Research Articles (English)
The technical feasibility of in situ upgrading technology to develop the enormous oil and gas resource potential in low-maturity shale is widely acknowledged. However, because of the large quantities of energy required to heat shale, its economic feasibility is still a matter of debate and has yet to be convincingly demonstrated quantitatively. Based on the energy conservation law, the energy acquisition of oil and gas generation and the energy consumption of organic matter cracking, shale heat-absorption, and surrounding rock heat dissipation during in situ heating were evaluated in this study. The energy consumption ratios for different conditions were determined, and the factors that influence them were analyzed. The results show that the energy consumption ratio increases rapidly with increasing total organic carbon (TOC) content. For oil-prone shales, the TOC content corresponding to an energy consumption ratio of 3 is approximately 4.2%. This indicates that shale with a high TOC content can be expected to reduce the project cost through large-scale operation, making the energy consumption ratio after consideration of the project cost greater than 1. In situ heating and upgrading technology can achieve economic benefits. The main methods for improving the economic feasibility by analyzing factors that influence the energy consumption ratio include the following: (1) exploring technologies that efficiently heat shale but reduce the heat dissipation of surrounding rocks, (2) exploring technologies for efficient transformation of organic matter into oil and gas, i.e., exploring technologies with catalytic effects, or the capability to reduce in situ heating time, and (3) establishing a horizontal well deployment technology that comprehensively considers the energy consumption ratio, time cost, and engineering cost.
The Qingshankou Formation shale oil in the Gulong Sag is an important oil and gas reservoir in the Daqing oilfield, with geological resources of 15.1 billion tons. The fabric of shale can reflect not only its genesis but also the nature of the reservoir space, its physical properties, oil content, and development value. Here, the characteristics of clay minerals in the Gulong shale oil reservoir were studied via electron microscopy, with the primary focus on the microfabrics and reservoir space; thereafter, the in situ accumulation was studied and discussed. Electron backscattering patterns revealed that nanometer pores and fissures were well developed in the Gulong shale oil reservoir. The nano pores were mostly 20-50 nm in diameter (median 20-30 nm), irregularly shaped, mostly, polygonal, and connected with nanofissures. The widths of nanofissures ranged mostly between 10-50 nm (median 20-30 nm); moreover, these fissures were mainly formed by F-F condensation of clay sheets (clay domains). The coagulation of clays was closely related to organic matter, especially algae. The clay colloids were negatively charged due to isocrystalline replacement; hence, metal cations were absorbed around the clay, forming a positive clay group. The positively charged clays subsequently adsorbed negatively charged humic acid (organic matter) and initially degraded algae to form an organic clay flocculant. When the organic clay flocculates reached the threshold for hydrocarbon generation and expulsion, the volume of organic matter decreased by 87%; thereafter, the generated and expelled hydrocarbon filled the nearby pores formed by this contraction. Moreover, the discharged hydrocarbon could not migrate due to capillary resistance (~12 MPa) of the nanopores; hence, the nanopores formed a unique continuous in situ reservoir within the Gulong shale oil. This study demonstrated that the Gulong shale oil reservoir is an actual clay-type shale reservoir with numerous nanopore and fissures. During coagulation, a large amount of organic matter (including layered algae) was absorbed by the clay, forming an organic clay condensate that could have provided the material foundation for hydrocarbon generation at a later stage. Thermal simulation experiments revealed that the volume of organic matter decreased sharply after hydrocarbon generation and expulsion.
