Sequence Stratigraphy Study of the Late Quaternary Activity of the Nankou-Sunhe Fault in Its Northern Segment,Beijing     

Zhang Shimin  Wang Dandan Liu Xudong  Ren Junjie  Luo Minghui  Zhang Guohong  Zhao Guocun  Wang Rui  Zhang Yingli 《中国地震研究》2008,22(3):334-347

A test drilling exploration was implemented across the northern segment of the Nankou-Sunhe fault in the Beijing plain, and a combined borehole section was built by sequence stratigraphy, lithologic facies analysis, magnetic susceptibilityand absolute chronology to investigate the episodic activities of the fault since 60 ka BP. The results show that the active stages of the fault are 60 ka to 47 ka BP, 36 ka to 28 ka BP, and 16 ka BP to present. Other intervals are relatively stable. The average vertical slip rate is 0.35 mm/a from 60 ka to 37 ka BP, 0 mm/a from 37 ka to 3：2 ka BP,0.78 mm/a from 32 ka to 12 ka BP,and 0.35 mm/a since 12 ka BP. Compared with the conventional analyses on lithology and sedimentary facies, the sequence stratigraphy method has certain advantages in the studies of borehole strata comparison and episodic activity of buried faults.  相似文献   

数值模拟技术在风电场宏观选址上的应用   总被引：1，自引：0，他引：1       下载免费PDF全文

谢今范  王玉昆  张亮  张婷  于莉 《气象与环境学报》2013,29(5):148-153

现有气象站分布稀疏,难以全面反映潜在大风区域。数值模拟技术通过提高分析区域的空间分辨率,弥补气象站点分布稀疏的缺陷。利用中尺度天气预报模式WRF对吉林省西部地区风能资源进行了数值模拟。结果表明：数值模拟结果反映了实际风速日变化和年变化规律,10 m、50 m、70 m高度模拟值与实际观测值相关系数分别达到0.889、0.862和0.865,均达0.001 的显著水平;模拟结果揭示了地面观测资料未反映出来的潜在大风区。经实际立测风塔观测证实,数值模拟技术可以用于风电场宏观选址。同时揭示了模拟的风速较实际风速大,且模拟风速空间分布差异小于观测的风速,说明现有数值模式模拟的精确度还存在着局限性,风电场微观选址仍依赖于立测风塔进行实地观测。  相似文献   

中国大陆科学钻探主孔榴辉岩中重晶石的发现及其意义   总被引：1，自引：0，他引：1  

杨红  张立飞  刘福来 《地质学报》2006,80(12):1892-1897

在中国大陆科学钻探主孔榴辉岩中发现了重晶石。重晶石以包裹体形式保存在石榴子石中,多为浑圆状,表面积平均约250μm2。通过电子探针测试,重晶石中SrO含量大多超过20%,为锶重晶石,其化学分子式为(Ba0.4836~0.6180Sr0.3787~0.4722Ca0.0064~0.0889)S0.9688~0.9963O4。同时还发现榴辉岩中的石榴子石有柯石英假象,温压条件计算表明该榴辉岩的峰期温压条件为696~730℃,2.9~3.2GPa。电子探针成分测定包裹这些重晶石的石榴子石为峰期变质矿物,这进一步说明重晶石也经历过超高压变质。重晶石通常形成于强氧化和高盐度流体作用的条件下,本文的研究表明超高压变质过程中至少出现了一定范围内的强氧化环境和高盐度流体作用,但其地球动力学意义有待进一步研究。  相似文献   

