云南思茅盆地景谷地区下白垩统曼岗组风成砂岩沉积学特征及其古气候意义   总被引：2，自引：0，他引：2  

袁桃  吴驰华  伊海生  龚政  王立成  曾令旗 《地质学报》2015,89(11):2062-2074

本文通过野外剖面的观察和实测,室内薄片鉴定、阴极发光分析、粒度分析、扫描电镜及能谱测试分析,研究了云南思茅盆地景谷地区下白垩统曼岗组风成砂岩沉积学特征,详细了解了风成砂岩的发育特征,以期为研究区白垩纪古气候研究提供新的资料,为我国钾盐勘探提供一定的地质依据和新的思路。研究结果表明:1研究区曼岗组主要出露一套中—细粒石英砂岩、岩屑石英砂岩,发育中—大型交错层理、平行层理,碎屑颗粒分选中等-好,以次圆状-圆状为主,孔隙不发育,杂基含量少;2曼岗组中段发育具平行层理的石英砂岩,粒度分布呈双众数,带状分布,石英颗粒为浑圆状,颗粒表面见Fe、Mn质薄膜,颗粒表面具明显的碟形坑等特征,属于典型的风成砂岩,初步判定其沉积环境为风成沙丘和丘间沉积;3景谷地区下白垩统曼岗组风成砂岩,整体表现为干热型气候,曼岗组中段为丘间沉积,曼岗组上段和下段为沙丘沉积。其在搬运沉积成岩过程中经历了强烈的物理、化学风化作用,整体表现为氧化环境,风力较大,风速稳定,持续时间长。此外,可能还经历了一段时期的湿润性气候环境,这可能与大气降水、大气环流带的迁移,以及白垩纪海侵作用等有关。  相似文献   

Evidence of multi-stage faulting by clay mineral analysis: Example in a normal fault zone affecting arkosic sandstones (Annot sandstones)     

《Journal of Structural Geology》2015

Fault affecting silicoclastic sediments are commonly enriched in clay minerals. Clays are sensitive to fluid–rock interactions and deformation mechanisms; in this paper, they are used as proxy for fault activity and behavior. The present study focuses on clay mineral assemblages from the Point Vert normal fault zone located in the Annot sandstones, a Priabonian-Rupelian turbidite succession of the Alpine foredeep in SE France. In this area, the Annot sandstones were buried around 6–8 km below the front of Alpine nappes soon after their deposition and exhumed during the middle-late Miocene. The fault affects arkosic sandstone beds alternating with pelitic layers, and displays throw of about thirty meters. The fault core zone comprises intensely foliated sandstones bounding a corridor of gouge about 20 cm thick. The foliated sandstones display clay concentration along S–C structures characterized by dissolution of K-feldspar and their replacement by mica, associated with quartz pressure solution, intense microfracturation and quartz vein precipitation. The gouge is formed by a clayey matrix containing fragments of foliated sandstones and pelites. However, a detailed petrographical investigation suggests complex polyphase deformation processes. Optical and SEM observations show that the clay minerals fraction of all studied rocks (pelites and sandstones from the damage and core zones of the fault) is dominated by white micas and chlorite. These minerals have two different origins: detrital and newly-formed. Detrital micas are identified by their larger shape and their chemical composition with a lower Fe–Mg content than the newly-formed white micas. In the foliated sandstones, newly-formed white micas are concentrated along S–C structures or replace K-feldspar. Both types of newly formed micas display the same chemical composition confirmed microstructural observations suggesting that they formed in the same conditions. They have the following structural formulas: Na_0.05 K_0.86 (Al _1.77 Fe_0.08 Mg_0.15) (Si_3.22 Al_0.78) O₁₀ (OH)_2. They are enriched in Fe and Mg compared to the detrital micas. Newly-formed chlorites are associated with micas along the shear planes. According to microprobe analyses, they present the following structural formula: (Al_1,48 Fe_2,50 Mg_1,84) (Si_2,82 Al_1,18) O₁₀ (OH)₈. All these data suggest that these clay minerals are synkinematic and registered the fault activity. In the gouge samples, illite and chlorite are the major clay minerals; smectite is locally present in some samples.In the foliated sandstones, Kubler Index (KI) ((001) XRD peak width at half height) data and thermodynamic calculations from synkinematic chlorite chemistry suggest that the main fault deformation occurred under temperatures around 220 °C (diagenesis to anchizone boundary). KI measured on pelites and sandstones from the hanging and footwall, display similar values coherent with the maximal burial temperature of the Annot sandstones in this area. The gouge samples have a higher KI index, which could be explained by a reactivation of the fault at lower temperatures during the exhumation of the Annot sandstones formation.  相似文献   

