The reservoirs of the Linhe Formation in the Linhua well area, Hetao Basin, exhibit strong heterogeneity, significant variations in petrophysical properties, and complex pore structures, which have restricted hydrocarbon exploration and development. Based on 12 sandstone samples collected from the study area, a comprehensive investigation was conducted by integrating multiple analytical approaches, including casting thin-section petrography, scanning electron microscopy (SEM), mercury intrusion capillary pressure (MICP), and waterflooding visualization experiments using real-sandstone micromodels. This study systematically characterized pore types, fractal characteristics, and waterflooding flow responses, clarified the relationships among fractal dimensions, reservoir properties, and flow response, and revealed the controlling effects of fractal characteristics on waterflooding pathways and displacement patterns. The results show that, based on petrophysical properties and oil-test characteristics, the reservoirs in the study area can be classified into three types: typeⅠ (high-quality reservoirs), type Ⅱ (moderatequality reservoirs), and type Ⅲ (poor-quality reservoirs). Type I reservoirs are dominated by primary intergranular pores, with locally developed enlarged dissolution pores and a certain proportion of micropores, forming a wellconnected effective pore network with distinct preferential flow channels. Type II reservoirs are characterized by the co-development of intergranular pores and dissolution pores, with local coexistence of macropores and micropores. Type III reservoirs are dominated by tiny intergranular pores and intercrystalline micropores, with small pore sizes, poor connectivity, and an overall compact structure. The average fractal dimensions of type I, type II, and type III reservoirs are approximately 2. 88, 2. 81, and 2. 75, respectively, corresponding to complex, moderately complex, and relatively simple and compact pore systems. The visualized waterflooding experiments indicate that the three reservoir types exhibit “ finger-like to network-like,” “ finger-like to uniform,” and “ network-like to uniform” displacement patterns, respectively. Overall, fractal dimensions shows a good correspondence with waterflooding flow response: higher fractal dimensions are generally associated with complex pore structures, well-developed preferential flow channels, and stronger heterogeneous flow, whereas lower fractal dimensions commonly correspond to slow and relatively uniform flow under compact pore-structure conditions. The integrated application of multiscale pore-structure characterization, mercury-intrusion-based fractal analysis, and waterflooding visualization experiments using real-sandstone micromodels establishes the relationship between reservoir fractal characteristics and displacement patterns, reveals the controlling effect of static pore structure on dynamic flow response, and provides a basis for fine reservoir evaluation, differentiated development, and well placement in the study area.

To address the limitations of traditional detection methods in deep goaf applications, such as insufficient resolution and high cost, the authors developed a seismic frequency imaging data processing workflow based on the principles and methods of the seismic frequency imaging method, aiming to effectively identify deeply buried goafs by analyzing the frequency response characteristics of underground media. The goaf along Southeast Lake Road in Changchun was selected as the study object, where the passive-source seismic frequency resonance exploration method was adopted. Passive-source seismic signals were acquired using an ALLSEIS-3CLF integrated short-period seismometer. The raw signals were first preprocessed using noise filtering, amplitude equalization, and instrument response correction to improve signal quality. Spectral information was extracted via the fast Fourier transform. Frequency-domain stacking, the correspondence between resonant frequency and formation depth, transfer-function forward modeling, and least-squares iterative inversion were further combined to obtain formation wave impedance parameters and construct wave impedance-depth profiles. Finally, borehole data were used to verify the accuracy of the inversion results. The results show that this method can effectively identify deep goafs. Due to rock collapse, fracture development, and differences in filling materials, the goaf exhibits significant low-wave-impedance anomalies, accompanied by weakened wave impedance stratification and irregular spatial distribution. The imaging results along the two survey lines clearly reveal the spatial distribution characteristics of the deep goaf along Southeast Lake Road in Changchun. The identified anomalies are consistent with the coal-seam goaf locations revealed by boreholes, and the overall relative error is within 5%, confirming the reliability of the method. The seismic frequency imaging method enhances the response of deep geological targets through resonance effects and can identify deeply buried goafs based on the frequency response characteristics and wave impedance differences of underground media. The method effectively characterizes the location, burial depth range, and boundary features of goafs, require no artificial seismic source and is relatively low cost, thereby providing an effective technical approach for goaf safety evaluation and remediation.

To evaluate the hydrocarbon generation potential and exploration significance of the dark mudstonesof the  Jiufengshan Formation in Dayangshu Basin, core samples from the Jiufengshan Formation of Well X1 in the central part of the basin were selected for testing, including total organic carbon (TOC), rock pyrolysis, chloroform bitumen “A”, soluble organic matter group components, vitrinite reflectance (Ro), and organic carbon isotopes. Theresults indicate that the organic matter abundance in the dark mudstones of the Jiufengshan Formation exhibits significant vertical heterogeneity. The organic matter abundance is relatively high in the Member 3 of Jiufengshan Formation which consists primarily of moderate-quality source rocks; the Member 1 of Jiufengshan Formation is predominantly composed of poor-quality source rocks, though some local sections meet the criteria for good-quality source rocks; the Member 5 of Jiufengshan Formation has low organic matter abundance, limited hydrocarbon generation potential, and is classified as a non-source rock. The organic matter type is predominantly type Ⅲ overall, with local samples in the Member 3 of Jiufengshan Formation exhibiting type Ⅱ 2 --Ⅱ 1 characteristics. Maturity shows a staged evolution with increasing burial depth: the Member 5 of Jiufengshan Formation is in the immature stage, the Member 3 of Jiufengshan Formation is in the low-maturity to early oil-generating stage, and the Member 1 of Jiufengshan Formation has entered the mature to high-maturity stage, with gas-generating potential in the deeper sections. Overall, the soluble organic matter in Jiufengshan Formation is dominated by saturated hydrocarbons, characterized by a relatively low asphaltene mass fraction and a high saturate / aromatic hydrocarbon ratio. Combined with carbon isotope characteristics, this indicates a reducing sedimentary water environment, with the source rock derived from a mixture of terrestrial higher plants and lower aquatic organisms. Comprehensive analysis suggests that the members 1 and 3 of Jiufengshan Formation locally possess favorable hydrocarbon-generating material foundations and thermal evolution conditions, making them promising hydrocarbon exploration units within the Jiufengshan Formation.

