For the problem of low awareness of deep oil， the main control factor of different kinds of reservoirs and deep crude oil accumulation model in Shuangcheng fault depression of Songliao basin, we make sure the main controlling factors such as the thickness of source rock, the hydrocarbon expulsion intensity, the formation of entrapment and its relationship with the main accumulation period, the sand-source configuration, the overpressure and filling resistance, on the base of rock-eval, chloroform asphalt “A” and homogenization temperature of inclusion. The result is that: 1) There are four kinds of reservoirs, such as fault-anticline, anticline and fault-lithologic reservoir in the 3rd Member of Denglouku Formation in the west structure and the east fault bench, tight reservoir in the 4th Member of Yingcheng Formation within the central sub-sag. 2) The structure reservoir in the 3rd Member of Denglouku Formation is controlled by the union of mudstone, oil-source fault and effective trap. The abundant source rock is the material base for oil reservoir, and the structure trap in the 3rd Member of Denglouku Formation is almost complete before the hydrocarbon expulsion, fault is the main target for oil migration, the configuration relationship of sandstone and source determine the effective of structure trap. 3) The tight oil in the 4th Member of Yingcheng Formation is under the control of lithologic trap, source and overpressure. The tight oil is controlled by the hydrocarbon expulsion intensity, while overpressure is the main power for tight oil charging. We set up three kinds of accumulation models in different regions based on forming condition and main controlling factors of tight oil, such as “reservoir and source separate, migration along the fault in long distance and enrichment in the high point” in west structure, “reservoir and source nearby, long distance transmission of faults and connected sandstone in short distance, accumulate in effective trap” in east fault bench, and “reservoir superpose on source, overpressure drive and migrate along the fissure, enrichment in sweet points” in the central sub-sag.

In order to clarify the tight oil and gas charging periods and their contribution to the formation of the Cretaceous Fuyu oil layer in the Sanzhao sag of the Songliao basin, a comprehensive study was conducted on the micro-oil inclusions and their associated aqueous inclusions in the Fuyu oil layer using methods such as thin section identification, inclusion temperature measurement, and fluorescence spectroscopy. The charging periods and accumulation contribution of oil and gas in this area were discussed in combination with reservoir burial history. The results show that the oil and gas in Fuyu oil layer of Sanzhao sag have the characteristics of multi-stage charging and accumulation, which is generally characterized by two stages of crude oil charging and accumulation. The first stage occurred in the period of 77-74 Ma at the end of Nenjiang Formation, corresponding to the first stage of charging. The second episode occurred during 67-65 Ma at the end of the Mingshui Formation, corresponding to the second, third and fourth episodes. The tight oil filling in the second stage (the end of Mingshui Formation) of Fuyu oil layer in Sanzhao sag contributes  to the current reservoir, with a contribution rate of 83%, and the contribution rate  of  the first stage (the end of Nenjiang Formation) of tight oil filling   is 17%. After comparing the contribution of oil filling in the two periods, it is considered that the crude oil filled in the late Mingshui period contributes greatly to the present reservoir.

The Chang 9 Member of Ansai area in Ordos basin has produced high-yield crude oil, which has good exploration prospects. The geochemical characteristics of Chang 9 crude oil and Chang 7 and Chang 9 source rocks in Ansai area were studied by using organic geochemical and biomarker analysis methods, and then oil-source correlation analysis was carried out. The results show that the average Pr/Ph value of Chang 9 crude oil is 1.86, formed in a weak reduction-weak oxidation environment. The ααα-20R C27-C28-C29 sterane configuration is inverted “L” type, indicating a mixed source dominated by terrestrial higher plants. C29sterane  20S/(20S+20R) is 0.48-0.51 and C29 sterane ββ/(αα+ββ) is 0.52-0.53, indicating that the crude oil is mature. The organic matter types of Chang 7 source rocks are mainly Ⅱ-Ⅲ and Ⅲ, deposited in a weak reduction-weak oxidation environment, and generally entered the peak oil generation period. The mass fraction of regular steranes is dominated by C29>C28>C27, indicating that they are closely related to the input of terrestrial higher plants. The organic matter types in Chang 9 are mainly Ⅱ-Ⅲ and Ⅲ, which was deposited in a weak reduction-weak oxidation environment, and has generally entered the peak oil generation period. The content of C29 in regular steranes is the highest, indicating that it is closely related to the terrestrial higher plant composition. According to the oil-source correlation, the crude oil of Chang 9 Member in Ansai area is a mixed source of Chang 7 and Chang 9 source rocks.

