Based on the abundant seismic, wells and geochemical data, studies were carried out on the formation mechanism and hydrocarbon accumulation controlling factors of sublacustrine fans of the third member of Dongying Formation in LD10 structural area, Liaozhong depression, Bohai Bay basin, and the hydrocarbon enrichment regularity was discussed. According to the research, the “chain island” type paleogeomorphology of Liaoxi uplift controlled the source condition, and the area near the main sand passages had a better development environment with bigger thicknesses and more periods. Single event fans and external configuration fans were confirmed by borehole seismic calibration, and boundary description methods were established by integration between geology and geophysics.  The deep structural background, the distance between the fans and source rock, and the pattern between the fault and the fans jointly controlled the hydrocarbon charging intensity in the LD10 structural area. Under the conditions of double deep ridges, smaller distance from the main source rock layers, and forward charging from fault to fans, the goal fans could form high hydrocarbon columns. These new understanding and methods were used to guide the exploration practice, with LD10-6 medium-large sublacustrine fans oilfield discovered in the Dongying Formation in the western slope of Liaozhong depression, which is a breakthrough in the exploration of sublacustrine fan of Paleogene in Bohai sea area.

The western slope of Songliao basin is an important oil sands metallogenic belt in China. In order to further clarify the characteristics of Cretaceous oil sands resources in the central and southern parts of the area, the basic geological survey work has been implemented with five oil sands investigation wells and one hydrological investigation well in the Dagang area of Jilin. Based on core observation, geophysical log interpretation, and oil content test of core samples, a comprehensive geological study was carried out. The results show that, the oil sands of the Cretaceous Yaojia Formation are located at a depth from 175 m to 208 m, and the lithology is mainly siltstone and fine sandstone. The oil content level of the core reaches oil immersion grade, with a maximum oil content of 16.02% and an average oil content of 8.23%. The oil sand formation logging curve is characterized by low natural gamma value, high acoustic velocity value, medium to high resistivity and low density. The oil sands formation is divided into four sub-layers (S1, S2, S3, S4) and oil content characteristics are analyzed. Vertically, the oil content is non-homogeneous and increases gradually with depth. The average oil content of S3 and S4 in the lower part of the reservoir is 10.80 % and 11.40 %, respectively, reaching the grade of rich ore. The effective thickness of each sub-layer varies widely in the vertical direction, with a maximum value of 3.10 m and a minimum value of 1.20 m. The average effective thickness of the lower S3 and S4 sub-layers is 2.90 m and 1.90 m respectively, which is obviously better than the upper S1 and S2 sub-layers. On the scale of oil-sand development, the distribution area of S3 sub-layer is the largest, and the area of sand body with effective thickness≥2 m is about 270 m×160 m, and the thickness center is located in the southeast of the well area, and the thickness is thinned from the thickness center to the northwest; The distribution area of S4 sub-layer is the second largest, and the area of sand body with effective thickness≥2 m is about 250 m×120 m, its thickness center is located in the middle of the well area. In terms of planar spreading, its distribution area is large in the southeast and northwest directions, and the distribution area in the middle zone is slightly smaller, with a nearly dumbbell shape, the thickness thins from the thickness center to the north-east and south-west directions. On sand deposition characteristics, controlled by the sedimentary evolution of the regional shallow water delta, high-quality oil sands are mostly deposited in the fine sandstone of the divergent river channel, especially the S3 and S4 sub-layers located in the lower part of the reservoir have obvious deposition patterns of multi-phase superimposed river lateral accumulation sand bodies. In general, the S3 and S4 sub-layers have high oil content, large effective thickness and considerable spreading area, and are the main reservoir of high-quality oil sands in the area.

The Jiufotang Formation has huge hydrocarbon resources in the Ludong depression of Kailu basin, but there is less research on the relationship between Milankovitch cycle and sedimentation patterns, especially fine-grained sedimentation, which restricts the prediction of source rock distribution. In this study, wavelet and spectrum analyses of natural gamma log data were used to divide the Milankovitch cycle of the Upper Member of the Jiufotang Formation, and the sedimentary environment at that time was compared with the divided cycle to clarify the stratigraphic sedimentary response characteristics. The results show that 13 Class Ⅳ cycles, 25 Class Ⅴ cycles and 66 Class Ⅵ cycles can be identified in the Upper Member of  Jiufotang Formation. According to the lithology and long eccentricity characteristics of the sedimentary rocks in the Upper Member of  Jiufotang Formation, it can be divided into two stages of sedimentary environment evolution: Warm and humid climate half-cycle and cold and dry climate half-cycle. In the warm and humid climate half-cycle, the increasing depth of waterbody benefits the deposition of fine-grained sedimentary rocks. The warm and humid climate period is the period of hydrocarbon source rock development, and the cold and dry climate period is the period of reservoir development. Combining with relevant geochemical data, the development sites of reservoirs and hydrocarbon source rocks can be predicted.

