Fluid–rock interactions during continuous diagenesis of sandstone reservoirs and their effects on reservoir porosity          下载免费PDF全文

Leilei Yang  Tianfu Xu  Keyu Liu  Bo Peng  Zhichao Yu  Xiaomeng Xu 《Sedimentology》2017,64(5):1303-1321

The Cretaceous sandstone reservoir in the Kuche Depression, Tarim Basin, western China, was investigated with reference to its reservoir property evolution during diagenesis. Six general diagenetic stages were recognized through petrographic, mineralogical and geochemical analyses. Fluid–rock interaction experiments were conducted under these six continuous diagenetic conditions, that is with a simulation sequence of compaction → early diagenesis → organic acid incursion I → elevated temperature/pressure → organic acid incursion II → late diagenesis. Corresponding to these six experimental stages, a total of six models were constructed. Finally, an extended model of fluid–rock interaction during diagenesis at a geological timescale (from 30 Ma to present) was constructed after various parameters had been validated. Results demonstrate that the diagenetic stages from both the experimental and numerical simulations generally matched findings obtained from the petrographic and geochemical analyses: (i) With compaction becoming weakened, cementation by various minerals was gradually increased. (ii) Quartz overgrowth occurred because the contemporaneous sedimentary water was alkaline. (iii) Most minerals (for example, calcite and feldspar minerals) displayed dissolution owing to the first organic acid incursion, resulting in the visual porosity increasing to 29·26%. (iv) Increases in temperature and pressure caused a minor fluctuation of the porosity change. (v) The cement that formed during earlier stages largely dissolved with the second organic acid incursion. (vi) During the last stage, the reservoir fluid was diluted by sedimentary alkaline water and most minerals precipitated under an alkalic environment. The present porosity simulated is about 11·4%, comparable with the actually measured data. This study demonstrates that the combination of petrographic observations, laboratory experiments and numerical simulations can not only reconstruct the diagenetic process, but also provide a quantitative evaluation and prediction of reservoir petrophysical properties.  相似文献   

The episodic geomorphological-sedimentary evolution of different basins in the Fenwei Graben and its tectonic implication     

Xiaomeng Hu  Tianhang Zhou  Shun Cai 《地理学报(英文版)》2017,27(11):1359-1375

There are a series of basins in the Fenwei Graben. Field survey found that there took place several paleolake regressions or intensive stream down-incisions in all basins during the Mid-Late Quaternary. The lowest and oldest paleosol/loess units overlying three of the lacustrine terraces or alluvial ones and some paleomagenetism data from the lacustrine sediment indicate that the onset times of three paleolake regressions or intensive stream down-incisions are synchronous with the formation of L₉, L₆ and L₂ respectively in the Weihe Basin, S₈, S₅ and S₁ respectively in the Linfen-Taiyuan-Xingding Basins, and L₈, L₅ and L₁ respectively in the Datong Basin. The difference in the onset time of each lake regressions or intensive stream down-incision in different basins reveals that the farther the basin is from the Tibetan Plateau, the later it took place. Taking these field facts and the former research results in terms of the regional tectonic movement into account, it is inferred that the tectonic movement of the Tibetan Plateau most probably controlled such geomorphologicalsedimentary evolution in the graben.  相似文献   

蒲阳河流域地下水水化学及同位素特征   总被引：3，自引：2，他引：1       下载免费PDF全文

沈萌萌  郭华明  李晓萌  修伟  倪萍  张迪 《水文地质工程地质》2017,(2):8-14

保定西部山前地区位于太行山及华北平原交界带,为缓解极端气候灾害对生产生活的影响,维持地下水资源的可持续开发利用,开展相关的地下水水化学及同位素特征研究。研究区地下水化学类型以HCO3—Ca·Mg、HCO3·SO4—Ca·Mg及SO4·HCO3—Ca·Mg为主,区内地下水主要来源于大气降水,流域内地表水补给地下水;地下水中化学成分为Ca2＋、Mg2＋、HCO-3、SO2-4,主要来源于岩石风化作用,同时受到人类活动的影响,地下水中硝酸盐含量明显升高;由于受到褶皱构造的控制,流域的上游及平原区均出现年龄大于60年的地下水,多数岩溶水年龄较复杂,从现代水到大于60年的水均有分布。研究成果为流域内水资源的合理开发利用提供建议,区内岩溶地下水的开发将在一定程度上缓解极端天气的影响。  相似文献   