With the development of technology and research, more and more scholars have realized that the study of shale oil reservoir characteristics is very important for the selection of “sweet spots/segments”. By studying the “four characteristics” of the shale oil reservoir in the Second Member of Funing Formation, Subei basin, such as oil content, reservoir property, mobility， and compressibility, the reservoir space characteristics are described in detail, and the main controlling factors affecting the reservoir property are analyzed, which provides strong support for further exploration and evaluation and large-scale development in this area. The results show that the Second Member of Funing Formation mainly develops laminated or layered shale, and its mineral composition is clay minerals (35.4% on average), felsic minerals (39.1% on average), and carbonate minerals (19.8% on average), w(TOC) is 0.5%-2.0%, Ro is 0.9%-1.1%, and porosity is 1.8%-5.2%. The lamellar structure is the most prominent fabric feature of the shale in the Second Member of Funing Formation, which is mainly composed of felsic and clay lamination. According to the characteristics of “abundant organic matter + structural characteristics + lithology”, the shale of the Second Member of Funing Formation can be divided into 6 lithofacies. According to the comprehensive evaluation of “four characteristics”, the medium organic laminated/layered shales are the favorable lithofacies. The main reservoir space types are bedding seams, structural seams, intergranular pores, and clay mineral intercrystalline pores. However, the reservoir space types differ among lithofacies, mainly affected by lithology, mineral composition, and the degree of lamination development, as well as minor structural effects. Comprehensively analyzing the “four properties” of the six lithofacies of the Funing Formation, the middle and lower parts of the organic-rich laminated/layered shale are the geological sweet spots for shale oil exploration and development.

In order to find relatively high-quality reservoirs under the background of deep burial and strong heterogeneity, this paper takes Pinghu Formation in Xihu sag of East China Sea basin as an example. Based on the combination of intuitive micro-area observation, indirect mercury intrusion characterization and porosity/permeability test, the types of diagenetic facies are first divided based on reservoir sedimentology analysis, and then the differential reservoir capacity characteristics of different diagenetic facies are clarified, and the reservoir capacity of diagenetic facies is evaluated. The study shows that the Pinghu Formation is deposited in a deltaic-tidal transitional system with bi-directional hydrodynamic conditions of rivers and tides. The sand bodies are primarily developed in submerged divergent channels, estuarine dams, tidal channels, sand flats, and mixed flats, which are mainly fine-grained and very fine-grained. Lithologic characteristics are mainly feldspathic sandstones and lithic feldspathic sandstones. Three types of diagenetic phases are classified based on the difference in intensity of diagenetic types, including feldspathic dissolution facies, ductile-rich compaction facies, and calcareous cementation facies. The porosity-permeability and pore structure of the same diagenetic facies type are uniform, while the physical properties vary significantly among diagenetic facies. The three types of diagenetic facies are evaluated in terms of porosity, permeability and maximum connected pore throat radius. Among them, the porosity of feldspar dissolution facies is more than 15%, the permeability is more than 10.0×10-3μm2, the maximum connected pore throat radius is more than 5.0 μm, and the physical properties are better than ductile-rich compaction facies and calcareous cementation facies. Therefore, feldspathic dissolution facies is the most favorable reservoir sand body type.

For the high CO2 condensate gas reservoir in Libra block, the fluid phase behavior in the reservoir is very complex due to the injection of CO2 in the later stage of reservoir formation, which brings great challenges to the prediction of oil ring volume. Through phase equilibrium calculation model, component gradient distribution theory, and visual injection experiment, this paper describes the oil-gas phase behavior of the reservoir during CO2 injection, reveals the dynamic change of oil ring volume, and puts forward a new method for predicting oil ring volume of secondary condensate gas reservoir with high CO2 based on gas cap gas component fitting. The following research results are obtained. 1) The fluid phase behavior and volume change of oil ring under CO2 injection can be divided into four stages. At the beginning of CO2 injection, CO2 dissolves in the oil and the volume of oil ring expands. In the early stage, CO2 dissolves, replaces and extracts the light components in the oil, so that the volume of the oil ring decreases rapidly. In the middle stage, CO2 mainly extracts the light and medium components of oil, so the volume of the oil ring decreases slowly. At the later stage, the mass transfer of CO2-oil almost stops, so the proportion of oil ring volume further decreases due to the compression effect. 2) The strong fluidity of light components makes the gas composition of gas cap uniform, and the gravity differentiation makes the oil ring composition gradient change longitudinally. 3) On this basis, the strong correlation between gas cap gas composition, gas-oil ratio and oil ring volume are revealed. 4) The oil ring volumes ratio predicted by the new gas cap gas fitting method and field exploration at different well depths are 19.21% and 22.30%, respectively, which are in good agreement with the oil ring volume ratio (20.60%) obtained from the CO2 injecting visualization experiment.

