Mesozoic lacustrine shales represent significant source rocks in global unconventional oil and gas exploration. These shale systems record the complex responses of terrestrial organic matter (OM) enrichment under greenhouse climatic conditions. However, the mechanisms by which paleoclimate modifies the key factors controlling OM enrichment on a global scale remain unclear. More importantly, the thresholds at which these factors promote OM enrichment have not yet been established. To address this, geochemical data from 35 Mesozoic lacustrine basins worldwide were compiled. An interpretable machine-learning framework combining CatBoost and Shapley Additive Explanations (SHAP) was then developed to quantify the nonlinear relationships between total organic carbon (TOC) and paleoclimate, paleosalinity, redox conditions, paleoproductivity, terrestrial input, and sedimentation rate. The results show that paleoclimate emerges as the most significant predictor of OM enrichment in lacustrine environments, as it strongly regulates variations in paleosalinity, redox conditions, paleoproductivity, terrestrial input, and sedimentation rate, thereby leading to diverse OM enrichment patterns. The study further identified several thresholds favorable for OM enrichment, including CIA > 79.3, Sr/Ba between 0.6 and 1.77, MoEF between 0.78 and 13.42, Ti < 0.35%, Nixs > 21.54 ppm, and LaN/YbN > 1.34. Once Ti exceeds 0.35%, its diluting effect becomes dominant and leads to a marked reduction in OM enrichment potential. These findings refine the quantitative model of climate-driven OM enrichment and provide new insights into assessing hydrocarbon source-rock potential. Additionally, this study demonstrates the potential of interpretable machine learning for identifying hidden geological regularities from multidimensional geochemical big data.

The Qaidam Basin is endowed with abundant Tertiary hydrocarbon resources and possesses major exploration potential. Lacking an overall understanding on sequence stratigraphy and sedimentary facies of the basin is not favorable for making new progress in hydrocarbon exploration. In this study, using outcrop, core, well logging and seismic data, the Tertiary strata of the Qaidam Basin was divided into 7 second-order sequences, 12 third-order sequences and 24 system tracts. In addition, 7 sedimentary facies types were identified, i.e., diluvial fan, braided river, flood plain, fan delta, braided river delta, lacustrine deposit and turbidite fan. Six single sedimentary factors were selected for analysis, and with third-order sequences as the unit, the distribution and evolution of sedimentary systems were defined. For the controlling factors of lithofacies paleogeography, “snow mountains controlling lakes” and “fault steps control basins” were proposed. It is believed that under a compressional tectonic setting, lake level fluctuation is closely related to elevations of peripheral mountains, and lake water is sourced principally from mountain snowmelt. A higher structural uplifting amplitude will result in a larger area of mountain snow, a greater water supply and a larger lake area. Boundary faults of the basin retreated towards the mountains in a step way, resulting in an expanded basin. However, the faults advancing towards the center of the basin aroused basin shrinkage. From a sedimentary view, the distribution characteristics of Tertiary source rocks and reservoirs of the Qaidam Basin were analyzed; it is proposed that the periphery of the hydrocarbon generation center of the Shizigou–Mangya sag is the present-day optimum exploration zone, and the periphery of the hydrocarbon generation center of the Yiliping depression center is a potential favorable exploration zone.

In order to extract the remaining oil from the reservoir during the late stage of development, there is an increasing demand for precise research on the internal architecture of the reservoir. In this paper, the meandering fluvial point bar architecture of the Guantao Formation in Gudong Oilfield is quantitatively characterized through the integration of core, well logging, seismic data, and modern river geomorphology analysis. The models for the relationship between point bar length and width, as well as width and thickness, have been established. The investigation of modern meandering fluvial geomorphology shows that the point bar mostly undergoes downstream migration during lateral processes. In this context, geomorphologic parameters such as migration azimuth points, upstream deviation angle, and downstream deviation angle are proposed to quantitatively characterize the architecture of point bars. Statistical regression analysis of modern fluvial point bar geomorphologic parameters reveals a strong correlation between the upstream deviation angle and downstream deviation angle, as well as between the upstream deviation angle and the ratio of point bar width to looplength. Once the dimensions of the point bar and looplength are established, the upstream and downstream deviation angles can be determined, along with the migration azimuth points. The interlayer distribution pattern of the point bar can then be ascertained through a method of plane-profile interactive comparison. For small-scale architecture, the development proportion law of lithofacies in point bars is clearly discernible based on core data statistics. Subsequently, volume models for both point bars and different lithofacies are established.

