排序方式: 共有70条查询结果,搜索用时 781 毫秒
41.
Influence of the evolution of the Huanghe River estuary, especially that of four large avulsions in recent years 1953, 1960,
1964 and 1976 on the lower reach was discussed. From this some measures for solving the problem of sedimentation at river
mouth were proposed.
This paper was published in Chinese inOceanologia et Limnologia Sinica
13 (3): 218–224, 1982.
The main ideas of the first three parts of this article were included in the report delivered at the International Symposium
on River Sedimentation held in Beijing, March 24–29, 1980. 相似文献
42.
为探究生物地层格架下五峰组—龙马溪组孔隙结构特征,在笔石带划分的基础上结合孔隙结构特征及其影响因素将SY-3井五峰组—龙马溪组划分为LM5—LM7、WF4—LM4、WF2—WF3三个笔石带,并基于扫描电镜、低温氮气吸附实验、高压压汞实验等技术手段,分别对这三个笔石带进行孔隙结构特征的研究和对比。结果表明:LM5—LM7富集黏土矿物,主要发育较大孔径孔隙,以黏土矿物粒间孔为主;WF4—LM4富集有机质,主要发育较小孔径孔隙,以有机质孔为主;WF2—WF3富集石英,主要发育小孔径孔隙,以石英粒间孔为主,但大部分石英粒间孔被黏土矿物和有机质充填。LM5—LM7孔隙发育主要受TOC含量和矿物含量的影响,WF4—LM4孔隙发育主要受TOC含量影响,而WF2—WF3受矿物组分、有机质赋存特征及成岩作用等因素共同影响。不同笔石带由于沉积环境的差异导致其具有不同的有机质丰度及矿物组分,从而导致了孔隙结构的差异。 相似文献
43.
我国西北侏罗纪煤储量巨大,煤质优良,多低灰、低硫,被称为“优质煤”。在总结前人研究成果基础上,对其煤岩学特征及其地质控制因素进行了探讨。研究认为,不同地质背景下形成的煤其煤岩学特征表现各异,如新疆的艾维尔沟、阜康等矿区的煤可用于炼焦,神华煤可直接液化,吐哈盆地的煤具有成油潜力。西北中侏罗世煤普遍富含惰质组,贫矿物质最为显著,与我国东部石炭-二叠纪煤以及国外“冈瓦纳煤”均存在较大差异,西北侏罗纪煤煤岩类型独特,是大型内陆型盆地演化的产物,多属低变质烟煤,局部也有中、高变质烟煤和无烟煤,还出现一个褐煤矿点。在煤地质学与煤岩学、煤化学等方面的深入研究,对今后洁净、高效、合理地利用西北侏罗纪优质煤资源十分重要。 相似文献
44.
45.
Resources Conditions of Coalbed Methane Districts in China 总被引:1,自引:0,他引:1
TANG Shuheng China University of Mining Technology Beijing LIN Dayang China National Administration of Coal Geology Zhuozhou 《《地质学报》英文版》2000,74(3):701-705
The China National Administration of Coal Geology accomplished an assessment of coalbed methaneresources of China in 1988. The total amount of coalbed methane resources in China is 14336.944 billion m , occurring in recoverable coal seams and beneath weathering zones, with coalbed methane content equal to or higher than 4 m3 per ton and buried depths smaller than 2000 m, among which there are 967.51 billion m of predicted reserves and 13369.434 billion m of future reserves. The resources in coal reservoirs with methane content of more than 8 m per ton are 12444.087 billion m , and those with methane content between 4 to 8 m per ton are 1892.856 billion m . There are 35 districts in which the resources abundance is higher than 150 million m3 /km2 , 49 districts with the abundance between 50 million and 150 million m 3/km2 , and 31 districts with the abundance less than 50 million m3 /km2 . There is 9256.078 billion m3 of methane occurring in coal seams with buried depths less than 1500 m, and 5080.866 bi 相似文献
46.
47.
