fengcheng Formation in the southern Mahu Sag(Manan Sag).

This paper provides a comprehensively analyses of the volcanic rock characteristics, reservoir properties, and oil and gas geological features. Furthmore, an oil and gas accumulation model for volcanic rocks in the slope area is established.

Research has shown that Member 2 of the Fengcheng Formation in the southern Mahu Sag is mainly composed of basalt and tuff. The basalt with the volcanic overflow phase developed high-permeability reservoirs abundant in oil and gas. Overall, the crude oil is medium-high viscosity and light-medium waxy. Its distribution pattern of C₂₀, C₂₁, and C₂₃ tricyclic terpanes resembles a mountain peak, showing a significantly higher relative content of tricyclic terpanes. In contrast to crude oil, the distribution of tricyclic terpanes in in-situ source rocks demonstrates an upward pattern, with maturity parameters of biomarkers also displaying lower maturity characteristics. Based on the consistent research results of the carbon isotope characteristics of crude oil in the study area and in the Fengcheng Formation source rocks, it is infered that the oil reservoir in the study area has undergone multistage oil and gas charging.

The volcanic rocks in the study area exhibit strong vertical and horizontal heterogeneities, with crude oil density decreasing with depth. It is believed that oil and gas mainly migrate from low to high parts along permeable strata below volcanic rocks and enter volcanic rock reservoirs under buoyancy. They accumulate reservoirs in structures or lithological traps with relatively good reservoir properties and preservation conditions. This is a typical slope area-structure lithology-multistage volcanic rock oil and gas reservoir formation model.

The Sikeshu Sag of the southern Junggar Basin is tectonically located in the western thrust belt of the North Tianshan Mountains. The basin has undergone multiple stages and multidirectional tectonic movements since the Palaeozoic. Clarifying the structural characteristics and evolutionary process of the structural system in the study area is critical for petroleum exploration and development in such petroliferous basins.

Utilizing the seismic data interpretation and the outcrop geological investigation of the Sikeshu Sag, spatial-temporal variations in the structural patterns and stress fields were revealed, and a tectonic evolution model was established.

This study indicates that the compressional inversion and strike-slip structures were widely developed in the deep-buried layers of the Sikeshu Sag, but the thrust and decollement structures were more prevail in the shallow layers of the Sikeshu Sag. According to the structural style, the Sikeshu Sag can be divided into the southern compressional fault-fold belt, central strike-slip compressive-torsional belt, and northern uplift belt. The Sikeshu Sag experienced two periods of strong tectonic uplift, corresponding to the peak period of two stages of fault activity. The tectonic environment and stress field conditions underwent multiple changes: the NNW-SSE extension driven by the back-arc rifting during the late Carboniferous to early-middle Permian, the rift-depression transition triggered by the NNW-SSE extrusion of the Zaire orogenic movement during the late Permian to Triassic, the regional depression induced by the NNW-SSE extrusion of the peripheral orogenic belt and Chepaizi uplift during the late Jurassic to Palaeogene, and the reactivation of foreland caused by NS extrusion of North Tianshan Mountains during the Neogene.

This study explores the tectonic evolution of the Sikeshu Sag under multiphase stress fields, which favors the better understanding of the overall tectonic pattern changes in similar petroliferous basins and provides new insights for the next steps of petroleum exploration in the study area.

Accelerated the generation of natural gas hydrate is crucial for advancing hydrate-based technologies such as gas storage, gas separation, and CO₂ capture.

The kinetic characteristics of methane hydrate generated with the w_B=0.05% functionalized (hydroxylated, carboxylated, and aminated) multi-walled carbon nanotubes(MWCNT) system, and in combination with the w_B=1.0% L-leucine were investigated through constant temperature and constant volume methods.

The combination of multiwalled carbon nanotubes and carboxylated and hydroxylated multiwalled carbon nanotubes with L-leucine, significantly reduced the induction time for natural gas hydrate nucleation to approximately 25, 22, and 13 minutes, respectively. This promotion effect is comparable to that of the typical promoter sodium dodecyl sulfate, and the promotion effect is better than that of a single additive system. The methane storage density of the compounded system reached 136-142 mg/g. Analysis of both the average and instantaneous methane uptake rates indicated that multiwalled carbon nanotubes had minimal impact on the growth kinetics of methane hydrate during the growth phase. The growth of methane hydrate in both the compounded and L-leucine systems were similar, characterized by a rapid increase in uptake rate to a peak value, followed by a rapid decrease and eventual completion of the growth phase.

