Abstract:This paper is the result of geothermal geological survey engineering. Objective The Gonghe Basin, situated on the northeastern margin of the Qinghai–Tibet Plateau, is a significant experimental area for the exploration and development of hot dry rock (HDR) in China. The formation mechanisms of HDR within the Gonghe Basin remain controversial and have attracted considerable research attention. The current thermal state is of great significance for a deeper understanding the distribution patterns and formation mechanisms of high–temperature geothermal reservoirs. Methods In this study, extensive geophysical exploration and drilling data are integrated to describe the geological and geothermal architecture of the Gonghe Basin. A two–dimensional temperature field profile across the east–west axis is established through numerical simulation. Based on these results, the resource potential of HDR is assessed, and the key factors controlling HDR formation are analyzed. Results The Gonghe Basin hosts abundant HDR resources, with an estimated 2.48×10²¹ J within the depth of 5 km. The two–dimensional numerical simulation reveals significant temperature field variations between the eastern and western parts of the basin. The temperature field variations are consistent with the distribution of the basin's basement depth, which decreases from west to east. High–temperature anomalies are observed in the northeastern region, particularly around the Xinjie–Waliguan uplift belt. Conclusions On the basis of understanding the knowledge of predecessors, this paper proposes a comprehensive HDR formation mechanism from the perspectives of geological, geothermal, and geophysical backgrounds. The formation of HDR in the Gonghe Basin is controlled by multiple factors, including continuous heating by partial melting, heating and conducting heat by granite, heat controlling by neotectonic uplift and denudation, and heat preservation and accumulation by sedimentary covers.

Abstract:This paper is the result of geothermal geological survey engineering. Objective Hot dry rock is a clean and vast geothermal resource. China Geological Survey has been continuously implementing China's first hot dry rock geothermal power generation and grid connection project in Gonghe, Qinghai since 2019. Hot dry rock reservoirs are dense and require fracturing to form a permeable interconnected fracture network, creating a reservoir capable of accommodating a certain scale of heat exchange and water conduction. However, research on artificial reservoirs in high–temperature hard rock is relatively limited. Methods The successful construction of artificial reservoirs and effective inter–well communication are the core of successful hot dry rock development. Tracer tests are an effective means to study the above issues and characterize reservoir hydrogeological conditions. This study focuses on the hot dry rock test site in the Gonghe Basin of Qinghai, selecting sodium fluorescein and sodium bromide as tracers, and conducting tracer tests before and after large–scale fracturing. Results Before large–scale fracturing, tracer recovery rate and heat exchange volume were relatively low. After the transformation, reservoir fractures became more complex, reservoir connectivity improved, and the tracer recovery rate reached 14.14%. The heat exchange volume of fractures increased to 27 times, and the fractures became relatively homogeneous, effectively reducing the risk of heat breakthrough. Conclusions Tracer experiments can quantitatively evaluate the effectiveness of hot dry rock artificial reservoir fracturing. The research results have guiding significance for the conduct of hot dry rock tracer tests and the scientific development of high–temperature hard rock thermal storage.

Abstract:This paper is the result of geological survey engineering. Objective The magnitude and direction of in–situ stress are important parameters for well placement, fracturing design and reservoir evaluation in hot dry rock development. It is of great significance to study reservoir stress state for hot dry rock development. Methods In this paper, the characteristics of current stress field in the Gonghe Basin are analyzed based on regional geological structure evolution, focal mechanism solution and inversion results, statistics of joints and fissures, and in–situ stress measured data. Combined with the reservoir structure and stratigraphic lithofacies characteristics of GR2 well, a three–dimensional model is established, and the three–dimensional in–situ stress data of GR2 well in the Gonghe Basin is obtained through numerical simulation by using orthogonal anisotropic elastic constitutive relation. The regional tectonic stress field and occurrence conditions of dry hot rock resources are discussed. Results ① The simulated stress distribution is consistent with the theoretical value, which meets the requirements of initial displacement accuracy, and finally predicts the distribution characteristics of in–situ stress field in the well. ② In the depth range of 500~4500 m, the relationship of three principal stresses is principal stress is σ_v>σ_H >σ_h, indicating that the stress structure in this region is favorable to normal fault activity. ③ The maximum horizontal principal stress direction of the Gonghe Basin in Qinghai province is mainly NE direction compression deformation, which is conducive to low fluid permeability and low heat transfer of granite. ④ Under the action of a unified regional stress field, the faults may be come instability near the injecting well, when the continuous injection pressure on the ground reaches or exceeds about 19.9 MPa during the water injection development of 3900~4500 m depth in the study area, leading to the occurrence of medium and small earthquakes, which should be prevented in the development and utilization of the hot dry rock. Conclusions The research results have certain reference value for geodynamics research and the safe development and utilization of dry hot rock in the Gonghe Basin.