The microscopic test results can reflect abundant oil reservoir information. Currently, there is a growing number of microscopic testing technologies for micro-pores and fractures, but there is still a lack of the understanding of micropores. In order to compare various test techniques, Caoqiao buried hill of Le’an oilfield in Jiyang depression is taken as a typical study case, different fine microscopic specialized test techniques are used to analyze the characteristics of pore and fracture storage spaces, including the composition analysis of micro dissolved hole electron probe, scanning electron microscope, thin slice, and cathodic-luminescence tests. The microscopic characteristics and statistical laws of micro dissolution pores are specifically described. There are some new findings: organic matter, calcite, pyrite, dolomite, gypsum, and other components are found in the electron probe composition of micro dissolution pores of limestone. In thin sections, pores can be found between and inside gravels in limestone oil layers, and there is some calcite at the edges of dissolution pores. The dolomite is mainly composed of inter-granular pores. Through scanning electron microscopy (SEM) analysis, it is found that the crystalline pores of dolomite representing the block are two or more orders of magnitude larger than the dissolution pores of limestone. The brittleness of the rock and whether it is easy to fracture can be inferred through inter-granular pores or dissolution pores; By conducting cathodo-luminescence tests on rock samples, it is possible to distinguish several stages of pore filling materials, which are different in composition. Both SEM and mercury intrusion porosimetry can measure pore-throat sizes. Comparing the two techniques, SEM can measure local nanoscale pore-throat diameter, while mercury intrusion porosimetry can measure the micrometer scale pore-throat radius of a rock sample. From the perspective of application objects, the former is suitable for the pores and throats of minerals, while the latter is more suitable for the comparative research of pores and throats in oil exploitation blocks.

The Chuanjie basin in the Lufeng area of central Yunnan has recorded important information on the continental sedimentation and biological evolution of the Middle-Upper Jurassic in the Upper Yangtze region, providing a good carrier for the study of the Jurassic greenhouse earth climate environment. In this paper, the sedimentary, carbon-oxygen isotope and trace element geochemical systems of the Middle-Late Jurassic continental red beds in Chuanjie basin were studied to restore their paleoclimatic and environmental characteristics. Research suggests that the Jurassic Batonian to Early Kalo lakes in the Lufeng region were saline lakes with good sealing and gradually increasing salinity. During this period, the climate changed from relatively humid to dry, and the temperature was generally higher, showing a trend of gradually decreasing temperature from the early to late stages. The closure of the lake in the middle to late stages of the Kalo period weakened, making it a semi saline lake. During this stage, the climate changed from dry to relatively humid, and the temperature rose. However, the climate fluctuated violently, with frequent dry-wet alternations. During the Oxford Titang period, the lake’s closure further weakened and became a semi saline lake, with a generally stable humid climate. This work identified the Middle-Late Jurassic transition cold event (MLJT event) in the terrestrial red beds of the Lufeng area, providing an important reference for the study of the Mesozoic greenhouse earth climate environment and the comparative study of the terrestrial red beds in Southwestern China. The rapid change of climate in the late Middle Jurassic led to the rapid death of organisms, coupled with the transportation, sedimentation and rapid burial of rivers during the rainstorm period, resulting in the present biological burial characteristics of the Chuanjie basin.