Beach bar systems, as significant reservoirs in terrestrial lacustrine basins, have led to notable progress in understanding their formation mechanisms and controlling factors. However, under the complex basin setting during the fault-depression transition period, the distribution patterns, controlling mechanisms, and hydrocarbon exploration potential of different beach bar types remain poorly constrained. This study focuses on the Paleogene Second Member (Es2) in the Zhanhua Sag, Bohai Bay Basin, China, integrating well logs, core data, and 3D seismic interpretation to systematically analyze the sedimentary characteristics, dominant controls, and exploration potential of beach bar deposits. Three types are identified in the Es2: sandstone beach bars, carbonate-dominated beach bars, and clastic-dominated beach bars. Vertically, the scale of these deposits gradually increases from Part 4 to Part 1, while laterally, their distribution follows a tripartite coupling mechanism involving windfield, sedimentary sources, and basin structure: northeast-trending windfields drive wave action to form northwest-southeast-oriented beach bars; sediment supply intensity determines beach bar lithology (sandstone-dominated in high-supply zones vs. carbonate-dominated in low-supply zones); and the unique basin structure (steep slope-deep water-gentle slope) during the fault-depression transition controlled spatial differentiation. Reservoir characterization shows high porosity (25 %-30 %) but low permeability (20-50 mD), with 2-6 m thick sandy bars serving as prime exploration targets. In particular, stacked beach bars interbedded with mudstone seals in the southern gentle slope exhibit superior hydrocarbon accumulation conditions. These findings elucidate the genetic mechanisms of beach bars during a tectonic transition and their hydrocarbon enrichment patterns, providing critical geological references for lithologic reservoir exploration in analogous basins.

The upper Paleozoic gas reservoir in the Daniudi gas field, Ordos Basin, is one of the typical tight sandstone gas reservoirs in China. Research into the sequential order of reservoir densification and gas accumulation is the key to revealing the formation mechanism of tight sandstone gas reservoirs. However, this scientific issue is still a subject of debate in the Daniudi gas field. Based on a series of reservoir experiments and in combination with stratigraphic burial and thermal maturity history, a comprehensive study is conducted on the formation and natural gas accumulation processes of the upper Paleozoic sandstone reservoir in the Daniudi gas field. Study results indicate that the main causes of sandstone reservoir densification of the study area include long-term compaction, multistage quartz cementation and carbonate cementation. In accordance with the time order of reservoir densification and gas accumulation, the formation of tight gas reservoirs can be divided into two types: self-sourced and near-source accumulations. In the former, before sandstone reservoir densification occurs, low-maturity natural gas generated from coal rocks and dark mudstones enter the reservoir quickly, migrate towards structural highs as driven by buoyancy, and then accumulate and form gas reservoir in favourable lithologic traps. In the latter, after tight sandstone reservoirs are formed, high-maturity gas migrates along fractures formed in the Late Cretaceous and accumulate in the nearby reservoir with micro-fractures. The study results provide a new understanding of the formation process of tight sandstone gas reservoirs and provides a reference for the exploration and development of the same type gas reservoirs.