A comprehensive analysis suggests that the combination of MWCNTs and L-leucine synergistically enhances the nucleation rate of methane hydrate, whereas the process and rate of the growth phase are predominantly influenced by L-leucine. This study presents a new idea for exploring the differentiation mechanism of different types of additives in enhancing the kinetics of methane hydrate generation.

In order to accomplish the objective of sustainable development and utilization of geothermal energy, it is imperative to elucidate the optimal production-reinjection well spacing considering varying quantities and temperatures of reinjection.

The thermal reservoir of the Guantao Formation in northern Shandong Province is selected as the research subject, and a conceptual model and mathematical model for layered thermal reservoir development are established. COMSOL Multiphysics multifield coupling simulation software is employed to develop a geothermal production-reinjection well spacing calculator. The accuracy of the model is validated through parameter fitting and simulation results.

Based on the software APP development function, which is guided by the input of ordinary users, the relevant parameter input was simplified for ease of use, leading to the establishment of an application for calculating geothermal production-reinjection well spacing. In contrast to previous studies that solely focused on production-reinjection well spacing, this study calculates optimal spacings under various conditions to meet real-world operational needs. The results indicate that the optimal production-reinjection well spacings, without experiencing thermal breakthrough are 290, 330, 360 m and 390 m at flow rates of 40, 60, 80 and 100 m³/h respectively.

In the layered conductive sandstone thermal reservoir area of northern Shandong, a reliable geothermal production-reinjection well-spacing calculator was developed through simplification of the conceptual model and credible numerical simulation results. Hydrothermal numerical simulation serves as a robust approach to determine rational production-reinjection well spacings, which are crucial parameters for geothermal development and utilization projects including exploitation quantity, recharge quantity, injection temperature, and production-reinjection well spacing. These determinations contribute to the sustainable development and utilization of geothermal resources.

To elucidate the key factors governing ground settlement during the dewatering and excavation process, as well as to establish an empirical model based on these findings, this study systematically investigated a deep metro station excavation in Hangzhou, situated on a typical river terrace with a dual-layered geological structure.

Firstly, a numerical analysis method for settlement in braced excavations was proposed by incorporating a hybrid Mohr-Coulomb (MC)-Modified Cambridge (MMC) constitutive model, derived from the deformation mechanism of excavation soil and a comparison with actual monitoring data. Subsequently, the response surface method (RSM) was employed, to establish an empirical model for ground settlement caused by dewatering and excavation under dual-layer geological structure conditions in the study area, accounting for various operational factors and their interactions, and to analyze the zoning characteristics of ground settlement.

The findings suggest that the drawdown of the groundwater table, H_d, exerts the most significant influence on the surface settlement, followed by the depth of the underground diaphragm wall, H_w, and excavation width, B. Additionally, there is a notable interaction between B and H_d. The regression model developed based on these factors demonstrates high accuracy in predicting maximum surface settlement, H_m.

This study not only presents an empirical model for excavation engineering under similar geological conditions but also provides a practical framework for excavation design, construction, and monitoring. These contributions are crucial for effectively managing settlement deformation in excavations and their surrounding environments.

The spatial distribution of ground subsidence in the coastal area of Tianjin was predicted using a random forest machine learning model, in which the performance and significance of the variables were evaluated.

The random forest model was trained and validated in this study using datasets of ground subsidence in 2020, aquifer lithology, water level differences in aquifers in 2020, and hydrogeological parameters.

The results demonstrate the effectiveness of the random forest model for fitting and predicting ground subsidence (R²=0.98, RMSE=0.52 mm). Moreover, it is found that water level difference emerges as the most influential factor affecting ground subsidence, followed by lithology and hydrogeological parameters.

The present study introduces several novel contributions: ① utilization of spatial distribution data for training ground subsidence models; ② identification of significant controlling factors based on physical mechanisms; ③ assessment of the relative importance of these controlling factors. Additionally, this paper highlights the limitations and future directions in ground subsidence research, offering valuable insights for the rapid and accurate prediction of ground subsidence using the random forest model.

To assess contribution and seasonal variation in groundwater discharge (LGD) to lake water and nutrient budgets,

this study investigated Changhu Lake in the middle reaches of the Yangtze River. Field sampling was conducted during both the wet and dry seasons using multiple tracing techniques, including electrical conductivity (EC), stable isotope (²H and ¹⁸O), hydrochemical element (Ca²⁺ and Mg²⁺), and ²²²Rn isotope data. The ²²²Rn mass balance model was employed to quantify the LGD and associated nutrient fluxes in different seasons.