Microwave heating technology as an alternative to conventional heating methods in oil shale exploitation microwave heating technology has gained significant attention as an alternative to traditional heating methods in the exploitation of oil shale reserves. In order to investigate the thermal response of oil shale under microwave radiation, as well as the changes in porosity, permeability, and internal displacement, numerical simulations were conducted using COMSOL Multiphysics software. These simulations were based on a coupled 3D electromagnetic-thermal-permeability-solid mechanics model. The results revealed the following key findings: Under microwave heating conditions, the temperature of the oil shale reservoir increases rapidly. Moreover, as the microwave power increases, the rate of temperature rise significantly accelerates. Different power levels result in distinct timeframes required for the reservoir to reach its pyrolysis temperature, with the fastest heating occurring at 800 W microwave power. With prolonged heating, porosity and permeability gradually increase, especially at higher power levels, where the growth is more pronounced. At the 500th day of microwave irradiation, the average permeability of oil shale reached its peak under different power levels, with a permeability of 1.93×10-16 m2 observed at 800 W. Microwave heating leads to the weakening of mechanical properties and increased formation damage in the reservoir. When the microwave radiation power reaches 800 W, the maximum displacement reaches 3.8 cm. In summary, selecting a microwave power of 600 W demonstrates significant engineering application benefits for the in-situ pyrolysis of oil shale reservoirs.

Deep dolomite has been a key focus of deep exploration in recent years, with dolomite cementation commonly found in its internal pores. However, there is relatively less research on the combination of dolomite cement grain occurrence and its effect on pores. Therefore, taking the Longwangmiao Formation of the Lower Cambrian in the Gaomo area of the Sichuan basin as an example, comprehensive data such as core samples, thin sections, cathodoluminescence, carbon-oxygen isotopes, and inclusions were used to study the types, characteristics, structures, volume fraction, and their effects on pores of dolomite cement. The crystals of dolomite cement mainly have shapes such as semi rhombus, rhombus, ring shaped, saddle shaped, etc., with particle sizes ranging from powder crystals to giant crystals. Cement crystals and pores form three types of structures: lining, bridging, and embedding. Using the frequency of development (the number of samples that develop a certain structure/the total number of samples of granular dolomite or grain dolomite) to characterize the degree of development of a certain structure, the embedding structure is the most developed in dolomite (48.3%-89.5%), followed by the bridging structure (22.4%-73.7%), and the lining structure is the weakest (8.6%-55.2%). The inner lining structure and bridging structure are mainly developed in granular dolomite, with volume fraction of 0 to 15% and 25% to 50%, respectively, and their development degree increases with the volume fraction of fine-grained dolomite cement. Embedding structures are commonly developed in dolomite, with a volume fraction mainly ranging from 50% to 100%, and their development is positively correlated with the volume fraction of medium crystalline to giant crystalline dolomite. The inner lining structure and bridging structure are mainly formed during the syndiagenetic stage to the middle diagenetic stage, while the embedding structure is mainly formed during the late diagenetic stage. The formation of inner lining and bridging structures earlier can reduce the damage to pores caused by solution compaction during diagenesis, while the embedding structure can damage residual pores. Based on the porosity of the layers with mainly developed embedding structures, the porosity of the layers with mainly developed inner lining and bridging structures can be increased by 50%.

The Qimantage area is one of the important metallogenic belts in China, known for large scale deposits of Fe-Cu-Pb-Zn-W-Sn-Au-Co and other polymetallic mineral. The Nalingguolehexi area, located in the eastern section, is particularly rich in iron, copper, and zinc skarn polymetallic minerals. However, exploration and research of polymetallic minerals in the area are hampered by thick gravel, stones and sand dunes, limiting geological and geochemical measurement methods. This article focuses on the magnetic anomaly zones (M1 and M3) ofthe Nalingguolehexi (Naxi)  iron polymetallic ore. Using Surpac three-dimensional modeling software, three-dimensional solid models of each ore-controlling geological elements were established. Through advanced three-dimensional visualization technology, geological structure models were constructed. By integrating and analyzing abundant geological data, the spatial distribution laws of ore bodies and their spatial relationship with mineralization structures were clarified. This enhanced understanding of mineralization laws allows for a transparent view of the key Naxi area down to 1 500 m and identifies eight deep marginal prospecting target areas, supporting mineral resource prediction, evaluation, and exploration planning in the Naxi mining area.