Abstract:This paper is the result of geothermal geological survey engineering. Objective The Qiabuqia area within China's Gonghe Basin represents a key research zone for granite–hosted hot dry rock (HDR) systems. This study systematically investigates the caprock thickness variation and granite basement topography while elucidating the spatial configuration of granitic bodies to establish predictive models for HDR reservoir distribution. Methods Innovatively applying the Time–Frequency Electromagnetic (TFEM) method–traditionally employed in deep hydrocarbon exploration – to HDR characterization, we implemented a comprehensive workflow encompassing advanced data preprocessing, electrical parameter optimization, and constrained inversion modeling. Integrated interpretation of resistivity profiles with multi–source datasets (geological mapping, borehole logs, and auxiliary geophysical surveys) enabled three–dimensional reconstruction of stratigraphic architecture, granitic intrusion geometry, and HDR reservoir characteristics. Results (1) TFEM demonstrates exceptional capability in resolving electrical stratigraphy within 10 km depth. Resistivity profiles reveal a tripartite H–type structure comprising a sub–high–resistivity superficial layer (900–1400 m thickness, eastward–thinning), an intermediate conductive zone, and a high–resistivity basement. Granitic bodies exhibit A–type resistivity progression with depth, featuring westward–deepening top surfaces (–900 to –2900 m elevation). (2) Thermal logging–constrained models delineate distinct spatial configurations of the Qiabuqia and Dalianhai HDR reservoirs, demonstrating strong correlation with structural highs. Conclusions (1) Thermo–structural analysis identifies competent batholiths and stocks as preferential heat flow conduits, serving as prime HDR exploration targets. (2) This leads to the distribution characteristics of granitic bodies, which are deep rock bases, middle rock strains and shallow rock beds. (3) Resistivity anomalies within granitic masses reflect structural integrity gradients, with batholiths and stocks exhibiting superior mechanical continuity compared to fractured sill complexes.

Abstract:This paper is the result of geothermal geological survey engineering. Objective It is necessary to predict the characteristics, spatial distribution and density of natural fractures in granite reservoirs using high–precision seismic data and feature analysis methods, which provide scientific evidence for the construction of Enhanced Geothermal System (EGS). Methods This study adopted advanced 3D seismic techniques, including wideband, wide–angle, high–density sampling, as well as advanced processing methods such as structural–oriented filtering and multi–window dip scanning. The application of these techniques greatly improved the signal–to–noise ratio of seismic data, further optimizing the detection effect of the granite interior. At the same time, this study also combines 3D seismic attributes such as seismic attribute volume, maximum likelihood volume, coherence volume, curvature volume, variance volume, and ant volume with multi–azimuth constraints to accurately predict the spatial distribution density of fracture clusters. Results Through comprehensive attribute analysis and drilling imaging logging results, we reveal the regularity of the development of northeast and northwest fractures in granite–type hot dry rock reservoirs. These results are highly consistent with drilling imaging logging results, further verifying the accuracy and reliability of this research method. Conclusions This study successfully predicted the characteristics, spatial distribution, and density of natural fractures in granite–type hot dry rock reservoirs through high–precision seismic data and feature analysis methods. This method provides important evidence for fracture detection, drilling deployment, and mining plan determination in EGS engineering construction.

Abstract:This paper is the result of mineral exploration engineering. Objective The global energy transition and the rapid development of emerging industries have heighten the importance of securing a stable supply of critical minerals, which are essential for economic and technological transformation. This issue has garnered significant attention from governments and multinational enterprises, becoming a focal point in earth sciences research. Methods Through a systematic analysis, this paper examines the latest trend of global supply of critical minerals, identifies emerging research hotspots, and offers insights into future development. These findings provide valuable guidance for China's strategic planning in critical minerals and resource security. Results This study reveals that the stability of global critical minerals supplies has received a great deal of attention from the world's major economies and important manufacturing companies. The leading role of governments in shaping the supply chain of key minerals and the industrial chain is becoming increasingly evident. The methodology for determining critical list is evolving, the number of mineral species is expanding, but the overlapping mineral species are becoming more and more aggregated. With deeper research into mineralization processes and the occurrence of critical minerals, new deposit types are emerging. Manufacturing enterprises and mining enterprises are interfacing more closely, with a clear trend towards upward and downward integration, and investment institutions are increasing their support for investment in key minerals and research and development of new technologies. Conclusions As energy transition efforts intensify, the importance of critical minerals will continue to grow in the energy transition, driving increased demand, investment, and resource discovery. Notably, smaller critical minerals, such as lithium, may gain significance and emerge as major resources. Resource–rich nations like Australia and Canada are strengthening their supply advantages, while lost regions such as Central Asia and Europe are reasserting their roles in the market, marine mineral resources exploration and development on the agenda. The global supply landscape is likely to become more diversified. Advances in technology, innovations in alternative processes, and the iteration of recycling technology will open new avenues for the securing critical mineral supplies.