Results show that LGD rates during the wet and dry seasons were 64.52 mm/d and 14.95 mm/d, respectively, with significant differences between these seasons. Furthermore, during the wet and dry seasons, groundwater carried TN inputs of approximately 25.68×10⁶ g/d and 5.58×106 g/d, respectively. The TP inputs were approximately 8.14×10⁶ g/d and 0.17×10⁶ g/d in the wet and dry seasons, respectively. The differences in the LGD rates between the wet and dry seasons lead to differences in groundwater carrying TN and TP inputs, and inputs of TP during the wet season is also influenced by agricultural activities during that period. Sronger precipitation and evaporation during the wet season drive greater LGD intensity and their carrying TN and TP fluxes.

The research can provide scientific reference for water resource management and aquatic ecosystem preservation efforts in the Changhu area.

Sensitivity analysis is an crucial tool in groundwater modelling for measuring the importance of various model inputs, enabling better allocation of limited funds and resources to reduce predictive uncertainty.

In this paper, we propose an enhanced hierarchical global sensitivity analysis method to quantify contribution of different types of input uncertainty to model outputs, and to assess the impact of each uncertain process on groundwater model predictions. To test and demonstrate the new method, a hypothetical case study of groundwater flow and contaminant transport is used to validate.

The results indicate that model uncertainty is the main source of prediction uncertainty in this case, and uncertainty from the geological model is more important than that of other models.

The proposed method offers a more comprehensive sensitivity analysis for groundwater models. Compared with traditional parameter sensitivity analysis, the new method can consider more uncertain input factors, significantly improve computational efficiency, and provide more useful sensitivity information for model users and managers.

In order to identify the sources of old kiln water and the causes of water pollution,

the technical approaches such as mine hydrogeological survey, hydrological analysis, hydrochemistry and isotope tracing are used to identify the source and characteristic pollution of old kiln water, and the causes of water pollution in the mining area is analyzed.

Results show that, the hydrological response of old kiln water in the study is sensitive to rainfall events. The old kiln water mainly comes from the rainfall collected by the roadway, dominant runoff channel and groundwater in the aquifer. The characteristic pollutants of mine water and roadway water are manganese and sulfate, and the characteristic pollutants of mine drainage are sodium and sulfate. Manganese and sulfate are mainly formed by the oxidation of pyrite and the dissolution of rhodochrosite. The leaching and infiltration of mine solid waste and the mixing of old kiln water are main causes of groundwater pollution, while the surface water is mainly affected by pollution of leaching and confluence from mine solid waste, roadway drainage and mine drainage.

The research results of this paper provide a scientific basis for water quantity formation and water quality evolution for mine water environment management.

The disputes among humans, water and land have seriously restricted the sustainable development of the Dongting Lake region (TDLR).

To address this issue, it is crucial to understand the evolution of the hydrological environment in the TDLR, enabling solutions to the competition for space between human activities and water. By determining the evolution of the human-water relationship in the TDLR over the past 500 years, the influences of natural and human factors on the evolution of the hydrological environment are studied.

Considering the characteristics of tectonic subsidence and sediment inflow in the TDLR, an evolutionary model of the hydrological environment induced by human activities and the geological environment was obtained, and not only the changing trends in the storage and drainage of water and sediment in the TDLR and Yangtze River but also the possibility of future evolution of the TDLR were clarified.

The key finding are as follows: (1) The continuous land reclamation has encroached on floodwater retention areas, significantly reducing Dongting Lake's flood storage capacity. (2) The construction of the Jingjiang Dyke has raised flood levels in the Jingjiang River and exerted a backwater effect on Dongting Lake, exacerbating flood disasters during the high-water period. (3) The straightening of the Jingjiang River has led to sediment deposition from Chenglingji to Wuhan, and the decline of the three distributaries of the Jingjiang River, causing shrinkage at the lake's inlets and blockage at its outlets. (4) Since the operation of the Three Gorges Reservoir, the sediment accumulation of the inflow water from Dongting Lake decreased significantly, and that of the Jingjiang reach below Chenglingji increased significantly. Under the influence of human activities, the flood storage capacity of Dongting Lake has decreased annually; therefore, the water inflow during flood periods is difficult to discharge, and dry water replenishment has gradually decreased; therefore, the dry period in the TDLR has lengthened, and water has difficulty flowing. As a result, both flood and drought disasters have intensified. (5) The Jianghan-Dongting Lake Plain is still undergoing rapid structural subsidence, but the rate of sedimentation exceeds the amount of tectonic settlement; hence, Dongting Lake is at risk of morphing into marshes and land.