Abstract: To clarify the vertical evolution of redox conditions during deposition of the Qingshankou Formation in the marginal shallow-lake area of the Songliao Basin, the authors investigate the PM002 section in Binxian County on the eastern margin of the basin. A total of 286 samples from an approximately 45 m thick transitional interval between the upper part of member 1 and the lower part of member 2 of the Qingshankou Formation were subjected to 10 cm resolution lithological description, loss on ignition (LOI) analysis, and X-ray fluorsescence spectrometry (XRF) analysis of major and trace elements. Aluminum (Al) normalization, enrichment factor (EF) calculation, principal component analysis ( PCA), and constrained incremental sum of squares ( CONISS) clustering were further applied to identify redox environmental variations. The results show that the studied interval is dominated by fine-grained sediments, mainly including mudstone, bioclast-bearing mudstone, and silty mudstone, with locally intercalated calcareous and dolomitic thin beds and developed dolomitic nodules. Five fifth-order depositional cycles characterized by “rapid deepening followed by gradual shallowing” are recognized. The mean U/ Th ratio is 0. 16, the mean V/ Cr ratio is 0. 45, and the mean Mo content is 0. 58 μg / g. In the Mo--U covariation diagram, all samples plot below the 0. 1 × SW ( seawater) reference line, indicating that the studied interval was generally deposited under oxic to weakly oxic conditions and did not experience significant large-scale authigenic Mo enrichment. Based on Z score standardized sensitive indicators, including LOI550, S / Al, Mn / Al, V/ Sc, and Fe / Mn, together with CONISS clustering, the section can be divided into six redox-evolution stages, namely Stages Ⅰ--Ⅵ, showing a non-steady-state transition pattern from relatively reducing, strongly oxic, weakly oxic, strongly oxic, weakly oxic to relatively reducing conditions. The fifth-order depositional cycles and CONISS stages do not correspond one-to-one, but instead display a cross-cutting coupling relationship, suggesting that redox variations were jointly controlled by depositional cyclicity, hydrodynamic disturbance, and local diagenetic processes. The maximum local sulfur content reaches 4. 24% , but it is clearly decoupled from Mo enrichment, indicating that sulfur enrichment mainly reflects short-term pore-water reduction or local sulfide fixation rather than a stable euxinic water column. Overall, the PM002 section records intermittent weak water-column stratification and its episodic breakdown in a marginal shallow-lake setting, and the redox conditions are characterized by pronounced non-steady-state fluctuations. 

Abstract: Long-term overexploitation of groundwater has induced significant land subsidence in Taobei District, Baicheng City, Jilin Province. To investigate the spatiotemporal characteristics of land subsidence and its association mechanisms with groundwater activities, Sentinel--1 images acquired from 2018 to 2021 were used to develop a SBAS--InSAR baseline optimization method constrained by dynamic normalized difference vegetation index (INDV ) thresholds to retrieve the spatiotemporal distribution of land subsidence. The GeoDetector method is employed to quantitatively analyze the spatial response relationships between land subsidence and nine environmental factors, while multivariate singular spectrum analysis (M--SSA) is applied to decompose the time series of land subsidence and groundwater levels and to analyze their coupling relationships. The results indicate that the INDV - based baseline optimization effectively improves interferometric pair quality, increasing the proportion of valid interferograms by approximately 17. 3% and significantly reducing the root mean square error. The study area is dominated by slight subsidence, with an average deformation rate of - 1. 93 mm/ a, mainly ranging from - 15 to 10 mm/ a, and subsidence is concentrated in agricultural irrigation areas. Soil sand content and clay content exhibit the strongest explanatory power for the spatial differentiation of subsidence. The interaction between two factors significantly enhances explanatory capability, among which the interaction between distance to water bodies and soil sand content is the most significant (q = 0. 091), indicating that hydrological conditions and soil properties jointly control the spatial pattern of subsidence. Time series decomposition shows that seasonal fluctuations are the dominant driving factor of both land subsidence and groundwater variations, and their seasonal components are highly correlated. Groundwater level changes exhibit an approximately 133 d lag in driving surface deformation, reflecting the delayed response of pore water pressure adjustment in aquifers and soil consolidation compression. Overall, groundwater overexploitation caused by agricultural irrigation is the primary driving mechanism of land subsidence in Taobei District.