Successful breakthroughs have been made in shale oil exploration in several lacustrine basins in China, indicating a promising future for shale oil exploration and production. Current exploration results have revealed the following major conditions of lacustrine shale oil accumulation: (1) stable and widely distributed shale with a high organic abundance and appropriate thermal maturity acts as a fundamental basis for shale oil retention. This shale exhibits several critical parameters, such as total organic carbon content greater than 2%, with optimal values ranging from 3% to 4%, kerogen Ⅰ and Ⅱ1 as the dominant organic matter types, and vitrinite reflectance (Ro) values greater than 0.9% (0.8% for brackish water environments). (2) Various types of reservoirs exhibiting brittleness and a certain volume of micro-nanoscale pores are critical conditions for shale oil accumulation, and these reservoirs have porosities greater than 3% to 6%. Moreover, when diagenesis is incipient, pure shales are not favorable for medium-to-high maturity shale oil enrichment, whereas tight sandstone and hybrid rocks with clay content less than 20% are favorable; however, for medium-to-late-stage diagenesis, pure shales with a clay content of 40% are favorable. (3) The retention of a large amount of high-quality hydrocarbons is the factor that best guarantees shale oil accumulation with good mobility. Free hydrocarbon content exceeding a threshold value of 2 mg/g is generally required, and the optimum value is 4 mg/g to 6 mg/g. Moreover, a gas-oil ratio exceeding a threshold value of 80 m3/m3 is required, with the optimal value ranging from 150 m3/m3 to 300 m3/m3. (4) High-quality roof and floor sealing conditions are essential for the shale oil enrichment interval to maintain the overpressure and retain a sufficient amount of hydrocarbons with good quality. Lacustrine shale oil distributions exhibit the following characteristics: (1) major enrichment areas of shale oil are located in semi-deep to deep lacustrine depositional areas with external materials, such as volcanic ash fallout, hydrothermal solutions, and radioactive substances with catalytic action, as inputs; (2) intervals with “four high values and one preservation condition” govern the distribution of shale oil enrichment intervals; and (3) favorable assemblages of lithofacies/lithologies determine the distribution of enrichment area. According to preliminary estimates, China has 131×108 to 163×108 t of total shale oil resources with medium-to-high thermal maturity, among which 67×108 to 84×108 t is commercial. These resources are primarily located in the Chang 71+2 interval in the Ordos Basin, Qing 1+2 members in Gulong sag in the Songliao Basin, Kongdian and Shahejie formations of Cangdong sag, Qikou sag and the Jiyang depression in the Bohai Bay Basin, and Lucaogou Formation in the Junggar Basin.
The buried hill in the Jizhong depression contains abundant petroleum reserves and are important production areas. The Ordovician buried hill has restricted the discovery of new oil and gas exploration targets because of its strong reservoir heterogeneity and complex reservoir-controlling factors. Based on a large volume of core, thin section, logging, seismic, and geochemical data and numerous geological analyses, the reservoir-forming conditions and modes were systematically analyzed to guide the exploration and achieve important breakthroughs in the Yangshuiwu and Wen’an slope buried hills. The study revealed that three sets of source rocks of the third and fourth members of the Shahejie Formation from the Paleogene and Carboniferous-Permian were developed in the Jizhong depression, providing sufficient material basis for the formation of buried hill oil and gas reservoirs. The reservoir control mechanism involving the three major factors of “cloud-karst-fault” was clarified, and karst cave, fracture fissure-pore, and cloud pore type reservoir models were established, thereby expanding the exploration potential. Controlled by the superposition of multi-stage tectonic processes during the Indosinian, Yanshanian, and Himalayan, two genetic buried hill trap types of uplift-depression and depression-uplift were formed. Based on the analysis of reservoir-forming factors of the Ordovician buried hill, three buried hill oil and gas reservoir-forming models were identified: low-level tectonic-lithologic composite quasi-layered buried hill, medium-level paleo-storage paleo-block buried hill, and high-level paleo-storage new-block buried hill. Comprehensive evaluations indicate that the reservoir-forming conditions of the low-level tectonic-lithologic composite quasi-layered buried hill in the northern portion of the Jizhong depression are the most favorable and that the Sicundian and Xinzhen buried hills are favorable areas for future exploration.