Coastal wetlands, a unique type of wetland with complex hydrologic and biogeochemical cycles, have ignificant carbon sequestration potential. Research on soil organic carbon (SOC) is critical for understanding carbon cycle, climatic regulation, and ecosystem health.

This study focused on four typical vegetation types grown in the coastal wetlands of Lianyungang, namely, Mudflats, Seepweed, Spartina alterniflora and Reeds. We analyzed the distribution characteristics of soil organic carbon content across different plant communities, and utilized statistical methods such as pearson correlation analysis, redundancy analysis (RDA), and structural equation modeling (SEM) to explore the regulatory effects of plant community characteristics and soil physicochemical properties on soil organic carbon. Particular attention was given to the relationships between environmental factors of coastal wetlands and soil organic carbon content.

Horizontally, the soil organic carbon content of the different plant communities decreased in the following order: Reeds ((7.79±4.72) g/kg)>Spartina alterniflora ((7.42±3.14) g/kg)>Seepweed ((4.95±3.40) g/kg)>Mudflats ((3.66±1.90) g/kg). Vertically, the soil organic carbon content decreased with increasing depth within 0-50 cm. Additionally, significant correlations were found between SOC content and soil physicochemical properties, as well as plant community characteristics. The results of the redundancy analysis indicate that soil organic carbon content is negatively correlated with BD (bulk density) in different wetland types but is positively correlated with SWC (soil water content), height, diameter, coverage, AGB (above ground biomass) and BGB (below ground biomass). The structural equation model showed that the soil water content was the most important factor affecting soil organic carbon content in coastal wetlands.

These findings can not only promote a better understanding of coastal wetlands from their ecosystem structure and function but also provide relevant data support for policy making on global climate change.

The coastal sedimentary environment is fundamental to the comprehending the evolution and movement of groundwater. To investigate the impact of the distribution and mobility of brackish groundwater along the southern coast of Laizhou Bay,

this study collected samples from two archetypal Quaternary boreholes (LZ01 and LZ02), extracted pore water using the mechanical squeezing technique, and measured the grain size composition of the sediments and the Cl^- content of the pore water.

Both boreholes are dominated by fine-grained sediments with an average particle size of 5.5ϕ. Based on the sediment lithology and grain size parameters, it was found that the LZ01 and LZ02 boreholes contained 10 and 9 alternating sedimentary facies, respectively, revealing three sets of marine stratigraphic units since the late Pleistocene. The porewater was found to be predominantly composed of brine (saline) water, with the Cl^- profile displaying three peaks corresponding to the three sets of marine stratigraphic units. These results demonstrate the presence of residual ancient marine brine water in the sediment and its permeation into neighboring sediments. In this study, it was observed that the hydraulic index of sedimentary water exhibited a clear zonal pattern, with the vertical change rate of Cl^- serving as a crucial indicator. Notably, under moderate hydraulic conditions, Cl^- displayed a robust diffusion and migration capability in pore water, as confirmed by detailed particle size analysis. The dominant particle size range for pore water migration was 45.61-111.47 μm.

The paleo-marine transgression events in the study area controlled the distribution of brine, while low permeability and lithological combinations played a significant role in the preservation of ancient brine. The results of this study provide a theoretical basis for research on the origin of brine, groundwater salinization, and migration in the Laizhou Bay coastal plain.

Soil-air partitioning is a critical process influencing the environmental fate of volatile organic pollutants and a significant contributor to the risk of respiratory exposure.

Four typical soils-loess, red soil, black soil and sand were used to identify the soil factors affecting the partitioning of trichloroethylene. The partitioning behaviour of trichloroethylene at the soil-atmosphere interface was quantitatively investigated by single-factor controlled batch experiments, and the quantitative relationship between the trichloroethylene soil gas partition coefficient and soil factors was determined.

The results showed significant differences in the soil-gas partition coefficients of the four typical soils (black soil>red soil>sandy soil>loess soil). The main influencing factors for the partition coefficient of black soil were primarily particle size, water content, and organic matter content. Whereas, for the other three soils, the main factors were particle size and water content.

