The organic-rich shale of the Lower Cambrian Shuijingtuo Formation in the Yangtze area is considered a high-quality source rock in South China. Geochemical proxies are used to reveal the formation and preservation conditions of the Shuijingtuo shale in Yichang in the middle Yangtze area. Geochemical proxies for paleoredox (U/Th, V/Cr, Ni/Co, and U-EF versus Mo-EF), paleoproductivity (Ba/Al, Cu/Al, and Ni/Al), and terrigenous influx (Al and Ti) have been employed to interpret the mechanism of organic matter (OM) accumulation. The total organic carbon (TOC) contents of the Shuijingtuo shale is between 0.19 wt% and 4.77 wt% (with an average of 1.38 wt%). The shale can be divided into two intervals based on TOC content, the lower interval with high TOC (TOC >2 wt%) and the upper interval with low TOC (TOC <2 wt%). The results of the geochemical proxies show that the lower interval shale was formed in an anoxic setting with fair paleoproductivity and relatively low terrigenous influx. The upper interval shale was deposited mainly under oxic conditions, with gradually enhanced oxidation, decreased productivity, and relatively high terrigenous influx compared to the lower interval shale. The water mass inferred by the Mo/TOC ratios was a restricted environment with episodic upwelling in the lower interval. The TOC contents display a positive correlation with both the paleoredox and paleoproductivity proxies, indicating that anoxic/dysoxic and high productivity favored OM accumulation. The Co x Mn versus Cd/Mo relationship also suggests that the OM accumulation is chiefly determined by preservation in a restricted environment. These data indicate that the redox condition acts as the dominant factor for OM accumulation. A depositional model is proposed that emphasizes the importance of preservation for OM accumulation of this shale.

The organic-rich shale of the Lower Cambrian Shuijingtuo Formation is an important hydrocarbon source rock in South China. The geochemical characteristics of this shale were investigated to determine the provenance, weathering conditions, sedimentary recycling, paleoclimate, and tectonic setting of the Shuijingtuo Formation in Yichang in the Middle Yangtze area. The shale is relatively enriched in CaO, P2O5, Mo, U, V, Cd, and Cu. The rare earth element (REE) patterns of the shale exhibit light rare earth element (LREE) enrichment and heavy rare earth element (HREE) depletion. It has weak negative Eu and Ce anomalies, which are similar to the characteristics of passive margin deposition. The analysis of the carbonate dilution effect conducted in this study reveals that carbonate dilution has a greater effect on the MgO, Ba, Sc, and Zr contents. The provenance discrimination diagrams suggest that the shale is primarily derived from a mixture of intermediate and felsic igneous source rocks, which were similar to Tonalite-trondhjemite-granodiorites (TTGs) in composition. The chemical index of alteration (CIA) values and the A–CN–K ternary diagram indicate that the source area of the shale experienced a low degree of chemical weathering under a cold and arid climate in the early period and a moderate degree of chemical weathering under a warm and humid climate in the later period. The relationship between Zr/Sc and Th/Sc indicates that the shale was deposited by the first cycle of sedimentation rather than via reworking. The discriminant function diagrams, major element ratios, immobile trace element ratios, and ternary relationships between La, Th, Sc, Zr, and Co indicate that the source rocks were deposited in a passive margin tectonic setting. It is suggested that the Ezhong old land, which is predominantly composed of the Huangling granite and the Kongling complex (composed of intermediate and felsic igneous rocks) was the source area.

泥盆系佘田桥组泥岩是南方页岩气勘探重点层位之一.为揭示湘中坳陷邵阳凹陷佘田桥组泥岩岩相特征及其发育控制因素,基于系统岩心描述、矿物组分和地球化学采样及测试,对邵阳凹陷佘田桥组泥岩岩相类型、沉积环境特征及其对岩相发育的控制进行了研究,探讨沉积环境演化对岩相类型发育的控制作用.结果表明,佘田桥组泥岩依据矿物组分含量主要识别出硅质泥岩、混合质泥岩、硅质岩、钙质泥岩4种岩相类型,进一步垂向上可划分为5个岩相组合段.岩相组合段Ⅰ和Ⅲ相对富硅质,而组合段Ⅱ、Ⅳ和Ⅴ钙质含量相对较高.沉积环境分析表明佘田桥组泥岩形成于大陆边缘背景;主要处于相对干热气候条件,其中在早期和中期发育相对温湿气候,中期时相对最为温暖潮湿;海平面先上升后下降;中段泥岩中具有过量硅富集特征,主要为生物成因,而受热液作用影响较小;陆源碎屑输入相对较为稳定,在中期时相对最低.沉积环境演化和岩相发育之间的响应关系表明,岩相的发育主要受到古气候、陆源碎屑供给、海平面变化和生物作用等的综合控制,泥岩硅质组分主要来自陆源碎屑输入,生物作用富硅造成了中段硅质富集,而后期当气候向干热转化时,钙质组分增加,泥岩岩相向富钙方向演化.

