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LI Hai-peng KOU Long-jiang QIN Shu-hong College of GeoExploration of Science Technology Jilin University Changchun China 《吉林大学学报(地球科学版)》2006,(Z2)
理论和实际资料证明,在渗透性地层,低频斯通利波出现的频散和能量衰减与地层渗透率有关,因此可利用斯通利波的传播速度和能量衰减等特性来估算地层渗透率。斯通利波的能量和渗透率负相关。因为斯通利波能量代表了斯通利波的有关信息,因此可以认定斯通利波和渗透率负相关。 相似文献
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利用钻孔超声成像的图像特征进行岩石风化程度分类 总被引:2,自引:0,他引:2
钻孔超声成像方法能精确地反映井壁的光滑情况, 进而判断岩石的风化发育程度, 确定风化层的厚度。阐述了钻孔超声成像的走时和振幅图像特征, 给出了1个在香港地区的应用实例。 相似文献
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利用M-LDARS闪电定位系统对北京及其周边地区1995~1997年6~9月的闪电观测数据, 分析闪电活动的时空分布特征。结果表明:闪电活动在时间分布上存在两个峰值时段, 13 :00~21:00和23:00~次日05 :00。通过对总地闪、分时段及峰值时段的地闪密度分析, 发现北京及周边地区闪电活动有几个明显的集中区域, 地闪高密度区主要出现在下垫面为山脉和水体的地方, 闪电活动与下垫面的水汽条件关系密切, 且正、负地闪的空间分布也呈现较大差异, 表明雷暴云的电荷结构存在一定差异。 相似文献
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论三维等时线叠加反偏移中的有关问题 总被引:6,自引:2,他引:6
孙建国 《吉林大学学报(地球科学版)》2002,32(3):273-278
利用几何射线理论和一种考虑了积分域边缘贡献的二维稳想法,研究了三维等时线叠加反偏移中的反偏移场,反偏移加权函及反偏移孔径。结果证明,在有限孔径条件下,反偏移场的结构比已发表的结果要复杂和多。即使在最简单的条件下,反偏移场也是由反偏移信号的反偏移噪声(孔径效应)叠加而成的。而且,反偏移场的结构强烈地依赖于反偏移孔径边缘的位置。为了消除孔径效应,应采用最佳反偏移孔径和针对有限孔径的加权函数。根据定义,最佳反偏移孔径为稳相点的第一和第二Fresnel区之和。在第一Fresnel区内,有限孔径和加权函数与文献中所给出的加权函数完全一致。而在第二Fresnel区内,有限孔径加权函数为常规的加权函数与一窗函数的乘积。在反偏移孔径的边缘上,有限孔径加权函恒取零值。 相似文献
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A stochastic channel embedded in a background facies is conditioned to data observed at wells. The background facies is a fixed rectangular box. The model parameters consist of geometric parameters that describe the shape, size, and location of the channel, and permeability and porosity in the channel and nonchannel facies. We extend methodology previously developed to condition a stochastic channel to well-test pressure data, and well observations of the channel thickness and the depth of the top of the channel. The main objective of this work is to characterize the reduction in uncertainty in channel model parameters and predicted reservoir performance that can be achieved by conditioning to well-test pressure data at one or more wells. Multiple conditional realizations of the geometric parameters and rock properties are generated to evaluate the uncertainty in model parameters. The ensemble of predictions of reservoir performance generated from the suite of realizations provides a Monte Carlo estimate of the uncertainty in future performance predictions. In addition, we provide some insight on how prior variances, data measurement errors, and sensitivity coefficients interact to determine the reduction in model parameters obtained by conditioning to pressure data and examine the value of active and observation well data in resolving model parameters. 相似文献
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Quantitative analysis of variations in depositional sequence thickness from submarine channel levees 总被引:2,自引:0,他引:2
Abstract Thickness variations across‐levee and downchannel in acoustically defined depositional sequences from six submarine channel‐levee systems show consistent and quantifiable patterns. The thickness of depositional sequences perpendicular to the channel trend, i.e. across the levee, decreases exponentially, as characterized by a spatial decay constant, k. Similarly, the thickness of sediment at the levee crest decreases exponentially down the upper reaches of submarine channels and can be characterized by a second spatial decay constant, λ. The inverse of these decay constants has units of length and defines depositional length scales such that k?1 is a measure of levee width and λ?1 is a measure of levee length. Quantification of levee architecture in this way allowed investigation of relationships between levee architecture and channel dimensions. It was found that these measures of levee e‐folding width and levee e‐folding length are directly related to channel width and relief. The dimensions of channels and levees are thus intimately related, thereby limiting the range of potential channel‐levee morphologies, regardless of allocyclic forcing. A simple sediment budget model relates the product of the levee e‐folding width and e‐folding length to through‐channel volume discharge. A classification system based on the quantitative downchannel behaviour of levee architecture allows identification of a ‘mid‐channel’ reach, where sediment is passively transferred from the through‐channel flow to the levees as an overspilling flow. Downstream from this reach, the channel gradually looses its control on guiding turbidity currents, and the resulting flow can be considered as an unconfined or spreading flow. 相似文献
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Under seismic excitation, liquefied clean medium to dense cohesionless soils may regain a high level of shear resistance at large shear strain excursions. This pattern of response, known as a form of cyclic mobility, has been documented by a large body of laboratory sample tests and centrifuge experiments. A plasticity-based constitutive model is developed with emphasis on simulating the cyclic mobility response mechanism and associated pattern of shear strain accumulation. This constitutive model is incorporated into a two-phase (solid–fluid), fully coupled finite element code. Calibration of the constitutive model is described, based on a unique set of laboratory triaxial tests (monotonic and cyclic) and dynamic centrifuge experiments. In this experimental series, Nevada sand at a relative density of about 40% is employed. The calibration effort focused on reproducing the salient characteristics of dynamic site response as dictated by the cyclic mobility mechanism. Finally, using the calibrated model, a numerical simulation is conducted to highlight the effect of excitation frequency content on post-liquefaction ground deformations. 相似文献