Abstract: Volcaniclastic reservoirs are widely developed in the Lower Cretaceous Huoshiling Formation in the Longfengshan area, Changling Fault Depression, Songliao Basin, and constitute an important target interval for reserve growth and production enhancement in deep volcanic hydrocarbon reservoirs. To address the difficulties in identifying the emplacement environment and the unclear reservoir-forming mechanisms of these volcaniclastic rocks in a deeply buried and complex diagenetic setting, the authors systematically investigated the identification markers and reservoir-forming mechanisms of subaqueously emplaced volcaniclastic rocks in the Huoshiling Formation, Longfengshan area, using core observation, cast thin section analysis, SEM -- EDS analysis, and porosity and permeability measurements. The results indicate that the studied rocks are assigned to the volcaniclastic apron subfacies within the explosive facies and are dominated lithologically by trachyandesitic and andesitic volcanic breccias and crystal-lithic tuffs. Macroscopically, their subaqueous emplacement environment is characterized by interbedded “sedimentary-volcanic-sedimentary” sequences and the mixing of exotic components such as semiconsolidated mudstones and carbonized plant debris. Microscopically, it is typified by products of magma-water interaction and subsequent diagenetic alteration, including plastic vitric clasts with quench rims, quench cracks in feldspar crystals, chlorite infilling, and albitization rims. The reservoir space is dominated by cavernous pores, sieve pores, and moldic pores formed by secondary dissolution, while primary microfractures play an important role in improving permeability. The average porosity of the rocks is 6. 88% , and the average permeability is 0. 936 × 10 - 3 μm 2 , indicating overall characteristics of medium-high porosity and low permeability reservoirs. Furthermore, a reservoir evolutionary model of “ early infilling for pore preservation and late dissolution for pore enhancement” was revealed for subaqueously emplaced volcaniclastic rocks. Specifically, during the early diagenetic stage, authigenic chlorite infilling and albitization rims partly resisted mechanical compaction during burial, thereby preserving the framework of primary intergranular pores. During the middle diagenetic stage, organic acid-rich fluids migrated along residual pores and primary microfractures, causing differential dissolution of unstable components such as early chlorite infillings, plagioclase, and intermediate lithic fragments. This facilitated the reopening of residual primary pores and the formation of secondary pores. These research findings deepen the understanding of the reservoirforming mechanisms of subaqueous volcaniclastic rocks in continental lacustrine basins and provide a theoretical basis for the prediction of deep, high-quality reservoirs in the Longfengshan area. 

 With the development of sensor and unmanned aerial vehicle platform technologies, high-resolution airborne point cloud data can be rapidly obtained, providing support for precise geometric information of features. In urban areas, the types of features are complex and targets are mixed, which significantly increases the difficulty of extracting buildings. Especially in high-resolution point clouds, buildings often have blurred edges and which are stuck together with adjacent trees and vehicles, leading to missed extraction or incorrect extraction problems. To address these issues, the authors propose an ATCA-ConvNet neural network that integrates a convolutional attention mechanism. The CBAM module is introduced to adaptively adjust the channel and spatial weights of the feature map, guiding the network to focus on the key features of the task and enhancing the ability to identify local details, thereby improving the accuracy of building point cloud extraction. To verify the model performance, two typical urban areas were selected to construct a building point cloud extraction dataset, and the model was validated based on the dataset. The experimental results show that ATCA-ConvNet has better extraction effects when processing local detail features, can effectively identify building boundaries and distinguish buildings from other locally similar features, and has the highest mIoU of 73. 4% on all categories, with an overall accuracy OA of 91. 7%, significantly superior to other methods in the control group. Among them, the IoU value on the building category is 92. 9%, verifying the effectiveness of ATCA-ConvNet in handling building extraction tasks. In summary, the ATCA-ConvNet model can effectively complete the recognition and extraction of building point clouds in urban areas, demonstrating excellent overall accuracy and category balance, and significantly enhancing the model􀆳s adaptability and stability in extracting buildings in high-resolution, complex urban scenes.

Taking the Lower Cretaceous volcanic rocks in the Changling Fault Depression of the Songliao Basin as an example, the authors revealed the reservoirs of different seismic facies units based on the external geometries and internal reflection configurations of seismic facies combined with porosity, reservoir space characteris tics and distribution patterns from typical wells. The seismic facies are divided into six categories, including blocky disordered reflection (typeⅠ), layer-like subparallel reflection (type Ⅱ), layered parallel reflection (type Ⅲ), layer-like lenticular reflection ( type Ⅳ), layered discontinuous reflection (type Ⅴ), and layered subparallel reflection (type Ⅵ). The geological characteristics and reservoir quality of different seismic facies vary significantly. The high-quality reservoirs are mainly developed in the layer-like subparallel reflection, corresponding to rhyolite of the composite lava flow subfacies and simple lava flow subfacies of the effusive facies, with an average porosity of 12. 0% and dominated by primary vesicles. The layered subparallel reflection corresponding to coarse andesitic tuff of the volcanic clastic apron subfacies of the explosive facies, with an average porosity of 9. 0% and primarily consisting of secondary dissolution pores. The layer-like lenticular reflection corresponding to acidic lava or rhyolitic tuff of the simple lava flow subfacies of the effusive facies and the pyroclastic flow subfacies of the explosive facies, with an average porosity of 8. 1% and dominated by primary vesicles. The moderate-quality reservoirs are primarily developed in layered discontinuous reflection, corresponding to rhyolitic tuff interbedded with the thermal base surge subfacies and the pyroclastic flow subfacies of the explosive facies, with an average porosity of 7. 0%. The layered parallel reflection corresponding to intermediate basalt, basaltic andesite, or rhyolitic tuff interbedded with the simple lava flow subfacies of the effusive facies and the thermal base surge subfacies of the explosive facies, with an average porosity of 5. 7%. The poor-quality reservoir is primarily developed in blocky disordered reflection, corresponding to rhyolite of the lava dome subfacies of the extrusive facies, with an average porosity of 3. 8%.

