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1.
以沉积相分析和层序界面识别为依据,将川东-渝北地区下三叠统飞仙关组划分为2个三级层序(SQ1和SQ2)和6个体系域,编制各沉积体系域的层序-岩相古地理图.研究表明,SQ1层序时期,研究区受晚二叠世长兴末期的区域构造抬升影响,属于区域性缓慢海进-缓慢海退沉积旋回的产物,一度开阔深水的台盆逐渐变浅而转化为开阔台地沉积环境,台地边缘与台内鲕滩的沉积相分异和沉积作用十分活跃,是形成飞仙关组鲕滩储层的主要时期,尤以海侵期鲕滩最为发育;SQ2层序发育期,受海平面大幅度下降、水循环受限和干旱炎热气候的影响,区域沉积格局由开阔台地转化为局限台地,鲕滩逐渐消失,最终进入频繁暴露的蒸发台地环境,以沉积膏云岩为主,为飞仙关组天然气藏最重要的第一套区域性致密盖层发育层位. 相似文献
2.
四川仪陇—平昌地区,特别是环开江-梁平海槽区域的长兴组—飞仙关组蕴藏着大量油气资源,但其三级层序划分方案有待统一。基于最新的钻井岩心、测井、野外露头资料综合分析,识别出岩性岩相突变界面及局部暴露不整合界面2种Ⅱ型层序界面,将仪陇—平昌地区的长兴组-飞仙关组划分为4个三级层序,建立了层序地层格架。该区目的层主要发育典型的镶边台地沉积体系,至晚期海槽消失,发育陆表海型台地体系开阔台地及蒸发台地。长兴组沉积期,开江-梁平海槽范围逐渐扩大,高位域是生物礁发育的有利阶段,由于SQ2晚期海平面急速下降,其生物礁规模较SQ1时期有所减小;飞仙关组沉积早期海平面快速上升,鲕粒滩难以形成,随后进入整体海退阶段,至SQ3高位域时期,鲕粒滩连片发育。层序划分方案与礁、滩储层发育特征匹配,能够应用于下一步油气勘探。 相似文献
3.
川东北地区飞仙关组层序—岩相古地理特征和鲕滩预测 总被引：4，自引：0，他引：4
以沉积相和界面识别为依据,将川东北地区下三叠统飞仙关组划分为2个三级层序和6个体系域,在此基础上对飞仙关组层序地层学特征进行了分析,编制了各沉积体系域的层序—岩相古地理图和对鲕滩发育规律进行预测。结果表明:SQ1层序发育期,飞仙关组受持续海侵影响,形成以深水台盆为中心的台盆—台地边缘—开阔—局限—蒸发台地的相带展布格局,以海侵体系域的台地边缘和台内鲕滩最为发育,该体系域也是飞仙关组鲕滩相储层最发育的层位;SQ2层序发育期,受海平面大幅度下降和水循环受限及干旱炎热气候影响,区域沉积格局由开阔台地转化为局限台地,鲕滩逐渐消失,最终进入频繁暴露的蒸发台地环境,以沉积膏云岩为主,为飞仙关组天然气藏极其重要的第一套区域性致密盖层发育层位。 相似文献
4.
《海相油气地质》2015,(3)
四川盆地下三叠统飞仙关组发育碳酸盐台地相沉积体系,可划分为开阔台地、局限台地、蒸发台地、台地边缘、台地前缘斜坡和海槽盆地等六种相类型。以单井、野外剖面层序划分和连井层序地层对比为基础,将四川盆地下三叠统飞仙关组划分为两个三级层序(SQ1、SQ2)以及四个高位和海侵体系域,编制了全盆地下三叠统飞仙关组各体系域的层序—岩相古地理平面展布图。研究表明,四川盆地下三叠统飞仙关组自西南向东北的相带分异明显。在SQ1层序时期,四川盆地以开阔台地相和局限台地相沉积为主,在中部和东北部一带发育鲕滩和浅滩微相沉积;在SQ2层序时期,四川盆地的中部和东北部广泛发育局限台地潮坪亚相沉积。指出SQ1层序的高位体系域和SQ2层序的海侵体系域为飞仙关组中的鲕滩最为发育的层位,具有较好的油气勘探潜力。 相似文献
5.