Abstract:This paper is the result of mineral exploration engineering. Objective Under the background of the global carbon neutral and the green energy transition, lithium has become a global consensus as a key mineral. The exploration and development of Lithium resources in Africa have put on the agenda. To provide reference for international cooperation of Lithium industry in Africa, we analyze the metallogenic characteristics and exploration and development potential of Lithium deposits in Africa. Methods The paper summarizes the metallogenic characteristics of Lithium resources, and analyzes the development prospects of Lithium industry by tracking the exploration and development trends of lithium resources in Africa. Results Africa's proven resources are mainly LCT pegmatite deposits, distributed in the lithium rich pegmatite belt of Congo (DRC), Mali, Zimbabwe, Ghana and Namibia, which are characterized by large resources, high grade and favorable development conditions, so that it is attracting the investment of mining companies from Australia, China and the UK. Conclusions Africa has a late start in lithium exploration and slow development progress, but has good resource endowment. The current high–quality resources have been locked in advance, and it is expected to become a new growth point of global lithium resource supply in the future.

Abstract:This paper is the result of mineral exploration engineering. Objective Barite, as a dominant mineral resource in China, faces challenges such as low utilization efficiency. To ensure the security of China's barite resources, it is essential to further explore and develop barite reserves. This effort is of significant importance for supporting the development of the petroleum exploration industry and broadening its application fields. Methods This paper summarizes the metallogenic epochs, characteristics, genetic types, and material sources of barite deposits. Meanwhile, it systematically reviews the distribution, resource status, and applications of barite in China. This work provides a reference for future mining and application of barium sulfate in China. Results The genetic types of barite deposits in China can be classified into sedimentary, volcanic-sedimentary, hydrothermal, stratified hydrothermal, and weathering residual-slope accumulation types. Based on the sources of metallogenic fluids, barite can be divided into two end–members: submarine hydrothermal barite and biogenic barite. Globally, the proven reserves of barite are approximately 740 million tons. In China, barite is produced in 26 provinces, including Guizhou, Guangxi, Hunan, and Fujian. As one of China's critical minerals, it ranks as the world's second–largest producer, characterized by high–grade deposits and significant export volumes. Barite is widely used in various fields such as the oil and gas industry, advanced materials, medical treatment, military, and environmental protection sectors. Conclusions Barite deposits in China primarily formed during the Paleozoic and Mesozoic eras，with key regions including the Jiangnan, Qinling, and Guizhou–Guangxi areas, dominated by sedimentary–type deposits. The sources of barite metallogenic fluids for barite are diverse. Geochemical signatures indicate that the metallogenic materials originate from submarine hydrothermal fluids, while biomarker compounds and heavier sulfur isotopes indicate a biogenic origin. As one of the crucial advanced materials, barite requires a focus on enhancing its deep processing capabilities, developing its strategic emerging industries, and expanding its application fields within the framework of future intensive, efficient, and green industrial development mechanisms. The future prospecting potential for barite in China should focus on the following aspects to discover more abundant barite resources: Firstly, emphasis should be placed on exploring super–large and large barite deposits in the southern margin of the Yangtze Platform. Secondly, the exploration of low–grade barite deposits and associated barite deposits, similar to those in the Gansu–Qinghai–Ningxia barite metallogenic region, should not be overlooked. Finally, continuous exploration and development in regions such as North China and Xinjiang.