Abstract: Vehicle-borne ground penetrating radar system can efficiently detect road cavities and play an important role in urban safety management. The stability of integrated GNSS / IMU positioning for the vehicle-borneground penetrating radar system is significantly degraded in urban canyons due to the accuracy decreases of GNSS. The robustness of GNSS / IMU integrated navigation can be improved by robust filter based on the normalized innovation squared. However, clear variations arise in outlier suppression and useful information utilization, due to the distinct attenuation characteristics and truncation mechanisms of different robust kernel functions. To investigate the suitability and robustness differences of various kernels in complex observation environments, the GNSS / IMU integrated navigation performance of four robust kernel functions, namely Cauchy, Student-t, Tukey, and Huber, is compared within the error-state Kalman filter (ESKF) framework using measured data collected on the urban expressway in Changchun. The results indicate that the Cauchy and Student-t kernels achieve superior robustness performance through their heavy-tailed distributions with asymptotic attenuation characteristics, with the latter being slightly more robust than the former. Compared with the conventional ESKF, the position RMSE, velocity RMSE, and the 95th percentile of position error ( P95) are improved by 11. 1% and 12. 1% , 3. 0% and 4. 9% , and 22. 3% and 21. 0% for the Cauchy and Student-t kernels, respectively. The Huber kernel exhibits relatively weak robustness due to its linear attenuation and lack of truncation. Compared with the conventional ESKF, the improvements are limited to 4. 5% , 0. 6% , and 15. 3% in position RMSE, velocity RMSE, and P95, respectively. The Tukey kernel exhibits the lowest robustness among the four candidates, as its strong truncation results in insufficient utilization of useful information and severe accuracy degradation. This study provides a reference for robust kernel function selection and algorithm design in GNSS / IMU integrated navigation of vehicle-borne ground penetrating radar system in complex urban environments. 

Abstract: Diabase has been increasingly verified as an important reservoir in hydrocarbon exploration and development, however, its strong heterogeneity makes predicting favorable reservoirs difficult. Current studies have not yet established a quantitative response relationship between crystallization degree and reservoir properties, and the lack of a unified classification evaluation standard severely restricts the fine-scale evaluation and exploration deployment of such reservoirs. This study investigates diabase with different crystallization degrees from the third member of Shahejie Formation in Linnan Subsag. A crystal size distribution (CSD) method with manual intervention was used to quantify crystallization degree, and in combination with the cooling and crystallization characteristics of shallow intrusive rocks, a three-tier classification scheme-fine-grained, medium-grained, and coarse-grained diabase-was established for Linnan Subsag using crystal size thresholds of 200 μm and 400 μm for the first time. Porosity-permeability measurements, cast thin sections, scanning electron microscopy, and high-pressure mercury intrusion analyses were integrated to examine the relationship between crystallization degree and reservoir properties, revealing a positive correlation between them. Mechanistically, during the magmatic cooling and crystallization process, coarse-grained diabase experienced longer mineral crystal growth times and larger crystal sizes, leading to well-developed intergranular pores. Furthermore, the connected pores between feldspar crystals in the coarsegrained structure facilitate the influx of later diagenetic fluids and promote dissolution, resulting in the formation of dissolution pores. Consequently, coarse-grained diabase exhibits significantly superior pore structures and storagepermeability properties compared to medium- and fine-grained diabase, identifying it as the most promising lithology for diabase reservoirs.

Abstract: Accurate detection of fire zones is an important prerequisite for effective coal mine remediation. Coalfield fire zones occur in steep terrain and are accompanied by severe surface smoke cover, which restricts ground geophysical surveys and makes it impossible to guarantee detection accuracy. Based on the characteristics of high magnetic susceptibility and low resistivity of fire zones, the synergistic detection technique combining semiairborne electromagnetic and airborne magnetic methods is suitable for complex terrain conditions, compensates for the limitations of individual methods, and enhances the resolution of the spatial distribution of fire zones. However, existing 3D inversion methods for electromagnetic and magnetic data do not adequately address remanent magnetization from combustion or complex terrain, which leads to poor delineation of subsurface fire zone distributions. The authors developed a 3D magnetization intensity vector and resistivity inversion technique for complex terrain, which effectively obtains the subsurface 3D resistivity and magnetization intensity distributions and provides a precise and efficient technical means for fire zone remediation. The Haizhou open-pit coal mine, once the largest open-pit mine in Asia, has undergone severe ground landslides, subsidence, and fissuring after closure due to subsurface fire zones formed by spontaneous combustion of autochthonous residual coal and historical mining activities. The terrain is complex, and conventional 3D electromagnetic and magnetic inversion methods do not meet detection requirements. Therefore, the synergistic detection technique combining semi-airborne electromagnetic and airborne magnetic methods was applied in the Haizhou open-pit coal mine area. After systematic data processing, the developed complex terrain inversion technique was used to perform 3D magnetization intensity vector and resistivity inversion. Based on the distribution patterns of high magnetization intensity and low resistivity, a comprehensive interpretation identified 17 fire zones. Field investigations validated the accuracy of the inferred results, and the identified fire zones were classified into 3 types: type Ⅰ corresponding to subsurface spontaneous combustion of residual coal (4 sites), type Ⅱ corresponding to shallow coal gangue combustion or accumulation (12 sites), and type Ⅲ corresponding to suspected fire zones (1 site). 