Based on the sedimentological and geochemical analysis of total organic carbon (TOC) and major and trace elements in the marine Upper Ordovician-Lower Silurian Wufeng-Longmaxi Formations in Yichang, Central Yangtze area, paleoredox conditions (indicated by U/Th, V/Cr, Ni/Co, TOC-TS-Fe diagram, and Mo-U covariations), paleoproductivity (indicated by Ba-bio, Ba/Al, P/Ti, Ni/Al, Cu/Al, and Zn/Al), terrestrial detrital influx (indicated by Ti and Al), paleoclimate (indicated by chemical index of alteration and Rb/Sr), and upwelling (indicated by Co x Mn) are revealed within the framework of sea-level changes. The influences of these factors on organic matter enrichment are also discussed. The results identify four third-order sequence boundaries in the Wufeng-Longmaxi Formations; each sequence can be divided into one transgressive systems tract (TST) and one regressive systems tract (RST) according to sea-level changes. The high-TOC interval mainly developed in TST1 (average 3.44%) and TST2 (average 3.68%). The analysis of geochemical indicators shows that during the TST1 depositional stage, the climate was dry and cold, the bottom water was in a stable anoxic condition accompanied by rising sea level, and the seawater had moderate-high paleoproductivity. In the RST1 stage, extensive sea-level fall occurred, and the water was anoxic, with decreased productivity and weakened organic matter accumulation. In the TST2 stage, the sea level rise rapidly, extensive anoxicity and high productivity of the water produced the most ideal environment for organic matter enrichment and the highest TOC. In the RST2 stage, sea level slowly fell, the water column gradually became a stable oxidized environment, productivity was low, the terrestrial detrital influx increased and tended to stabilize, and the climate gradually changed to warm and humid conditions, forming relatively organic-poor shale. The upwelling mainly developed during the period of TST1 to TST2, and ceased in the RST2. The correlation analysis between TOC and the above indicators and the Co x Mn versus Cd/Mo diagram show that TOC is chiefly controlled by paleoredox, paleoproductivity, climatic conditions, and terrestrial detrital influx, indicating that preservation conditions are the crucial factor. Sea-level change played a key role in preservation conditions. In the transgression stages, sea-level rise led to the enhancement of reducing water, which controlled the organic matter enrichment in shale.

A reliable and effective model for reservoir physical property prediction is a key to reservoir characterization and management. At present, using well logging data to estimate reservoir physical parameters is an important means for reservoir evaluation. Based on the characteristics of large quantity and complexity of estimating process, we have attempted to design a nonlinear back propagation neural network model optimized by genetic algorithm (BPNNGA) for reservoir porosity prediction. This model is with the advantages of self-learning and self-adaption of back propagation neural network (BPNN), structural parameters optimizing and global searching optimal solution of genetic algorithm (GA). The model is applied to the Chang 8 oil group tight sandstone of Yanchang Formation in southwestern Ordos Basin. According to the correlations between well logging data and measured core porosity data, 5 well logging curves (gamma ray, deep induction, density, acoustic, and compensated neutron) are selected as the input neurons while the measured core porosity is selected as the output neurons. The number of hidden layer neurons is defined as 20 by the method of multiple calibrating optimizations. Modeling results demonstrate that the average relative error of the model output is 10.77%, indicating the excellent predicting effect of the model. The predicting results of the model are compared with the predicting results of conventional multivariate stepwise regression algorithm, and BPNN model. The average relative errors of the above models are 12.83%, 12.9%, and 13.47%, respectively. Results show that the predicting results of the BPNNGA model are more accurate than that of the other two, and BPNNGA is a more applicable method to estimate the reservoir porosity parameters in the study area.