井下钻探和地震资料显示表明四川盆地北部下三叠统飞仙关组发育多套鲕粒滩储层, 该套储层也是飞仙关组主要的天然气产层.通过鲕粒滩储层发育段井震标定, 并结合鲕粒滩储层地震正演数字模型分析结果, 建立了飞仙关组不同层段鲕粒滩储层发育所对应的4种地震响应模式, 总结了不同地区鲕粒滩储层地震响应的异常特征.在此基础之上分别对飞仙关组一段、二段、三段开展连片二维地震测线地震相分析, 通过地震相与沉积相对应关系分析, 恢复四川盆地北部地区飞仙关组一段、二段、三段沉积相特征, 综合鲕粒滩储层地震异常特征与沉积相分布区, 预测了飞仙关组鲕粒滩储层在该地区的分布特征.飞仙关组一段、二段存在环陆棚相的台地前缘斜坡-台地边缘鲕滩相-开阔台地相沉积体系, 台地边缘鲕滩相在陆棚相东、西两侧沿北西向呈条带状展布, 分布面积大于4400km2, 飞仙关组三段全区演变成开阔台地沉积, 鲕粒滩分布广阔, 主要分布在龙岗-元坝、剑阁、九龙山、河坝-黑池梁、普光-铁山坡等大部分地区, 面积达15000km2, 因此, 四川盆地北部下三叠统飞仙关组鲕粒滩气藏勘探潜力巨大. 相似文献
6.
四川盆地东部晚二叠世-早三叠世飞仙关期礁、滩特征与海平面变化 总被引：67，自引：6，他引：67
据四川盆地东部上二叠统-下三叠统飞仙关组沉积特征和储层分布规律,认为区内长兴组生物礁和飞仙关组鲕粒滩特征和分布与海平面升降有关。长兴期生物礁发育于海平面快速上升阶段的缓坡坡折地带和缓坡内的局部,当生物礁的生长速度低于海平面的上升速度时,形成海侵追补型生物礁,当生物礁生长速度大于海平面上升速度时,则构成海侵并进型生物礁;飞仙关鲕粒滩形成于海平面下降阶段的台地边缘和台内局部地区,单一台地边缘鲕粒滩分布广、厚度大,而台内鲕粒滩数量虽多,但单一厚度小,分布范围窄。总体来看,长兴生物礁发育层位逐渐向海侵方向升高,而飞仙关鲕粒滩随海退的进行,向台地增生方向迁移。区内上二叠统-下三叠统飞仙关组是一次较大规模海平面升降过程中的产物,海侵始于吴家坪初期,长兴期海平面快速上升,至飞仙关初期达到最高海平面,海平面开始下降,直至飞仙关末期。 相似文献
7.
在层序地层学和沉积学理论指导下,以油气勘探为目标.针对川东南地区飞仙关组,取三级层序体系域作为成图单元,采用体系域压缩法和瞬时法进行层序岩相古地理编图,详细探讨了川东南地区早三叠世飞仙关组古地理特征及演化.研究表明:川东南飞仙关期发育海相地层,可识别出2个三级层序:SQ1和SQ2,二者皆为Ⅱ型层序.SQ1TST期,由于海平面的上升,研究区发育较深水环境的混积陆棚;进入SQ1HST期由于前期的沉积填充,盆地水体逐渐变浅盆地进入了开阔台地沉积环境,开始了鲕滩发育演化阶段.SQ2TST和SQ2EHST期研究区沉积格局基本上延续了SQ1HST期沉积特征,其中鲕滩在SQ2EHST进入了发展最高峰期;SQ2LHST由于相对海平面下降和沉积物的继续填充,研究区转入局限台地沉积环境,沉积-套区域上分布广泛的紫红色泥岩、白云岩、膏岩组合.SQ2EHST为研究区鲡粒滩最发育层位,具有较大的勘探价值. 相似文献
8.
川东北元坝地区长兴组-飞仙关组碳酸盐岩台地边缘以生物礁滩和鲕粒滩沉积为特征:台地边缘最初在吴家坪晚期出现,在经历了长兴期台地边缘礁滩的形成和消亡、印度早期台地边缘鲕粒滩形成和消亡两个阶段的演化后,最终在印度晚期被填平补齐。碳酸盐岩台地边缘演化受到包括地形的几何形态、水动力条件、沉积速率及空容纳空间增长速率的控制。 相似文献
9.
本文根据岩芯、岩石薄片、钻井和地震等资料的研究成果,将川东北元坝地区飞仙关组划分为两个三级层序：SQ1相当于飞仙关组一段、二段,SQ2相当于飞仙关组三段、四段。SQ1、SQ2由海侵体系域和高位体系域构成,缺少低位体系域。SQ1—TST期,元坝地区主要位于浅水碳酸盐台地上,为开阔台地相沉积,靠近东部为陆棚斜坡相沉积,从西到东依次发育开阔台地-台地边缘-斜坡相沉积。SQ1层序沉积时期,全区呈现西薄东厚的楔形几何形体。SQ2层序沉积时期,由于SQ1期的填平补齐作用,致使研究区整体演变为浅水碳酸盐台地沉积,沉积格局差异不大,以海侵和高位体系域为特征,对应海侵期的开阔台地和高位期的蒸发台地沉积。 相似文献
10.