长江南京段历史洪水位追溯 总被引:14,自引:0,他引:14
沿长江南岸幕府山、燕子矶岸段的石灰岩崖壁上,保留着数道受江水浸淹形成的色深且具有溶蚀孔隙的水平印痕,沿江一线分布。在采石矶岸段的岩壁上也存在着高程大致相当的水位痕迹,反映出是保存在长江南岸岩壁上的区域性洪水位遗迹。经查阅现代水文记录与历史文献,分析对比区域地貌与沉积地层,初步论定:高出长江江面5~6 m,高程分别为8.5 m和9.5 m的第一道和第二道水位遗迹是与现代长江洪水位相当的古洪水位遗迹,目前虽然已脱离长江江面,但现代长江洪水仍可达到此高度,其重现期为10~50年;高程为10.5 m的第三道水位遗迹较南京有文字记载的百年一遇特大洪水位仍高出0.3 m,相当于南京地区100~200年一遇的大洪水水位,由此印证长江南京段防洪堤高度合适;而最高的一道古水位遗迹高程为12.8 m,可能相当于全新世高海面时的洪水位。 相似文献
48.
瓦埠湖位于淮河中游南岸,属于淮河流域最大的湖泊.根据2011年8月-2015年12月对瓦埠湖湖区3个监测点位、入(出)湖河流4个监测断面的水质监测数据,选用内梅罗水污染指数法和单因子指数法,以总氮、总磷、铵态氮和高锰酸盐指数为评价指标对瓦埠湖湖区水体和主要入(出)湖河流水质现状进行评价,结果表明:瓦埠湖湖区总体水质状况为轻度污染、Ⅳ类水质,其主要污染源为农业面源污染和生活污染;部分入湖河流受农业氮、磷污染的影响水质较差,其中庄墓河污染情况最为严重.因此,必须加强流域的水环境综合整治工作,控制农业面源污染对流域水环境的影响. 相似文献
49.
苏北盆地是一个以箕状断陷为特点的复合型沉积盆地。文章根据2004年夏采集的苏北盆地宝应钻孔(BY1)97m沉积物的124个样品11种常量元素SiO2,Al2O3,TiO2,Fe2O3,MgO,MnO,CaO,K2O,Na2O,P2O5和SO2的地球化学特征分析,探讨了海相沉积环境与陆相沉积环境的元素分布特点、成因、相互之间的联系和物质来源。根据沉积物常量元素含量的垂向变化,结合沉积相、岩性特征、有孔虫分析、古地磁及14 C定年,分析了苏北盆地2.58Ma以来不同阶段海陆交互作用下的常量元素变化特点,反映了苏北平原在第四纪曾经历了4次海水淹覆, 海-陆交互堆积作用明显, 经滨浅海→泻湖→湖泊→洼地,最后由河流冲积物覆盖成陆。 相似文献
50.
DU Shuheng 《《地质学报》英文版》2021,95(3):937-945
This study aimed to show anisotropic poroelasticity evolution in ultra-low permeability reservoirs under pore pressure, confining pressure, and temperature. Several groups of experiments examining Biot’s coefficient under different conditions were carried out. Results showed that Biot’s coefficient decreased with increased pore pressure, and the variation trend is linear, but the decreasing rate is variable between materials. Biot’s coefficient increased with increased confining pressure; the variation trend is linear, but the increasing rate varies by material as well. Generally, Biot’s coefficient remains stable with increased temperature. Lithology, clay mineral content, particle arrangement, and pore arrangement showed impacts on Biot’s coefficient. For strong hydrophilic clay minerals, expansion in water could result in a strong surface adsorption reaction, which could result in an increased fluid bulk modulus and higher Biot’s coefficient. For skeleton minerals with strong lipophilicity, such as quartz and feldspar, increased oil saturation will also result in an adsorption reaction, leading to increased fluid bulk modulus and a higher Biot’s coefficient. The study’s conclusions provide evidence of poroelasticity evolution of ultra-low permeability and help the enhancing oil recovery (EOR) process. 相似文献