The formation and preservation conditions of the organic matter (OM) in the Upper Devonian Shetianqiao Formation were investigated to assess the mechanism of the OM enrichment in the shale in the Shaoyang sag. The total organic carbon (TOC) contents of the shale range from 0.2% to 4.4%. The shale can be divided into three intervals. The terrestrial input during Interval 2, as indicated by the Al2O3 and Ti proxies, was relatively small. The chemical alteration index (CIA) shows that the Shetianqiao Formation mainly formed in a warm and humid climate, however, climate cooling occurred in Interval 2. Intervals 1 and 3 were mainly deposited in a restricted environment, whereas Interval 2 experienced upwelling. The climate cooling may have been the driver for the upwelling. The UEF, MOEF, and Mo-U covariation diagrams indicate that Interval 2 was mainly deposited under reducing conditions, whereas Intervals 1 and 3 were chiefly formed in an oxidizing environment. The Cu/Al ratios and excess Si (Si-xs) suggest that Interval 2 was formed in significantly higher marine productivity than Intervals 1 and 3. The plot of Co (ppm) x Mn (%) versus Cd/Mo, the logarithmic relationship between Co (ppm) x Mn (%) and TOC, and the good correlations between TOC and the productivity proxies suggest that productivity was the primary factor for the OM enrichment. We constructed a depositional model that emphasizes the control of productivity driven by upwelling on the OM enrichment.

高等学校开设《海洋科学导论》公选课对于提高全民海洋意识、服务国家海洋强国战略具有重要意义.文章从中国地质大学《海洋科学导论》公选课课程建设实践出发,分析了该课程主要特点,提出了高校开设此课程的重要意义,论述了具体的教学内容和教学形式.最后讨论了该课程教学改革的主要途径,包括:采用多媒体教学、视频教学、虚拟仿真教学相结合的形式,将抽象的知识形象化;采用案例教学的形式,启发学生自主思考;由多名教师共同完成课程教学,深入浅出;课堂中强化海洋强国和保护海洋意识.通过这些改革措施,有利于激发学生兴趣,有效提高教学质量.

2019年中国地质大学(武汉)参与了9校联合实习——"长江口及邻近海域海洋科学联合实习活动".此次活动涵盖海洋科学下设的海洋物理、海洋化学、海洋生物和海洋地质四个二级学科,非常成功.联合实习是极佳的实践教学形式,6届自然地理学、地质学以及前5届海洋科学的联合教学实践诠释了其价值所在.联合实习不但共享资源和优势互补,而且突破学科壁垒,拓展了学生的思维.联合实习对于推动学科发展、提升实践教学水平具有重要的科学价值.

依据鄂西宜昌地区五峰组-龙马溪组页岩X射线衍射全岩分析、X射线衍射黏土矿物分析、物性分析、含气性测试和地球物理测井等资料,对区内页岩储层发育特征和页岩脆性特征进行了研究和综合评价.结果表明:宜昌地区五峰组-龙马溪组页岩依次主要由石英、黏土矿物、长石、白云石、方解石、黄铁矿等组成;具有自底部"高硅、低黏土"页岩向上过渡为"低硅、高黏土"页岩的发育特征.页岩孔隙度主要为1.01％～1.77％,平均1.29％,渗透率主要为0.001×10-3～0.843×10-3μm2,平均0.234×10-3μm2,属于低孔特低渗储层;五峰组-龙马溪组下部页岩含气量普遍大于1 m3/t,厚度可达20 m.脆性矿物含量法脆性分析结果显示,页岩脆性指数分布于39.6％～89.6％之间,平均55.4％,其中底部10 m厚的页岩脆性指数均大于60％,利于储层压裂改造后形成复杂的裂缝网络系统.弹性参数法脆性分析结果显示,五峰组-龙马溪组页岩杨氏模量主要为25.2～67.5 GPa,平均38.9 GPa;泊松比主要为0.177～0.327,平均0.297;脆性指数主要介于8.5％～97.3％之间,平均33.2％;其中底部13 m厚的页岩具有典型高杨氏模量、低泊松比和高脆性指数的特征.页岩脆性综合评价结果表明,五峰组-龙马溪组底部9m厚的页岩发育相对最优杨氏模量和泊松比条件,脆性属于中-高等程度,造缝能力强,可压裂性好.将页岩段划分为4类可改造储层,其中底部2714.4～2723.4 m段页岩具有泊松比相对最小、含气性最好、脆性最优和有机质含量高等特征,构成研究区最优改造层段.