The relationships between the soil gas partition coefficient of TCE and soil factors in black soil can be quantitatively expressed as follows: K_SA=-0.744X₁-0.224X₂+0.704X₃; sand: K_SA=-0.724X₁-0.222X₂; loess: K_SA=-0.291X₁-0.268X₂; and red soil: K_SA=-0.589X₁-0.338X₂ (X₁: water content; X₂: particle size; X₃: organic matter content). These research aids in a deeper understanding of the distribution behaviour of trichloroethylene at the soil-atmosphere interface in typical soils in China and the influence of soil factors and provide a theoretical basis for the quantification of multifactor coupling effects and health risk assessment in the process of soil gas partitioning.

To better interpret the geological information contained in geophysical logging data and expand the application scope of well logs in geology,

several typical cases of representative logging data are analyzed. This analysis seeks to enhance the use of well logs in geological research. Logging data can aid in the deployment of sidetracking wells by identifying tectonic occurrences and variations in their combination characteristics. Image log data also enable determintion of palaeocurrent directions and the identification of bidirectional provenance supply, thus providing refined and scientifically calibrated interpretations in alignment with geological understanding.

Logging data, often regarded as the "eyes" of geologists, are advantageous for identifying and evaluating pores, caves, fractures, and other subsurface features. These data are crucial for discovering hydrocarbon reservoirs and facilitating the fine and continuous calculation of reserve parameters. The coupling relationships between mudstone resistivity, acoustic interval transit time, and in situ stress in logging curves can also be used to indirectly predict the quality of ultradeep reservoirs and hydrocarbon productivity. Moreover, combining geology, logging, and seismic activity allows for the delineation of hydrocarbon traps and supports oil and gas exploration and production.

The analysis of these typical cases assists geologists in better interpreting the geological information in logging curves and further broadens the application field and scope of geophysical logging data.

For the early selection and evaluation of unconventional gas resources such as shale gas and dissolved gas, it is often difficult to obtain formation burial depth by seismic structural interpretation due to the lack of seismic data. Therefore, it is necessary to effectively predict the burial depth of the target layer using other non-seismic data.

Both regional geological maps and digital elevation model (DEM) are widely covered and easily accessible basic data. In this study, a new method for predicting structural height and buried depth of target layer is established by superposing regional DEM information with geological map which contains the attitude of stratum, trend of underground structures, as well as the relation between buried depth of underground layer and age of surface layer.

This method is effective for predicting the burial depth of Marine strata with relatively stable sedimentary thickness. The buried depth of the Lower Silurian Longmaxi Formation in Sichuan Basin and its periphery is predicted based on 36 geological maps with scale of 1∶200 000 and DEM data, and then the contour map of the buried depth of Longmaxi Formation provides important parameters for the evaluation of shale gas preservation conditions in this area.

The method of predicting the burial depth of Marine strata by using non-seismic data such as regional geological map and DEM can not only provide effective support for the early selection evaluation of shale gas, but also can be applied to the resource evaluation of water-soluble gas in deep high-pressure aquifers and the structural optimization of CO₂ geological storage in deep saline aquifers.

As one of the most crucial information carriers for predicting mineralized geological bodies, exploration geochemical data play a significant role in the identifying and extracting mineralization-associated anomalies as well as in analyzing deep-level mineralization information.

Based on the scale invariance and generalized self-similarity characteristics of the spatial distribution of geochemical elements, this paper uses Cu and Au in the 1:50 000 exploratory geochemical data of the Duolong mineral district as an example and conducts a study using fractal/multifractal and singularity theories to identify the spatial distribution patterns of ore-forming elements and extract anomalies. The multifractal spectrum which is derived by the exploratory moment method for the whole study area, the fault buffer zone and the stratigraphic zone, is used to describe the relative enrichment and depletion of elements in the local area and to analyze the local singularity of Cu and Au mineralized elements, so as to identify and extract weak and low anomalies of mineralized elements and delineate potential mineralization zones.

Both Cu and Au exhibit mineralization-favoured patterns in the Duolong mineral district, with the Cu showing weak enrichment in the region and Au being over-enriched on a local scale. The intersections of the east-west and northeast-trending faults, as well as the Jurassic strata, are identified as the most promising locations for mineralization in this region.

The spatial distribution of the local singularity index is mapped to characterize the distribution features of Cu and Au geochemical anomalies, therefore, the central and northern regions of the ore district are subsequently identified as potential areas for mineralization.