In order to provide evidence for the Neoproterozoic great oxidation event on the northern margin of the North China craton, this paper investigates the sedimentary environment of the Nanfen Formation in Tonghua area. Petrology, geochemistry, and isotope geochemistry have been used on marlstones and shales to explore the tectonic setting, the degree of oxidation and reduction, and its response to the Neoproterozoic great oxidation event. The results show that the Nanfen Formation is composed of purple and yellow-green shales and marlstones, with marine sedimentary characteristics. Ni/Co ratio, V/Cr ratio, V/(V+Ni) ratio, Mo content, and total organic carbon content indicate that the sedimentary environment was oxidized during the forming period of Nanfen Formation. The oxidation degree of the Nanfen Formation fluctuated in the early evolutionary stage, and remained stable in the late stage. This proves that the Neoproterozoic great oxidation event occurred on the northern margin of the North China craton and responded well to the Neoproterozoic great oxidation event in South China.

The Tugurige gold deposit is a large-scale gold deposit which is located in the Xing’an-Mongolia Orgenic Belt(XMOB). In order to investigate the source of its ore-forming fluids, a systematic study of the carbon and oxygen isotopes of the deposit was conducted. Results show that the average carbon isotope δ13CV-PDB value of the green calcite is -8.85‰, while the average oxygen isotope δ18OV-SMOW value is 11.65‰. The trends in δ13C and δ18O reflect a transformation of calcite from low to high enrichment levels, indicating two distinct mineralization stages. On the basis of previous research, this study proposes that the origin and composition of ore-forming fluids differ across these stages of mineral deposit formation: In the stage Ⅱ, the ore-forming fluids mainly originated from deep-seated magmatic water, whereas in the stage Ⅲ, seawater-derived carbonates were mixed. Comparing the C-O isotope compositions between the Baoyintu Group and regional formations revealed significantly depleted oxygen isotopes, indicating water-rock interactions during the ore-forming process. Simulations of water-rock reactions indicate that soluble carbon in the ore-forming fluids mainly existed in the form of HCO3-. The simultaneous δ13C and δ18O values of the ore-forming fluid, -9.2‰ and 8‰ respectively, imply that the initial fluid originated from magma and subsequently interacted with marine carbonate rocks in the surrounding rocks during the evolution process. Comprehensive research on the Tugurige gold deposit highlights it typical characteristics of a magmatic hydrothermal gold deposit, with geological features, mineral symbiosis, and fluid characteristics all indicating a close relationship with magmatic hydrothermal activity.

The Cenozoic basalts in Fujian are widely developed and contain abundant mantle xenoliths, whose mineralogical characteristic provide insights into the properties of lithospheric mantle. This study conducted electron microprobes, clinopyroxene LA-ICP-MS trace element, and in-situ Sr isotopes analyses on the minerals in Cenozoic basalts and peridotite xenoliths from Xiamen along the Fujian coast, as well as Mingxi and Minqing in the inland region. The results indicate that the clinopyroxenes in both basalt and peridotite xenoliths are predominantly diopside. The peridotite xenoliths are divided into two groups based on mineralogical characteristics: Group A (Mg# > 90), representing an ancient, refractory lithospheric mantle, and Group B (Mg# < 90), representing a younger, modified enriched lithospheric mantle. Group A clinopyroxene exhibit slight negative anomalies in high-field strength elements Nb and Ti, and strong negative anomalies in Hf, Zr, and Ta. In Group B peridotite, clinopyroxene shows differences, with slightly negative anomaly in high high-field strength elements Zr and Hf and a pronounced negative anomaly in the large ion lithophile element Ba. The clinopyroxene in both the phenocrysts and matrix of the basalt exhibits LREE enrichment and HREE depletion, with the rims showing greater depletions in high-field strength elements Th and Nb compared to the cores, along with enrichments in large ion lithophile elements Sr and Eu. Most clinopyroxenes in both Group A and Group B xenoliths have experienced silicate melt metasomatism, while a few Group A clinopyroxene suggest a mix between silicate and carbonate melt metasomatism. In-situ Sr isotope ratios for clinopyroxene range from 0.702 57 to 0.703 67, with most rims showing higher 87Sr/86Sr ratios than the cores, like due to interaction with materials of higher 87Sr/86Sr ratios. The Fujian peridotite probably represents a newly modified lithospheric mantle of the Pacific plate subduction asthenosphere mantle, following decompression ascent.