Abstract: Downhole heaters are critical equipment for the in-situ conversion of oil shale, and their heat transferperformance directly influences heating efficiency and energy consumption. Based on conventional heat exchangers, the authors propose a downhole convective shell-and-tube electric heater adapted to the wellbore diameter constraints of oil shale in-situ conversion through dimensional optimization. A helical baffle design is introduced to enhance the shell-and-tube heat exchange structure. According to this, two types of heater prototypes with different structures have been developed respectively. To analyze the heat transfer performance and irreversible losses of the downhole heating system for oil shale in-situ conversion, a high-temperature and high-pressure experimental platform was established. Experimental investigations were conducted on both shell-and-tube and helical structures under various heating powers and air volumetric flow rates, focusing on key heat injection parameters. The performance of the two configurations in terms of heat exchange and energy utilization was analyzed by comparing parameters such as wall temperature, heat transfer coefficient, thermal efficiency, comprehensive performance index, dimensionless entropy production, and thermal resistance. The experimental results demonstrate that, compared to the shell-andtube structure, the helical structure effectively reduces the peak wall temperature of the electric heating rods. Within the tested power and flow rate ranges, the heat transfer coefficient increased by 51. 4% to 66. 5% , and thermal efficiency improved by 2. 7% to 3. 7% . Regarding the comprehensive performance indicator K / Δp 1 / 3 , the helical structure showed an increase of 17. 1% to 37. 5% over the shell-and-tube structure, indicating superior heat transfer and flow resistance synergy. Furthermore, it exhibited lower irreversible losses in terms of entropy production and thermal resistance, demonstrating a clear advantage in enhancing energy utilization. 

The increasing demand for target detection accuracy in applications such as land resource surveys, urban planning, ecological monitoring, and disaster early warning, using high-resolution remote sensing images from drones and satellites, has exposed limitations in traditional detection methods. These limitations are particularly noticeable when there are significant scale differences, complex backgrounds, low contrast, and sparse samples. In particular, detecting small targets in multi-scale and complex background scenes has been challenging. To address these issues, this paper proposes an improved YOLO small target remote sensing image recognition algorithm called PSC --YOLO. It is based on the YOLO11n framework and incorporates multiple feature enhancement and optimization mechanisms. These additions improve the models ability to handle small targets and complex backgrounds. First, the PMKCA module is introduced into the backbone network. It uses parallel multi-core convolution and channel attention mechanisms to enhance multi-scale feature extraction and improve global feature modeling. Second, the SPPCA module is embedded into the SPPF feature fusion layer. It employs multi-scale pooling and channel attention mechanisms to boost small target perception. Next, the C3k2 HLCA module is integrated into the C3k2 structure. It enhances local feature representation and optimizes feature expression using channel attention mechanisms, which further improves small target detection accuracy. Finally, an adaptive confidence threshold adjustment function is designed to optimize the NMS process. This reduces redundant detection boxes and improves performance. Experimental results show that PSC--YOLO outperforms YOLOv5, YOLOv10, YOLO11n, and YOLOv12 on the NWPU VHR--10 dataset. For the mAP50 and mAP50--95 metrics, PSC--YOLO achieves a 0. 8% and 2. 0% improvement over YOLOv5, a 1. 5% and 2. 0% improvement over YOLOv10, a 0. 8% and 2. 0% improvement over YOLO11n, and a 1. 5% and 2. 0% improvement over YOLOv12. The results demonstrate that PSC --YOLO effectively reduces missed detections in complex background and multi-scale target scenarios. It also improves small target detection accuracy and provides better stability. This method offers more precise information support for the automated interpretation and intelligent decision-making of remote sensing images.

To finely characterize the reservoir structure of unconfined slope channels in gravity flow deposits of
Baiyun Sag, Pearl River Mouth Basin, the authors took the X Gas Field in Baiyun Sag as the research object. Com-
prehensive use was made of core, logging, seismic inversion and other data to study the internal structure and quan-
titative characteristics of unconfined channel reservoirs at different levels. A fine characterization method for the in-
ternal structure of unconfined channels was established, and the contacted and connected relationship of channel
sandbodies were revealed. The research results show that: ① The study area mainly develops medium-fine-grained
feldspathic quartz sandstone. Core grain size data points are basically parallel to the C = M baseline, with massive
mud gravels and intense bioturbation without obvious incised bedforms, indicating an unconfined channel system.
② The channel system in the study area develops four composite channel sequences, multiple composite channels
and isolated channels. The width of composite channel sequences is on the kilometer scale, with an aspect ratio of
133--136. The width of composite channels is approximately 1 000 m, with an aspect ratio of 10--55. The scale of
solated channels is difficult to determine, with a width of about 50--100 m and an aspect ratio of 4--8. ③ There are
four superposition modes of sandbodies inside the unconfined channels, including vertical isolated, channel-channel
lateral superimposed, channel-channel lateral juxtaposed, and isolated channels. Among them, the incised-super-
imposed reservoir structure has the best connectivity, the juxtaposed reservoir structure has good connectivity, and
the isolated reservoir structure is disconnected. This research achievement can be used to guide the precise develop-
ment and development adjustment of oil and gas fields in unconfined gravity flow channels.