Abstract:This paper is the result of geological survey engineering. Objective Landslides pose a significant risk to major constructions and human safety in mountainous areas, and the early identification and monitoring of landslide has become an important way to prevent risk. Methods This paper briefly introduces the basic principle of InSAR technology and its development history, and introduces the current research status of its application in landslide identification and monitoring. Results The three types of landslide InSAR identification are regional, key sections and single landslide. InSAR monitoring of landslides mainly focuses on large landslides with significant risk, and highlights the research progress in monitoring method and early warning modeling. On this basis, the main challenges faced by InSAR technology in landslide identification and monitoring research at this stage are pointed out, including: the challenge of geometrical distortion in side–view imaging under complex terrain conditions, detecting large gradient deformation of landslides, atmospheric delays and vegetation penetration, etc. InSAR technology in landslide application still exists problems such as insufficient capacity of large–scale monitoring, low degree of automation of processing process, and insufficient degree of data analysis and mining. Conclusions The future development direction of InSAR technology in landslide identification and monitoring is prospected. With the continuous improvement of the application level of InSAR technology, it will effectively promote the new leap in landslide disaster risk prevention.

Abstract:This paper is the result of environmental geological survey engineering. Objective Oxygen is one of the basic elements that make up living matter, and the oxygen cycle in nature is the basic guarantee for life activities. Oxygen isotope technology is a powerful tracer that can effectively indicate biogeochemical cycling processes and has been widely used in ecological and environmental research. Methods This paper reviewes the fractionation mechanism of oxygen isotopes and its application in soil–vegetation–ecological environment by reviewing a large number of literatures on oxygen isotopes. Results Depending on the large isotope mass ratio difference, oxygen isotopes can undergo the greatest degree of isotope fractionation under natural conditions. The application of oxygen isotopes mainly includes three aspects: (1) Tracing the source of environmental pollutants; (2) Paleoenvironment and paleoclimate restoration; (3) Tracing the geographical origin of food (animals). Conclusions In practice, oxygen isotopes are usually used together with other isotopes (hydrogen, carbon, nitrogen, etc.) to track multi-dimensional climate, vegetation development, and geographical location. In the future, oxygen stable isotopes can be combined with substitute models in the fields of global change, such as tree rings, foraminifera, loess, and salt lakes, and play a more important role in environmental ecology research.

Abstract:This paper is the result of mineral exploration engineering. Objective Apatite is a mineral commonly present in igneous, metamorphic, and sedimentary rocks. Its crystal structure can host various elements such as Sr, Mn, REEs, U, Th, F, Cl, and others. Apatite's chemical composition is dictated by magma and hydrothermal processes, which makes it a subject of interest for many researchers. Methods This paper reviews common methods and the latest research achievements of apatite in mineralogy, isotope chronology, deposit geochemistry, artificial intelligence, and exploration indication. Results Elemental (e.g., Sr, Y, and REEs) and Sr-Nd isotopic compositions of magmatic apatite can help identify the source of its parental magma. Elements such as Ce, Eu, Ga, and Mn can indicate the oxidation state of the magma, while F and Cl can be used to estimate the volatile content of the melt. The U-Pb isotope system of apatite can record the crystallization age of its host rock. Low-temperature thermochronology is often used to study the degree of denudation after ore deposit formation. Hydrothermal apatite's structure and composition bear information about the fluid, which can indicate the fluid source, properties, and other information related to magmatic-hydrothermal mineralization processes. Artificial intelligence techniques such as machine learning can process massive amounts of apatite data to discriminate rock types and deposit types. Conclusions Apatite is a mineral that is crucial for studying mineral deposits and exploring ore deposits. Future researches should focus on the relationship between hydrothermal apatite and the metallogenic process. Additionally, combining artificial intelligence with apatite analyses to trace the diagenetic and metallogenic process is a promising avenue for further study.

Abstract:This paper is the result of energy exploration engineering. Objective The primary goal is to identify and classify favorable areas for CBM exploration and development, providing a scientific basis for future exploration efforts in Guizhou Province. Methods Based on geological exploration data and laboratory sample analyses, key reservoir characteristics of the major coal seams (No. 6, No. 14, and No. 27) were systematically assessed. Parameters such as coal seam thickness, gas content, permeability, reservoir pressure, and coal–body structure were analyzed. Using a five–index evaluation method, 19 gas–bearing areas were classified. Results (1) The three major coal seams exhibit greater thickness in the southwest and thinner deposition toward the northeast. The average gas content is 11.73 m³/t, with gas accumulation primarily controlled by synclinal structures. (2) Seven extensive gas–bearing areas were identified, with the Bide–Santang Basin and the Jinlong–Qianxi–Jinsha syncline group exhibiting gas contents exceeding 16 m³/t. (3) The average well–tested permeability of the coal seams is 0.173 mD, indicating a medium–low permeability reservoir. Permeability decreases from west to east and with increasing depth, with significant variations across different seams. (4) The average reservoir pressure is 4.98 MPa, with an average pressure coefficient of 0.86, indicating a predominantly underpressured state. A transition from underpressure to normal and overpressure is observed from east to west. (5) Coal structural characteristics vary spatially, with primary and fragmented coal types dominant in the east, while granulated and pulverized coal types are more prevalent in the west. Conclusions Based on the evaluation, seven Grade I, eight Grade II, and four Grade III favorable CBM areas were identified. The Grade I areas, including the Tucheng, Yangmeishu, Dahebian, Shuigonghe, Bide, Zhitang, and northern Jinlong synclines, demonstrate significant CBM exploration and development potential. The Grade II areas include the Gemudi, Jinpen, Santang, northern Qianxi, Jinsha, Liuchang, and Molaoba synclines, while the remaining synclines are classified as Grade III.