 During the Indosinian period, small granitic bodies or stocks were wildly developed in the Songpan-Garze orogenic belt. This study focuses on the granitic body in Qiuzhi area of Qinghai Province, located along the southern margin of Songpan-Garze orogenic belt. The petrogenesis and tectonic setting of the granitic body are discussed through petrography, zircon U-Pb chronology, zircon Lu-Hf isotope, Sr-Nd isotope of whole rock and whole rock geochemistry. The results show that the granites in Qiuzhi area are mainly granodiorite, characterized by weak sodium enrichment (Na2O/K2O =0.97-1.34) and a low aluminum saturation index (A/CNK=0.99-1.08), thus classified as weak peraluminous calc-alkaline series granites. Rare earth element patterns show enrichment of light rare earth elements and depletion of heavy rare earth elements, along with a right-leaning distribution. The rocks are enriched in Rb, K,U, Th, La, Ce, Nd, Zr, Hf and Y, while being depleted in Ba, Sr ,Ta, Nb, P and Ti. The weighted average age of granodiorite zircon 206Pb/238U is (215.4±1.4) Ma (MSWD=1.05, n=23), indicating a Late Triassic diagenetic age. Zircon Hf isotopic values (176Hf/177Hf)i range from 0.282 377 to 0.282 437, with εHf(t) between -9.44 and -7.19, and two-stage model ages (TDM2) from 1 840 to 1 702 Ma. The initial Sr isotope values (87Sr/86Sr) i of whole rock range from 0.709 783 to 0.710 530, εNd(t) ranges from -8.2 to -7.8, and the two-stage model ages (TDM2) range from 1 659 to 1 630 Ma. These findings suggest that the magma source is the partial melting of the ancient crust material, exhibiting characteristics of calc-alkaline I type granite. By correlating regional geological data with the geochemical characteristics of the petrosphere, it is concluded that Qiuzhi granitic body is a product of lithospheric delamination, asthenosphere material upwelling, and lower crustal partial melting within the background of Late Triassic post-collision environment.

The Gaojiadian pluton, located in the eastern Hebei Province on the northern margin of the North China craton, is a composite batholith that intruded during the early Yanshan period. It primary rock types include diorite, syenite, granite, with transitional varieties present. The pluton hosts hydrothermal vein-type gold deposits, primarily found in granite and diorite.To accurately determine the invasion period of the Gaojiadian pluton, four rock samples were analyzed by zircon chronology and trace element characteristics using LA-ICP-MS zircon U-Pb dating. The results indicate crystallization age of (197.4±1.9) Ma for quartz syenite, (176.7±1.2) Ma for fleshy-red biotite monzonitic granite, (175.8±1.7) Ma for gray-white biotite monzonitic granite, and (175.3±1.9) Ma for diorite-porphyrite, suggesting an intrusion age from the Early to Middle Jurassic. Dark diorite enclaves within the granite imply a mixed crust-mantle origin formed in an extensional tectonic setting. Zircon trace elements of all samples exhibit a left-leaning rare earth partitioning pattern with strong Ce positive anomalies and varying degrees of Eu negative anomalies. The zircon saturation temperature ranges from 682 to 824 ℃, representing the initial magma formation temperature. The magma exhibited a gradual cooling trend over evolutionary time and shares a similar partitioning pattern and crystallization temperature range with regional magmatic zircons. The high Ce4+/Ce3+ values of zircon represent relatively high oxygen fugacity, revealing the stronger mineralization potential of the Gaojiadian pluton, especially in the biotite monzonitic granite.

Aiming at the problem of the in-situ stress field in long and deep buried tunnels, taking the deep buried tunnel of  Yellow River to Xining diversion project in Qinghai Province as the background, the regional tectonic evolution analysis, on-site hydraulic fracturing testing, and numerical deduction methods were used to determine the in-situ stress characteristics of each section of the tunnel. The research results show that the tunnel of  Yellow River to Xining diversion project is affected by the compression movement of the blocks in the northeast margin of the Qinghai-Xizang Plateau, and the main compressive stress direction is NE-NEE direction; The stress field of the tunnel  can be divided into three regions, with the maximum horizontal principal stress lateral pressure coefficient of 2.0 in the Laji section; The maximum buried depth of the tunnel when crossing the Laji Mountain exceeds 1 400 m, and the maximum horizontal principal stress exceeds 70 MPa, which may have a significant impact on the stability of the tunnel surrounding rock.

