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1.
An economic and precise processing system for microgravity surveys is presented. Three computer processing modes covering areal ground and underground measurements, measurements in vertical shafts, and measurements of vertical gravity gradients with a 3 m high tower are dealt with. Diagrams for manual calculation of gravity effects of prismatic walls, vertical shafts, and horizontal galleries, as well as programs for calculation of accurate terrain corrections and corrections for gravity effects of bodies with complicated ground-plan are proposed. The method of processing microgravity data is two to three times quicker than any traditional way, with maximum accuracy preserved in resulting gravity micro-anomalies. Applications from the field of mining geophysics and archaeology are included.  相似文献   

2.
高阶统计量油气检测方法研究   总被引:12,自引:2,他引:12       下载免费PDF全文
利用高阶统计量比功率谱函数包含更多信息并具有对高斯噪声不敏感的优点,及地震信号的高阶谱特征,本文提出一种新的利用地震属性参数(高阶谱特征参数)进行油气检测和识别的方法. 理论模型和实际资料的检验结果不仅证实了地震信号的高阶谱特征所对应的地质意义,而且得出了含水砂岩和含气砂岩的高阶谱属性规律,可以直接用来进行油气预测,其油气预测效果比常规振幅类属性具有更好的抗噪声能力.  相似文献   

3.
The results of geophysical surveys carried out in the Kopili Hydel Project site in the United North Cachar and Mikir Hills district, Assam, to locate and trace underground caverns in limestone are presented. Electrical resistivity observations over known limestone caverns showed significant anomalies (high resistivity). In the course of the systematic electrical resistivity survey conducted at the eastern fringe of the Umrong basin to study the competency of the proposed reservoir, a number of indications of possible caverns in limestone were obtained and a few of them have been verified by drilling. An analysis of the electrical resistivity data also suggests that the deep seated caverns are aligned along an axis trending NNW-SSE, which may represent a zone of weakness– presumably a fault–that has influenced the formation of the caverns in preferred direction. Drilling over a few of the geophysical indications have corroborated the presence of a fault along the eastern fringe of the Umrong basin.  相似文献   

4.
A high sensitivity thermometer using a thermistor sensing element was designed for practical measurements in the field. The most suitable procedures for the elimination of diurnal and seasonal variation of temperature, the influence of vegetation cover and of other effects were investigated. Positive results of geothermic measurements have been acquired on sulfide deposits. By far the most important results of geothermic measurements have been obtained in hydrogeological problems, e.g. the investigation of circulation of underground water. In the case of prospection for cold mineral waters the combination of geothermic measurements with gasometric analyses is very useful. As the classical domain for geothermic investigation, prospection for hot water is to be mentioned.  相似文献   

5.
使用人工神经网络进行我国大陆强震时间序列预测   总被引:6,自引:2,他引:6       下载免费PDF全文
使用人工神经网络对中国大陆最大地震时间序列进行预测,预测次年的中国大陆最大地震震级,结果表明该方法具有较好的预报效果。还表明中国大陆强震活动除了与强震时间序列本身有关外,还与全球的强震活动,太阳黑子活动等有密切的非线性关系。  相似文献   

6.
The gravity anomaly caused by a deviation of a density interface that is of constant profile but finite extension (a so-called 2 1/2-dimensional structure) can be expressed in polynomial form that can be inverted. Numerical experiments with synthetic structures show the viability of this inversion method.  相似文献   

7.
本文根据大华北地区地震分布的空间特征,提出“直接多点测位法”,旨在用来预测该区域内未来可能发生强震的地区。该方法的具体步骤是,在任一地震区外选取4个参考点,将该区内发生的各次地震震中相对参考点的地心夹角表示在坐标平面上,使可从中找出震中空间运动规律。震中的迁移符合马尔科夫过程。由此,可预测该区域未来发震的概率。经预测检验,该方法是可行的。本文还利用该方法对华北地震区未来地震趋势作了预测。  相似文献   

8.
The seismic velocity of sedimentary rocks is determined by the porosity, the velocity in the matrix and that in the fluid. The last two are known experimentally. The velocity can be measured from the surface. By applying the time average equation we can find the porosity. If the only difference at two points is the nature of the fluid in one layer, the ratio of the reflectivities of the layer at these points determines the nature of the fluid; this ratio is equal to the ratio of the amplitudes at these points. The size of the reservoir can then be found. The method can be applied to both oil exploration and production. It is more accurate in the latter case because more information is available than in the former case. The method is also more effective in developing discovered fields than the conventional method of relying only on the geological structural configurations.  相似文献   

9.
Transiel is the name given to a qualitative, time domain induced polarization (IP) method. The aim of the method is twofold: to locate and to distinguish between deep and shallow polarizable media. This discrimination is based on the data analysis, which distinguishes Transiel from the conventional IP methods. Two case histories are presented: one related to mineral prospecting and the other to geothermal exploration. The information supplied by Transiel on the deep polarizable layers is checked at each test site by an independent inversion of the recorded transients. At the mineral test site, the method correctly predicts the target location. In this particular survey, the maximum penetration depth of the method is 700 m. At the geothermal test site, a fair correlation is found between IP anomalies and the productive wells. Since the method's penetration depth does not exceed 500 m, we believe that the observed IP anomalies are related to reduction phenomena occurring in the overburden and leading to pyrite formation. We suppose that these phenomena are caused by thermochemical exchanges between the reservoir and the overburden above zones of high reservoir permeability.  相似文献   