As China’s industrialization advances, the demand for molybdenum continues to grow, leading to an expansion in mining and a corresponding increase in molybdenum tailings. These tailings not only occupy significant land but also pose environmental risks, such as pollution and geological hazards like dam breaks and debris flows. Despite these challenges, molybdenum tailings remains a valuable resource, rich in minerals with promising potential for comprehensive utilization. This paper analyzes the distribution of molybdenum ore resources and the composition characteristics of molybdenum tailings, highlighting the necessity and feasibility of their comprehensive use. It introduces the recovery of valuable minerals, including feldspar, calcite, molybdenum, tungsten, and iron from molybdenum tailings, and reviews their applications in construction, agriculture, mine filling and other aspects. While recoverying valuable metals does not fully address the surplus of molybdenum tailings, large-scale applications in building materials and tailings filling are possible. However, the effectiveness of these materials depends on performance metrics such as strength, wear resistance, and durability, while agricultural applications must also mitigate heavy metal pollution.

The Liujiushan Cu deposit is located in the eastern end of the northern Great Hinggan Range, part of the easternmost edge of Central Asian orogenic belt. This study presents detailed field geology, petrography, elemental geochemistry and geochronology of diorite porphyry and monzonite porphyry to reveal the petrogenesis and geodynamic setting of these intrusive rocks. Magmatic zircons from diorite porphyry and monzonite porphyry yielded a weighted average age of （132.6±2.6） Ma (n=5) and （132.4±1.3） Ma (n=22), respectively. The LA-ICP-MS zircon U-Pb ages show these intrusive rocks were emplaced at ~132 Ma, consistenting with the molybdenite Re-Os isotopic dating of （134.1±0.8） Ma, which constrains Cu mineralization to the Early Cretaceous. The diorite porphyry (52.98%-59.83% w(SiO2)) and monzonite porphyry (66.90%-67.56% w(SiO2)) are classified as intermediate to acidic hypabyssal intrusive rocks, enriched in the large ion lithophilic elements and deleted in high field strength elements, representing island arc alkaline and of adakitic rock types, respectively. Their parental magmas originated from an enriched mantle. All these studies show that the diagenesis and mineralization resulted from subduction of the Kula slab beneath Eurasian continent.

In order to explore the interfacial shear properties between silty clay and concrete in seasonal frozen soil area, the freeze-thaw cycles test and the interface direct shear test of silty clay-concrete binary with different freeze-thaw cycles, normal stress and moisture content of soil were completed, and the changes of interface shear strength, shear strength parameters and shear strength damage degree were discussed. Through direct shear tests, the variation rules on shear properties of the interface and strength parameters were investigated. The results showed that the strain-stress relation underwent strain hardening phenomenon, which can be divided into elastic deformation stage (0-3 mm) and elastoplastic deformation stage (4-15 mm). The freeze-thaw cycles deteriorated the interfacial shear strength, that is, by causing damage to the soil, the friction angle and cohesion of interface were reduced, thereby reducing the interfacial shear strength. With the increase of the number of freeze-thaw cycles, the damage degree of interfacial shear strength increased. However, when the freeze-thaw cycles were 0 and four times, the shear strength damage was rapid, and the damage was slow when the freeze-thaw cycles were 12-20 times, in which the maximum interfacial shear strength damage degree was 25%. With the increase of moisture content of soil, the increase of moisture content of soil weakened the shear strength, the friction angle of interface decreased, however the cohesion first rose and then reduced. When the soil moisture content was 20.7%, the cohesion reached the maximum. The rising of normal stress enhanced the shear strength.

The instability mode and shear behaviour of saturated loess are the basis for analyzing seismic deformation of loess foundation and their structures. To reveal the unique strength attenuation and deformation deterioration of saturated loess under cyclic loads, the dynamic soil strength, development of the pore pressure and instability modes of the saturated loess were investigated by the cyclic triaxial test, subjected to the initial shear stress (qs) and the cyclic shear stress (qc). The experimental results show that: When qs<qc, the loess samples exhibit the cyclic mobility failure type; When qs≥qc, the reconstituted loess samples exhibit the flow failure type, while the intact loess exhibit the plastic strain accumulation failure type. The cyclic stress ratio (RCS) and the cyclic resistance ratio (RCR,10) of the loess samples increases first and then decreases with the increase of the initial shear stress ratio (RSS). At the initial stage of cyclic loading, the pore pressure in loess samples increases rapidly with the cyclic mobility and plastic strain accumulation failure types, and the pore pressure development curves show the trend of “organ” or “hornt” type. The growth rate of the initial pore pressure in the loess samples with the flow failure type is relatively slow. When the pore pressure reaches a certain cycle, it increases sharply and the pore pressure curve shows a “sickle” type. A chart is established by considering the influence of initial stress state (qs/qc) and the initial pore pressure development index (K1-2), it can be used to predict the failure mode of saturated loess under cyclic loading.