Addressing the complex engineering challenges of a excavated metro station in Chengdu that partially traverses existing buildings, this study adopted a localized undercut and expansion excavation strategy through comprehensive comparative analysis and finite element simulation. The research proposed a scientific method for determining the boundary between open and undercut excavation, and delved into various aspects of key construction technologies such as settlement control, primary support for undercut excavation, and secondary lining, including pre-construction dewatering, ground surface grouting reinforcement, and numerical simulation analysis, as well as advanced support during construction, excavation sequence control, and secondary lining structure construction. The research results indicate that, compared to the traditional open-cut method, the undercut and expansion excavation technique can significantly reduce demolition difficulties, It has significantly cut the investment in project costs by approximately 104 million yuan and shortened the construction period by two months. The key to successful construction lies in accurately determining the boundary between open and undercut excavation, which is recommended to be set outside the structural haunch and 3 m away from the building foundation. Meanwhile, combining sleeve valve pipe ground surface grouting with tube well dewatering measures can effectively control ground surface settlement. During construction, it is necessary to flexibly select construction methods based on the span of the undercut tunnel and the characteristics of surrounding rocks, properly handle the nodes of the primary support structure, ensure effective connection between secondary lining construction and the removal of the primary support structure, and attach great importance to the application of construction monitoring.

In order to prove the existence of water migration in ice under vibration loading and to investigate the law of water migration in ice, vibration tests were carried out under negative temperature conditions with artificial column ice as the research object, and the migration of liquid water in ice was investigated by changing the ambient temperature and loading frequency. First, in combination with the load characteristics of heavy fully loaded trucks borne by highways in permafrost areas, with 55 kPa as the load amplitude and the cyclic vibration frequency set to 2 880-28 800 times, the cyclic vibration loaded layered column ice water migration test was carried out under the conditions of －3 ℃, 0.5 Hz; Then, the vibration test was carried out under the conditions of -5 to the water migration test of artificial column ice under cyclic vibration loading was carried out at －1.0 ℃ and 0.1-0.5 Hz; Finally, the test data were fitted. The results show that: Under vibration loading, the liquid water in the ice migrates along the structural cracks in the loading direction; At different ambient temperatures, the amount of water migration increases exponentially; At different loading frequencies, the amount of water migration grows in stages in the form of a segmented function. When the loading frequency and load amplitude are constant, the amount of water migration and the peak growth rate increase with the increase of ambient temperature and decrease with the decrease of temperature, and the moisture migration measured at -1 ℃ is about 3.75 times of that at -5 ℃; The closer to the melting point, the faster the peak growth rate occurs, and the slower the opposite is. When the ambient temperature and load amplitude are constant, the moisture migration and the peak growth rate increase with the increase of frequency and decrease with the decrease of frequency, and the amount of water migration measured at 1.0 Hz is about 2.04 times of that at 0.1 Hz; The faster the loading frequency is, the faster the peak growth rate appears, and the slower the opposite is.

Due to the limitation of setting the upper boundary at the free surface located at the water table, the Theis well model in unconfined aquifers has some problems such as unsound theoretical basis and unreasonable physical meaning of parameters. To overcome these issues, firstly, the well model is revised by moving the free surface from the water table to the air entry plane, and takes the Boussinesq equation located at the air entry plane as the governing equation, and derives the analytical solution of the model; Then, a parameter inversion model is constructed to calibrate the model parameters. By comparing the revised model drawdown and the theoretical drawdown of the classical model with the measured drawdown, it verifies the rationality of the well revised model proposed in this paper. Then, the variation characteristics of the air entry plane elevation under the modified well model are discussed by using parameter sensitivity analysis. Finally, the computational method and variation characteristics of seepage velocity in the vertical direction of the air entry plane are discussed. It is found that the drawdown curve obtained by the revised model coincides with the measured drawdown curve; The air entry plane elevation increases with increasing distance from the center of the well and the specific yield and decreases with increasing pumping flow rate. In the early stage of pumping, the air entry plane elevation decreases with increasing hydraulic conductivity, but the opposite is true in the late stage of pumping. The calculation results of the analytical expressions of the seepage velocity in the vertical direction based on the water balance relation at the air entry plane (based on the linearized or non-linearized equation, using complete solutionor approximate solution) and based on continuity equation of seepage flow at the air entry plane (based on the linearized equation, using complete solution) under five conditions are basically consisent, and the trends of the curve are consistent with each other, showing a nonlinear increase with the prolongation of pumping time.