10.
本文利用速率面拟合法,选择辽宁地区三期二组精密水准测量成果进行速率面拟合计算,绘制了垂直形变变化速率图,继而分别分析辽西及辽南现今垂直运动  相似文献   

11.
新疆主要地震区pp回归综合预报模型研究   总被引:6,自引:1,他引:6       下载免费PDF全文
应用基于pp回归理论的数值型地震综合预报软件系统,选择了b值、Cb值、Ab值等15个测震学参量,建立了它们与响应变量(未来任意时段内最大地震震级)的pp回归模型.对新疆4个主要地震区分别给出了各区的建模岭函数及综合预报模型.回顾检验及实际预报结果均表明该模型的预报效果是较为理想的.  相似文献   

12.
The use of the gravity method to predict rock bursts in mines is based on the relationship between the development of a dilatancy process in the exploited rock mass and the time-dependent gravity anomalies induced by this phenomenon. The differences between successive observations of anomalies and the time behaviour of their trend amplitudes as precursors of preceding changes of rock stability are interpreted. The centres of zones of induced rock density variation are determined by computing the position of singular points of the differences between anomalies. Two gravity surveys have been carried out in the Radbod coal mine (Germany). The first survey took place at the level of the Dickebank seam (depth 1030 m), the second in the Sonnenschein seam (depth 1090 m). The observations were made with Worden and LaCoste-Romberg (D-type) gravimeters. The differences between successive anomalies were less than 100 μGal. In the case of the Dickebank seam, the position of singular points demonstrates the effect of two approaching longwalls on a previously mined-out seam and on the gallery in which the gravity observations were made. In the case of the Sonnenschein seam, the trend amplitudes show distinct variations in the formation of the approaching longwall below the edges of all previously mined-out seams. In particular, the effect of a remnant pillar has caused the largest gravity gradients. This result corresponds to the existence of a zone of rock-burst hazard known from test drilling. The computed singular points are grouped together under the remnant pillar indicating two local hazard zones. Both results, the observed development of rock instability with time and the information about the position of the disturbed rock mass relative to the mine workings, are of importance, subsurface gravity surveying can therefore be a valuable tool for predicting rock-bursts.  相似文献   

13.
14.
本文利用等效代换的方法建立计算瞬变电磁响应的概念及方法,通过视电阻率的计算,进行实测剖面的二维电阻率成像,并利用该成像技术进行场地勘探,获得良好的效果。  相似文献   

15.
The finite element method, here viewed as a special case of the Galerkin projective method, is applied to the modelling of magnetotelluric problems, and its adaptation to geological profiles is outlined. A novel method for obtaining surface field values, involving matrix representation of the normal derivative operator, is presented in detail. Results obtained by this method are compared with well-known infinite series solutions for the vertical fault and the outcropping dyke. Two profiles containing sulphide zones are also modelled, the results being compared with field data; satisfactory agreement is obtained.  相似文献   

16.
用地磁场总强度空间线性相关方法,分析了辽宁省及周围地区几次中强地震发震的地磁前兆特点,并给出了发震时间、地点的判别方法。  相似文献   

17.
The inversion of a gravity profile associated with a twodimensional distribution of mass with constant difference in density is dealt with, in an initial approximation, by using a polynomial of appropriate degree. The method can be applied successfully, for example, to sedimentary basins. Some examples confirm the applicability of the method, which can be readily programmed on a computer.  相似文献   

18.
A theoretical study is presented of the effect of source/receiver patterns with fixed phase difference on the radiation/receiving characteristics of the single elements of the pattern in linear elastic media. The radiation characteristic of two vertical vibrators in phase and in counterphase is investigated in detail. By introducing source/receiver patterns the characteristics become dependent on dimension of the pattern, frequency and angle of observation in the horizontal plane. The types of waves generated by source patterns are, independent of phase differences, equal to those generated by single sources. With two vertical vibrators in phase radiation of P-waves can be improved relative to that of SV-waves. With two vibrators in counterphase radiation of SV-waves in vertical directions is enhanced relative to that of P-waves; this may be a valuable method of SV-shear wave generation in exploration seismics. SV-wave amplitudes larger than P-wave amplitudes can be expected at angles larger than 5°–10° with the vertical.  相似文献   

19.
1.测点布设及观测方法实验场地位于福建省南靖县汤坑盆地中央。盆地内分布有F_1、F_2、F_3和F_44组断裂,其中F_1为张性兼压扭性断裂,F_2为扭性断裂,F_3为张扭性断裂,F_4为压扭性断裂(图1)。  相似文献   

20.
我国地震人员伤亡预测研究及问题讨论   总被引:4,自引:0,他引:4  
  相似文献   

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