In order to availably protect embedded petroleum pipelines through a slope particularly under seismic actions, a new frame-type stabilizing pile with the pipelines covered is proposed. On the basis of determining the seismic landslide thrust force on the structure by the pseudo-static method，the load section of the structure located above the sliding surface is taken as the plane frame structure which is taken as the plane rigid frame structure with fixed bottom. A super-static plane rigid frame structure model is used to analyze the loading section. The part of the structure below the slip surface called the embedded section is actually two independent piles buried in the stable layer, which can be analyzed using the elastic beam on foundation model under lateral loads on their tops. Thus, a calculation method of internal forces and displacements of the frame-type stabilizing pile is established by combing the two parts. The results of an example show that the deviation between the proposed and the numerical bending moments and shear forces of the front and rear piles as well as the upper and lower beams of the frame-type stabilizing pile is within 20%, and the proposed results are relatively conservative. The influence of horizontal seismic coefficient on the internal forces is obvious. The maximum value of the internal forces increases approximately linearly with the seismic coefficient, while the influence of vertical seismic coefficient is slight. The maximum internal force of the structure is linear positive correlation with soil unit weight and nonlinear negative correlation with cohesion and internal friction angle of soil, respectively. As soil shear strength parameters increase, the internal forces of the front and rear piles together with the upper and lower beams tend to be close, respectively. The maximum internal forces of the two piles and the two beams are nonlinear positive and negative correlation with flexible rigidity of the piles, respectively； But are approximately linear positive and negative correlation with embedded depth of the piles, respectively. The separation between adjacent structures has obvious influence on the structural internal forces, but the row spacing between the two piles in the same structure has slight effect on them.

In order to explore the influence of different evaluation units on the assessment of regional landslide susceptibility, the landslide susceptibility of Yunyang County in Chongqing, a typical county in the Three Gorges reservoir area, was studied based on grid units and slope units. Twenty-two evaluation factors such as elevation, slope and curvature were selected. Combined with 988 historical landslide data in the study area, slope units were extracted from 30 m×30 m raster data, and geospatial databases of landslide impact factors were established based on slope units and grid units. The landslide susceptibility model was constructed by random forest and Bayesian optimization algorithm to evaluate the landslide susceptibility in the study area. The results indicate that the susceptibility assessment can be divided into five levels: low, moderately low, medium, moderately high, and high. In the landslide susceptibility model based on the grid units, the three factors of elevation, distance from the road and slope contribute greatly to the landslide occurrence. In the model based on slope units, the three factors of INDV (normalized difference vegetation index ), profile curvature and plane curvature contribute greatly to the landslide occurrence. The landslide density of both models increases with the increase of susceptibility level. Compared with grid units, slope units can better explain the relationship between terrain, and the landslide susceptibility model with slope units （AUC=0.744） as the minimum evaluation unit is more accurate than grid units （AUC=0.714）.

In order to determine the ratio of similar materials commonly used in physical simulation experiments, four raw materials including river sand, barite powder, gypsum and cement were selected, and orthogonal design was adopted. Bone glue ratio (ratio of river sand mass and  barite powder mass to gypsum mass and cement mass), water-paste ratio (ratio of cement mass to gypsum mass) and barite content (ratio of barite powder mass to aggregate mass), with five levels for each factor, were set to carry out density test and acoustic emission test under uniaxial compression. The sensitivity of different proportions to the physical and mechanical indexes of similar materials and the indexes of damage degree were determined. The experimental results show that the density, compressive strength and elastic modulus of similar materials under the influence of bone glue ratio have the largest range, which are 0.13 g/cm3, 2.60 MPa and 247 MPa, respectively, F-test has the largest value, and the significance is the highest. Poisson’s ratio has the largest range under the influence of barite content, which is 0.09, and has the highest significance. The relative cumulative damage degree (D) had the largest range (0.25) under the influence of bone glue ratio, and the F test value was the most significant. In general, the bone glue ratio controls the density, compressive strength, elastic modulus and D of similar materials.