川东北达县-宣汉地区飞仙关组沉积相与储层分布 总被引：5，自引：0，他引：5
达县—宣汉地区下三叠统飞仙关组是受控于鄂西渝东海盆和广旺海盆之间的碳酸盐台地。通过地表露头、钻井和地震等资料的研究,认为飞仙关组主要发育开阔台地、碳酸盐台地暴露浅滩和局限台地3个沉积相单元。飞仙关早期,继承了晚二叠世沉积格局,西部为开阔台地,向东依次为台地暴露浅滩、局限台地和开阔台地。随着滩规模的逐渐扩大,浅滩逐渐向东迁移。飞仙关三期,全区经历短暂的海侵,至飞仙关四期演变为均一的局限台地相,属于典型的碳酸盐台地浅滩沉积模式。储层以发育大套溶孔白云岩为特征,岩石类型主要为鲕粒白云岩、残余鲕粒白云岩、糖粒状残… 相似文献
11.
CSAMT 法在辽西康杖子区深部探矿中的应用 总被引：5，自引：0，他引：5
可控源音频大地电磁法(CSAMT)具有探测深度大、横向分辨率高、抗干扰能力强的特点,在深部找矿勘探中有着重要的指导意义。肖家营子铜钼矿床是辽西地区一个大型矽卡岩型金属矿床,大部分矿体是隐伏矿体,矿区外围的康杖子区与本区有相似的成矿地质环境,成矿地质条件优越.矿体与围岩电性差异明显,通过应用CSAMT,矿体具有低电阻特点,根据成果推断解释,对深部有利成矿部位进行了钻探验证,取得了理想的探矿效果,在矿区外围取得第二深度空间找矿重大突破。 相似文献
12.
13.
Julie Okpala 《GeoJournal》1990,20(1):37-43
This paper traces the development of geographic education in Nigeria and examines the views of geographers, other academics,
students and the public at large about the importance of geography. Geography's value is immense despite the non-professional
nature of the discipline. Nevertheless, there is a need to define geography's status and ensure career prospects for students.
The Nigerian Geographical Association (from classroom teaachers to top geographers) must promote geography, improve its status
in schools and universities, and continuously restructure its content and methods to address pertinent social needs. 相似文献
14.
Trends in landslide occurrence in Nepal 总被引：2，自引：0，他引：2
David N. Petley Gareth J. Hearn Andrew Hart Nicholas J. Rosser Stuart A. Dunning Katie Oven Wishart A. Mitchell 《Natural Hazards》2007,43(1):23-44
Nepal is a mountainous, less developed kingdom that straddles the boundary between the Indian and Himalayan tectonic plates.
In Nepal, landslides represent a major constraint on development, causing high levels of economic loss and substantial numbers
of fatalities each year. There is a general consensus that the impacts of landslides in countries such as Nepal are increasing
with time, but until now there has been little or no quantitative data to support this view, or to explain the causes of the
increases. In this paper, a database of landslide fatalities in Nepal has been compiled and analysed for the period 1978–2005.
The database suggests that there is a high level of variability in the occurrence of landslides from year to year, but that
the overall trend is upward. Analyses of the trends in the data suggest that there is a cyclicity in the occurrence of landslide
fatalities that strongly mirrors the cyclicity observed in the SW (summer) monsoon in South Asia. Perhaps surprisingly the
relationship is inverse, but this is explained through an inverse relationship between monsoon strength and the amount of
precipitation in the Hill District areas of Nepal. It is also clear that in recent years the number of fatalities has increased
dramatically over and above the effects of the monsoon cycle. Three explanations are explored for this: land-use change, the
effects of the ongoing civil war in Nepal, and road building. It is concluded that a major component of the generally upward
trend in landslide impact probably results from the rural road-building programme, and its attendant changes to physical and
natural systems. 相似文献
15.
16.