西湖凹陷砂岩储层具有砂体厚度薄、砂泥互层发育以及横向变化快的特点,传统的地球物理方法很难精细地刻画砂体空间分布.将层序地层学与地质统计学反演相结合,在建立等时地层格架的基础上,构建相应的地球物理模型,在正确的沉积学理论指导下,对西湖凹陷平湖斜坡带平湖组砂岩储层开展砂体的时空分布预测研究.研究结果表明,平湖组可划分出3个三级层序,下部砂体单层厚度较大,横向连续性好,平面连片发育;中部以泥岩为主,砂体孤立发育,连续性差;上部砂体增多,单层厚度较薄,横向连续性好.结合钻井实际资料分析表明,砂体预测结果垂向分辨率可以达到1～2 m.地质统计学反演有效解决了西湖凹陷平湖斜坡带薄层砂体识别的难题,可为研究区有利储层预测提供重要支撑.

基于钻井岩心资料,对贵州岑巩区块下寒武统变马冲组黑色页岩取心段进行系统采样、主微量元素测试及沉积地球化学分析.研究结果表明:1)古盐度判别指标Sr/Ba及Rb/K分布显示,下寒武统变马冲组黑色页岩沉积时期属局限海背景 下的半(微)咸水—淡水相沉积,变马冲组一段—三段古盐度垂向变化不大;Sr丰度与碳酸盐矿物含量之间具明显的响应关系;2)古氧相指标V/Cr、Ni/Co、U/Th比值及δU值分布表明变马冲组黑色页岩沉积为氧化为主、间或贫氧的环境,V/(V+Ni)比值判别偏于还原环境;3)古气候判别参数"C"、Sr/Cu及SiO2/Al2O3比值表明该套页岩沉积期主体属温湿气候,利于有机质形成;4)古水深及离岸远近判别参数Rb/Zr、Sr/Ba比值分布显示水体较浅、离岸较近的沉积特征,结合物源及沉积构造背景 指征参数分析,变马冲组黑色页岩属大陆边缘离岸较近、水体较浅的陆源碎屑沉积.此研究认识揭示了岑巩区块下寒武统沉积环境的演化,进而为该套黑色页岩的有机质富集机理及页岩气选区评价提供一定的地质依据.

文章首先分析了层序地层学课程教学现状,然后以层序地层学课程为例,基于前沿应用型学科专业课程特性,从理论教学、实践教学和教学考核方式三个方面探讨了前沿应用型专业课程教学方法.

湘中坳陷泥盆系佘田桥组是中扬子地区页岩气勘探的重要层系之一,本文在对钻井岩芯描述、野外露头剖面观测及系统的地球化学采样测试分析基础上,对湘中坳陷邵阳凹陷佘田桥组沉积特征、沉积相类型及沉积环境进行了研究,建立了佘田桥组垂向沉积相序及其沉积环境演化.研究认为,邵阳凹陷内佘田桥组主要发育台缘斜坡相、台间盆地相、台地相及潮坪相沉积,其中过渡相区垂向上发育台缘斜坡相-台间盆地相—台缘斜坡相—局限台地相充填序列,而在相对浅水台地区主要发育潮坪相—台地相—潮坪相沉积序列,表明沉积相横向上变化快,指示邵阳凹陷碳酸盐台地和台间盆地横向相间的沉积格局.垂向演化序列指示水体具有先缓慢加深后逐渐变浅的发育特征,与区域内海平面先上升后下降趋势相一致.镁铝比值指示佘田桥组形成于稳定海水环境,其中在中段相对最大,表明该时期水体相对最深.利用U/Th、U*、V/(V+Ni)、V/Cr指标对环境氧化还原条件进行分析,结果表明台缘斜坡处佘田桥组总体上处于氧化环境,但在中期发育稳定还原环境,反映该时期广泛海侵作用导致的水体变深.依据生物来源Ba及Ba/Al比值分析了佘田桥组沉积期古海洋生产力条件,结果显示生产力具有自下而上逐渐减小的发育规律.综合分析表明,余田桥组地化指标分析结果与沉积相特征及演化具有一致性,水体氧化还原条件构成了有机质富集的主控因素;在佘田桥期中期的广泛海侵作用下,台间盆地相区发育相对最优保存环境和生烃物质条件,构成了区内页岩气勘探最有利层段.