The residual oil in the fluvial reservoir of Gudong Oilfield is still widely developed even after decades of development. In order to explore the remaining oil in the subsurface fluvial reservoir, we need to have a better understanding on fluvial sandbody characteristics. This paper aims to demonstrate how to quantify anatomy on meandering fluvial architecture. Sedimentologic data from core descriptions of Guantao Formation in Gudong Oilfield were used to identify architectural elements. The upper Guantao Formation consists of ten lithofacies composing five different types of architectural elements. By integrating the available core, well logs, and seismic data, the fluvial sandbody distribution was analyzed. To characterize the fluvial channel geomorphology, we used seismic inversion to explore the stratigraphic correlation and stacking patterns of different channels, and the sandbody isopach map was obtained by the sandbody thickness in each layer. The architectural elements distribution in the plane was mapped by the sandbody isopach map and its profile characteristics. According to the investigation of meandering fluvial outcrops, subsurface meandering fluvial seismic geomorphology, and modern river morphology, the upstream-bar portions are always eroded because of the downstream channel migration. Statistics on the morphometric parameters (bar width/looplength, upstream deflection angle, downstream deflection angle, etc.) of modern meandering river (Ob River) were obtained from the Google Earth. It is found that the bar width/looplength and upstream deflection angle, upstream deflection angle and downstream deflection angle in modern meandering river have a good relationship, and we can have a quantitative architectural characterization on the point bar. This study quantified lithofacies thickness and proportion in different architectural elements of Guantao Formation, which ensures a high resolution anatomy on the small scale architecture. By using this method, the lithofacies proportion in each architectural element was computed, and through the statistics of architectural elements proportion in the Gudong Oilfield, the different lithofacies proportions in the block 6 can be computed.

In order to extract the remaining oil from the reservoir during the late stage of development, there is an increasing demand for precise research on the internal architecture of the reservoir. In this paper, the meandering fluvial hierarchy architecture of the Guantao Formation in Gudong Oilfield is quantitatively characterized through the integration of core, well logging, seismic data, and modern river analysis. The quantitative characterization of these elements was achieved by utilizing the modern fluvial geomorphology relationship formula and a dense well array control. The models for the relationship between point bar length and width, as well as width and thickness, have been established. The investigation of modern meandering fluvial geomorphology shows that the point bar mostly undergoes downstream migration during lateral processes. In this context, geomorphologic parameters such as lateral azimuth point, upstream deviation angle, and downstream deviation angle are proposed to quantitatively characterize the architecture of point bars. Statistical regression analysis of modern fluvial point bar geomorphologic parameters reveals a strong correlation between the upstream deviation angle and downstream deviation angle, as well as between the upstream deviation angle and the ratio of point bar width to looplength. Once the dimensions of the point bar and looplength are established, the upstream and downstream deviation angles can be determined, along with the lateral azimuth point. The interlayer distribution pattern of the point bar can then be ascertained through a method of plane-profile interactive comparison. For small-scale architecture, the development proportion law of lithofacies units in point bars is clearly discernible based on core data statistics. Subsequently, volume models for both point bars and different lithofacies units are established.

Beach bars are important reservoirs and have good exploration potential in several petroliferous basins globally. At present, we urgently need to make a further study on beach bars based on previous studies to promote the process of oil and gas exploration and development, regardless of modern or ancient sedimentation. Using satellite maps, research achievements of predecessors and theoretical analysis as our references, we selected four typical areas of beach bars. Based on field surveys and core observations, we tried to divide beach-bars into three types, corresponding to five architectural units. We applied manual and machine learning recognition to categorize the architectural units observed in the study areas. Based on the sedimentary and environmental characteristics of architectural units, we summarized the sedimentary evolution stages and established the sedimentary models of each beach bar. The results indicated that the beach bars could be divided into shore beaches, submerged beaches and bars, based on different sedimentary and environmental characteristics. The shore beach includes the backshore and part of the foreshore (swash zone). The submerged beach has a swamp, part of the foreshore (except the swash zone) and the shoreface. Bars may appear anywhere on the shore-shallow sea/lake. The architectural units of beach bars were divided into five subtypes, corresponding to four evolutionary stages based on hydrodynamic traits and the sedimentary environment. Additionally, a discrimination standard was established based on principal component analysis and Bayesian discrimination on the Shahejie Formation of the Dongying Depression while using fine-scale recognition to verify the units. The coincidence between manual recognition and machine recognition results was 94.8%. We hope that our methodology and models will help address the limitations in previous studies on beach bar reservoirs and will help promote improvements in the related theories and optimization of their exploration and development.

为明确东营凹陷北部盐22区块沙四上亚段砂砾岩沉积特征及空间演化规律,结合岩心观察、FMI成像测井资料、测井及地震资料,对研究区岩相组合类型、分布特征及演化规律进行了深入分析.结果表明:研究区沙四上亚段发育近岸水下扇沉积,根据成像测井及岩心资料划分了砾岩相、砂岩相和泥岩相三大类岩相类型及6种岩相组合类型,建立了研究区砂砾岩扇体早期退积—晚期进积的发育演化模式.整体上,东营凹陷北部盐22区块沙四上亚段近岸水下扇发育演化受古气候变化、事件性重力流、湖水位变化及构造活动共同控制.研究结果为研究区扇体内部的砂体发育规律研究及油气勘探开发提供了地质依据.