Takeshi Nose Dr. 《GeoJournal》1985,10(3):261-276
Conclusions During the last ten years, aquaculture, especially mariculture has undergone remarkable expansion to counter-balance the gap between the supply and demand of fishery products in Japan. Its expansion has also been supported by the traditional preference of the Japanese people for seafood. Mariculture is now being forced to change its structure due to adverse economic circumstances such as the rise in the cost of energy, feeds and other materials for culture, low market prices, deterioration of environmental conditions, and many other factors. Before these constraints can be resolved, advanced scientific knowledge and technologies must be integrated to develop new types of aquaculture. Expansion of maricultural activities to more open-sea and off shore areas would be one route to follow. Technologies for the development of formulated diets not only for young but also for adults and larvae, establishment of feeding standards, prevention of epizootic diseases must support the establishment of modern aquaculture.The culture-based fisheries, or marine ranching, is becoming a subject for further development in Japan. Much research work has been conducted with a great degree of governmental support. Establishment of a net work of seedstock production farms has made it possible to carry out releasing experiments on a large scale. A newly integrated restoration system could be developed on the basis of these experiments, even though the profits resulting from the artificial restoration of stocks is not thouroughly verified at present. The commencement of a national scheme for culture-based fisheries would be a manifestation of the enthusiasm of the Japanese fish industry. 相似文献
17.
2010年,美国铀矿总共施工7 209个钻孔,总进尺1 493 520 m;生产铀1 628.55 t;铀矿业总支出费用为2.773亿美元,其中铀矿地勘费支出为3 450万美元,占铀矿业总费用的12.44%。铀矿地勘钻探费用为4 460万美元,占铀矿业总费用的16.08%。 相似文献
18.
硫代砷是富硫化物地下水中砷的重要形态,对环境和人类健康有潜在威胁。目前硫代砷研究程度尚低,本次主要针对国内外地下水（地热水）中硫代砷的存在形态,水文—生物—环境地球化学过程,样品保存,定量检测方法等方面进行研究。结论如下:pH, 氧化还原电位,硫化物含量和微生物作用等是影响地下水中硫代砷稳定存在和形态分布的重要因素。含铁矿物能与水中的硫代砷形成配位键对其进行吸附,吸附性普遍弱于（亚）砷酸盐,因此,地下水中硫代砷可能表现出更强的迁移性。用于硫代砷检测的自然水样在采集中可采取过滤,速冻,厌氧和低温短期保存的操作流程,以减缓该形态的转化甚至消失。色谱联用ICP-MS系统可用于自然水样中硫代砷的分离定量检测,紫外—可见分光光度法和X射线吸收光谱法在不同场景下也可对硫代砷进行定量和表征分析。地热水和浅层地下水中均可能存在硫代砷,由于水样中硫代砷的不稳定性,室内检测和分析难以准确反映现场过程,因此,野外样品保存技术和现场检测方法的更新可能在未来有更大研究空间,值得进一步探索。 相似文献
19.
内蒙古苏尼特地下水氟污染形成机理研究 总被引：4，自引：1，他引：3
为了研究内蒙古苏尼特地区地下水氟污染机理,本文运用水文地球化学分类方法,从水文地质、水化学特征两方面研究其地下水的水质特征、氟的起源、分布规律及污染形成机理。研究结果发现:高氟地下水的主要水质类型为HCO3—Na型,pH值在7.08～9.38之间,氟浓度与井深有关,即井越浅,氟浓度越高;地下水中氟浓度最高达14.78mg/L,5～9月地下水氟浓度相对增长率在7.8～23.1之间;F-浓度与Li+、Br-相关系数达0.89和0.82,受断层影响的深层地下水中F-浓度几乎与Li+、Br-没有相关关系,这暗示着氟来源于浅部,并受到强烈的蒸发作用影响而使水中的氟浓缩;地质调查发现该地区还有数个萤石矿存在,显微镜分析结果证实表层土壤中普遍存在CaF2,地下水中的氟来自CaF2。高氟地下水存在于潜水层,深部含水层的地下水可供开采。从断层带涌出的水对潜水层有稀释作用。 相似文献
20.
Radon is a radioactive gas emanating naturally from uranium rich granites and shales. It may be emitted from the ground surface into the atmosphere as a gas, or it may be dissolved into stream water and transported over distance. The levels of radon gas in soils at ground surface depend on a number of factors relating to the source of the gas and to its transmission. Igneous rocks contain the highest mean concentrations of radium and uranium. The depth of cover is relevant also. Surveys over the years by the National Radiological Protection Board (NRPB) and others have indicated that the highest concentrations in the United Kingdom occur in Cornwall, Devon and northeast Scotland. However, recent reports have indicated that high concentrations of the gas may be detected in small pockets in counties outside of those considered at high risk. This survey relates to a series of measurements taken in and around Darlington, County Durham. The results showed the presence of small areas with strong concentrations of radon in soil gas, but only minor levels of dissolved gas in stream waters. 相似文献