Abstract:This paper is the result of oil and gas exploration engineering. Objective The marine black manganese–bearing carbonaceous shale of the Datangpo Formation, widely distributed in the mid–Neoproterozoic Nanhua strata of the Middle–Upper Yangtze Region, South China, has been extensively studied as a manganese deposit but remains poorly investigated regarding its petroleum geological characteristics. This study systematically analyzes the lithofacies paleogeography of the Datangpo Formation and evaluates its implications for hydrocaron accumulation, providing critical insights for guiding petroleum exploration in the southern China. Methods Through field surveys and comprehensive data synthesis of the Datangpo Formation, we systematically evaluated hydrocarbon conditions, source rock geochemistry, and reservoir–caprock assemblage, especially lithofacies and paleogeography. This integrated approach combined individual well log interpretation, multi–well correlation analysis, and lithofacies paleogeographic with advanced analytical techniques including organic geochemical testing, petrophysical characterization, and reservoir evaluation. Results The Datangpo Formation developed during an interglacial period, with its depositional architecture constrained by extensional riftdynamics. Sedimentary facies within the formationare classified into two principal types, seven subcategories and multiple microfacies. The sequence comprises a complete transgressive–highstand–regressive cycle. Hydrocarbon–prospective facies are limited shelf subfacies and lagoon subfacies, predominantly occurring in the first member. These intervals exhibitfavorableorganic geochemical index, and constitute potential source rock horizons. Conclusions The first member of the Datangpo Formation exhibits significant hydrocarbon–generation potential and viable shale gas prospects. Strategic areas including Songtao, Huayuan, Xiushan, Xiangtan and Hefeng, located at the confluence of Hunan, Chongqing and Guizhou Province, demonstrate favorable geological conditions for shale gas exploitation. This unit serves as a competent source rock capable of forming multiple prospective hydrocarbon reservoir assemblages. Notably, The Xiushan–Songtao–Huayuan sector along the tri–province boundary of Chongqing, Guizhou, and Hunan exhibits optimal source–reservoir coupling configuration, indicating promising targets for conventional petroleum exploration.

Abstract:This paper is the result of oil and gas exploration engineering. Objective Che–Mo synsedimentary paleouplift in Junggar basin is an important geomorphic unit that affects the structural style and reservoir distribution characteristics of Jurassic. The study of its development process is helpful to understand the basin mountain coupling relationship and the accumulation law of oil and gas reservoirs in Junggar basin. Methods Based on the logging data and seismic data of 41 wells in the abdomen of the basin, this paper makes a detailed analysis and isochronous comparison of Jurassic sand body and stratigraphic structure, and focuses on the synergistic evolution between the phased development of Che–Mo paleouplift and the orogenic belt around Junggar basin, especially Bogda mountain, and its influence on the basin boundary and sedimentary pattern. Results The evolution of Che–Mo paleouplift can be divided into three stages: initial development stage, rapid uplift stage and post uplift denudation stage. The initial development stage of Early Jurassic Che–Mo paleouplift has no or little influence on the distribution and structural style of Badaowan Formation and Sangonghe Formation. The study area is supplied by Zhayier mountain in the northwest and Kelameili mountain in the northeast, mainly forming braided river delta sedimentary system; The Middle Jurassic was the rapid uplift stage of Che–Mo paleouplift. In addition to the source supply of Zhayier mountain in the northwest and Kelameili mountain in the northeast, Bogda mountain also rose out of the water at the same time and began to supply the source, resulting in significant changes in basin boundary, stratigraphic distribution and structural style, resulting in large–area overlap of the first and second members of Xishanyao Formation, loss or denudation of the third members of Xishanyao Formation, The sedimentary system combination of Braided River Delta and beach bar is formed; The uplift of Che–Mo paleouplift in late Middle Jurassic and late Jurassic resulted in the denudation loss of Toutunhe Formation and Qigu Formation, forming a regional unconformity with Cretaceous. Conclusions The formation and evolution of Che–Mo paleouplift in Jurassic not only affected the sedimentary landform of the basin, but also significantly changed the basin boundary and provenance pattern, and led to significant changes in sedimentary system, stratigraphic structure style and distribution law.

