Frequency Distribution of Thickness of Sediments Bounded by Cenozoic Biostratigraphic Events in Wells Drilled Offshore Norway and along the Northwestern Atlantic Margin     

Frits Agterberg  Felix Gradstein  Gang Liu 《Natural Resources Research》2007,16(3):219-233

Sampling for microfossils in exploratory wells in basins with hydrocarbon potential is subject to considerable uncertainty, mainly because the samples usually are small and subject to caving. Biostratigraphic events defined on fossil taxa include their last occurrences of which the depths along the wells generally can be measured with precision. The RASC method for ranking and scaling of stratigraphic events produces an average basin-wide optimum sequence and zonation that can be used for correlation of strata between wells. In this optimum sequence the fossil events are ordered according to their occurrences in geological time. Depth differences between successive events in the optimum sequence satisfy a frequency distribution that is of interest for potentially increasing stratigraphic resolution. In this article the depth difference frequency distribution is modeled for three large Cenozoic microfossil data sets consisting of 30 wells in the North Sea Basin, 27 wells on the Labrador Shelf and Grand Banks, and 11 wells in the western Barents Sea. The shapes of the three frequency distributions satisfy bilateral gamma distributions with similar parameters. These distributions are fitted by the construction of straightlines on normal Q–Q plots of square root transformed average-corrected depth differences. The gamma distribution model is approximately satisfied except for small negative and positive depth differences, which have anomalous frequencies because of the discrete sampling method used in exploratory well-drilling to collect microfossils. It implies not only comparable average stratigraphic order of events, but also comparable average sedimentation rates in the three Cenozoic basins selected for study.  相似文献   

辽河盆地东部浅海地区层位标定方法     

罗运先  赵宪生  郭大江  徐雯琪 《物探化探计算技术》2007,29(4):313-316

地震反射层的地质层位是地震资料解释的基础,确定地震反射层的常用方法是利用声波测井资料,通过合成记录与反射层的标定。但声波测井的分辨率较高,地震记录的分辨率低,直接利用声波测井曲线制作合成记录,与实际地震记录进行层位标定常常不匹配。为提高层位标定的准确性,参考了多种测井曲线与岩性的对应关系,以及合成记录极性与岩性和层位的对应关系,在辽河盆地东部浅海地区实现了准确的层位划分。  相似文献   

地面伽马能谱测量应用于浅覆盖区地质填图数据预处理   总被引：3，自引：0，他引：3  

刘菁华  王祝文  田钢  郝立波  马力 《吉林大学学报(地球科学版)》2003,33(1):101-105

地面伽马能谱测量作为地质填图的辅助手段应用于浅覆盖区是一种尝试。利用地面伽马能谱测量数据的预处理来尝试消除浅覆盖对能谱测量的影响，通过野外试验数据和实测剖面数据的分析，进行了地表植被、局部干扰、测量几何条件、Th、K元素垂直分布分析，获得了数据预处理的简单方法，经过实测剖面的对比，证明方法是可取的。  相似文献   

Response spectral attenuation relationships for Singapore and the Malay Peninsula due to distant Sumatran‐fault earthquakes     

Kusnowidjaja Megawati  Tso‐Chien Pan  Kazuki Koketsu 《地震工程与结构动力学》2003,32(14):2241-2265

As part of the effort to assess the seismic hazards of Singapore and the Malay Peninsula, representative ground motion prediction models have to be established. Seven existing attenuation relationships developed for shallow crustal earthquakes in stable continent and active tectonic regions are examined, and they are found to consistently over‐predict the ground motions of Sumatran‐fault earthquakes recently recorded in Singapore. This may be attributed to the differences in the regional crustal structures and distance ranges considered. Since the number of recorded ground motions in the region is very limited, a new set of attenuation relationships is derived based on synthetic seismograms. The uncertainties in rupture parameters, such as stress drop, focal depth, dip and rake angles, are defined according to the regional geological and tectonic settings as well as the ruptures of previous earthquakes. Ground motions are simulated for earthquakes with Mw ranging from 4.0 to 8.0, within a distance range from 174 to 1379km. Besides magnitude and distance, source‐to‐station azimuth is found to influence the amplitudes of the ground motions simulated. Thus, the azimuth is taken as an independent variable in the derived ground motion attenuation relationships. The Sumatran‐fault segments that have the potential to generate a specified level of response spectral accelerations in Singapore and Kuala Lumpur are identified based on the newly derived ground motion models. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