In order to understand the sources of iodide in shallow groundwater in these typical aquaculture areas of the Pearl River delta as well as the health risks associated with drinking. This study analyzed a total of 21 representative samples from three different types of water sources: fish ponds, sewage treatment ponds, and groundwater in typical freshwater aquaculture areas of the Pearl River  delta. The results indicated that shallow groundwater in the study area had a water chemistry type primarily composed of Ca2+·HCO3- type with iodide concentrations ranging from 2-343 μg/L of the monitored sites. 33.3% of the monitored sites were high iodine type water sources that were concentrated and dispersed in the western part of the study area. According to principal component analysis, iodine fugacity in groundwater was encouraged by the neutral to mildly alkaline reducing environment, and the degradation and percolation of iodine-rich organic materials from fish pond waste may have made the situation worse. The major causes of shallow, highly iodized groundwater may include degradation of organic matter in carbonate-rich rocks, urbanization with reduced effluent, and waste leachate leaks. The results of water quality evaluation showed that 16.7% of the surface water (fish ponds, sewage treatment ponds) in the study area was Class Ⅳ, and the chemical oxygen demand (CODMn) and total nitrogen (TN) were the main factors exceeding the standard. Although the pH and iodide levels in some areas of shallow groundwater exceed the recommended levels, overall water quality is satisfactory, with the worst groundwater quality being Grade Ⅲ. The examination of the health risks associated with groundwater revealed that while adults are at minimal risk from high iodine drinking water, children have a risk entropy of J4 groundwater sources that is larger than 1.0. It is suggested to strengthen the routine monitoring of residential drinking well J4 iodide concentration to ensure the health of children drinking water.

Changes in meteorological elements have a highly important impact to the ecological environment of the mining area, especially in the cold and arid region of the Qinghai-Tibet Plateau, China. A comprehensive and systematic understanding of characteristics of historical meteorological changes plays a guiding role in the ecological environment protection for alpine mining areas. In this study, trends of precipitation, air temperature, and evaporation were comprehensively analyzed by linear tendency estimation, the ensemble empirical mode decomposition (EEMD), and Morlet wavelet analysis using monthly data from 1956 to 2022 in the Da Qaidam mining area of the Qinghai-Tibet Plateau. The normalized difference vegetation index (INDV) was extracted from three phases of Landsat satellite images with a spatial resolution of 30 m. Results showed that the climate in the study area developed towards warming and humidification with a slightly increasing trend of precipitation, a significantly trend of temperature, and a markedly decreasing trend of evaporation. No abrupt changes points were detected for precipitation and temperature, but a sudden change in evaporation existed in 1979. Evaporation increased slowly from 1956 to 1979, and decreased slowly from 1979 to 2022. Precipitation had a significant 12-month oscillation period from 2000 to 2016, while temperature and evaporation had a 12-month oscillation period throughout the entire study period. INDV data indicated that vegetation was mostly concentrated near the water bodies, and the coverage expanded and the growth activity enhanced over time in the entire study area. It is predicted that precipitation and temperature would continuously increase and annual evaporation would be in a relatively small period. The vegetation growth activity would be strengthened for next few years in the Da Qaidam mining area.

Laohutai coal mine, located in Fushun, Liaoning Province, has been exploited for almost a century and is one of the mining areas with serious mine earthquake disasters. However, due to the lack of dense seismic monitoring stations, the mine’s microseismic event monitoring capacity is insufficient. In order to  monitor the microseismic activity better, this study carried out  double-difference location of microseismic events in the mining area based on two linear dense seismic arrays deployed in  Laohutai coal mine from November 3 to 25, 2019. The relocation results indicate that the largest event of this microseismic activity was the ML 2.4 earthquake that occurred near  Hunhe fault, with an epicenter depth of 0.5 km. Before the occurrence of the Hunhe ML 2.4 earthquake, the microseismic events of ML >1.0 gradually increased and migrated to the western end of  Hunhe fault. After the occurrence of the Hunhe ML 2.4 earthquake, the microseismic activities in the mining region were mainly concentrated near  F1 and F2 faults in the mining area, and the depth of the epicenter was mainly concentrated between 0.2-1.5 km. The spatial and temporal distribution characteristics of the microseismic events indicate that the microseismic activity in  Laohutai coal mine may be affected by the Hunhe ML 2.4 earthquake, and fault activation may occur in the mining area. Additionally, we speculate that the F2 fault may be a NNW-trending buried fault extending to  Hunhe fault based on the observed distribution of the microseismic relocation.