Abstract: The magmatic rocks exposed in Xiyinkeng area (Jurong City, Jiangsu Province) belong to the Anjishancomplex. The rock type is mainly granodiorite porphyry, which is intruded by a small amount of intermediate-basicdykes such as quartz diorite porphyrite, diorite porphyrite, and diabase porphyrite. To determine the timing of mag-matism (crystallization / emplacement age) and geodynamic background, this paper conducted petrographic, zirconU--Pb chronology, and geochemical characteristics research on Xiyinkeng magmatic rocks. Zircon U--Pb dating in-dicated that granodiorite porphyry crystallized at (104. 45 ± 0. 29) Ma, followed by the emplacement of quartz dio-rite porphyrite at (104. 66 ± 0. 52) Ma, and subsequently diabase porphyrite intrusion at (101. 37 ± 0. 34) Ma, all occurring during the Early Cretaceous. Geochemical data show that the magmatic rocks in Xiyinkeng area are characterized by high potassium [w (K2O) 1. 96%--4. 05% ] and high alkalinity [w (Na2O) 2. 29%--4. 68% ], with A/ NK values ranging from 1. 38--2. 15, A/ CNK values ranging from 0. 62--0. 96, and Littmann indexes ranging from 1. 76--2. 59, indicating that they are metaluminous calc-alkaline series I-type granites. The diabase porphyrite exhibits higher rare earth elements enrichment ( ΣREE = 144. 61 × 10 - 6 - 182. 84 × 10 - 6, avg. 163. 73 × 10 - 6), with LREE/ HREE, (La/ Yb)N, and (Gd/ Yb)N ratios of 10. 81--12. 76, 13. 60--17. 62, and 2. 16--2. 33, respectively. In contrast, the rare earth element contents of granodiorite porphyry, quartz diorite porphyrite and diorite porphyrite are lower than those of diabase porphyrite (ΣREE = 94. 43 × 10 - 6 --143. 47 × 10 - 6, avg.
118. 79 × 10 - 6). The light and heavy rare earth element ratios (LREE / HREE) range from 14. 43--24. 48, the (La / Yb) N and (Gd / Yb) N are 22. 16--43. 70 and 2. 57--2. 87 respectively. The rocks are relatively enriched in large ion lithophile elements (Rb and La) and relatively depleted in high field strength elements (Nb, Ti and Ta), showing obvious characteristics of island arc magmatic rock. The Nb / Ta ratio is 11. 57--24. 68, which is close to that of continental crust, indicating the presence of a large amount of crustal material. Combined with previous research results, it is believed that the magmatic rocks in the Xiyinkeng area was formed in a back-arc extensional environment during the subduction and retreat of the Pacific Plate. It is the product of interaction between the lower
crust and mantle materials, classified as crust-mantle granite.

Abstract: Banded iron formation (BIF) is an important type of iron deposit formed during the early evolutionary history of the Earth. The Naxiguole BIF deposit is situated in the western segment of the East Kunlun Orogenic Belt. It is hosted within a medium-to high-grade metamorphic plagioclase amphibolite assemblage of the Neoprotero-zoic Jinshuikou Group and occurs as stratiform-lenticular bodies. With estimated resources of 75 Mt and iron grades ranging from 15% to 28. 83% , the ore primarily consists of magnetite quartzite exhibiting typical banded struc-tures. To gain a deeper understanding of the deposit genesis and provide a basis for regional mineral exploration, based on systematic field geological investigations combined with electron probe microanalysis (EPMA) of magne-
tite and whole-rock major and trace element geochemistry, this study systematically elucidates the geological charac-teristics, ore-forming material sources, and genetic type of the deposit. EPMA results reveal that magnetite exhibits high TFeO content (90. 01% --92. 98% ) and very low concentrations of TiO2, MgO, MnO, CaO, and Al2O3 (all < 0. 4% ), consistent with the composition of magnetite from typical BIFs. Whole-rock geochemical data indicate variable w (TFeO) (15. 45%--74. 74% ) and w (Al2O3) (1. 84%--17. 04% ) in the ore. The ore displays signifi-cant positive Eu anomalies (Eu / Eu∗PAAS = 1. 38--2. 12), positive Y anomalies (Y/ Y∗
PAAS = 0. 98--1. 42), low Eu /Sm ratio (0. 30--0. 51), and high Sm/ Yb (0. 69--2. 17) and Y/ Ho (26. 55--40. 73) ratios. Collectively, these geochemical characteristics indicate that the ore-forming materials were primarily derived from seawater mixed with minor proportions (0. 1% ) of high-temperature hydrothermal fluids. The absence of significant negative Ce anoma-lies in the ore, combined with the attributes of the host rocks, suggests formation in a reducing marginal sea envi-ronment. Integrating evidence from its strictly stratabound geological occurrence, typical magnetite quartzite mineral assemblage, and the characteristic geochemical signatures outlined above, this study identifies the Naxiguole iron deposit as a classic Superior-type BIF deposit.

Abstract: To address the limitation of existing suitability evaluation methods for underground space develop-
ment and utilization that predominantly rely on two-dimensional (2D) analyses and fail to accurately characterize
three-dimensional (3D) underground space, the authors propose a multi-elements 3D suitability evaluation method
based on a regular voxel model. By employing a voxel model as a unified evaluation framework, this study utilizes
multiple 3D spatial analysis techniques to construct geological models and multi-factor 3D voxel attribute models of
underground space. Combined with the analytic hierarchy process (AHP), an evaluation system incorporating con-
straint and graded indexes is constructed to evaluate the suitability of underground space development and utilization
in the Zhengzhou High-Tech Zone. The results indicate that over 65% of the underground space in the study area is
classified as highly suitable for development, with only a small proportion classified as restricted areas. Overall, the
engineering geological and hydrogeological conditions are favorable for development and utilization. In terms of spa-
tial distribution, the shallow layer exhibits the highest suitability, with a slight decrease in suitable areas as depth
increases. Horizontally, the western part of the study area shows greater development potential and suitability than
the eastern part. Compared with traditional 2D evaluation methods, the multi-factors 3D suitability evaluation meth-
od for underground space development and utilization based on 3D voxel model enables organization, management,
computation, and visualization of evaluation results at any spatial location. It effectively addresses the loss of verti-
cal information inherent in traditional 2D layered evaluation, enhances the evaluation resolution and result visibility
in the vertical dimension, and provides more comprehensive information and services for underground space plan-
ning and construction.