通过贝加尔裂谷系统北穆伊斯克(Severomuysk)段的密集地震台站线性网络获得的远距离强震记录,并利用P波接收函数技术,揭示了地壳和上地幔顶部的复杂分层块状结构。横波速度的分布表明构成北穆伊斯克地壳的地块具有不同性质。这些地块的西部聚散和地壳下部的分层证实了该地区隆起的堆积-碰撞起源。位于西伯利亚克拉通变薄的倾斜边缘上的北穆伊斯克段解释了该地区地壳碰撞效应的强度。2015年地震的震中深度与Muyakan 凹陷地壳上部的明显速度差异存在令人信服的相关性。
Well known for its abundant and extraordinary soft-tissue fossils, the Chengjiang fauna has witnessed the main phase of the Cambrian explosion and the first great congress of the ancestors of nearly all major phyla of animals on Earth. The large-scale survey and exploration of the fauna by Chinese paleontologists, partly in collaboration with international scientists, over the past 30 years can be broadly divided into three stages. In the first decade since 1984 (1984-1994), a large number of invertebrates, including basal animals and the protostomes of the early animal tree were discovered, but the subkingdom Deuterostomia was completely unknown. Then in the second decade (1995-2005), the great discoveries of various deuterostomes led to the construction of the basic framework of the Deuterostomia and then to the formation of the tripartite phylogenetic trees of early animals (TPTEA, including basal animals, protostomes and deuterostomes), for the first time. In the third decade (after 2005), the academic community began to think about the internal relationships between the formation of TPTEA and the multi-episode Cambrian explosion, leading to the new hypothesis of the three-episode Cambrian explosion. The Chengjiang fauna is important for deciphering the fauna structure, paleoecological environment, and so on. However, its core academic values mainly rest on two aspects. Firstly, The Chengjiang fauna, as the main phase witness of the Cambrian explosion, has created a nearly complete phylogenetic framework of the TPTEA on Earth for the first time. The three-phase radiation hypothesis reveals the essential connotation of the Cambrian explosion: a step-wise divergent evolution of animals, from basal to highly advanced groups, lasting about 40 million years. In the first phase, it gave birth to a bulk of basal animals (including some now extinct “animal” groups) in the latest Ediacaran, probably including some pioneer protostomes. The second phase took place in the first epoch of the Cambrian period (Terreneuvian), giving rise to the main invertebrate protostomes with a persistent prosperity of basal animals. The third phase proceeded in Cambrian Epoch 2 (represented by the Chengjiang fauna), which not only maintained the prosperity of basal animals and protostomes, but also, more importantly, gave birth to all the main phyla of the subkingdom Deuterostomia. Thus, the rudimental framework of the whole TPTEA has been shaped, with the termination of the major innovation events of the Cambrian explosion. Here, we discussed the evolutionary properties of Ediacaran biota, small shelly fossils and the Chengjiang fauna in the Cambrian explosion with emphasis on the biological properties of several important animal groups. The order Myllokunmingiida is the only known oldest vertebrate, while Yunnanozoon and Haikouella are neither vertebrates nor stem-group chordates but a special group of basal deuterostomes; Cheungkongella is a credible ancestor of the urochordate and it supports the classical hypothesis on the origin of the urochordates; and the gill slits were first invented in the members of the phylum Vetulicolia to provide key information on the origin of the deuterostomes. The second core value of the Chengjiang fauna is of profound humanistic and philosophical significance: the discoveries of the ‘first gill openings’, ‘first brain’, ‘first vertebrae’ and ‘first heart’ provide the pivotal evidence for solving the unsolved mystery of the origin of the main basic human organs as described in Darwin’s “The Descent of Man”. In addition, the morphological and anatomical information of the Chengjiang fauna can provide important clues for a better understanding of most components of Ediacaran and Cambrian metazoans.