Born scattering series is often limited by weak scattering assumptions when solving strongly seismic scattering problems, resulting in slow convergence or divergence. A simple and effective way is to improve the iterative algorithm using numerical analysis. One such method is the generalized successive over-relaxation (GSOR) iterative method, which can be applied to solve the Lippmann-Schwinger (L-S) equation and obtain the desired convergent Born scattering series. However, in strongly heterogeneous media, the GSOR iterative method may also face the challenge of slow convergence speed while calculating the high-frequency Green’s function. In this paper, the complex wavenumber Green’s function is utilized with the GSOR iterative method to numerically solve the L-S equation of the Green’s function. The complex wavenumber has imaginary components that enable localizing the energy of the background Green’s function and exponential decay, reducing the singularity of the background Green’s function. To reduce the condition number of the coefficient matrix, we further introduce the preconditioning operator and provide a preconditioned generalized successive over-relaxation (Pre-GSOR) iteration format. The convergent iteration series is obtained by selecting an appropriate damping factor and preconditioning operator. Then it is used to calculate the numerical Green’s function in the seismic strongly scattering media. Numerical results indicate that the Pre-GSOR iteration method for the complex wavenumber L-S equations can produce simulation results consistent with those obtained by direct methods for real wavenumber L-S equations. The condition number of the coefficient matrix in the Pre-GSOR iterative method for the complex wavenumber L-S equation is only 10% of the original condition number at high frequencies. Under the same number of iterations, the normalized convergence residual obtained by this method can be reduced by more than three orders of magnitude. The new method exhibits lower convergence error, better convergence, and strong adaptability to high frequencies, effectively mitigating the convergence stagnation problem encountered by the generalized over-relaxation iterative method for the real wavenumber L-S equation in strongly scattering media.

Shale oil tight reservoirs are developed in the middle and lower part of Permian in southeastern margin of Junggar basin. Brittleness prediction and evaluation are of great significance to its exploration and development. In this paper, the brittleness index of Permian tight reservoir in southeastern margin of Junggar basin is calculated by using petrophysical experiments, well logging data and prestack seismic data, and the Rickman classical formula method, the method of ratio of Young’s modulus and Poisson’s ratio, the Lamé coefficient method and the shear modulus method are compared, analyzed and evaluated. The results show that: 1) Compared with Poisson’s ratio, Young’s modulus has a better discrimination of lithology, and the mudstone distribution resolution represented by Lamé coefficient is higher；2) The method of calculating brittleness index based on logging multi-parameters obtained in the literature has a poor application effect, but the brittleness index calculated on the basis of converting shear wave velocity by Castagna’s formula has a good application effect；3) The change rates of elastic parameters inverted by YPD (Young’s modulus-Poisson’s ratio-density) formula and LMR (Lamé coefficient-density) formula can also indicate favorable reservoir, especially the density change rate is the best, and the characteristics of upper fan delta front and distributary channel can be well demonstrated by this attribute； 4) Petrophysical experiments and actual data applications show that ρE/σ is the best characterization formula of brittleness in the study area, and the effect is better than Rickman’s classic formula and other methods.

The quantitative prediction of water content in coal seams is of significant importance for solving the problems of water disasters in mines, improving the technological level of water prevention and control in coal mines, reducing the economic costs of water prevention and control, and enhancing the safety and economic benefits of coal mines. In order to realize the quantitative prediction of coal seam water content, this paper selects the rock of the Carboniferous Taiyuan Formation aquiferous area above the No. 5 coal seam roof in Ningwu Yushupo, Shanxi, and measures its physical properties and resistivity parameters. Based on the measurement results, the parameters in the Archies formula are analyzed and determined, and the rock physics model is established to quantify the relationship between electrical parameters and water saturation, reservoir pressure, lithology and pores. The study shows that: 1) The rock of the coal seam roof has the characteristics of low porosity and low permeability. 2) The effective pressure of the reservoir affects the resistivity of the coal seam roof rock.The increase of effective pressure leads to the  decrease of the  resistivity at low frequencies, but has almost no effect on the resistivity at high frequencies. 3) Water saturation significantly influences the resistivity of the coal seam roof rock. An increase in water saturation causes a decrease in resistivity at low frequencies, but has a weak effect on high-frequency resistivity. Low water saturation has a more significant impact on resistivity dispersion，  high water saturation has a relatively weak effect on resistivity dispersion,  and full saturation has no effect on resistivity dispersion. 4) The lithology of the coal seam roof is mainly sandstone, with the presence of mudstone, limestone, etc. Lithological differences have a significant impact on both dry and water-saturated samples, and the resistivity difference between different lithologies can reach two orders of magnitude. 5) Cementation index, saturation index, and lithology coefficient all change with depth, but at a relatively steady rate, and the water saturation can be effectively predicted by the rock physics model constructed by its average value.