中国大陆科学钻探主孔动态地温测量   总被引：8，自引：2，他引：6       下载免费PDF全文

何丽娟  胡圣标  杨文采  汪集旸  杨树春  袁玉松  程振炎 《地球物理学报》2006,49(3):745-752

介绍了大陆科学钻探主孔完钻后4次的钻井测温数据,地温梯度随深度的变化趋势,系统的热导率测试结果及其温压校正. 地温测量显示,浅部（100m以上）的4次测量结果有较大的区别,而100m以下测量温度趋于一致.在900～1600m井段,温度略有波动,可能存在地下水活动.到了深部,温度与深度呈现良好的线性关系. 在0～500m,500～2700m,2700～3600m及3600m以下这4个井段范围内,地温梯度随深度降低或增加的趋势交替变化,平均地温梯度248±34℃/km. 198块岩芯样品测试结果表明,热导率变化范围在1711～36 W/(m·K),平均2716±0403 W/(m·K). 依据实测的温度-深度进行温压校正后,热导率为1989～3652 W/(m·K),平均2808±0363 W/（m·K）. 热导率随深度的变化趋势与地温梯度的变化趋势并不能完全相互补偿,表明影响地温梯度的其他因素不容忽视. 大陆科学钻探温度测量,为今后进一步研究超高压变质带深部地热场及其地球动力学含义提供了可靠的基础数据.  相似文献   

Magnetostratigraphic reinvestigation of the Palaeocene/Eocene boundary interval in Hole 690B, Maud Rise, Antarctica     

Jason R. Ali  Dennis V. Kent  & Ernie A. Hailwood 《Geophysical Journal International》2000,141(3):639-646

Hole 690B, drilled on Maud Rise near Antarctica, provides one of the most important Palaeocene/Eocene boundary interval sections. Magnetostratigraphy plays a key role in dating Palaeocene/Eocene boundary events, but there are two problems with the published scheme in Hole 690B. The first concerns major mismatches of several magnetozones and biozones in the succession. The second is an unexplained pervasive declination cluster, which should not be present in these azimuthally unoriented piston cores. To resolve these issues, a palaeomagnetic reinvestigation was carried out on 98 specimens from 12 cores through the upper Palaeocene–middle Eocene section in Hole 690B.
The bulk of the samples carry an approximately uniformly directed magnetically hard component resulting in a declination cluster effectively identical to that of the earlier study. The spurious magnetization can be explained either as an 'inward-radial magnetization' or as a 'core-split overprint'. By estimating the extent of the overprint within each sample, it has been possible to construct a filtered magnetostratigraphy for the section. The result is that many of the magnetozone–biozone mismatches are eliminated, and the record of the 2.5 Myr Chron C24r, which brackets the various events associated with the Palaeocene/Eocene boundary, is considerably cleaner. It is not possible to define the upper and lower boundaries of this magnetochron, so we recommend that the dating of the events within this section be based on the biostratigraphy only.  相似文献   

Magnetic polarity sequences from downhole measurements in ODP holes 998B and 1001A,leg 165, Caribbean Sea     

Louvel  Véronique  Galbrun  Bruno 《Marine Geophysical Researches》2000,21(6):561-577

The magnetostratigraphy of sediments drilled at two sites (998 and 1001) in the Caribbean Sea during the Ocean Drilling Program (ODP) Leg 165 is established directly from downhole measurements. For the first time in the ODP, the magnetostratigraphy of sediments is determined from both logging magnetic data and paleomagnetic analysis of core material for an age interval of about 16 m.y. across the Cretaceous/Tertiary boundary. The total magnetic induction and the susceptibility of the surrounding sediment were recorded in situ and continuously by the GHMT (Geological High-sensitivity Magnetic Tool). The aim of processing these data is to determine the magnetic polarity. At Site 998 (Cayman Rise), no paleomagnetic results are available from the recovered cores given a hard secondary overprint. Nonetheless, a magnetostratigraphic sequence from early Miocene to late Oligocene is proposed from the analysis of the GHMT data. The comparison with biostratigraphic results shows the accuracy of the resulting magnetic polarity. At Site 1001 (Hess escarpment), cores were recovered in two holes thus allowing the comparison of the magnetostratigraphic results obtained from the GHMT data and from paleomagnetic analysis of core samples over a length of 200 m representing about 16 m.y. from early Eocene to late Cretaceous times. The sedimentation rates computed from the determined magnetochrons are very similar and correspond to the ones obtained from shipboard biostratigraphic results. One of the most striking result obtained from the magnetostratigraphic results, especially the GHMT data, at Site 1001, is the abrupt decrease in the sedimentation rate across the K/T boundary. This suppressed sedimentation lasted at least 4 Ma after the K/T event.  相似文献   