印度板块与亚洲板块的碰撞使喜马拉雅-青藏高原隆升,地壳增厚和生长扩展。探测青藏高原深部结构,揭露两个大陆如何碰撞,碰撞如何使大陆变形的过程,是全球关切的科学奥秘。深地震反射剖面探测是打开这个科学奥秘的最有效途径之一。20多年来,运用这项高技术探测到青藏高原巨厚地壳的精细结构,攻克了难以得到下地壳和Moho清晰结构的技术瓶颈,揭露了陆陆碰撞过程。本文在探测研究成果基础上,从青藏高原南北-东西对比,再到高原腹地,系统地综述了青藏高原之下印度板块与亚洲板块碰撞-俯冲的深部行为。印度地壳在高原南缘俯冲在喜马拉雅造山带之下,亚洲板块的阿拉善地块岩石圈在北缘向祁连山下俯冲,祁连山地壳向外扩展,塔里木地块与高原西缘的西昆仑发生面对面的碰撞,在高原东缘发现龙日坝断裂而不是龙门山断裂是扬子板块的西缘边界,高原腹地Moho 薄而平坦,岩石圈伸展垮塌。多条深反射剖面揭露了在雅鲁藏布江缝合带下印度板块与亚洲板块碰撞的行为,印度地壳不仅沿雅鲁藏布江缝合带存在由西向东的俯冲角度变化,而且其向北行进到拉萨地体内部的位置也不同。在缝合带中部,显示印度地壳上地壳与下地壳拆离,上地壳向北仰冲,下地壳向北俯冲,并在俯冲过程发生物质的回返与构造叠置,使印度地壳减薄,喜马拉雅地壳加厚。俯冲印度地壳前缘与亚洲地壳碰撞后沉入地幔,处于亚洲板块前缘的冈底斯岩基与特提斯喜马拉雅近于直立碰撞,冈底斯下地壳呈部分熔融状态,近乎透明的弱反射和局部出现的亮点反射,以及近于平的Moho都反映出亚洲板块南缘的伸展构造环境。
The Earth's surface is a complex system involving mutual interactions of its many components, including mountains, rivers, forests, farmlands, lakes and grasses. The interaction and mutual feedback of chemical elements in Earths surface layer can drive changes in chemical elemental distribution patterns. In this study, we evaluated the mechanisms and interactions driving the distribution patterns of macroelements, probiotics, halogens and heavy metals in soils in Southwest China, based on a systematic geochemical land-quality survey at a scale of 1250000. The results showed that the parent material determines the natural state of chemical elements in land resources. Epigenetic geochemical dynamics reshapes the distribution patterns of chemical elements in top soil; biogeochemical processes drive the evolutionary trends of land quality; and human activities, such as mining, disrupt the natural evolution of chemical elemental distribution patterns. The establishment of an epigenetic geochemical dynamics theory allows the construction of a framework for understanding the Earths surface layer and promoting technological innovations for the comprehensive geochemical investigation of land resources.