To simulate hydraulic fracturing and heat injection and extraction effect in hot dry rock reservoir, we established a  thermo-hydro-mechanical  coupling hydraulic fracture propagation and heat transfer model for simulating the complex fracturing fracture morphology of dry hot rock and conducting injection-production thermal analysis. Taking the hot dry rock（HDR） in Qinghai Gonghe basin as a reference, we constructed two case considered the geo-mechanical parameter characteristics and simulated the multi-well fracturing and heat recovery process, the numerical results of fracturing and heat injection and recovery show that: In HDR, the fracture initiation is influenced by the non-uniform stress field, exhibiting volumetric fracture characteristics. Fractures created through multi-well fracturing connect via natural fractures, providing over 95% of the heat exchange flow channels for heat injection and production. During heat injection and production, fluid mainly flows along the connected fractures, forming dominant heat exchange channels. This leads to a significant decrease in outlet temperature during the initial stage of heat injection and production, with the outlet water temperature dropping by 30-50 ℃ within the first three years, followed by a gradual slowdown in the later stages. Enhanced fracture complexity can increase effective heat transfer area, while optimized well placement and injection-production parameters improve thermal efficiency, enabling sustainable geothermal energy exploitation.

To investigate the heavy metal pollution status and ecological and exposure risks in agricultural soils of the water town area in Dongguan City, vegetable bases and agricultural land of large traffic arteries both sides within the water town area were selected as study sites. A total of 32 soil and vegetable samples each were collected from vegetable bases and agricultural land of large traffic arteries both sides for analysis. Firstly, the pollution characteristics of eight heavy metals, including Cd, Hg, As, Pb, Cr, Cu, Zn, and Ni, were evaluated using the single-factor pollution index (IP) and the Nemerow comprehensive pollution index (PN). And then, ecological risk assessment and agricultural product quality and safety assessment were conducted, and the causes of heavy metal pollution were finally investigated. The results showed that the mean values of the mass fractions of the remaining seven heavy metals in vegetable bases soils were lower than the city’s soil background values, except for Ni; The mean values of the mass fractions of the remaining six heavy metals in agricultural land of large traffic arteries both sides were lower than the  mean values in the water town area, except for Pb and Ni; And the mean values of the mass fractions of the remaining heavy metals, except for Pb, Zn, and Ni, were lower than the city’s soil background values. Based on the single-factor pollution index, heavy metal accumulation is observed in the soil of vegetable bases and agricultural land of large traffic arteries both sides. Within the vegetable bases, 6.67% of the sampling sites exhibit Cd mass fraction surpassing the risk screening values for agricultural soil. In agricultural land of large traffic arteries both sides, 17.64%, 23.53%, and 5.88% of the sampling sites display Cd, Pb, and Cu mass fraction exceeding the risk screening values for agricultural soil, all remaining below the regulatory thresholds for pollution risk. Evaluation of the Nemerow comprehensive pollution index showed that agricultural land of large traffic arteries both sides were slightly polluted to varying degrees, with 40.00% and 64.70% in the mildly polluted category, respectively. The ecological risk evaluation showed that the potential ecological hazard index (Ie) of Hg reached the medium ecological risk level in 6.67% of the study sites in the vegetable bases, and the ecological risk hazard index (Ir) was at the medium ecological risk level in 6.67% of the study sites. For agricultural land of large traffic arteries both sides, 11.76% of the study sites had Cd Ie at medium ecological risk level, 17.64% of the study sites had Hg Ie at medium ecological risk level, and 5.58% of the study sites had Ir at medium ecological risk level. The evaluation of the quality and safety of agricultural products showed that there were Cd exceedances in the soil of vegetable bases and in agricultural products in agricultural land of large traffic arteries both sides. The reason for the excess of heavy metals in vegetable bases is related to the application of chemical fertilizers and pesticides and agricultural land of large traffic arteries both sides have heavy metal pollution from transportation sources and pollution inputs from agricultural sources.

As a common environmental pollutant, accurate determination of the bioavailability of arsenic is essential for assessing potential health risks. In order to evaluate the environmental quality of agricultural soils more rationally, this paper explores a reliable and efficient method to extract bioavailable arsenic （the sum of the water-soluble, weakly acid-extractable, reducible, and oxidizable fractions of arsenic）  from soil. Based on the property that L-cysteine solution can effectively form chelates with arsenic, L-cysteine solution was selected as the extractant, and optimized around the parameters of mass fraction of extractant, extraction temperature, and ultrasonic time, etc. The mass concentration of arsenic in the soil in the effective state was determined under the conditions of different extraction temperatures and different mass concentrations of the extractant, respectively, and compared with the results of the sequential extraction to determine the optimal extraction conditions. The results showed that when the mass concentration of L-cysteine was 10 g/L, the ultrasonication temperature was 40 ℃, and the ultrasonication time was 30 min, the bioavailable  arsenic extracted of  DT-1 sample was 7.37 μg/g, closely matched the results of bioavailable arsenic obtained by sequential extraction （7.83 μg/g）.  Compared with the sequential extraction method, this method requires only one step of extraction and the extraction time is shortened by 65 h, which greatly improves the efficiency.