Abstract:This paper is the result of oil and gas exploration engineering. Objective The tight gas in the Shengbei subsag of the Turpan–Hami Basin has become an important field for expanding new exploration battlefields and discovering new reserves. The development characteristics and accumulation mechanism of tight reservoirs have become one of the key scientific issues that need to be solved urgently. Methods Using comprehensive research methods such as geochemistry, geophysics and oil and gas geology, the characteristics and accumulation stages of tight gas sources and reservoirs in the Middle Jurassic were systematically analyzed, and characteristics of overpressure development and the controlling effect on tight gas accumulation were determined. Results (1) The organic matter type of the main source rocks is mainly type III kerogen, and the whole is in the mature stage dominated by gas generation. Middle Jurassic developed low porosity and low permeability–low porosity and ultra–low permeability tight reservoirs, with an average porosity of 7.1% and an average permeability of 0.074×10^–3 μm². The pore type is dominated by secondary dissolution pores, while clay mineral interlayer pores, pyrite intercrystalline pores and micro–fractures are developed. (2) The Middle Jurassic developed overpressure caused by pressure conduction and hydrocarbon generation pressurization. The pressure coefficient was mainly distributed between 1.2 and 1.5. The overpressure top interface was located in the middle and upper part of the Qiketai Formation vertically. The overpressure is mainly distributed in the east and southeast of the Shengbei subsag, and the fault system controls the distribution range of the overpressure. (3) The hydrocarbon expulsion from source rocks lasted for a long time. From Late Triassic to the present, there have been at least two main periods of natural gas charging, and the two main accumulation periods are: Late Jurassic to Early Cretaceous and Paleocene to date. Conclusions The Middle Jurassic tight gas reservoirs are dominated by the accumulation model of "two–stage accumulation from far–source and near–source, pressure–fault coordinated transport, and fault–overpressure coordinated control". The research results in this paper will provide scientific basis and technical support for tight gas exploration and development in Shengbei Sub–sag.

Abstract:This paper is the result of oil and gas exploration engineering. Objective Through the study of shale formation and shale gas enrichment mechanism, the current study aims at finding out main factor controlling shale gas reservoir in the Carboniferous Tian’eping Formation in the Xiangzhong Depression as well as its enrichment patterns. Methods Carbonates carbon and oxygen isotopes as well as shale trace elements and major elements were analyzed at Well Xiangxindi 4 in order to recover paleo–environment and investigate the origin for the shale formation. Combined with the thermal evolution simulation of medium–low maturity shale gas reservoirs, the mechanism for shale gas enrichment is identified through petromineralogy, organic geochemistry, physical properties of shale gas reservoirs, existence forms of shale gas and tectonic preservation condition. Results (1) The organic–rich shale in Lower Carboniferous Tian’eping Formation were formed due to seawater stratification and seabed anoxia caused by the intensive climatic fluctuations in the Early Carboniferous. (2) The extensive and intense magmatic events in central Hunan led to the increase of locally paleogeothermal gradient and further caused secondary hydrocarbon generation in the Lower Carboniferous organic–rich shale. Shale gas in the Tian’eping Formation was formed owing to crude oil cracking and secondary hydrocarbon generation of organic matter. (3) Shale gas preservation was promoted due to decollement in the Ceshi Formation of the lower Carboniferous blocking the vertical escaping channel of the shale gas from the underlying Tian’eping Formation. Conclusions The shale gas of Lower Carboniferous Tian’eping Formation in Xiangzhong Depression is the common result of favorable facies zone controlling the total organic carbon content, magmatic thermogenesis controlling the reservoir physical properties and detachment structure controlling the preservation.

Abstract:This paper is the result of geological survey engineering. Objective The brittleness of shale reservoir is one of the parameters reflecting the fracturing quality of shale gas reservoir, which has an important influence on the degree of difficulty of fracturing and the shape of fracture network. Methods In order to accurately evaluate the brittleness characteristics of Niutitang Formation shale reservoir in Western Hubei, systematic sampling, whole rock mineral and clay content test, main and trace element content test, acoustic mechanics joint test and other analytical tests were carried out on five wells in the south wing of Huangling anticline in Western Hubei. The quantitative evaluation of shale brittleness was carried out by cluster analysis and principal component analysis. Results There is a close relationship between minerals and rock brittleness, and the cluster analysis method can quantitatively characterize the effective brittle mineral composition and non–effective brittle mineral composition in shale; The comprehensive quantitative evaluation formula of brittleness index based on rock mechanics, mineral composition and element composition is established by using principal component analysis method, which overcomes the limitation of single method and forms the brittleness index profile of Niutitang Formation shale section in Western Hubei. Conclusions The results of microseismic monitoring and fracturing show that the newly established brittle index profile can accurately indicate the high brittle layer of shale, and the fracturing effect is good.

