Renewable energy is characterized by seasonal and regional fluctuations, and large-scale underground hydrogen storage (UHS) is a promising technology for regulating the imbalanced energy supply and demand. Existing UHS studies and projects of either pure hydrogen or its mixture with methane are mostly conducted with salt caverns and saline aquifers, other types of formations, e.g., coalbed methane (CBM) reservoirs, have not been systematically examined for hydrogen storage. The hydraulic fractures created for CBM production have favorable permeation properties for potential hydrogen storage. A coal seam model was built based on realistic geological parameters from the Qinshui Basin in China, upon which compositional modeling was carried out to study the primary CBM depletion and subsequent hydrogen injection and withdrawal processes in the reservoir. Sensitivity analyses against crucial UHS operating parameters show that well shut-in period between primary depletion and UHS operations has a minor impact on hydrogen recovery. Larger cushion gas volume leads to higher initial hydrogen recovery. Larger working gas volume improves long-term hydrogen recovery but is constrained by cushion gas in initial cycles. Lower injection-withdrawal rates favor higher hydrogen recovery by exploiting reservoir pressure support in the early stage. The purity of hydrogen remains stable at about 94% during longterm cycling. In addition, the recovery of the optimized case obtained through the L25(56) orthogonal experiment reaches 97.01%, and the overall purity is stable. Case studies support that depleted CBM reservoirs can be used for long-term cyclic UHS by maintaining satisfactory hydrogen recovery. This study provides an instructive evaluation of large-scale UHS in depleted CBM reservoirs and serves as a comparative reference for other UHS operations.

Underground hydrogen storage in depleted shale gas reservoirs has emerged as a promising option for large-scale energy storage, with feasibility assessments relying on compositional simulations. The fidelity of such simulations hinges on accurate representation of key physicochemical processes, particularly gas adsorption, which governs phase partitioning in shale formations. However, adsorption is often treated deterministically in large-scale simulations, while optimization efforts emphasize operational and geological parameters. This minireview summarizes prevailing compositional simulation workflows and key performance metrics for shale and further synthesizes recent advances and gaps in H2/CH4 competitive adsorption, highlighting the scarcity and experimental difficulty of multicomponent adsorption data. The propagation of adsorption-related uncertainty to large-scale predictions is further discussed. An illustrative scenario demonstrates that different multicomponent adsorption models can significantly alter the predicted fraction of adsorbed H2 and the recovery factor. The magnitude of these variations can be comparable to or even exceed improvements achieved through typical operational optimizations. Such discrepancies indicate that adsorption representation is not a non-significant modeling input but a central factor influencing evaluation outcomes. These findings underscore the need to explicitly account for competitive adsorption in assessing underground hydrogen storage in shales. Furthermore, adsorption uncertainty should be systematically quantified and integrated into modeling workflows to secure the high-fidelity of compositional modeling underground hydrogen storage in shales.

Achieving commercial production from deep tight gas formations poses challenges to existing geological and engineering technologies. Xujiahe tight sandstone gas, deeply buried in the Western Sichuan Basin, is proven with enormous reserves; however, preliminary hydraulic fracturing trials mostly failed to bring up the productivity. From the angle of incorporating geological and engineering knowhow, we first adopted the carrier beds theory to distinguish the favorable zones in Xujiahe Formation, then a dual sweet spot identification criterion was established based upon analytic hierarchy process, which links major geological and engineering parameters together. Provided the identified sweet spot, hydraulic fracture conductivity was then optimized to maximize the productivity. Fracturing operational parameters consisting of fluid volume and pumping, proppant size and addition, and fluid formula were then screened to secure high conductivity. Implementation of this updated geological-engineering technical route in exploiting Xujiahe tight gas reservoirs turns out to be a great success with an average gas rate of 130 Mm(3)/d/well during the early production stage in 14 wells. Electromagnetic monitoring further demonstrated the effectiveness of precise massive fracturing by visualizing the morphology of fracture clusters. Comparative productivity analyses manifested the breakthrough of this technical route over preceding ones in Xuejiahe gas reservoirs, providing a superior reference for discovering and developing deep tight gas resources around the world.