Abstract: To determine the stratigraphic position of the Naitoushan marble in the eastern margin of the
Changbai Mountains basalt-covered area, the authors conducted a study on its paleosedimentary environment using
petrology and petrochemistry. The results show that the main rock types of the Naitoushan marble are medium-thick
bedded marble and medium-thin bedded dolomitic marble, indicating formation in a coastal-shallow marine evapora-
tive environment slightly closer to the continent. The w ( SiO2 ) of the major elements ranges from 2. 04% to
6. 21% , with a correlation coefficient of 0. 38 between SiO2and Zr, suggesting that the SiO2 content is not signifi-
cantly related to terrigenous detritus and is mainly of chemical sedimentary origin. The w (MgO + CaO + LOI)
ranges from 91. 37% to 96. 77% , indicating that the rock is predominantly composed of carbonate minerals with
minimal detrital components. The CaO/ MgO ratio ranges from 1. 41 to 24. 34, suggesting deposition in a relatively
enclosed coastal-bay marine environment. The Fe3 + / Fe2 + ratio is between 0. 05 and 0. 80, possibly reflecting for-
mation in a relatively dynamic and weakly neutral environment. Trace and rare earth elements analysis show that the
correlation coefficient between Ce anomaly (Ce/ Ce∗) and Eu anomaly (Eu/ Eu∗) is -0. 46, and -0. 25 with total
rare earth elements (REE). The Mn / Sr ratio ranges from 0. 01 to 0. 05, indicating that the rare earth elements in
the marble samples from the study area were hardly affected by diagenesis. The correlation coefficient between Zr
and Th is 0. 75, 0. 14 with ∑REE, 0. 47 with Ce / Ce∗, and - 0. 48 with Eu / Eu∗, indicating that the REE distri-
bution in the marble samples was barely affected by external materials. The Ce / Ce∗ ratio of 0. 82--1. 00 indicates a
weakly oxidizing environment during marble formation. The (Tb / Pr) N ratio of 1. 02--3. 13, and the (Tb / Yb) Nratio
of 0. 96 --1. 56 indicate a slight enrichment of middle rare earth elements, suggesting possible hydrothermal input.
The average Eu / Eu∗ value is 1. 17, with correlation coefficient of 0. 12 with Fe2 + and 0. 56 with Mn2 + , and 0. 20
with (Fe2 + + Mn2 + ), also implying hydrothermal influence. The average Gd / Gd∗ is 1. 05, indicating that human
factors in sample testing have been basically excluded. The Y/ Ho ratio ranges from 31. 53 to 44. 00, with an
average of 35. 17, suggesting formation in a inshore or restricted marine environment. Combined with regional
geological data, it is believed that the Naitoushan marble was formed in a relatively closed coastal-shallow marine
environment under oxidized to weakly oxidized seawater, accompanied by hydrothermal input. The rock assemblage
is correlated with the lower part of the Zhenzhumen Formation, representing its eastern extension.

Abstract: This study focuses on two fine-flake graphite metallogenic belts in the Shanxi Fault Uplift and South
Qinling regions of Henan Province. Through field geological surveys, sample testing, and comprehensive analysis, the
authors systematically investigated the distribution characteristics, enrichment regularity, and genetic mechanism of
fine-flake graphite. Research indicates that fine-flake graphite ore bodies primarily occur in the Chishangou Formation of
the Yinyugou Group within the Shanxi Fault Uplift and the Dagou Formation of the Douling Group in South Qinling,
demonstrating significant stratigraphic specificity. Spatiotemporal distribution analysis reveals that the ore-hosting strata
are mainly Paleoproterozoic, with deposits exhibiting a northwest-southeast trend, consistent with regional structural
trends. The ore bodies are strictly strata-bound and conformable with the host strata. The ore-forming materials originate
from a combination of organic and inorganic sources, with the deposit type classified as regional metamorphic.
Further research demonstrates that the fine-flake characteristics of graphite are primarily influenced by tectonic
stress, metamorphism and migmatization. These findings provide a scientific basis for a deeper understanding of the
metallogenic patterns of fine-flake graphite deposits in Henan Province.

Abstract: Water source quality safety is a major livelihood issue. With numerous water quality indicators and
complex influencing factors, timely evaluation of water source quality is particularly important. Most current evaluation
methods are relatively macro-level assessments based on existing quality standards, lacking relatively micro-level scien-
tific evaluation of water bodies in water source areas across different periods. Therefore, establishing a comprehensive
evaluation system can provide a theoretical basis and technical support for pollution risk early warning in drinking
water sources and for improving water environment quality. Based on the single-factor index evaluation method and
the Nemero index method, the authors introduce the concept of an environmental capacity index to construct a
multi-factor comprehensive environmental capacity index evaluation model and a Nemero method environmental
capacity index model. These two models were used to conduct a comprehensive evaluation of a drinking water source
in Dafeng District, Yancheng City, Jiangsu Province. Furthermore, based on the water quality evaluation, a health risk
assessment was introduced to analyze the human health risks associated with the water source, comprehensively ensuring
drinking water safety. The evaluation results indicate that the overall environmental quality of this water body shows
a trend of improvement, while the chemical oxygen demand (COD) indicator shows a deteriorating trend; all other
indicators show improving trends. Environmental quality in August was relatively poor within the year. The established
multi-factor comprehensive environmental capacity index model and the Nemero method environmental capacity index
model both can be used to evaluate water bodies in water source areas with stable categories. Among them, the improved
Nemero method environmental capacity calculates the weight of each pollution factor, avoiding the neglect of certain
pollutants with low concentration but high hazard. The total health risk of the water source area was around 1. 81 ×
10 - 4 a - 1-- 2. 30 × 10 - 4 a - 1, classified as high risk. Carcinogenic arsenic contributed the most to this risk,
followed by carcinogenic hexavalent chromium. Compared to non-carcinogenic risks, carcinogenic substances are
the main source of potential risk through the drinking water pathway.