柴达木盆地自然伽玛曲线在古气候及沉积环境研究中的应用   总被引：6，自引：2，他引：6       下载免费PDF全文

杨平  陈晔  刘泽纯 《古地理学报》2003,5(1):94-102

应用自然伽玛测井（GR）曲线反演古气候和古环境的方法在国际上逐渐得到重视并取得了进展，柴达木盆地第四纪应用其反演2.85Ma B.P来的古气候变化也取得了成功。本文以柴达木盆地侏罗系冷科1井和雨33井自然伽玛曲线并结合孢粉等地质资料进行了古气候与沉积环境分析，证明GR曲线是有价值的古气候研究参数。GR值的大小及古气候的干湿变化和沉积水体的深浅变化均有内在联系，GR曲线振幅与频率的变化快慢反映出沉积环境动荡与稳定的相对特征，据此对两口井的沉积环境演变作了具体分析。结合古气候与沉积环境综合分析，GR曲线的异常波动还具有特殊的指相意义。GR值增大-古气候加湿-沉积水体加深的同步表现特征是一般性规律，构造-古地理背景的变动可改变这一对应关系，因而提供了研究古地理演变的信息，进一步丰富了GR曲线研究的地质涵义。说明在侏罗纪古气候和古环境研究上，GR曲线是一有价值的参考指标。  相似文献   

低能伽马测井法在煤田勘探中的应用研究     

郭崇光 《中国煤田地质》2004,16(2):49-51

简要叙述低能伽马伽马(原称选择伽马，以下简称低能伽马)测井技术的基本原理和仪器使用方法，通过阳曲项目8个煤田孔的测井资料研究该方法在煤田勘探中的应用效果。结果表明：低能伽马测井法的纵向分辨率较高．在确定薄煤层、划分煤层簿夹石和复杂结构以及提高煤炭储量计算精度方面是其它测井方法无法取代的，在解释煤质成分方面也优于其它测井方法。  相似文献   

γ能谱法在放射性核素比活度检验中测量不确定度的评定     

曹诚彦  卞素珍 《岩矿测试》2004,23(1):56-61

建立放射性核素比活度检验的数学模型,分析产生测量不确定度的主要来源,采用相同条件下重复检验的数据和积累的数据以及外部提供的有效数据,在分别进行A、B类相对标准不确定度分量评定的基础上再进行合成相对标准不确定度评定.结果用于日常检验报告的测量不确定度项报出.  相似文献   

高精度航空物探综合站测量在找矿中的应用   总被引：1，自引：0，他引：1  

张文斌  熊盛青 《物探与化探》1998,22(5):321-328

本文介绍了应用高精度航空物探综合测量寻找金、钾盐、地下水以及进行岩性构造填图的方法技术及应用效果。重点阐述了应用F参数、灰色系统理论预测金矿;应用线性回归分析,结合主分量分析,消除K₂O干扰,圈定找钾靶区;利用航电-45°相位法划分水质,估计水量,寻找地下水;应用航磁、重力、伽马能谱综合信息进行岩性构造填图。  相似文献   

伽马能谱测量在侵入体岩石谱系单位填图中的应用     

邱元德  周蓉生  侯新生  贾文懿 《地质通报》1998,(3)

在１∶５万区域地质填图中,可利用γ能谱测量仪在现场测定各类侵入岩的Ｕ、Ｔｈ、Ｋ含量,Ｕ／Ｔｈ、Ｋ／Ｔｈ、Ｕ／Ｋ比值和γ照射量率等参数。通过对地面γ能谱测量资料与区域地质特征的综合分析,将攀枝花地区侵入体划分为１９个单元、６个超单元及一个超单元组合。还确认了色腰和矮郎河花岗岩为印支期,花滩花岗岩和同德闪长岩均为太古代古陆核的组成部分。  相似文献   

The Optical Layout Of The HEGRA Cherenkov Telescopes     

A. Akhperjanian  R. Kankanian  V. Sahakian  A. Heusler  C.-A. Wiedner  H. Wirth 《Experimental Astronomy》1998,8(2):135-152

The raytracing technique was used to derive a suitable design for the HEGRA system of Cherenkov telescopes, which is at present commissioned at La Palma. The reflectors with a diameter of 3.9 m consist of 30 spherical mirrors with focal lengths in the range of 4.88 – 4.94 m. It is shown that 93% of the photons from the Cherenkov light emitted by an extended air shower are contained in the camera pixels, 0.25° in diameter, for the full field of view of = ± 2.5°. The optical performance of the HEGRA design is compared to other layouts.  相似文献