基于多测点分析法的水平井高精度磁方位校正方法          下载免费PDF全文

刘建光  底青云  张文秀 《地球物理学报》2019,62(7):2759-2766

随着水平井、多分支井等技术的出现,随钻测量技术对磁方位精度的要求越来越高.常规单测点磁方位校正法误差较大,无法满足复杂结构对磁方位精度的需求.近年来,国外围绕Brooks多测点分析法的基本公式,建立了一系列优化后的多测点分析法来提高磁方位的精度.本文以多测点分析法的公式为基础,结合常规单测点磁方位校正法,推导出一套收敛的改进多测点分析法.并通过实验来验证改进后的多测点分析法的效果.用改进后的多测点分析法得到的方位角精度在0.2°以内,达到或接近国际先进水平.通过进一步开展数据处理和分析,该套算法可以应用于水平井、多分支井等大斜度钻井工程中的精确定位和导向.  相似文献   

台湾车笼埔断层深井钻探计划(TCDP)概述   总被引：1，自引：0，他引：1  

刘耀炜  陆斌  孙小龙 《国际地震动态》2006,(2):34-40

台湾车笼埔断层深井钻探计划(TCDP)是台湾车笼埔断层上进行的科学钻探工程。该计划于2004年开始实施,拟通过深达2 000 M的钻探,获取台湾1999年集集MW7.7地震深部断层带的岩芯样本和流体观测资料,并通过一系列的深井探测和观测研究,分析车笼埔断裂产生剧烈错动的原因。本文介绍了台湾车笼埔断层深井钻探计划(TCDP)的基本情况,论述了TCDP项目的科学假设、工作计划、合作项目以及近期的进展。全面了解TCDP相关内容,对我国大陆进行地震研究和深井钻探工作具有重要借鉴意义。  相似文献   

Look-ahead vertical seismic profiling inversion approach for density and compressional wave velocity in Bayesian framework     

Ahmed M. Daoud  Muhammad A. Abd El Dayem 《Geophysical Prospecting》2020,68(3):761-785

To reduce drilling uncertainties, zero-offset vertical seismic profiles can be inverted to quantify acoustic properties ahead of the bit. In this work, we propose an approach to invert vertical seismic profile corridor stacks in Bayesian framework for look-ahead prediction. The implemented approach helps to successfully predict density and compressional wave velocity using prior knowledge from drilled interval. Hence, this information can be used to monitor reservoir depth as well as quantifying high-pressure zones, which enables taking the correct decision during drilling. The inversion algorithm uses Gauss–Newton as an optimization tool, which requires the calculation of the sensitivity matrix of trace samples with respect to model parameters. Gauss–Newton has quadratic rate of convergence, which can speed up the inversion process. Moreover, geo-statistical analysis has been used to efficiently utilize prior information supplied to the inversion process. The algorithm has been tested on synthetic and field cases. For the field case, a zero-offset vertical seismic profile data taken from an offshore well were used as input to the inversion algorithm. Well logs acquired after drilling the prediction section was used to validate the inversion results. The results from the synthetic case applications were encouraging to accurately predict compressional wave velocity and density from just a constant prior model. The field case application shows the strength of our proposed approach in inverting vertical seismic profile data to obtain density and compressional wave velocity ahead of a bit with reasonable accuracy. Unlike the commonly used vertical seismic profile inversion approach for acoustic impedance using simple error to represent the prior covariance matrix, this work shows the importance of inverting for both density and compressional wave velocity using geo-statistical knowledge of density and compressional wave velocity from the drilled section to quantify the prior covariance matrix required during Bayesian inversion.  相似文献   

海上石油钻井中的惯性测量技术分析     

张桂莲  周战馨  卢明波 《海洋技术学报》2007,26(2):76-77,83

介绍了国内测井用惯性测量技术的现状,分析了适用于海上石油钻井平台上的油气井井眼轨迹惯性测量方案,并指出了基于光纤陀螺的测量方案是未来的发展方向。  相似文献