Abstract:This paper is the result of geological survey engineering. Objective Multiple sets of marine source rocks such as Cambrian–Ordovician, Silurian, Carboniferous–Permian, etc. are widely distributed in the northern Guizhou area of China, which have a good source–reservoir–caprock combination vertically and are of great natural gas resource potential and prospects for exploration and development. In order to better assess the natural gas resources in the area, on the basis of the discovery of the "four–story" composite natural gas reservoir in Anye 1 Well of the Anchang syncline in the Wulingshan area, northern Guizhou, this paper discusses the genesis of the Shiniulan Formation gas reservoir in the Anchang syncline. Methods Field geological works and indoor studies, geological probes and geochemical analyses, macroscopic observations and microscopic techniques, as well as literature researches were carried out. Results It is considered to be a slit–type carbonate gas reservoir, the gas is mainly derived from the underlying Longmaxi Formation, and the multiple stage tectonic movements in the area provided the driving force for its accumulation. Conclusions This research is significant for natural gas resources assessment of the region, and is also helpful for enriching and developing the theory of hydrocarbon accumulation in complex structural belts.

Abstract:This paper is the result of environmental geological survey engineering. Objective The CO₂–Enhanced Gas Recovery (CO₂–EGR) technology significantly augments natural gas extraction efficiency while concurrently facilitating the permanent subsurface sequestration of CO₂. This dual benefit substantially aids in achieving carbon neutrality goals. The mechanisms pivotal to enhanced recovery and storage include the competitive adsorption and diffusion of CO₂–CH₄ within nanopores. Methods This study focuses on the 2^nd section of Shanxi formation in the Yan'an Gas Field located in the Ordos Basin. Using molecular dynamics (MD) and grand canonical Monte Carlo (GCMC) methods, a model was established toinvestigate the competitive adsorption behaviors of CO₂–CH₄ mixed gases in the nanoporous matrices of key minerals, specifically quartz and illite, under reservoir–specific temperature and pressure conditions. Additionally, the study analyzes the correlation between the self–diffusion coefficient of CO₂ and the variabilities in temperature and pressure. Results The study yields several findings: (1) At an isothermal condition of 353.15 K and varying pressures from 5.9 to 17.7 MPa, both quartz and illite exhibit heightened adsorptive capacities for CO₂ in comparison to CH₄. Furthermore, the competitive adsorption selectivity for CO₂–CH₄ is found to be greater in quartz pores than in illite pores. (2) Under similar isothermal conditions and at a constant pressure of 11.8 MPa with temperatures ranging from 313.15 K to 373.15 K, the competitive adsorption selectivity for CO₂–CH₄ in both quartz and illite pores is observed to diminish with increasing pressure and temperature. (3) Under conditions of low pressure (5.9 MPa) and high temperature (373.15 K), there is an enhancement in the mobility and diffusion efficiency of CO₂ within both CO₂–CH₄–quartz and CO₂–CH₄–illite systems. Conclusions Quartz and illite have higher CO₂ adsorption capacity, greater CH₄ displacement capacity, and better CO₂ storage effect.

Abstract:This paper is the result of environmental geological survey engineering. Objective This paper aims to investigate the distribution characteristics, the contents and distribution of soil elements in different sedimentary facies of Quaternary, the control factors and the sources of sediment materials in Xiong’an New Area, and to provide geochemical bases for the study of regional palaeogeographic evolution and epigenetic geochemical environments. Methods Based on the surface element content data obtained from the geochemical survey and monitoring of land quality in Xiong’an New Area, this study employs multivariate statistical methods (such as elemental content analysis and ratio tracing) to reveal the relationship between regional elemental geochemical distribution patterns and the epigenetic environment. Results The soil in the alluvial–lacustrine plain subregion has the characteristics of low value of SiO₂ and Na₂O, and high value of Al₂O₃, Fe₂O₃, MgO, CaO, K₂O and Na/Rb. The soil in the alluvial–diluvial plain subregion is characterized by high SiO₂ and Na₂O, and low Al₂O₃, Fe₂O₃ and Ca/Ba. The distribution of soil geochemical major elements is primarily controlled by chemical weathering intensity of source sediments, while epigenetic environment also influences the depletion and enrichment of major elements. The source area is currently in the stage of moderate chemical weathering dominated by plagioclase weathering, with no evidence of potassium metasomatism in weathering products. The soil parent materials in each sedimentary facies are mainly derived from the mature continental quartz source of Taihang uplift on the west side of Xiong’an New Area. Additionally, in the subregion of alluvial plain, parent materials of a small proportion of samples are from mafic volcanic and neutral igneous rocks. Conclusions Geochemical indicators such as soil element contents, element ratios and element combinations (Rb–U–Ga, Fe–Mg–Ni–V) can effectively differentiate sedimentary facies environments in the study area and serve as reliable tracers for soil parent material properties.