Underground hydrogen storage (UHS) is a promising technique for achieving cost-effective large-scale energy storage. Currently, research and practice related to UHS mainly focus on the storage of hydrogen and hydrogen-methane mixtures in salt caverns and saline aquifers. Shale gas formations are widespread around the world, the stimulated reservoir volume (SRV) with improved porosity and permeability created by hydraulic fracturing could be used for hydrogen storage; meanwhile the surrounding shale could seal the SRV tightly to prevent leakage. This research explores the feasibility of utilizing depleted shale gas reservoirs for pure hydrogen storage and evaluates the effects of operational parameters by combining adsorption experiments and numerical simulations. Isothermal adsorption experiments using methane and hydrogen were performed on shale samples from the Longmaxi Formation. Langmuir equation fitting yielded that the maximum adsorption capacities for methane and hydrogen were 3.81 cm3/g and 1.70 cm3/g, respectively, with corresponding Langmuir pressures of 6.25 MPa and 2.34 MPa. The shale gas reservoir model established with a fractured horizontal well can store 4 × 107 m3 of hydrogen for an extended period. The average recovery factor over 30 injection-withdrawal cycles conducted over 33 years exceeds 0.924. Larger injection-withdrawal rate, longer cycle length and shorter fracture half-length are conducive to hydrogen storage, whereas fracture conductivity has a minor effect. This study serves as a preliminary reference for geological and engineering parameter optimization and economic evaluation of future UHS in shale gas reservoirs.

Low-permeability oil reservoirs are difficult to develop using conventional methods due to their tight characteristics, resulting in low recovery factor. In the Hongliuquan Field of the Qaidam Basin in China, the sandstone reservoirs have low permeability and crude oil viscosity is high, leading to a recovery factor of only 18

The ultra-deep Shunbei Oil and Gas Field in Tarim Basin in China is characterized by ultra-high temperature, ultra-high pressure, high H2S content, and moderate CO2 content. The formation depth reaches 8000 m, mainly consisting of oil reservoirs, volatile oil reservoirs, and gas reservoirs. Gas lift and flooding are major measures deployed for enhancing oil recovery in Shunbei Field, during which the tubing corrosion emerges as a challenge, reducing the development efficiency. Therefore, an experimental evaluation of the tubing corrosion has been conducted in response to the corrosion conditions in strip regions #1, #4, and #5 in Shunbei Field. Experimental results show that the tubing in the nitrogen gas lift conditions all exhibit slight corrosion, but this can still meet the service requirements of the tubing. Under the nitrogen gas huff and puff conditions, the corrosion rate of the steel gradually increases with the rising temperature. Under the condition of water alternating gas injection, the steel corrosion rate is around 0.8 mm/a, which cannot meet the long-term service requirements. Through grey relational analysis of the factors affecting corrosion, the influence order of each factor derived is: temperature > oxygen content > pressure. Therefore, special attention and regular corrosion inspections should be carried out for the pump hanging section at high temperatures in the wells. This study provides important guidance for the corrosion control for nitrogen gas injection operations in Shunbei Oil and Gas Field.

Shale oil and gas resources are abundant and widely distributed in the world. Research on shale oil is growing rapidly recently, and shale oil is expected to become a major contributor to the oil production growth in the near future. Shale cores drilled from Luo 69, Fanye 1, Niuye 1 and Liye 1 wells have been systematically analyzed in terms of mineral composition, pore structure, and porosity and permeability stress dependency using thin section examination, X-ray diffraction (XRD), scanning electron microscopy (SEM), nitrogen sorption, and porosity and permeability apparatus. Clay content in these wells ranges from 16.55