 The pilot demonstration area of Well MH1 in the northwest margin of  Junggar basin (MH1 well  area) exhibits fractures of varying scales in the Permian and Triassic formations. The formation mechanism of these fractures is complex, the subsequent stimulation is frequent, and the existing forms are various, which seriously restrict the development process of horizontal wells. Based on improving the signal-to-noise ratio and resolution of seismic data, this paper establishes the small-scale hidden fault identification process and model, and further guides horizontal well drilling through a combination of optimal azimuth superposition scheme, continuous wavelet transform seismic data frequency boosting, matrix singular value decomposition for denoising, iterative processing of structure-guided filtering, fracture enhancement filtering, multi-attribute fusion, and artificial intelligence (AI)-based fault recognition. The results show that by combining various geophysical methods with AI technology, this paper establishes a small-scale concealed fault identification process and model suitable for MH1 well area, significantly improves the fault identification accuracy, optimizes the drilling trajectory of horizontal wells in MH1 well area, successfully avoids high-risk fault zones, reduces the incidence of leakage events by about 20%, and reduces the problem of pressure and channel interference by about 15%.

Numerical simulation of seismic wave fields is crucial for seismic exploration, seismic data processing, and the study of Earth’s structures. The wave equation numerical simulation method takes into account the dynamic and geometric characteristics of seismic wave propagation, providing a solid theoretical basis for studying the mechanism of seismic wave propagation and interpreting complex geological structures. It is currently one of the most widely used methods for simulating seismic wave fields. This article surveys five wave equation-based numerical simulation methods: The finite difference method is easy to understand, but suffers from numerical dispersion issues; The pseudo spectral method offers high accuracy but low efficiency; The finite element method is suitable for complex models but requires substantial computational resources; The spectral element method is appropriate for high-precision problems but demands significant computational memory; And the deep learning method based on physics-informed neural networks demonstrates strong adaptability, though it comes with high training costs. The theoretical foundations, applicable conditions, and latest advancements of these five numerical simulation methods are described respectively. In the future, seismic wave field numerical simulation methods should integrate cutting-edge technologies such as deep learning, optimize boundary conditions to simulate actual boundary reflections, and enhance the precision and efficiency of simulations.

The traditional spectral blueing frequency broadening methods have a limitation in the calculation of spectral blueing operators, leading to poor effects when applied to post-stack seismic frequency enhancement. To address this, a frequency-division spectral blueing broadening technique based on matching pursuit is proposed. Firstly, the matching pursuit method is employed to accurately divide the post-stack seismic data into multiple frequency-split seismic bodies. Then, during the calculation of the spectral blueing operators for each frequency band, a weighting approach is introduced to determine the weights of the optimized spectral blueing operators for each frequency band based on the differences in energy across different frequency bands. Finally, the optimized spectral blueing operators are convolved with seismic reflection coefficients to obtain high-resolution seismic data. Actual tests on post-stack seismic data demonstrate that, compared with traditional spectral blueing methods, the frequency enhancement method proposed in this paper improves the high-frequency component information of post-stack seismic data. After frequency expansion, there are more seismic event axes and  the  resolution is higher. Through a series of operations such as attribute extraction, well seismic calibration, and inversion of the seismic data before and after processing, it is verified that the high-frequency components of the frequency-enhanced seismic data are effective and can more accurately delineate faults and identify thin-layer sand bodies.