沉积物不同提取态有机物特征及水文地球化学意义——以河套盆地典型研究区为例          下载免费PDF全文

李晓萌  郭华明  曹永生  张迪  修伟 《水文地质工程地质》2017,(2):40-47

地下水系统中有机物（OM）特征和活性对于地下水化学特征的形成和演化起着十分重要的作用。将内蒙古河套盆地表层湖相沉积物按10 cm间隔采集,并对沉积有机质的性质及来源进行重点分析。测量了不同深度上不同岩性沉积物的色度、水溶性有机物（WEOM）和盐溶性有机物（SEOM）含量及其光谱学特性。结果显示,沉积物的色度（R530-520）与TOC含量呈现相反的变化趋势:色度值较大时,TOC含量反而较小。相对于细砂层,黏土层的色度值较低,但TOC含量较高。相同的沉积物中,SEOM含量高于WEOM,但WEOM更易迁移至地下水中。有机物的光谱指数表明,WEOM以微生物来源为主,而SEOM以陆源为主。通过三维荧光光谱分析发现,荧光强度和沉积物有机碳（SOC）含量呈正相关;黏土层沉积有机物荧光强度更高;WEOM和SEOM均含类腐殖质成分和类蛋白成分,但SEOM中腐殖质成分较高;类腐殖质是所研究的沉积物中OM最主要的存在形式。  相似文献   

北京地区降水极值时空演变特征   总被引：4，自引：0，他引：4       下载免费PDF全文

宋晓猛  张建云  孔凡哲  王国庆  贺瑞敏  朱奎 《水科学进展》2017,28(2):161-173

为了科学评估变化环境下城市地区降水结构变化和深入认识特大型城市降水极值演变特征,以北京市为例,采用《北京市暴雨图集》中6种历时（10 min、30 min、1 h、6 h、24 h和72 h）的年最大暴雨统计数据和北京地区45个雨量站点1960-2012年汛期（6-9月）逐日降水观测资料,分别选择年最大值法和百分位阈值法,基于暴雨图集中的6种历时暴雨的统计特征值和两种百分位阈值下（95%和99%）的3种极端降水指标（发生次数、降水量和降水贡献率）分析北京地区降水极值的时空变化特征。研究结果表明:① 北京地区降水极值的空间分布受地形特征和城市化发展等因素影响而呈现出从东向西递减的趋势,且形成了局部区域高值中心;② 近50年来北京地区极端降水发生频次、极端降水量和极端降水的贡献率均表现出显著的下降趋势,在95%（99%）阈值条件下极端降水发生次数、极端降水量和极端降水贡献率的下降速率分别为0.13次/10 a（0.04次/10 a）、11.59 mm/10a（5.28 mm/a）和2%/10 a（1%/10 a）;③ 两个阶段（1960-1985年和1986-2012年）的城区与近郊的极端降水指标差异表现不同,1960-1985年在极端降水频次方面郊区占优,而极端降水量和贡献率则是城区较高,1986-2012年3个指标均表现为城区较高。  相似文献   

汾河地堑湖盆第四纪地貌—沉积特征的构造控制   总被引：4，自引：1，他引：3  

胡小猛  郭家秀  胡向阳 《地理学报》2010,65(1):73-81

野外对临汾、太原盆地第四纪中晚期所发育的湖积地貌-沉积特征调查发现,湖盆在对应于S8、S5和S1古土壤开始发育时期(时代分别为0.77Ma BP、0.55Ma BP和0.13Ma BP)曾发生了三次强烈湖退,这三次湖退都是构造原因所致的;而在L11-S8、L8-S5、L5-S1黄土古土壤堆积发育期间(时代分别对应于0.96～0.77Ma BP、0.74～0.55Ma BP和0.47～0.13Ma BP)、以及S1古土壤发育以后的时期(时代为0.07Ma BP之后)出现的却是缓慢湖侵或盆地下沉。根据这些发现并结合地球物理学前期已获得的有关盆地深部上地幔结构及活动规律,本文提出了盆地湖侵-湖退过程的构造控制模式。在上地幔强烈上拱→减弱或渐趋稳定→再次强烈上拱的构造循环中,地表湖盆会以大幅快速湖退→缓慢湖侵→再大幅快速湖退这样的表现与之对应。盆地地表的地貌-沉积发育与地下的上地幔活动应具有因果关系。  相似文献   

数值预报AI气象大模型国际发展动态研究          下载免费PDF全文

黄小猛  林岩銮  熊巍  李佳皓  潘建成  周勇 《大气科学学报》2024,47(1):46-54

数值预报是研究地球系统的重要工具,有助于加深科学家对大气、海洋、气候和环境等复杂系统之间相互作用和变化过程的理解,在防灾减灾、气候变化和环境治理等方面发挥着不可或缺的作用。随着模式复杂度和分辨率的提高,传统数值模式在气候变化研究和气候预测方面取得了迅速的进展,但也面临一些挑战,需要得到数据同化、集合耦合、高性能计算和不确定性分析等多方面的支持。而近年来,“AI+气象”的交叉研究在气象领域引起了广泛关注。基于多种深度学习架构的人工智能大模型,依托强大的计算资源和海量的数据进行训练,能够以新的科学范式进行高效数值预报。气象大模型不断涌现,一些科技公司如华为、英伟达、DeepMind、谷歌、微软等,以及国内外高校如清华大学、复旦大学、密歇根大学、莱斯大学等发布了多个涵盖临近预报、短时预报、中期预报和延伸期预报等不同领域的气象大模型。这标志着人工智能与气象领域的交叉融合已经达到新的高度。尽管气象大模型在现阶段取得了较大突破,但其发展仍然面临弱可解释性、泛化能力不足、极端事件预报强度偏低、智能预报结果过平滑、深度学习框架能力需要拓展等诸多挑战。  相似文献   