The Ordovician -Silurian (O - S) transition was characterized by significant changes in global climate, marine redox conditions, and biological evolution, which include global seawater euxinia, the onset of the Hirnantian glaciation, and large-scale extinctions. During this time, the marine sulfur cycle was disrupted, and the pyrite sulfur isotope (delta 34 S py ) showed a large positive excursion. This excursion is closely tied to the Hirnantian glaciation, with delta 34 S py increasing at the start of and decreasing at the end of the glaciation. Although it is thought that variations in marine sulfate concentration and primary productivity are responsible for the positive excursion in delta 34 S py , contemporary marine sediment delta 34 S py data suggest that sedimentary processes can also lead to significant fluctuations in delta 34 S py . To assess the impact of local changes in sedimentary conditions on this positive delta 34 S py excursion event, we conducted detailed depositional and geochemical analyses of sedimentary pyrite found in black shales from the Wufeng-Longmaxi formations in the Weiyuan area of the Sichuan Basin, China. These sedimentary pyrites include three types: framboidal, euhedral, and laminated pyrite. Bulk sample sulfur isotope analyses revealed that delta 34 S py values vary from -16.2%o to 15.8%o (mean = - 3.8%o, n = 22). In situ analyses of delta 34 S py show that different pyrite crystals exhibit a range of intragranular delta 34 S py values that are likely indicators of diagenesis. Variations in bulk sample delta 34 S py are strongly and negatively correlated with the proportion of framboidal pyrite, i.e., lower levels of framboidal pyrite content resulted in a higher bulk sample delta 34 S py value, suggesting diagenetic alteration controls on delta 34 S py . In addition, the delta 34 S py excursion in the WufengLongmaxi formations also appears to be compatible with lithological changes related to sedimentation rate. The delta 34 S py values from the Guanyinqiao Bed, which consists of calcareous shales, are higher than those from black shales with a relatively low sedimentation rate. Our results suggest that the positive delta 34 S py excursion during the O - S transition during the Hirnantian glaciation is controlled not only by diagenetic alterations but also by local sedimentation rate.

雷达目标所属作战平台判别是电子对抗侦察情报处理的关键步骤,直接影响电子对抗情报生成质量,进而影响电子对抗决策.针对截获雷达目标所属平台判别问题,提出一种基于Apriori算法的雷达目标所属平台判别方法.首先,利用云模型分别对截获脉冲不同类型的特征参数进行建模,消除截获脉冲特征参数模糊性、不完整性;然后,利用信息熵理论对截获脉冲所属辐射源的型号进行识别;最后,提出了数据挖掘+Apriori算法,建立数据库存储信息、人员识别经验信息与平台识别历史记录多维分析框架,实现了雷达目标与所属平台配属关系判别.仿真结果表明:在已知雷达数据库样本量较大的情况下,所提方法仍有较高的准确率和识别效率.

The Upper Miocene Huangliu sandstones of the Dongfang district are currently regarded as an important exploration target in the Yinggehai Basin. Affected by the anomalous diagenetic environments of high temperature, overpressure, and CO2 fillings, the diagenetic evolution of the Huangliu sandstones appear complicated characteristics and subsequently exert a significant influence on reservoir development. Integrated methods employed in this study include an electron microscope, cathode luminescence, X-ray diffraction, scanning electron microscope, electron microprobe, stable isotope analysis, homogenization temperature, and physical property tests. By the comparative researches between the AF-1 and AF-2 areas of the Dongfang district, the aim of this study is to investigate the complex diagenetic modifications and their controlling effects on reservoir quality and development mechanism. With similar sedimentary features, the reservoirs in the AF-1 area exhibit slightly higher porosity than those of the AF-2 area. The permeability in the AF-1 area shows one or two orders of magnitude lower than that of the AF-2 area, and throats size distribution act as a critical factor to cause distinct diversities of permeability. In the AF-1 area, the later appearance of overpressure contributed to stronger compaction intensity and more loss of primary porosity. The dissolution induced by CO2-rich thermal fluids in late stage enhanced the secondary porosity significantly and improved the total porosity. However, extensive dissolution cause abundant precipitation including carbonate cement and authigenic illite in a closed diagenetic system, which lead to the decrease of reservoirs’ permeability. As for the AF-2 area, earlier occurrence of overpressure restrained mechanical compaction obviously and further retarded corrosion of organic acid, which preserved high proportions of primary porosity. Due to lesser impact by CO2 filling, the AF-2 area had a poor intensity of dissolution and cementation, and the authigenic illitization was also restrained significantly, which effectively prevented heavy damage on reservoir quality, and especially for permeability. Based on the diagenetic evolution pathways, two types of porosity evolution patterns are established. The effect degree on diagenesis by high temperature, overpressure, and CO2 filling vary significantly between the AF-1 and AF-2 areas. The two areas show different pathways of diagenetic evolution, forming two development patterns and exhibiting different reservoir types.