The Upper Devonian Shetianqiao Formation mudstones are considered to be the most petroliferous shale gas source rocks in the Shaoyang Sag of Xiangzhong Depression in China. These Shetianqiao dark mudstones have been collected systematically to investigate their geochemical characteristics by analysing their major elements, trace elements, and rare earth elements (REEs), in order to reveal their provenance, palaeoenvironment and tectonic setting. The results show that the total REEs content (ΣREE) of dark mudstone is 34.22–246.62 ppm (average 131.66 ppm) and characterized by low ΣREE, light rare earth element (LREE) enrichments, negative Eu anomalies, and minor negative Ce anomalies. The normalized distribution pattern of REE, Eu anomaly, as well as discrimination diagrams of trace elements and REEs, are applied to explain the source rock types and properties of Shetianqiao mudstones. The results indicate that the sediments have a weak sedimentary recycling and mainly originated from the upper continental crust, and the source rocks of the black mudstones are mainly constituted by felsic granite. The Ce anomaly, Th/U, V/Sc, V/Cr, and V/(Ni + V) ratios of the dark mudstones suggest a long‐term oxidizing depositional environment interrupted by a short period of a dysoxic/anoxic depositional environment in the middle section of the formation. This short period corresponds to a dramatic marine transgression with relatively high TOC. The La/Ce, LaN/SmN, Ce anomaly, and normalized REE distribution pattern characteristics indicate that the depositional process of the Shetianqiao mudstones has consistently been influenced by the regional upwelling hydrothermal activities. The chemical index of alteration (CIA) and Al2O3‐(CaO* + Na2O)‐K2O triangular plot reveal that a warm and humid climate with moderate chemical weathering in the source areas of the Shetianqiao mudstones occurred during the deposition. The ratio of major elements, trace elements, and REEs are used to analyse the tectonic setting of the depositional area which suggests that the source area is dominated by continental island arc tectonic setting. Combined with the previous regional studies, it is concluded that the continental island arc granite formed by plate collisions in the Caledonian stage constitutes the main source of the Shaoyang Sag during the Shetianqiao period. The depositional environment was not stable due to the lasting influence of deep hydrothermal activities. The upwelling currents controlled by hydrothermal activity transport nutrients to the study area, resulting in the formation of organic‐rich mudstones.

目前,沉积物波的成因还是存在很多争议.通过详细的地震资料解释,发现南海南部海域有一个规模巨大的海底滑坡,滑坡体长达160 km.从剖面上看,滑坡体结构完整,由减损带、加积带、滑阻带、破坏体、滑脱面、滑坡后壁、冠上裂缝、横向裂缝等结构要素组成.在如此低的海底坡度(仅0.3°～0.5°)上形成如此大规模的滑坡体,推测是地震活动触发的.加积带内发育沉积物波.形态特征和剪应力分析显示,沉积物波形成于减损带的推挤作用.加积带中部推力最大,导致下部为逆时针剪切,上部为顺时针剪切.因此,沉积物波属于海底滑坡引起的软沉积物变形.软变形沉积物波是海底滑坡的一种特殊标志,因此这项研究有助于发现海底滑坡,也有助于海底工程的减灾防灾工作.