Digital rock technology enables the precise digital characterization of core samples and facilitates the study of microscale rock physical properties through numerical simulations. Unconventional reservoir rocks display distinct features across various scales, and multiscale imaging technology can capture the rock’s microstructure at resolutions ranging from sub-nanometer to millimeter levels. However, single-resolution scanning methods fail to resolve cross-scale structural information, making the development of multiscale, multiresolution, and multicomponent digital rock models crucial to overcoming this limitation. Existing multiscale digital rock modeling methods can be broadly categorized into two main approaches: image fusion modeling, which relies on mixed overlays, template matching and deep learning, and pore network integration modeling, which incorporates explicit micropore networks, additional throat networks, and fracture systems. The image fusion approach accurately represents the three-dimensional distribution of pores and minerals across various scales and supports multiphysics simulations. However, its computational efficiency constrains its ability to manage large-scale discrepancies in hybrid modeling. Conversely, the pore network integration approach allows for modeling across multiple contiguous scales, requires less storage space, and offers high numerical simulation efficiency, although it is limited to certain physical properties. Moreover, digital rock workflows still face challenges, such as the precise extraction of minerals and the determination of suitable representative elementary volumes. Future research should focus on optimizing models using experimental data, studying physical properties as needed, and integrating homogenization and equivalent theory modeling to develop specific application systems that enhance well-logging interpretation and hydrocarbon reservoir development.

Fully convolutional neural network has been widely used in semantic segmentation of remote sensing images, and the accuracy and efficiency of feature classification are high, but for remote sensing images with uneven distribution of features, the accuracy of feature classification is low. In order to improve the classification accuracy of remote sensing images, this paper enriches the input data features by adding priori knowledge methods, uses the dense link method to improve the reuse rate of features in the process of up and down sampling, combines the loss function Dice Loss that can optimize the intersection of union and the Focal Loss that can improve the accuracy of difficult classification categories as the loss function of the network, and uses the LayerScale module to accelerate the model convergence and suppress irrelevant features while emphasizing useful features, improves input, network structure and loss function of U-Net to optimize the effect of semantic segmentation. The results show that, compared with the original U-Net, the improved U-Net based on Gaofen image  dataset is improved by 0.023 3, 0.040 9 and 0.066 5 in terms of pixel accuracy, average pixel accuracy and mean intersection of union, respectively, which improves the classification accuracy of ground objects and achieves better classification effects.

Deep learning segmentation method is one of the hot topics in the field of remote sensing image segmentation. The mainstream deep learning methods include convolutional neural networks, transformer neural networks, and a combination of the two. Feature extraction is an important part of image segmentation. In addition to using convolution and other methods to extract features, recent research has focused on some new feature extraction paradigms, such as graph convolution and wavelet transform. In this article, the region construction attribute of clustering algorithms is utilized, and the improved clustering algorithm is used as the backbone feature extraction module while the convolution and visual transformer are used as auxiliary modules to obtain richer feature representations. On the basis of the module, a new hierarchical remote sensing image semantic segmentation network (NHNet) is proposed. The performance of NHNet semantic segmentation is evaluated and compared with other methods on the LoveDA remote sensing dataset. The results show that NHNet based on multi-feature extraction achieved competitive performance, with an average intersection-to-union ratio of 49.64% and a score of 65.7%. At the same time, ablation experiments show that the auxiliary module improves the accuracy of clustering algorithm segmentation, increasing the average intersection-to-union ratio of NHNet by 1.03% and 2.41%, respectively.