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61.
Stochastic Structural Modeling 总被引:3,自引:0,他引:3
Lars Holden Petter Mostad Bjørn Fredrik Nielsen Jon Gjerde Chris Townsend Signe Ottesen 《Mathematical Geology》2003,35(8):899-914
A consistent stochastic model for faults and horizons is described. The faults are represented as a parametric invertible deformation operator. The faults may truncate each other. The horizons are modeled as correlated Gaussian fields and are represented in a grid. Petrophysical variables may be modeled in a reservoir before faulting in order to describe the juxtaposition effect of the faulting. It is possible to condition the realization on petrophysics, horizons, and fault plane observations in wells in addition to seismic data. The transmissibility in the fault plane may also be included in the model. Four different methods to integrate the fault and horizon models in a common model is described. The method is illustrated on an example from a real petroleum field with 18 interpreted faults that are handled stochastically. 相似文献
62.
Rockfall susceptibility has been analysed in mountain cliffs of the Cantabrian Range, North Spain. The main aim of this analysis has been to build a predictive model of rockfall activity from a low number of environmental and geological variables. The rockfall activity has been quantified in a GIS. The cartographic information used shows the spatial distribution of all the recent talus screes as well as their associated source areas in the rock-slopes. The area relation At/Ar (recent talus scree polygon/source basins) in the rock slopes has been used as the rockfall activity indicator. This relation has been validated in 50 pilot rock-slopes and compared with the relation number of recent rock fragments/source basin, obtained from field work. The environmental factors causing rockfall depend on the rock slope situation, and these are: altitude and sun radiation on the rock cliff. The geological factors considered are: lithology, relative position of the main discontinuities with respect to the topographic surface and two morphologic parameters: the roughness and slope gradient. A logistic regression analysis has been applied to a population of 442 limestone and quartzite rock cliffs. The dependent variable is the rockfall activity indicator, which allows the definition of two classes of rock cliff units: low and high activity. The independent variables are altitude, sun radiation (equinox radiation, summer solstice radiation, winter solstice radiation), slope roughness, slope gradient,anisotropy and lithology. Results suggest that it is possible tobuild a valid cartographic predictive model for rockfall activity in mountain rock cliffs from a limited number of easily obtainable variables. The method is especially applicable in massive rock slopes or in regions with uniform rock mass characteristics. 相似文献
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64.
通过对库尔勒机场1991—2000年出现沙尘天气的统计分析,总结出了库尔勒地区沙尘天气的天气、气候特征及预报指标;确定了预报沙尘天气的隶属函数,并对其进行了历史回报。 相似文献
65.
本文介绍利用NOAA极轨气象卫星AVHRR资料监测森林草原火点的原理和方法。对甘肃省1992年10月至1996年12月监测到的火点进行时空统计,分析了火灾监测中可能产生的误差原因,并提出相应改进措施。 相似文献
66.
Observations show that the sequences of microsecond-scale pulses are produced in cloud flashdischarge processes.In the present work we report on measurements of larger bipolar pulses(LBP)of the radiation fields which are classified into four types according to their waveshapes andpolarities of initial peak.Either positive or negative pulse contains two kinds of waveshapes:onewith a smooth rise and the other with 2 or 3 fast-rising pulse superimposed on the initial half cycle.The pulse waveshape characteristics in both time and frequency domains are as follows.Among2908 samples there are 45% of the positive polarity and 55% of the negative polarity.The positivepulses tend to have distinctly smaller values than negative pulses in rise time,half width and zero-crossing time of the initial peak.The peaks of positive pulse spectra tend to occur at a higherfrequency than those of negative pulses.Despite differences above,positive and negative pulseshave a similar total duration. 相似文献
67.
柱撑蒙脱石制备与表征 总被引:47,自引:2,他引:47
本文采用多种方法制备keggin离子,并探索出制备稳定keggin离子的适宜酸碱度,用此柱化剂制备出层间距为2.4~2.5nm的柱撑蒙脱石。应用X射线走向衍射技术、红外光谱、差热分析对往撑蒙脱石进行表征,用BET、吡啶吸附考察了其表面物理化学性质。结果表明,用Keggin离子制备出的柱撑蒙脱石其层间距在自然状态下为2.4~2.5nm,350C灼烧,层间距稳℃定在1.8nm,且具有耐热性能好、较大的比表面积和较强的Lewis酸位中心等特点. 相似文献
68.
69.
The ability of seismological criteria to identify earthquakes from underground explosions depends partly on the orientation of the earthquake source. Well-determined double-couple moment tensor solutions for a large number of earthquakes have been published in the Harvard centroid moment tensor (CMT) and United Slates Geological Survey (USGS) catalogues. Statistical analyses of these catalogues indicate that the distribution of the orientation of earthquake mechanisms is not random. The distribution of the T axes shows significant clustering around the downward vertical, indicating that a larger number of earthquake mechanisms radiate compressional P -wave energy to teleseismic distances from near the maximum of the radiation pattern than is predicted if earthquake sources are randomly oriented double couples. The clustered T axes correspond to compressional dip-slip mechanisms, and it is this type of mechanism which is believed to cause both the m b : M s (the ratio of body-wave to surface-wave magnitude) and first-motion criteria to misidentify an earthquake as an explosion. 相似文献
70.
本文对西南极菲尔德斯形变网GPS监测数据的误差特性进行分析,利用数理统计原理检验了数据中的系统误差,提出了削弱这类系统误差的方法。该方法有3个特点:1.以监测网中两个稳定点为基准;2.对监测网数据进行尺度因子改正与坐标变换迭代计算;3.归算后监测网点位结构不变。经改化处理后的数据,基本上消除了系统误差的影响。 相似文献