东营凹陷永北地区砂砾岩油藏储量丰富,然而由于储层非均质性强、沉积期次划分和砂体分布样式研究不够精细,影响了该区油藏评价与开发.综合运用岩心、测录井、地震等方法,建立研究区沙四上亚段砂砾岩储层构型的分级方案,总结了构型单元类型及其特征,井震综合刻画了4～5级构型单元的空间分布样式.其中8砂组主要发育近岸水下扇舌状体构型单元,辫状沟道砂砾岩整体呈退积式交错叠置分布;7砂组主要发育扇三角洲朵叶体,水下分流河道呈进积式冲刷切割与叠置分布.研究成果可为同类型地区的油藏评价与开发生产提供重要指导.

河流相储层内部隔夹层研究对其储层内部构型表征及剩余油挖潜具有重要指导作用.本文以沾化凹陷孤东油田六区为例,基于岩心、测井资料,对远源砂质辫状河的单井、连井以及平面发育特征进行了分析;基于沉积微相控制和岩心、测井标定,对不同层次的隔夹层进行了识别以及特征描述;基于密井网的约束对心滩内部夹层的规模与产状进行了表征.结果 表明:单层间夹层多是物性夹层,单砂体之间夹层包括泥质夹层与泥砾夹层,增生体之间的夹层为落淤层,落淤层宽度为80～400 m,长度为350～1 630 m,落淤层在滩头倾角约为2.03°,在滩尾倾角为1.28°,在两翼倾角为1.58°.利用界面约束方法,对储层内部夹层进行了构型建模,建立了一套能够进一步深度表征辫状河内部非均质性的构型模型.

Alluvial fans in humid regions are different from arid alluvial fans for the special sedimentary characteristics and distribution pattern. In this paper, we systematically studied the sedimentary facies of Jurassic Badaowan Formation in the northern margin piedmont belt of Junggar Basin based on the comprehensive analysis of geological and geophysical data acquired. The results show that under the comprehensive influences of tectonic setting, paleo-provenance and paleo-climate, large-scaled humid alluvial fans are developed in the piedmont belt of Hala'alt mountain. The fluvial activity of alluvial fan is stronger and more stable in the humid type than that in the arid type. Three subfacies are identified in the humid alluvial fan, i.e. the upper fan, middle fan and lower fan. The middle fan can be further divided into braided river channel and the peat bog. Then we build the sedimentary facies model based on the microfacies types and distributions. This model is significantly different from arid alluvial fan in lithologic features, sedimentary sequences, distribution scales and microfacies match patterns. The reservoir distribution is mainly controlled by the favorable microfacies, lithofacies and depositional fabric. We suggest that the braided river channel glutenite lithofacies and grit lithofacies in the middle fan subfacies are the most favorable reservoir facies belt for hydrocarbon accumulation.

The Upper Paleozoic sedimentary succession in the Ordos Basin, Norther China, contains typical tight gas sandstones. Densification process and diagenetic evolution of these sandstones are poorly known but are important for exploration of reservoirs. Herein, petrographic features of these rocks are described by using scanning electron microscopy (SEM) and cathodeluminescence. In addition, inclusions in quartz overgrowth and calcite cementation are examined with homogenization temperature measurements, and Raman spectroscopy. The sandstones are mainly quartz sandstone, lithic quartz sandstone and lithic sandstone, with a medium to coarse grain size and good sorting. The reservoir properties are quite poor, with low porosity and permeability. Densification of the Upper Paleozoic sandstones are attributed to long-term mechanical compaction and multi-stages of siliceous and calcite cementations. Moreover, the quartz dissolution due to the presence of alkaline fluid forms intragranular and intergranular pores, thus providing the main space for the sandstone reservoirs. During the diagenetic evolution, tight sandstone reservoirs have experienced various stages of rapid burial and strong compaction, alternate acidic and alkaline actions, formation of reservoirs, uplifting and rework, with great differences between these stages in mineral assemblage and reservoir physical property. Massive hydrocarbons were generated following Stage II of quartz overgrowth in which the number of quartz dissolved pores substantially increased because of more intensive alkaline dissolution. The hydrocarbons preferably flow into the reservoir strata with better properties, thus forming tight sandstone gas reservoirs.