内蒙古突泉盆地侏罗系油气发现及工作展望   总被引：1，自引：0，他引：1  

陈树旺  张健  公繁浩  孙守亮  苏飞  甄甄  周新桂  李世臻  黄桂雄 《地质与资源》2015,24(1):1-6

突泉盆地是公益性油气基础地质调查项目在大兴安岭中南部火山岩覆盖区已发现的油气新区,有望成为实现松辽外围侏罗系油气新区、新层系勘探突破的远景盆地.基于突泉盆地地质背景、沉积特征与烃源岩发育特征,阐述了突参1井和突D1井的地质设计思路及其油气发现情况,并从原型盆地恢复、烃源岩评价、火山岩覆盖区勘探方法以及非常规致密油的超低孔、超低渗储层等方面,对下一步工作进行了探讨.  相似文献   

改进的贝叶斯迭代反演方法及其在白云岩致密储层识别的应用     

马琦琦  孙赞东  杨柳鑫 《物探与化探》2019,(2):234-243

由于低孔隙度和低渗透率的白云岩致密油储集层的纵波阻抗与其围岩差异非常小,利用叠后反演技术难以有效预测储层,而可以提取丰富弹性信息的叠前反演是解决此问题的有效手段,但是由于噪声等问题,叠前反演方程有较强的不适定性,笔者在贝叶斯框架下引入了改进的多变量柯西分布和改进的低频约束因子,重新推导了反演方程,获得了新的目标函数,有效地减少了反演的不适定性,从而提高了反演的稳定性,并结合迭代的思想来不断更新反演求解过程中的背景纵横波速度比值,从而增加了反演结果的精度。模型数据测试和实际资料应用都证明了该方法的稳定性和适用性。统计表明,利用提出的反演方法,目的层段内优质储层厚度预测吻合率高达89.75%。因此,此方法对类似硅质致密储层的勘探有重要的借鉴意义。  相似文献   

脱气温度和样品粒径对致密砂岩低温氮气吸附实验结果的影响     

李传明  薛海涛  王民  卢双舫  李进步  田伟超 《矿物岩石地球化学通报》2019,(2):308-316

基于静态体积法的低温氮气吸附实验已广泛用于分析致密储集层的孔隙结构。本文探索了脱气温度和样品粒径对松辽盆地高台子致密砂岩低温氮气吸附实验结果的影响。结果显示,110℃的脱气条件并不能清除束缚水而使得孔隙体积、比表面积均偏低,300℃的脱气条件容易破坏样品中黏土矿物的结构令孔隙体积、比表面积减小,200℃是比较合适的脱气温度,既能去除束缚水又不破坏黏土矿物结构。样品粒径从5～10目减小至10～30目,氮气探测的孔隙数量增多使比表面积、孔体积增大。从10～30目减小至180～200目,黏土矿物相对含量降低令比表面积、孔体积显著减小;小于200目的样品中减少的黏土矿物主要集中在大于200目的岩样中,因此大于200目岩样的测定结果最高。因此,10～30目是利用低温氮气吸附实验寻求分析致密砂岩储集层特征的最佳粒径范围。  相似文献   

双稀疏字典和FISTA的地震数据去噪          下载免费PDF全文

张良  韩立国  方金伟  张盼  刘争光 《地球物理学报》2019,62(7):2671-2683

地震数据的随机噪声去除是地震数据处理中的一项重要步骤,双稀疏字典提供了两层稀疏模型,比单层稀疏模型可以更好地去除噪声.该方法首先利用contourlet变换对地震数据进行稀疏表示,然后在contourlet域中使用快速迭代收缩阈值算法（fast iterative shrinkage-thresholding algorithm,FISTA）对初始字典系数进行更新,接着采用数据驱动紧标架（data-driven tight frame,DDTF）在contourlet域中得到DDTF字典并通过FISTA得到更新后的字典系数,最后通过DDTF字典和更新后的字典系数获得新的contourlet系数,并对新的contourlet系数进行硬阈值和contourlet反变换得到去噪后的数据.通过模拟数据和实际数据的实验证明：与固定基变换去噪方法相比,该方法可以自适应地对地震数据进行稀疏表示,在地震数据较为复杂时得到更高的信噪比;与字典学习去噪方法相比,该方法不仅拥有较快的去噪速度,而且克服了字典学习因为缺少先验约束造成瑕疵的缺点.  相似文献   