Quasi-continuous tight gas sandstone reservoirs have been discovered widely in the eastern margin of Ordos Basin (Linxing area) within the marine-continent transitional strata in the upper Paleozoic. Differences in formation water chemical properties, water-rock reactions, and diagenetic evolutions between the Taiyuan Formation and the Lower and Upper Shihezi Formations are attributed to various degrees of densification of sandstones, which significantly restrain the exploration and development of tight gas reservoirs. This study utilizes the petrographic features, electron probe, X-ray diffraction, and chemical properties of formation water to establish the diagenetic sequence of tight sandstone reservoirs and finds that the diagenetic systems of the Taiyuan Fm. were more closed than those of the Shihezi Fms., with enrichments in Ca2+and depletions in Mg2+ and Fe2+. Here, we suggest that the dissolution of feldspars and rock fragments, the siliceous cementation, and the transformation of clay minerals are controlled by the K+/H+ ratios of the formation water. In the Taiyuan Fm., the low K+/H+ ratios resulted in a complete illitization reaction in the closed CaCl2 type formation water, and the migration rate of K+ controlled the proportion of the illite contents in the open NaHCO3 type formation water. In the Lower Shihezi Fm., the rapid consumption of H+ caused the elevation of the K+/H+ ratios, leading to the cease of illitization reaction and preservation of kaolinites and K-feldspars. In the Upper Shihezi Fm., the illitization reaction was inefficient, and smectites were transformed to chlorites. Hence, differentiated sandstone densification models are established to characterize different water-rock reaction systems. Typically, clay minerals and ferrous carbonate cements could form seepage barriers around the thick sandstone layers and promote the formation of independent closed high-pressure micro-diagenetic systems. Consequently, the overpressured reservoirs that underwent relatively weak compaction, dissolution, and cementation (Type Ⅰ) and the chlorite-enriched overpressured reservoirs (Type Ⅱ) tend to preserve partially primary pores and form secondary pores, which should be treated as the “sweet spot” target area for the further exploration of tight gas.

The underground thermal fluid is one of the significant factors controlling the formation and quality of reservoirs. The Huangliu Formation (N1h) in YF1 area of the central depression belt in the Yinggehai Basin, South China Sea, is characterized by intense thermal fluid activities related to mud diapir and large-scale shallow-water gravity flow deposits. The multi-episodic invasion of high-temperature and CO2-rich thermal fluid into the formation induces complex water-rock reaction during diagenetic process, providing a preferable investigation opportunity for revealing how thermal fluid affects reservoir quality. This study characterizes the reservoirs in the formation through core and thin section analyses as well as physical property test. The reservoirs are dominated by fine-grained sandstone characterized by medium porosity (15.2–21.3%) and lower permeability (0.56–15.75mD). Based on an analysis of casting thin section, cathode luminescence (CL), scanning electron microscope (SEM), carbon and oxygen isotope, inclusion test, and electron-probe microanalysis (EPMA), we systematically investigate the diagenetic patterns and pore evolution process for the reservoirs in the formation. The episodic invasion of thermal fluid occurred approximately 0.4 Ma ago plays an important role in controlling reservoir development: The CO2-rich formation water induces massive late-stage dissolution, resulting in a higher proportion of dissolved pores (38.7–46.4%), which improves the porosity of reservoirs at a depth of 2600–3100 m. Nevertheless, the late dissolution together with carbonate cementation occurred in closed diagenetic system blocks most seepage channels. Furthermore, the relatively high level clay mineral transformation in the YF1 area leads to a higher content of authigenic illite (44–62%) in the formation. Massive authigenic illite severely blocks the pore throats in fine sandstone, reducing permeability. This study offers an insight to the understanding of mud diapir-derived thermal fluid affecting and controlling the quality of reservoirs in some areas of the Yinggehai Basin.