青年教师教学能力的培养与提升，对于大学专业课程教学质量的提高具有重要的意义，而青年教师教学比赛是促进青年教师成长与发展，提高教学质量和教学水平的有效途径。本文结合山东省高校青年教师教学比赛的参赛经历，从比赛意义、材料组织、参赛细节等方面阐述心得体会，并从“以赛促教”提升青年教师课堂组织能力、提高教学效果等方面展开论述，为青年教师打造属于自己的精品专业课堂提供一些思路。

Fluvial facies sand bodies are important reservoirs for oil and gas resources. In this study, the sedimentary characteristics and evolutionary patterns of braided and meandering fluvial deposits in the Neogene Guantao Formation of the Zhanhua Sag, Bohai Bay Basin were analyzed using cores, well logs and three-dimensional seismic data, and the quantitative information of the sand bodies in different fluvial deposits were characterized with dense well-net constraints. Through the calibration between the core and wireline logging data, the developmental characteristics of the sand bodies in the braided and meandering deposits were clearly defined base on single-well sedimentary microfacies interpretation templates. Composite fluvial channel sand body facies associations develop in braided fluvial or high-sinuosity meandering fluvial deposit, and single fluvial channel sand body facies associations develop in a mid-sinuosity meandering fluvial deposit. The fluvial sedimentary evolutionary model was established based on the reconstruction of sedimentary characteristics. Factors such as the relative sea or lake level, climate, and tectonics control the change of the river. During the late period of Guantao Formation deposition, the tectonic movement tended to be stable; thus, climate change was the most important factor in the fluvial style change and the lake level rise also showed an influence. There is a positive correlation between the width and thickness of the braided fluvial channels and the mid-sinuosity meandering fluvial channels; however, this is relatively poor for the high-sinuosity meandering fluvial channels.

为探讨压汞法在煤孔隙研究过程中的适用性和局限性,以褐煤、气肥煤、瘦煤、无烟煤4种不同煤级以及无烟煤的4种不同粒度煤样品为研究对象,通过对压汞数据的分形维数特征讨论认为:煤的压汞过程可以明显分为前进汞阶段、进汞阶段以及后进汞阶段3个阶段.结果 表明,在应用压汞仪对煤样品进行孔隙分析及数据处理时,不能直接进行煤的全孔径分析,而应充分考虑到前进汞阶段和后进汞阶段对压汞数据的影响.

孤东油田馆上段54—68小层为辫状河沉积,储层内部结构复杂.该油田面临综合含水率特高、剩余油高度分散、稳产难度大等问题,开展储层层次结构的精细解剖是解决该问题的关键.为此,以心滩内部的精细构型表征为切入点,通过对砂体内部结构单元的解剖,分析孤东油田六区馆上段远源砂质辫状河心滩构型,以明确砂质辫状河储层内部不同级别的构型特征.采用密井网精细对比的方式,实现了对砂质辫状河心滩内部增生体规模的定量表征;确定了心滩宽度、长度及厚度等4级构型单元的参数范围,其中心滩宽度为100～350 m,长度为400～500 m,厚度为4～12 m;明确了心滩长度与宽度呈正相关,宽度与厚度呈近似正相关.确定了落淤层与增生体等3级构型参数分布特征,落淤层在滩头、滩尾及两翼平均倾角分别为0.93°,0.53°和1.47°,长轴方向的心滩内部单一增生体的长度为280～800 m,宽度为165～400 m,估算落淤层长度为250～700 m,宽度为150～350 m.

本文总结了近8年来对本科留学生开设地质学基础实验全英文课程授课探索与实践的经验体会.结合外国留学生的实际情况和特点,对全英文实验教学拟订了“三个模块、三个结合、多方位考核”为一体的教学体系,该体系兼顾了专业基础—实践能力—科研意识的一体化培养,有效地激发了学生的兴趣点,提高了教学质量.