Study of Fractal Characteristics of the Cementation Index in Shale Gas     

LIU Hongqi  LIU Shiqiong  LUO Xingping  SUN Yangsh  TIAN Jie  LIANG Lixi  LIU Xiangjun 《《地质学报》英文版》2020,94(2):456-466

  相似文献   

Geochemistry and detrital zircon U–Pb dating of Pliocene-Pleistocene sandstones of the Chittagong Tripura Fold Belt (Bangladesh): Implications for provenance     

《Gondwana Research》2020

The Bengal Basin originated during the collision of India with Eurasia and Burma. The provenance analysis of the Chittagong Tripura Fold Belt (CTFB), which is the folded eastern flank of the Bengal Basin as well as the Neogene belt of the Indo-Burman Ranges (IBR) is key to better understand the possible sources of sediment input from the complex interplay of the Indian, Eurasian and Burma plates. We report new whole rock geochemical and detrital zircon U–Pb data from the upper Neogene sandstones of Tipam-Dupi Tila formations (Pliocene to Plio-Plestocene succession) from the CTFB. Detrital zircon U–Pb age spectra show three predominant peaks at <200 Ma, 480–650, ∼800–1000 Ma. The geochemical discriminations and elemental ratios of Eu/Eu* (∼0.70), La/Sc (∼16.13), La/Co (∼15.76), Th/Sc (∼2.95), La/Th (∼5.67), Th/Co (∼2.87), Cr/Th (∼4.63) as well as Chondrite-normalized REE patterns with flat HREE, LREE enrichment, and negative Eu anomalies for the Tipam and Dupi Tila formations are suggestive of a dominantly felsic source area experiencing moderate to intensive chemical weathering (Chemical index of alteration, CIA - 57 to 81) and have a recycled provenance orogen related to active continental or passive margin settings. Integrated geochemical and zircon U–Pb studies reveal that the main sediment input might have been from the Himalayan orogen with significant arc-derived detritus, possibly from the Gangdese arc as well as from the Burma magmatic arc.  相似文献   

致密砂岩层内强钙质胶结物成因机制及其意义——以鄂尔多斯盆地三叠系延长组长7油层组为例     

崔景伟  朱如凯 《吉林大学学报(地球科学版)》2020,50(4):957-967

通过岩心和薄片观察,利用荧光显微镜、阴极发光显微镜、同位素质谱仪、冷热台等设备,对鄂尔多斯盆地长7油层组强钙质胶结砂岩及其附近含油砂岩开展研究。结果表明：钙质胶结是致密砂岩储层含油非均质性的主要因素,胶结期次主要为一期;簇同位素揭示该期钙质胶结物的形成温度为18~42℃,对应地质时代为中晚三叠世—中侏罗世,为早成岩期产物,推测与盆地早期小规模构造运动相关;相邻的含油砂岩中油气包裹体伴生的同期盐水包裹体的均一化温度为90~120℃,结合盆地模拟揭示油气主要为一期充注,充注期为100~130 Ma,处于早白垩世;长7油层组不含油致密砂岩内钙质胶结物形成时间早于含油砂岩内石油的充注时间。  相似文献   

叠前反演方法在致密砂岩气储层预测中的应用     

薛明喜  陈开远  田泽华  贾曙光 《地质力学学报》2018,24(1):42-50

以鄂尔多斯东缘A区块为例,通过岩石物理正演分析,论证了储层岩石物理参数的敏感性,确定利用纵波阻抗与纵横波速度比参数进行储层的识别。在此基础上进行正演模拟,研究了地震的极限分辨率及不同厚度砂体的地震响应特征,确定了运用叠前地质统计学反演为核心的储层预测技术对该研究区太原组进行储层预测研究,以解决该区储层薄、横向变化快、单一岩石物理参数无法区分岩性等问题。地质统计学反演结果表明,该方法能有效的预测厚度大于3 m的储层。对比研究区内11口测井解释厚度与储层反演厚度表明,储层反演预测厚度平均误差为7.5%,其中5口盲井的平均误差为10.2%,一口新钻井的砂体厚度预测误差为1.73%,为该区的井位部署提供了可靠的资料参考。   相似文献