转型期北京社区公共空间对邻里交往的影响机理：本地居民与移民的对比分析   总被引：5，自引：0，他引：5  

刘志林  王晓梦  马静 《地理科学》2020,40(1):69-78

利用2017年北京市36个小区的居民问卷调查数据,并基于POI数据测量小区尺度上步行道、公园、交通站点、商业设施、学校5类公共空间与设施的可达性,采用结构方程模型考察社区公共空间对本地居民、外来移民邻里交往的不同影响作用和机理。研究发现,在城市转型与居住分异的背景下：典型公共空间（步行道、公园）在促进邻里交往的作用上不如交通站点、商业设施等准公共空间设施;相较于外来移民,本地居民的邻里交往水平更容易受到社区公共空间的影响。  相似文献   

Analysis of Structural Styles in Northern Segment of Tancheng-Lujiang Fault Zone   总被引：1，自引：0，他引：1  

WANG Shuqin  SUN Xiaomeng  DU Jiyu  WANG Yingde  XU Qiangwei  TIAN Jingxiong 《地质论评》2012,58(3)

郯庐断裂带(郯城—庐江断裂带)北段在中—新生代发生多期不同性质活动,形成各具特色的构造样式.各种构造样式和地层间切割或覆盖关系的匹配研究,为限定断裂带活动期次及时代,建立郯庐断裂带北段变形序列提供了第一手资料.不同构造样式反映了断裂带由老至新经历了以下5个重要的变形事件:①密山县知—镇韧性剪切带黑云母40 Ar/39 Ar等时线年龄为161±3Ma,是郯庐断裂带再次发生大规模左旋走滑活动并扩展到东北地区的产物;②四平市叶赫镇负花状断层系以及早白垩世早期东北断陷盆地群的形成,是郯庐断裂带北段在早白垩世早期发生强烈的走滑—伸展作用的重要依据;③四平市石岭子镇佳木斯—伊通断裂大型逆冲断层系和断层相关褶皱、桦甸县敦化—密山断裂"逆地堑"、沈阳—哈尔滨逆冲断裂是郯庐断裂带北段特征最明显、分布最广泛的构造样式,它们形成于晚白垩世嫩江运动—晚白垩世末期,反映了这一时期郯庐断裂带北段遭受到广泛而又强烈的右旋走滑—逆冲作用;④佳伊、敦密古近纪地堑是右旋走滑、伸展双重机制控制的产物;⑤在渐新世末期古近纪地堑的构造反转结束了地堑的演化;中新世郯庐断裂带北段上地幔剪切控制了新生代含幔源包体火山口沿断裂有规律的分布.上述5个重要的变形事件由老至新组成了郯庐断裂带北段较为完整的构造演化序列,它们是不同地球动力学机制的产物.  相似文献   

Morpho-Sedimentary evidence of the Huoshan Fault’s late Cenozoic right-lateral movement in the Linfen Graben, Shanxi Graben System, North China   总被引：1，自引：0，他引：1  

Xiaomeng Hu  Lili Wang  Jiao Zhe  Hailong Lu 《Frontiers of Earth Science》2010,4(3):311-319

The Huoshan Fault, being of NEN strike, is one of the most important faults in the Shanxi Graben System of North China; it is the location of the 1303 A.D. Hongtong earthquake (M_S = 8.0). The late Pleistocene and Holocene offset of some gullies that cross the fault and some fault scratches have proved its right lateral movement during the late Quaternary; however, until now, geological evidence to support the movement in the Neogene and early Quaternary was scarce. Our work provides further crucial evidence that supports both its movement in the late Cenozoic and the total right-lateral displacement since the Pliocene. The difference in the outcrop heights of the Pliocene sediment along the fault, the difference in the geomorphological development along the fault, the inconsistency in the lithological composition of the Pliocene proluvial gravels with the rock types within the catchments of the current upper stream, and the offset of the Pliocene alluvial gravels all completely indicate that the fault has always moved right-laterally since the Pliocene. Additionally, this evidence indicates that the accumulative displacement is up to 12.5 km. Based on the horizontal and vertical displacement of the fault since the Pliocene, the time-averaged horizontal slip rate of the fault is estimated to be about 3.5 mm/a, while the ratio of the horizontal to vertical offsets is about 3.8; these data are roughly close to the results that were acquired from the Holocene and the present movement of the fault. This similarity in the tectonic movement parameters may imply that the intensity as well as the configuration of the regional stress field has remained constant, and that no significant changes have taken place since the Pliocene.  相似文献