To investigate the rare earth element (REE) fractionation patterns, grades, and their influencing factors in different ore blocks of the Bayan Obo REE--Nb--Fe symbiotic deposit, and to provide guidance for research on REE patterns and directional mineral processing at Bayan Obo, elemental mass fraction was conducted using inductively coupled plasma mass spectrometry on samples from different ore blocks of TK13--04 core in the main orebody. Results show that two distinct REE fractionation patterns exist in the main orebody. The REE fractionation pattern of the middle dolomite Fe--REE ores differ from that of the upper and lower dolomite REE ores. The former exhibits an “initial upward inclination followed by rightward inclination” characteristic with increasing from La to Nd and then decreasing from Nd to Lu. In contrast, the latter shows a “rightward inclination” pattern with gradually decreasing from La to Lu. The middle dolomite Fe--REE ores have a lower mass fraction of total REEs compared to the upper and lower dolomite REE ores. The total REE mass fraction is closely related to the degree of light-to-heavy REE (LREE--HREE) fractionation, the REE fractionation pattern, and the total iron (TFe) mass fraction. Higher degrees of LREE --HREE fractionation and higher La/ Nd ratios correlate with higher total REE mass fraction. When the TFe is below 20%, there is no definitive correlation between TFe and the REE mass fraction. However, when the TFe mass fraction exceeds 20%, the total REE mass fraction decreases significantly. Compared to the average proportions of individual light REEs (LREEs) in the mining area, the proportion of Ce in the middle dolomite Fe--REE ore block of TK13--04 is significantly lower ( ~37%), while the proportion of Nd is significantly higher ( ~40. 7%), exceeding the proportion of Ce that is typically the dominant REE in the deposit. The proportion of La in the middle dolomite Fe--REE ore block is also reduced ( ~9%) and the proportions of Pr and Sm are increased. Therefore, the middle dolomite Fe --REE ore blocks hold greater potential for the utilization of Nd, Pr, and Sm elements. For the utilization of La and Ce, development of the upper and lower dolomite REE ore block would likely yield more substantial benefits.

This study is the first to analyze the geothermal resource occurrence conditions and the formationevolution mechanisms in the southern part of Taiyuan City, Shanxi Province, from both geothermal geophysical and geothermal water isotope geochemical perspectives. Based on geophysical exploration data and geothermal water isotope chemical analysis, and combined with regional geological data, a comprehensive study of the geothermal field in southern Taiyuan is conducted. The geophysical methods primarily include gravity, magnetic, and electrical surveys, which are used to analyze the structural characteristics and reservoir distribution of the geothermal field. The geochemical methods mainly include hydrochemical and isotopic analyses, aimed at revealing the origin, evolution, and water-rock interaction processes of thermal groundwater. The geophysical exploration results indicate that the Taiyuan Basin as a whole exhibits a low gravity field and negative magnetic anomalies, reflecting a deeply buried basement and strong tectonic activity, which provide favorable heat sources and reservoir spaces for the formation of geothermal fields. The southern geothermal field of Taiyuan is located at the southeastern margin of the basin, where the gravity field shows a distinct gradient zone, and the magnetic anomalies are characterized by negative values, suggesting the presence of concealed fault structures that serve as channels for deep thermal flow upwelling. Moreover, an apparent arcuate low-resistivity zone exists within the geothermal field, inferred to represent the geothermal reservoir, further demonstrating the favorable conditions for geothermal resource accumulation in this area. Geothermal water isotope geochemical analysis reveals that the thermal groundwater in the southern Taiyuan geothermal field originates from meteoric water, undergoing processes of infiltration, leaching, and transformation into sedimentary (semi-confined) water. During this process, water interacts with surrounding rocks through leaching, dissolution, and cation exchange. Stable components accumulate in the groundwater, while unstable components precipitate, thus forming the hydrogeochemical characteristics of modern geothermal water. The formation of the geothermal field in southern Taiyuan is mainly controlled by the favorable regional geological structure, the development of concealed faults, and the good storage capacity and permeability of the geothermal reservoir.

novel integrated learning-based method for igneous reservoir fluid identification is proposed to address the limitations of traditional approaches in handling complex lithological variations and heterogeneous reservoir spaces, which are crucial for global oil and gas resource development. In this paper, the Adaptive Multi-- Objective Swarm Crossover Optimization (AMSCO) innovatively combined with an engineered extreme gradient boosting (XGBoost) based on deep forest method for fluid identification in complex lithologic igneous reservoirs using conventional logging data sets. Methodologically, firstly, the AMSCO algorithm is used to optimize the imbalanced conventional logging data set, effectively solving the problem of class imbalance in the data set, providing a more balanced data basis for subsequent model training. Secondly, a cross-adaptive XGBoost and deep forest (CXDF) is constructed by fully utilizing XGBoost􀆳s advantages in processing large-scale and high-dimensional data, as well as the excellent performance of deep forest in feature extraction and classification tasks. Thus, the
accurate identification of reservoir fluids in complex lithologic igneous rocks is achieved. Then, to verify the effectiveness of this method, the model was applied to the simulated well together with support vector machine (SVM), XGBoost and XGBoost-based deep forest for comparison. Finally, the model is applied to the actual stratum. The results show that the evaluation index of the proposed method in the simulated well is superior to other methods, especially in the identification of non-water-producing reservoir fluids. In the application to actual formations, this method maintains high identification performance in different reservoirs with different fluid structures, and shows good generalization ability and stability.