Yoko-Dovyren层状纯橄岩-橄长岩-辉长岩地块位于西伯利亚克拉通南部的一处褶皱构造框架中(俄罗斯贝加尔湖地区北部)。该地块的结构在其厚度最大的中部得到了着重研究。剖面底部主体成分为斜长橄榄岩,并依据内部的堆晶成分变化从下往上可分为五个主要的地层序列:纯橄岩→橄长岩→橄榄辉长岩→橄榄辉长苏长岩→石英辉长苏长岩以及含易变辉石的辉长岩。该地块的矿化包括铜-镍矿化、低硫型富铂族元素(PGE)矿化以及铬铁矿化等。另外,该地块也含多种非金属矿物原材料,如硼矿化、透辉石、各种镁质硅酸盐岩等。它们也包括纯橄岩、异剥橄榄岩和橄长岩,并以较高的品质产出,有望采掘加工成为建筑材料(水泥、混凝土、沥青混凝土和建筑陶瓷)。综合利用矿物原材料可增加矿床价值,并有助于建设环保型采矿工作体系。
本文研究了东西伯利亚玉矿的开发史。从新石器时代起,东西伯利亚的玉就已成为需求量很大的一种矿物资源。赋存于贝加尔湖区丰富的玉石促进了当地石雕艺技的蓬勃发展。西伯利亚的玉因形成机理迥异而绚丽多彩,该区玉石成因原则上可分为“去超基性岩化型”和“去碳酸岩化型”两种不同类型。东西伯利亚的玉成为重塑当地数千年来文明发展史的标志。文章概述了东西伯利亚的玉在亚洲北部古代社会中和当代科学研究中的重要价值和意义,讨论了该种玉的天然属性对艺术品和工业品制备过程中可能出现的各种问题,展示了东西伯利亚的玉的独特魅力及其与系列化设计工艺品间的差异。
石膏是矿山开采及冶炼等工业过程产生的大宗固体废弃物。工业活动产生的废液普遍有高含量的砷等有毒元素,这导致所产生的石膏也含有较高浓度的砷等有毒元素。研究砷在石膏中地球化学行为和归趋对含砷石膏的砷污染控制具有重要的理论和实际意义。然而目前对含砷石膏中不同形态的砷的定量测定和分析尚存在问题。本文在不同pH值的条件下共沉淀砷和石膏,利用电感耦合等离子体质谱(ICP-MS)、同步辐射X-射线吸收近边光谱(XANES)和电子顺磁共振(EPR)对石膏中掺杂态和表面吸附沉淀态的砷进行定量分析。ICP-MS的结果表明随着pH从2升高到12 和14,石膏中砷的含量由57×10-6 增加到 67 470×10-6和63 980×10-6。同步辐射X-射线吸收近边光谱和电子顺磁共振光谱分析表明石膏样品中主要含有五价砷。在2≤pH≤7.5时,固体样品中同步辐射吸收边后的峰形状和掺杂态砷的形状类似,而在pH≥8时,其边后峰的形状发生明显的变化;粉末电子顺磁共振(EPR)定量分析表明在2≤pH≤7.5时砷在石膏中的含量和ICP-MS的分析结果一致,而在pH≥8时其含量明显小于ICP-MS的分析结果。这些结果揭示了在2≤pH≤7.5时,砷在石膏中主要以掺杂态的形式存在,而在pH≥8时大部分砷是以吸附态或表面沉淀的形式存在。五价砷在石膏中的含量和固定机制随着pH值的变化而变化,其研究对了解尾矿中石膏对砷污染的控制作用具有重要作用。此外,研究石膏中由辐射导致的g约为2.33的[AsO3]2-自由基电子顺磁共振特征峰,有助于补充和完善石膏的电子顺磁共振特征谱在地质测年及辐射剂量学中的应用。
Baranevskoy金-银矿床产于巴尔喀什火山的火山口,该火山坐落在堪察加中部矿区东南部。本文基于矿物学原理和流体包裹体数据分析探讨了Baranevskoy金-银矿床的成矿环境及其物理化学条件。Baranevskoy金-银矿床的围岩为中新世—上新世的安山岩和玄武岩。热液蚀变活动随深度逐渐变化,从而可以进一步划分出最深部的石英带、中部的石英-绢云母(明矾石)-黄铁矿-铁钛氧化物带及其伴生的石英-绢云母-伊利石-黄铁矿矿物组合和浅部的石英-冰长石-水云母-黏土矿物-碳酸盐岩带。成矿早期存在密集浸染的铜矿化,主要矿石矿物有黄铜矿、斑铜矿、砷黝铜矿-黝铜矿,并在Rhzavaya矿脉中存在少量的自然金。其中砷黝铜矿-黝铜矿系列以砷黝铜矿和黝铜矿两个端员作为代表,且以黝铜矿为主。成矿后期产出代表晚期金-银矿化的自然金、黄铁矿、黄铜矿、闪锌矿、方铅矿、碲化物和硫酸盐等标志性矿物。早期铜矿化(第一期)被认为是中硫阶段,紧随其后的为低硫型金-银矿化(第二期和第三期)。金从第一期到第三期都有沉淀。经研究发现,自然金也赋存于变质围岩的岩石裂隙内。早期的自然金相对富银,其中金的摩尔分数为59%~65%,低于后期(第二、第三期)自然金中金的摩尔分数(64%~72%)。流体包裹体显微测温结果显示,位于中部(Central)矿脉的包裹体均一温度为190~280 ℃,Rzhavaya矿脉的包裹体为190~240 ℃,产出自然金的蚀变围岩中石英的包裹体温度为230~310 ℃。包裹体总体表现出低盐度(0.9%~2.4% NaCleq)特征,推测存在大气水的混入。