Although extremely high Hg contents are known in the Lower Cambrian sedimentary successions, the extent and spatial-temporal distribution of sedimentary Hg anomalies in these successions remain unclear. Here, we report concentrations of Hg, total organic carbon (TOC), total sulfur (TS), and major and rare earth elements of the Lower Cambrian (similar to 525 Ma) sedimentary rocks at the Dongxihe section in the interior of the Yangtze Platform, South China. We investigated the sedimentary Hg enrichment mechanism and the spatial-temporal fluctuations of Hg in the Lower Cambrian and compiled published Hg (Hg/TOC) data from the Upper Neoproterozoic to the Lower Cambrian to trace the potential Hg sources. Our study verified that hydrothermal vents provide an excess Hg source for the sedimentary Hg enrichment in the Dongxihe section, which is supported by the positive Eu anomaly and major element. The major elements show more Fe and Mn enrichment in the upper part than the lower part, indicating more hydrothermal contribution in the upper part. Additionally, the records of the spa-tial-temporal distribution of Hg show that most of the sections (including shelf, slope, and basin) in South China show strong sedimentary Hg enrichment, which can be attributed to widespread hydrothermal venting. By reconstructing fluctuations of Hg during the Late Neoproterozoic to the Early Cambrian, we proposed that in the context of the Gondwana continent assembly, the prevalent hydrothermal ventilation event during the Early Cambrian not only induced the abnormal enrichment of sedimentary Hg but also played a crucial role in shaping the marine environment and ecosystem during this period.

以下扬子陆域地区官地1井下寒武统幕府山组海相泥页岩岩心样品为研究对象,综合运用场发射扫描电镜、X衍射分析、气体吸附、高压压汞和有机地球化学分析等实验测试手段,系统研究了官地1井幕府山组泥页岩孔隙结构特征和孔隙发育影响因素.研究表明:①?官地1井幕府山组泥页岩矿物组成以石英、方解石胶结物和黏土矿物为主,其总有机碳含量较高,有机质类型以I型干酪根为主且均处于过成熟阶段;②?泥页岩孔隙类型主要为基质孔隙(粒间孔隙和粒内孔隙)、有机质孔隙和微裂隙,其中以有机质孔隙含量居多,而粒间孔隙面孔率占比最高;③?有机质丰度对有机质孔隙的孔径和比表面积具有一定的影响,压实作用则构成过成熟阶段孔隙演化的主要因素,而刚性矿物具有一定的支撑作用并对有机质孔隙的保存具有积极意义;④?分形维数与总有机碳含量和比表面积相关性较好,而与孔隙体积相关性弱,反映孔壁粗糙程度及孔隙结构复杂程度受有机质丰度影响.

LPI雷达信号由于采用复杂调制方式而具备低截获性能,在新体制雷达中被广泛应用.针对采用复杂调制方式的LPI雷达信号识别问题,提出一种基于对角积分双谱的信号识别方法.首先,对复合调制LPI雷达信号进行建模分析,给出了不同调制信号在双谱特征上的差异.然后,针对提取双谱特征计算量较大的问题,提出一种利用双谱特征中的对角积分双谱进行复合调制LPI雷达信号识别的方法,通过降维处理降低了计算量.最后,通过仿真实验验证了方法的有效性和可行性,实验表明,在信噪比为10 dB的条件下,该方法对复合调制LPI雷达信号的识别准确率在95％以上.