Based on an integrated investigation of well logging, seismic data, cores and outcrops, the Niubao Formation in the Lunpola Basin was subdivided into one first order sequence, three second order sequences, cor?responding to the first, second and third members of Niubao Formation, and seven third order sequences from base to top, namely SQ1, SQ2, SQ3, SQ4, SQ5, SQ6, and SQ7. Two sequence stratigraphic patterns including faulted slope zone and flexure slope break zone were identified within the sequence stratigraphic framework. There are several exploration targets, including fan deltas on the gentle slope of HST and large?scale low stand fans in the slope break zone of LST in the flexure slope break zone, and high stand braided river deltas and large?scale low stand fans in the slope break zone in the faulted slope zone. A sedimentary model was established through the analyses of spatial and temporal distribution of the sequences. Three main sand bodies developed in the Niubao Formation, namely the northern, southwestern and eastern sand bodies, and their distribution was controlled by the slope break zone.

Based on the applications of thin section, cathode luminescence, scanning electron microscope and X-ray diffraction, this paper studies the reservoir characteristics, diagenesis features and their influences on the development of reservoir pores for the Chang 8 oil group of Yanchang Formation in southwestern Ordos Basin. Results show that the reservoir is characterized by low composition maturity, low structure maturity, low porosity/ultra-low porosity and ultra-low permeability which belong to tight reservoir. The reservoirs develop medium intensity of compaction, moderate to strong cementation, relatively strong dissolution, suggesting that it is in stage B of the middle diagenetic evolution. The main diagenetic types include mechanical compaction, cementation by carbonates, quartz and clay minerals, and dissolution which have directly influenced the reservoir quality. In the early diagenetic period, the rapid compaction and cementation of carbonate had rapidly destroyed the reservoir quality, while the particles lining of chlorites had protected the reservoir space. In the middle diagenetic stage A, secondary dissolution pores were formed as soluble clastic grains were dissolved by the acidic fluid with organic matters maturation. The dissolution has played a constructive role for the pore generation and preservation. In the middle diagenetic stage B, the later compaction and cementation further reduced the reservoir quality. The analysis of pore evolution demonstrates that the initial reservoir porosity is about 30.59%. 16.925% overall porosity is lost through compaction, 11.65% porosity loss is due to cementation, and 6.36% porosity was created by dissolution. Finally, the reservoir is holding 8.375% porosity in present.

Based on the comprehensive analysis of the cores,thin sections,reservoir property and mercury injection data,this work analyzed the characteristics of reservoir structure and control factors of reservoir quality and made classification and evaluation to the Chang 8 oil group tight sandstone reservoirs of Yanchang Formation in the Zhenjing area,southwestern Ordos basin.The results show that Chang 8 sandstone reservoirs have low porosity and extremely low permeability.The reservoirs are characterized by the pore structure of fine-micro pore throat,high displacement pressure and poor sorting,which can be divided into 3 types.The reservoirs of type Ⅰ curve have the best reservoir property of pore permeability.The material basis for the depositions dictated the original porosity and permeability.The distributary channels and subaqueous distributary channels develop the optimal reservoir performance.Compaction and cementation are the main factors to damage the reservoir properties.Dissolutions are constructive factors for the improvement of reservoir properties.Combined with the sedimentary facies and pore characteristics of the reservoirs,the porosity,permeability,pore displacement pressure,median pressure and median pore throat radius were chosen to perform a cluster analysis to classify the reservoir types.The reservoirs of Chang 8 oil group were divided into 3 types.Type Ⅰ is the best reservoirs.Type Ⅲ is the relatively worst reservoirs.The type Ⅰ reservoirs are mainly distributed in the overlapping part of distributary channels and superimposition part of subaqueous distributary channels,where the reservoir quality is the best and the most favorable exploration targets are present.

准噶尔盆地腹部中生界不整合面对于隐蔽油气藏的形成具有重要的意义。在对构造背景深入研究的基础上,依据对钻井岩心、综合录井、地震反射等方面的分析,将不整合界面类型归结为上超/削蚀型、整一/削蚀型、上超/整一型、整一/整一型4种类型。分析了下三叠统上仓房组底界、中侏罗统头屯河组底界、下白垩统吐谷鲁群底界和下侏罗统八道湾组底界4个重要的不整合面特征,认为区内不整合的分布受控于盆地的类型。发现不整合面具有明显的3层结构:界面之上砂砾岩、砂岩层;界面之下的风化粘土层;界面之下的半风化岩石。认为不整合面有助于形成多层系削截型岩性圈闭,同时可以作为油气聚集的遮挡层和储集层。