卤族元素诸如氯和溴作为地球化学示踪剂,常用于指示岩浆、变质岩和热液的来源和演化过程。而认清溴在造岩矿物中的形态和结构有助于丰富和完善其在地质环境演变中的示踪作用。但是,溴在造岩矿物中的含量极低导致大多数结构分析方法都无法使用,因此造岩矿物中微量溴的结构研究极具挑战性。本文采用 81Br魔角旋转核磁共振(MAS NMR)光谱和同步辐射吸收光谱(XAS)技术,首次对富氯造岩矿物中的微量溴进行了结构分析。结果表明溴离子在方硼石中的微区结构不同于该矿物中三配位Cl原子的结构环境,而与Mg3B7O13Br中八面体配位的溴离子相似,表明即使在微量条件下也存在域偏析。而对其他富氯造岩矿物的Br K边X光吸收近边结构(XANES)光谱白线峰的位置和扩展X射线吸收精细结构(EXAFS)分析表明微量溴离子替代了这些矿物中氯的位置,导致局部结构扭曲膨胀。溴离子在造岩矿物中的这一微观结构研究结果可为探索氯和溴在地质演变过程的指示作用提供新的科学依据。
为了深入了解日本东北俯冲带的地震构造及火山活动，利用布设在日本列岛上密集地震台网所记录到的高质量浅震及深震到时数据，反演求得了该区域地壳及上地幔的三维P波和S波速度结构。为了最大程度地利用地震数据提取模型空间中更为精细的速度结构信息，采用不规则网格模型来进行地震层析成像反演。所得的高分辨率成像结果清晰地显示，2008 年岩手地震(M 7.2)位于高低速异常的转换区，而且震源区的地壳介质非均匀性极强。在震源区的下地壳及上地幔顶部存在着明显的低速异常，可能代表了岛弧岩浆和流体在该深度处的储集。研究结果表明，2008 年岩手地震的产生受到了来自上地幔楔的岩浆和流体的影响，且这些岩浆和流体与俯冲太平洋板块的脱水作用有着密切的联系。
阿穆尔板块西部边界在蒙古境内的空间位置尚不清楚,并且活动断层构造及其沿线地壳的应力状态研究较少。本文在沿此边界的三个区域——杭爱—肯特构造鞍部、布尔古特地块(鄂尔浑—土拉交汇处)和色楞格地块(包括色楞格凹陷和布伦—努鲁隆起),利用空间图像解译、地形起伏度分析、地质构造资料以及构造压裂和沿裂缝位移资料重建构造古应力,对活动断层进行研究。研究表明,活动断裂继承了古生代和中生代古构造的非均质性。这些断层沿着板块边界并不是单一的带,而是成簇的。它们的运动取决于走向:亚纬向断层是具有一定逆分量的左旋走滑断层,北西向断层是逆断层或逆冲断层,通常具有右旋走滑分量,海底断层是右旋走滑断层,北东向断层是正断层。位于色楞格凹陷和杭爱东部的断裂构造的活动始于上新世。逆断层和走滑断层与上新世情况不符,但多与更新世地貌相符,表明其活动年代较晚,为更新世时期。利用构造断裂和沿断裂的位移,重建活动断裂带变形末阶段的应力应变状态,结果表明断裂在最大挤压轴的北北东和北东方向上以压缩和走滑为主。只有在色楞格凹陷内,以扩张和走滑类型的应力张量为主,且在最小挤压轴的北西走向尤为显著。在南部,杭爱东部(鄂尔浑地堑)内有1个以扩张机制为主的局部区域,说明蒙古中部断裂在更新世—全新世阶段的活动以及现代地震活动主要受与印度斯坦和欧亚大陆汇聚过程相关的东北方向的附加水平挤压的控制。使研究区地壳产生走滑变形、贝加尔湖裂谷发散活动以及阿穆尔板块东南运动的另一个因素是东南方向软流圈流动对岩石圈底部的影响。阿穆尔板块和蒙古地块之间的边界在构造结构上是零碎的,代表了覆盖整个蒙古西部变形带的边缘部分。
南大西洋裂解造成的非洲和南美洲的大陆分离到了广泛认可,该区域也与大陆漂移学说的诞生密切相关。但大陆漂移的驱动力从其提出至今一直存在争议,定量化分析大西洋裂解过程中板块运动的驱动力显得尤为重要。我们研究了南大西洋两侧被动大陆边缘盆地区域的两条深反射地震勘探剖面,在构造地质解译基础上,详细估算了非洲大陆的莫霍面倾角,得到了沿莫霍面地壳重力滑移剪切力的大小,用于解释大西洋裂解过程中非洲大陆运动的动力机制。结果说明,非洲大陆板块在地幔上涌形成的倾斜界面上能够产生强大的重力滑移力,且南部驱动力大于中部。大陆板块依靠连续的地幔热上涌和重力滑移力会持续漂移。该模型能够合理解释大西洋上诸多线状分布的大陆残片的成因机制,也能合理解释南大西洋南部宽度大于中部的内在原因,最后对南大西洋的打开过程进行了精细的构造演化史恢复。该研究为板块运动提供了一个新的动力模式,为认识板块运动驱动力提供了更为精确的约束信息。