Abstract:This paper is the result of environmental geological survey engineering. Objective The new pattern of harmonious coexistence between humans and nature is influencing the research concept of geological ecological organic systems. Understanding and mastering the distribution characteristics of lithium in different geological environments can help improve the utilization efficiency of lithium resources and promote green transformation of development methods. Methods Focusing on the needs of geological work, this study analyzed the distribution characteristics, ecological, environmental, and biological health effects of lithium in different geological environments through extensive surveys, field sampling, physical and chemical property testing analysis using interdisciplinary research methods. Results The regional and multi–field coupling distribution characteristics of lithium in various spheres (hydrosphere: ocean floor, groundwater, rivers, lakes, glacier meltwater, snow water and rain; lithosphere: Continental crusts, rocks and soil; atmosphere and biosphere) were clarified. The spatial–temporal distribution characteristics and regional differences of lithium were analyzed. The influencing factors for complex biological, geological, geochemical processes as well as spatial–temporal patterns for each layer's large amount but complicated elements were preliminarily summarized. The distribution features for key layers with respect to land biosphere was enriched while a comprehensive evaluation index system was improved for large–scale lithium resource bases. A systematic quantitative evaluation model was established to assess changes in lithium concentration on surface water, groundwater, and soil caused under human activities (mining), revealing unique ecological and environmental effects associated with "key layers" along with both lack or excess health effects from lithium. Conclusions Research on the distribution characteristics and ecological and environmental effects of lithium in different geological environments shows that pegmatite–type lithium resource development has overall safety control over its impact on ecology and environment while there are still some critical issues that need to be resolved regarding clean efficient development and utilization for clay–type and brine–type Lithium resources. With further deepening research into theoretical problems related to lithogenic mechanisms coupled with interdisciplinary basic research applications and simulation technology will make breakthrough progress possible towards understanding migration and transformation mechanisms associated with Lithium elements. While physiological amounts are beneficial to health excessive levels within organisms can cause certain side–effects even toxic reactions so it is necessary to continue conducting systematic studies on eco–environmental and biological health effects across different types and sources of Lithium resources providing theoretical basis support towards safe rational development strategies concerning strategic emerging minerals along with promoting eco–civilization construction efforts within China.

Abstract:This paper is the result of marine geological survey engineering. Objective There are high–quality natural fine sand distributed along the coast of Xiangyun Island in Hebei, which is a famous coastal tourist island. Simultaneous investigation and research on the concentration of suspended sediments and nearshore current in this area is of great significance to the ecological environment of Xiangyun Island and its nearshore engineering. Methods The current velocity and flow direction of the sea area were continuously profiled by ship–borne Acoustic Doppler Current Profiler (ADCP), and the distribution of suspended sediments in the sea area was qualitatively discussed according to the backscatter intensity recorded by the instrument. Results (1) The current in Xiangyun bay is mainly parallel to the coastline, which has obvious reciprocation. The magnitude of flood current was obviously larger than ebb current, the flood current was gradually weakened along the shore direction, however the ebb current in the southwest of Xiangyun bay increased along the shore direction; (2) During the transition from flat tide to ebb tide in Xiangyun Island sea area, the current turning starts from the bottom water, and the current turning and tide level change have certain lag; (3) The data of backscatter intensity shows that: there was a high concentration layer in Xiangyun bay coastal area, and the concentration increases along the shore direction, and the concentration of suspended sediment gradually decreases from northeast to southwest. Conclusions Xiangyun Island coastal waters under the action of the tidal current, suspended sediment along Xiangyun Island shoreline from northeast to southwest, is the main reason for the Xiangyun Island in the northeast section erosion and the southwest section deposition.

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