显著性目标检测旨在提取图像场景中最显著的目标成分.常规的显著性目标检测算法主要对单一的图像进行处理,得到的检测结果往往不够准确,存在检测错误的情况.为解决上述问题,提出基于协同特征的显著性目标检测算法,通过利用图像组之间的协同性来实现对显著目标的准确检测.通过在已公开的数据集进行实验表明,所提算法在检测效果上优于目前的主流算法,具有较强的鲁棒性.

军队力量体系改革重塑对院校人才培养提出更高要求,面向实战化开展教学课程改革势在必行.装备类课程作为军校本科学历教育相关专业课程体系中的核心类课程,对学员岗位任职能力培养和军人职业长远发展具有关键作用.针对部队实战化训练对人才培养的现实需求,依据教育部对高等教育"金课"建设要求,以军队院校生长学员装备类课程建设为例,在分析装备类课程"水课"本质特点的基础上,以"金课"具有高阶性、创新性和挑战度的"两性一度"衡量标准为切入点,从对接岗位需求、适应转型要求、聚焦实战标准和着眼能力培养四个方面,提出了装备类课程的教学理念、教学内容、教学模式和考评机制改进措施,探索了装备类"金课"课程的建设方向.

显著性目标分割旨在提取图像场景中最显著的目标成分.在以往算法中,人们往往基于图像自身的显著要素如对比度、边界背景性等设计低层次人工特征或者深度语义特征进行显著性目标的分割,忽略了人类自身的视觉注意特征.为解决这一问题,提出眼动预测和多层次邻域感知的显著目标检测算法.首先,根据GBVS原理预测人眼感兴趣区域,并基于该感兴趣区域生成目标种子;其次,对图像进行超像素分割,联合颜色、纹理、视觉注意等多维度特征计算超像素之间的相似性权重;再次,基于目标种子和节点权重,在多个分割尺度下采用元胞模型对显著性种子进行传播,使得初始目标种子能够扩散至整个显著目标;最后,基于sigmoid强化和多尺度融合生成最终显著目标分割图,较好地解决了复杂场景下显著目标的检测问题.在公开数据集上的实验结果表明,所提算法在检测精度和适用性上优于目前的主流算法.

莺歌海盆地乐东地区是我国典型高温超压天然气勘探领域,其关键储层黄流组砂岩以天然气富含CO2为特征,对其中石英颗粒内裂隙包裹体的研究能为CO2来源和天然气成藏信息提供重要线索.本文通过对黄流组砂岩石英颗粒内包裹体进行岩相学、显微测温与激光拉曼分析,结果表明黄流组砂岩石英颗粒内正常捕获流体包裹体均一温度主要分布在155～165℃与170～180℃两个温度区间,流体包裹体成分为CO2(气)和H2 O(液)两种或CO2(气)和CO2(液)、H2 O(液)三种.这些特征表明乐东地区黄流组至少经历两期富含CO2的热液活动,记录了埋藏晚期无机CO2在火山活动或深大断裂发育期充注成藏的信息.

针对非均匀目标区域中的热点区域覆盖优化场景,提出一种分布式无人机网络覆盖优化算法.首先对满足网络连通性的最少无人机节点数目和热点区域覆盖范围进行估计,其次融入热点区域信息改进布谷鸟算法位置更新方程并重构优化目标函数,然后对发现概率参数进行自适应调整,最终实现热点区域覆盖率的重点优化.在仿真实验分析中,在相同仿真环境下与标准布谷鸟算法和其他经典算法进行对比,结果表明所提算法的热点区域覆盖率较其他算法提升了约4％,迭代次数减少了约30次,证明了该算法收敛速度快、耗时少,能够更加有效地提高热点区域的覆盖率.