Fractured reservoir is a kind of fluid-bearing fracture-porous medium, and the quantitative characterization of fracture parameters plays a critical role in the exploration and development of unconventional hydrocarbon reservoirs. However, conventional reservoir prediction methods primarily based on amplitude information are limited in revealing the complex characteristics of fractured reservoirs. This paper focuses on fluid-saturated orthogonal fractured reservoirs and thoroughly analyzes the velocity dispersion and attenuation characteristics of media containing both horizontal and vertical orthogonal fractures. An anisotropic reflectivity method is employed to simulate the frequency-dependent amplitude variation with offset (AVO) response of a single-interface dispersive sandstone reservoir. Based on this, a Bayesian inversion framework driven by the responses of horizontal and vertical orthogonal fracture models is developed to achieve multi-parameter quantitative inversion of porosity, fracture density, and fracture radius in fractured reservoirs. The results demonstrate that porosity, fracture density, and fracture radius are highly sensitive to velocity dispersion. At low frequencies, the frequency-dependent PP wave reflection coefficient exhibits significant variations with both frequency and incidence angle, and the amplitude increases linearly with the incidence angle. This highlights the substantial influence of fracture parameters on the frequency-dependent AVO response. Inversion results show that the proposed method achieves high accuracy in posterior probability distributions under varying fracture parameter conditions, with particularly improved applicability and reliability in predicting fracture radius in small-scale fractured reservoirs.

Fine reservoir description has always been the focus of development and production of unconventional oil and gas resources, but the vertical resolution of conventional logging curves is difficult to satisfy the effective identification of thin layers at centimeter or even millimeter scale. Aiming at this problem, this paper proposes a two-level knowledge migration super-resolution method for large-scale difference in logging curves to improve the vertical resolution of logging curves, thus realizing high-resolution target reservoir fine description in low-cost cases, using integrated machine learning as the basic tool and the perspective of multi-view and multi-scale as the core. The microsphere resistivity, natural gamma ray, and acoustic time difference curves with better formation response are selected as the target curves, and the construction of a mapping model from the information of high-resolution imaging resistivity curves to the target logging curves is realized, which in turn realizes the large-scale difference super-resolution of target logging curves , and the super-resolution results are compared with different super-resolution methods. The results show that the correlation coefficients between the super-resolution curves obtained by the method of this paper and the real high-resolution curves are greater than 0.9, which are improved by 3.6% to 16.0% compared with the comparison methods, and the mean square error,the root mean square error, the mean absolute error, the mean absolute percentage error, the symmetric mean absolute percentage error  are reduced by 28.9% to 90.8%, 15.7% to 69.8%, 24.4% to 74.7%,  25.0% to 74.2%, and 25.2% to 77.4% , respectively. Therefore, the method of this paper is able to largely realize the millimeter-level super-resolution processing of the existing conventional logging curves, and the obtained super-resolution curves are able to roughly capture the formation changes, which alleviates the difficulty of the problem of effective identification of fine reservoirs.

The study of well log cyclostratigraphy is mainly based on the Milankovitch astronomical theory, using logging data as a proxy for astronomical cycles to investigate scientific issues in geology, environment, climate, and other fields. Currently, there is still a lack of specialized software for the processing and analysis of well log cyclostratigraphy both domestically and internationally. In this paper, a well log cyclostratigraphy analysis module is developed using Java language based on the CIFLog software, which includes necessary functions such as preprocessing, astronomical testing, filtering and tuning. The effectiveness of each function is verified using theoretical curves as test data. We select the Th content data from natural gamma ray spectroscopy  logging of  Qingshankou Formation in Well SK-2 in  Songliao basin for processing and successfully identify and extract 13 long eccentricity signals. The sedimentation rate is estimated to be 5.6 cm/ka, and a floating astronomical time scale has been  established.

Addressing the challenge posed by the uneven distribution of various features and the low classification accuracy of urban remote sensing images, we propose a novel method for remote sensing image classification that integrates parallel attention and weight balance algorithm. Leveraging the semantic segmentation network architecture of DeepLabV3+ and ResNet50, our method combines channel attention and spatial attention algorithms in parallel to improve the network's feature extraction capability. Additionally, to address the issue of imbalanced feature category proportions in remote sensing images, we propose a feature category weight balance algorithm to improve the classification accuracy of minority feature categories. To validate the effectiveness of our network model for classification, we conduct experiments using Vaihingen and Postdam datasets. The experimental results demonstrate promising performance metrics: The remote sensing image classification algorithm that integrates attention mechanism and weight balance is validated in the Vaihingen dataset with pixel accuracy, mean intersection over union, and mean F1 values of 96.66%, 90.35%, and 96.66%, respectively. In the Postdam dataset, the pixel accuracy, mean intersection over union, and mean F1 values of the validated data are 95.74%, 81.47%, and 91.82%, respectively. From the classification details, incorporating an attention mechanism and a weight balance algorithm significantly enhances the recognition accuracy of cars, which account for a relatively small proportion. Specifically, the pixel accuracy of cars in Vaihingen dataset has improved by 26.44%, and in  Postdam dataset, it has increased by 21.84%, leading to commendable classification results.